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Wound healing is a complex biological process crucial for tissue repair, especially in chronic wounds where healing is impaired. Liposomes have emerged as promising vehicles for delivering therapeutics to facilitate wound repair. Liposomes have been explored as effective carriers for therapeutic agents. However, traditional methods of liposome preparation face significant challenges, particularly in achieving consistent stability and precise control over drug encapsulation and release. This study addresses these challenges by pioneering the development of Hybrid Liposomes (HLPs) using microfluidic technology, which provides more controlled characteristics through precisely managed formulation parameters. Notably, the formation of Polydopamine (PDA) polymer within HLPs facilitates pH-responsive drug release, making them well-suited for acidic wound environments. Furthermore, surface modification with Folic Acid (FA) enhances cellular interaction with the HLPs. In vitro and in vivo studies demonstrate the efficacy of HLPs loaded with Hyaluronic Acid (HA) or Phenytoin (PHT) in promoting wound healing. Microfluidics optimizes the stability of HLPs over 90 days, underscoring their potential as a potent, antibiotic-free drug delivery system. In conclusion, this research advances the understanding of microfluidic optimization for HLPs, offering cutting-edge drug delivery systems. The transformative potential of targeted HLPs through microfluidics holds promise for revolutionizing wound healing and inspires optimism for effective therapeutic interventions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study aimed to synthesize phenytoin (PHT)-loaded water chestnut starch-based biomaterials and evaluate their drug release kinetics for use in transdermal drug delivery systems for antiepileptic therapy. Hierarchical microparticles (HMPs) extracted from human hair were also used to improve the PHT release efficiency. The physicochemical characteristics of PHT, HMPs, and the prepared biomaterials were evaluated by physical properties, antimicrobial activities, FE-SEM, FT-IR, XRD, 1 H NMR, and 13 C CPMAS solid-state NMR. The photothermal effect and the PHT release profile were confirmed through 808 nm NIR laser irradiation. After 30 min of the laser exposure, the temperature of the HMP-added biomaterials increased by 1.50-1.59 times compared to that of without the HMPs. PHT release in buffers and artificial skin test under NIR laser irradiation enhanced by 1.20-1.85 times owing to the photothermal effect. The release kinetics in pH buffer and artificial skin were determined using the Fickian diffusion and Korsmeyer-Peppas models. Additionally, to verify the transdermal penetration of PHT, drug-release simulations were conducted using rhodamine B in agar blocks and pig ears. The results implied that the photothermal effect of the HMPs enhanced the penetration of the drug., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Ultrathin molecularly imprinted polymer (MIP) films were deposited on the surfaces of ZnO nanorods (ZNRs) and nanosheets (ZNSs) by electropolymerization to afford extended-gate field-effect transistor sensors for detecting phenytoin (PHT) in plasma. Molecular imprinting efficiency was optimized by controlling the contents of functional monomers and the template in the precursor solution. PHT sensing was performed in plasma solutions with various concentrations by monitoring the drain current as a function of drain voltage under an applied gate voltage of 1.5 V. The reliability and reproducibility of the fabricated sensors were evaluated through a solution treatment process for complete PHT removal and PHT adsorption-removal cycling, while selectivity was examined by analyzing responses to chemicals with structures analogous to that of PHT. Compared with the ZNS/extracted-MIP sensor and sensors with non-imprinted polymer (NIP) films, the ZNR/extracted-MIP sensor showed superior responses to PHT-containing plasma due to selective PHT adsorption, achieving an imprinting factor of 4.23, detection limit of 12.9 ng/mL, quantitation limit of 53.0 ng/mL, and selectivity coefficients of 3-4 (against tramadol) and ~ 5 (against diphenhydramine). Therefore, we believe that the MIP-based ZNR sensing platform is promising for the practical detection of PHT and other drugs and evaluation of their proper dosages., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

The current study developed an innovative design for the production of smart multifunctional core-double shell superparamagnetic nanoparticles (NPs) with a focus on the development of a pH-responsive drug delivery system tailored for the controlled release of Phenytoin, accompanied by real-time monitoring capabilities. In this regard, the ultra-small superparamagnetic iron oxide@silica NPs (IO@Si MNPs) were synthesized and then coated with a layer of gelatin containing Phenytoin as an antiepileptic drug. The precise saturation magnetization value for the resultant NPs was established at 26 emu g -1 . The polymeric shell showed a pH-sensitive behavior with the capacity to regulate the release of encapsulated drug under neutral pH conditions, simultaneously, releasing more amount of the drug in a simulated tumorous-epileptic acidic condition. The NPs showed an average size of 41.04 nm, which is in the desired size range facilitating entry through the blood-brain barrier. The values of drug loading and encapsulation efficiency were determined to be 2.01 and 10.05%, respectively. Moreover, kinetic studies revealed a Fickian diffusion process of Phenytoin release, and diffusional exponent values based on the Korsmeyer-Peppas equation were achieved at pH 7.4 and pH 6.3. The synthesized NPs did not show any cytotoxicity. Consequently, this new design offers a faster release of PHT at the site of a tumor in response to a change in pH, which is essential to prevent epileptic attacks., (© 2024. The Author(s).)

Frequent change of wound dressings introduces wound inflammation and infections. In this study, we electrospun phenytoin (PHT) loaded ethyl cellulose (EC) microfibers and solvent cast tetracycline hydrochloride (TCH) loaded carboxymethyl cellulose (CMC) films with the aim to demonstrate tailorable in vitro drug release behaviors suitable for long-term use of wound dressings. Results from tensile testing showed a significant decrease in average elastic moduli from 8.8 ± 0.6 to 3.3 ± 0.3 MPa after incorporating PHT into EC fibers. PHT-loaded EC fibers displayed a slow and zero-ordered release up to 80 % of the total drug at 48 h, while TCH-loaded CMC films demonstrated a rapid and complete release within 30 min. Furthermore, drug-loaded EC/CMC composites were fabricated into fiber-in-film and fiber-on-film composites. Fiber-in-film composites showed stage release of TCH and PHT at 8 h, while fiber-on-film composites demonstrated simultaneous release of PHT and TCH with a prolonged release of TCH from CMC films. In general, electrospun PHT-loaded EC microfibers, solvent cast TCH-loaded CMC films, and their composites were studied to provide a fundamental scientific understanding on the novelty of the ability to modulate drug release characteristics based on the composite designs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This research aimed to develop the phenytoin-loaded bionanosuspension by utilising the novel biopolymer from Juglans regia andreduce the long-term treatment cost of epilepsy and increase the efficiency of therapy. A novel biopolymer with remarkable inbuilt properties was isolated and used in the development of a nano capsulated dispersed system. The diverse proportions of phenytoin and biopolymer with different ratios 1:2, 1:3, 1:4, 1:5 and 1:8 were taken for the planning of details PJNC1-PJNC5. The bionanosuspension was assessed for dispersibility, pH, % entrapment efficiency, stability study and in vitro drug discharge. The formulation PJNC2 with 1:3 drug biopolymer proportion showed significant outcomes for various assessments with t50% of 16.51 h and r 2 estimation of 0.9884. PJNC2 showed 92.07%±2.5 drug delivery in 36h and was stable. The bionanosuspension was found to be stable and safe for the delivery of nanosized phenytoin utilising the biopolymer having a remarkable stabiliser cum retardant property.

Although some commercial excipients for improving the solubility of highly crystalline drugs are widely used, they still cannot cover all types of hydrophobic drugs. In this regard, with phenytoin as the target drug, related molecular structures of polymer excipients were designed. The optimal repeating units of NiPAm and HEAm were screened out through quantum mechanical simulation and Monte Carlo simulation methods, and the copolymerization ratio was also determined. Using molecular dynamics simulation technology, it was confirmed that the dispersibility and intermolecular hydrogen bonds of phenytoin in the designed copolymer were better than those in the commercial PVP materials. At the same time, the designed copolymers and solid dispersions were also prepared during the experiment, and the improvement of their solubility was confirmed, which is in accordance with the simulation predictions. The new ideas and simulation technology may be used for drug modification and development.

In this study, a novel wafer based on Hydroxypropyl methylcellulose (HPMC) was prepared as a wound dressing for the simultaneous delivery of phenytoin (PT) and insulin; evaluation of the cutaneous wound repair property was performed too. Due to its low water solubility, PT was encapsulated in polymeric micelles (PM) by the film hydration method at different polymer/drug ratios and characterized in terms of particle size (PS), polydispersity index (PdI), zeta potential (ZP), drug loading (DL) %, entrapment efficiency (EE) %, and drug release. Then, the optimized PT loaded PM (PT-PM) was embedded in the wafers prepared from the HPMC polymer, alone or in combination with Carbopol 940 (CB) and xanthan gum (XG). This wafer also contained a fixed amount of insulin (PT-PM-Insulin-wafer). The obtained wafers were evaluated in terms of morphology, water uptake ability, porosity, bioadhesion and hardness features. Finally, the efficacy of the PT-PM-Insulin-wafer was assessed in full-thickness excision wound models. The optimized PT-PM showed the PS of 84.05 ± 1.80 nm, PdI of 0.28 ± 0.22, ZP of -3.38 ± 0.26 mV, DL of 15.63 ± 0.01%, EE of 92.66 ± 0.08%, and the release efficiency of 59.95 ± 0.03%. The results obtained from the XRD studies of PT-PM also demonstrated the transition of the crystalline nature of the PT to the amorphous form, while FTIR studies showed some intermolecular interaction of PT and the Soluplus ® copolymer chain. It was also found that the incorporation of XG into HPMC wafers influenced the microstructure, thus increasing the porosity, water uptake ability and bioadhesion. Compared with other groups, the PT-PM-Insulin-wafer group showed the enhancement of wound closure through increasing collagen deposition and re-epithelialization. The present study, therefore, revealed that the PT-PM-Insulin-wafer group might have very promising applications for wound healing.

Thymoquinone is a main bioactive compound of Nigella sativa L. (N.sativa), which has been used for clinical studies in the treatment of seizures due to its beneficial neuroprotective activity and antiepileptic effects. It has been evidenced that thymoquinone may inhibit the activity of cytochrome P450 2C9 (CYP2C9). However, little is known about the effect of thymoquinone or N.sativa on the pharmacokinetic behavior of phenytoin, a second-line drug widely used in the management of status epilepticus. In this study, we systematically investigated the risk of the potential pharmacokinetic drug interaction between thymoquinone and phenytoin. The inhibitory effect of thymoquinone on phenytoin hydroxylation activity by CYP2C9 was determined using UPLC-MS/MS by measuring the formation rates for p-hydroxyphenytoin (p-HPPH). The potential for drug-interaction between thymoquinone and phenytoin was quantitatively predicted by using in vitro-in vivo extrapolation (IVIVE). Our data demonstrated that thymoquinone displayed effective inhibition against phenytoin hydroxylation activity. Enzyme kinetic studies showed that thymoquinone exerted a competitive inhibition against phenytoin hydroxylation with a K i value of 4.45 ± 0.51 μM. The quantitative prediction from IVIVE suggested that the co-administration of thymoquinone (>18 mg/day) or thymoquinone-containing herbs (N.sativa > 1 g/day or N.sativa oil >1 g/day) might result in a clinically significant herb-drug interactions. Additional caution should be taken when thymoquinone or thymoquinone-containing herbs are co-administered with phenytoin, which may induce unexpected potential herb-drug interactions via the inhibition of CYP2C9., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The optimized geometry, FT-Raman, FT-IR, surface-enhanced Raman scattering, UV-Vis spectra, frontier molecular orbital analysis, molecular electrostatic potential analysis, and local and global reactivity descriptors of diphenylhydantoin (DPH) and diphenylhydantoin@AuNPs (DPHA) molecule have been investigated with the help of density functional theory method (B3LYP/6-31++G [d,p] together with LANL2DZ) and was compared and analyzed with the corresponding experimental data in order to identify their structural and bonding features responsible for their bioactivity. In-silico (molecular docking) biological activity screening of the molecules together with the in-vitro (SERS and MTT assay) analysis confirms the anticancer activity of DPH and DPHA molecules. The results of the structure-activity studies and bioactivity studies signify that the DPHA molecule is more active than the DPH molecule against lung cancer., (© 2021 John Wiley & Sons Ltd.)

Dual-drug delivery systems were constructed through coaxial techniques, which were convenient for the model drugs used the present work. This study aimed to fabricate core-shell electrospun nanofibrous membranes displaying simultaneous cell proliferation and antibacterial activity. For that purpose, phenytoin (Ph), a well-known proliferative agent, was loaded into a polycaprolactone (PCL) shell membrane, and as-prepared silver-chitosan nanoparticles (Ag-CS NPs), as biocidal agents, were embedded in a polyvinyl alcohol (PVA) core layer. The morphology, chemical composition, mechanical and thermal properties of the nanofibrous membranes were characterized by FESEM/STEM, FTIR and DSC. The coaxial PVA-Ag CS NPs/PCL-Ph nanofibers (NFs) showed more controlled Ph release than PVA/PCL-Ph NFs. There was notable improvement in the morphology, thermal, mechanical, antibacterial properties and cytobiocompatibility of the fibers upon incorporation of Ph and Ag-CS NPs. The proposed core-shell PVA/PCL NFs represent promising scaffolds for tissue regeneration and wound healing by the effective dual delivery of phenytoin and Ag-CS NPs., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

CYP2C9 encodes a cytochrome P450 enzyme responsible for metabolizing up to 15% of small molecule drugs, and CYP2C9 variants can alter the safety and efficacy of these therapeutics. In particular, the anti-coagulant warfarin is prescribed to over 15 million people annually and polymorphisms in CYP2C9 can affect individual drug response and lead to an increased risk of hemorrhage. We developed click-seq, a pooled yeast-based activity assay, to test thousands of variants. Using click-seq, we measured the activity of 6,142 missense variants in yeast. We also measured the steady-state cellular abundance of 6,370 missense variants in a human cell line by using variant abundance by massively parallel sequencing (VAMP-seq). These data revealed that almost two-thirds of CYP2C9 variants showed decreased activity and that protein abundance accounted for half of the variation in CYP2C9 function. We also measured activity scores for 319 previously unannotated human variants, many of which may have clinical relevance., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

The particles of phenytoin (Phe), a poorly water-soluble model drug, were bead-milled alone or co-milled with a hydrophilic waxy additive using an ultra cryo-milling technique in liquid nitrogen (LN 2 ) to improve its dissolution properties. However, the micronized drug particles adhered and aggregated, resulting in poor handling in manufacturing processes such as blending or tableting. To improve the dissolution profile and powder properties of the drug simultaneously, the milled products were secondarily processed together with larger spherical particles by mechanical powder processing. These secondary products were composite particles with a core-shell structure, with fine drug particles adhered and deposited on the core, based on order mixing theory. As a core, three types/sizes of spherical pharmaceutical excipient particles were applied. The resultant composite particles produced much faster release profiles than just milled or co-milled mixtures. In addition, the composite particles showed good micromeritic properties depending on the size of the core particles. These results indicate that the ultra cryo-milling and subsequent dry composite mixing is a potential approach for developing drug particles with improved dissolution.

Hydantoins, including the antiepileptic drug phenytoin, contain an amide nitrogen and an imide nitrogen, both of which can be alkylated. However, due to the higher acidity of its proton, N 3 can be more easily alkylated than N 1 under basic conditions. In this study, we explored methods for direct N 1 -selective methylation of phenytoin and found that conditions using potassium bases [potassium tert-butoxide ( t BuOK) and potassium hexamethyldisilazide (KHMDS)] in tetrahydrofuran (THF) gave N 1 -monomethylated phenytoin in good yield. The applicable scope of this reaction system was found to include various hydantoins and alkyl halides. To explore the function of methylated hydantoins, the effects of a series of methylated phenytoins on P-glycoprotein were examined, but none of methylated products showed inhibitory activity toward rhodamine 123 efflux by P-glycoprotein.

Phenytoin is a long-standing, anti-seizure drug widely used in clinical practice. It has also been evaluated in the context of many other illnesses in addition to its original epilepsy indication. The narrow therapeutic index of phenytoin and its ubiquitous daily use pose a high risk of poisoning. This review article focuses on the chemistry, pharmacokinetics, and toxicology of phenytoin, with a special focus on its mutagenicity, carcinogenicity, and teratogenicity. The side effects on human health associated with phenytoin use are thoroughly described. In particular, DRESS syndrome and cerebellar atrophy are addressed. This review will help in further understanding the benefits phenytoin use in the treatment of epilepsy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Ltd.)

Lipid-core nanocapsules (LNCs) were recently reported by our group as a suitable binder system to produce fluidised bed granules. However, there is still a lack of knowledge about the influence of using these nanocarriers loaded with a drug on the properties of the granules and their in vivo performance. Therefore, this study was designed to produce innovative fluidised bed granules containing phenytoin-loaded LNCs (LNC PHT ) as a strategy to evaluate the influence of the presence of the drug-loaded nanocarriers on their in vitro and in vivo properties. Granules were produced using a mixture of maltodextrin and phenytoin (1:0.004 w/w) as substrate. They were prepared by fluid bed granulation using water or LNC PHT as the liquid binder, affording good yields (73-82%) of granules with low moisture content (<5%). Granules prepared with LNC PHT had larger mean size (122 μm) compared to maltodextrin primary particles (50 μm) due to the formation of solid bridges. Moreover, the use of LNC PHT as the liquid binder improved their powder flow properties. The nanocarriers were recovered after aqueous dispersion (3.00 mg.mL -1 of PHT) with a redispersibility close to 90%. After reconstitution in water, granules containing LNC PHT showed an improved dissolution behaviour compared to those prepared without them. In addition, they showed a higher mucoadhesive effect due to a combined effect of the LNC PHT and maltodextrin in the interactions with porcine intestinal mucosa. Regarding the in vivo studies, granules containing the combination of non-encapsulated PHT and PHT-loaded lipid-core nanocapsules increased the latency to seizures compared to placebo granules, showing effective anticonvulsant effect in mice. In conclusion, the use of drug-loaded nanocapsules as binder is an encouraging approach to produce fluidised bed mucoadhesive granules with improved technological properties and in vivo performance., Competing Interests: Declaration of competing interest The authors report no conflicts of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Application of hollow fiber-based electromembrane extraction was studied for extraction and quantification of phenytoin from exhaled breath condensate (EBC). Phenytoin is extracted from EBC through a supported liquid membrane consisting of 1-octanol impregnated in the walls of a hollow fiber, and into an alkaline aqueous acceptor solution inside the lumen of the fiber. Under the obtained conditions of electromembrane extraction, that is, the extraction time of 15 min, stirring speed of 750 rpm, donor phase pH at 11.0, acceptor pH at 13.0, and an applied voltage of 15 V across the supported liquid membrane, an enrichment factor of 102-fold correspond to extraction percent of 25.5% was achieved. Good linearity was obtained over the concentration range of 0.001-0.10 µg/mL (r 2 = 0.9992). Limits of detection and quantitation were 0.001 and 0.003 µg/mL, respectively. The proposed method was successfully applied to determine phenytoin from EBC samples of patients receiving the drug. No interfering peaks were detected that indicating excellent selectivity of the method. The intra- and interday precisions (RSDs) were less than 14%., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Today, efficient straightforward biocompatible drug carriers have revoluted advanced drug delivery systems. The study aims to investigate the modification of halloysite nanotubes by chitosan (CTS) and pectin (PCN) for forming a new pH-sensitive bionanocomposites via Layer-by-Layer method. The main objective of this study is to improve loading efficiency and control release of phenytoin sodium (PHT) prepared in various pH. The formation of nanocomposite was confirmed through using FTIR, zeta-potential, TG, SEM, XRD, and UV spectroscopy analyses. Based on the obtained results, HNT/CTS/PCN nanocomposite prepared with the molar ratio of 2:1:2 had the best loading capacity (34.6 mg/g) compared with pure HNT (18.3 mg/g). In-vitro studies showed that prepared bionanocomposites had a low release of PHT in the simulated gastric fluid while having a more controlled release in the simulated intestinal fluid. Because of the loading efficiency and controlled release profile, the composites exhibited great potential for the controlled drug delivery of PHT., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The focus of the present work was to investigate compatibility between commonly used diluents and the drug (salt and acid form of the phenytoin). Lactose monohydrate (LMH), lactitol hydrate (LCT), and mannitol (MNT) were selected based on commercial products information of phenytoin sodium (PS) and phenytoin acid (PHT). Binary mixtures of the drug-diluent were stored at 60°C and 40°C/75% RH. Similarly, two commercial products, namely Product-A and Product-B, were also investigated in in-use stability. Color of PS-LMH changed from white to yellowish-brown and pH dropped by 3.4 units after 4 weeks exposure. FTIR, XRPD, and NIR chemical images indicated disproportionation in PS-LMH and PS-LCT mixtures stored at 40°C/75% RH. Furthermore, PS-LMH also indicated chemical interactions as indicated by distortion of LMH peaks. PHT-diluent mixture did not exhibit any physical and chemical modifications. Product-A changed color, increased weight, dropped pH value, and exhibited disproportionation and chemical reactions. The dissolution of Product-A decreased from 83.3 ± 1.4 to 7.1 ± 4.4% on 8 weeks exposure to 30°C/75% RH. On the other hand, Product-B did not change; however, dissolution decreased by 15%. In conclusion, PS showed disproportionation and chemical reactions with LMH. Therefore, LMH should be avoided in PS formulations.

Coaxial electrospinning with the ability to use simultaneously two separate solvents provides a promising strategy for drug delivery. Nevertheless, controlled release of hydrophilic and sensitive therapeutics from slow biodegradable polymers is still challenging. To address this gap, we fabricated core-sheath fibers for dual delivery of lysozyme, as a model protein, and phenytoin sodium as a small therapeutic molecule. The sheath was processed by a gelatin solution while the core fibers were fabricated from an aqueous gelatin/PVA solution. Microstructural studies by transmission and scanning electron microscopy reveal the formation of homogeneous core-sheath nanofibers with an outer and inner diameter of 180 ± 48 nm and 106 ± 30 nm, respectively. Thermal gravimetric analysis determines that the mass loss of the core-sheath fibers fall between the mass loss values of individual sheath and core fibers. Swelling studies indicate higher water absorption of the core-sheath mat compared to the separate sheath and core membranes. In vitro drug release studies in Phosphate Buffered Saline (PBS) determine sustained release of the therapeutics from the core-sheath structure. The release trails three stages including non-Fickian diffusion at the early stage followed by the Fickian diffusion mechanism. The present study shows a useful approach to design core-sheath nanofibrous membranes with controlled and programmable drug release profiles., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Crystalline cellulose is a common inactive pharmaceutical additive. If this material can also be used to construct beads for the wet milling of pharmaceutical compounds, it could possibly address issues related to wear and contamination associated with zirconia and polyethylene beads. In this study, the model drug phenytoin was milled with spherical crystalline cellulose (SCC) in liquid nitrogen. The particle size of the milled product was found to be comparable to that obtained using zirconia beads, verifying the feasibility of using SCC beads for this purpose. Using a design of experiment approach, the bead amount, agitation speed, and milling time were all determined to have a significant effect on the milled particle size, giving a D50 value as low as 0.3 μm. No breakage of the SCC beads was observed during the milling process in durability tests under conditions that will degrade spherical D-mannitol beads, showing that this material exhibits sufficient durability. In addition, the variation in elastic modulus between beads was minimal. Because SCC is commercially available and easy to handle, the present wet milling technique is considered to have potential applications to the manufacture of pharmaceuticals on an industrial scale, as it shows sufficient milling capability and durability., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Phenytoin is a low solubility anticonvulsant drug. It has, nonetheless, other possible therapeutic indications, such as neuropathic pain, including trigeminal neuralgia, or wound healing. Its use has decreased due to side effects, but nasal/intranasal administration could significantly increase drug safety and efficacy. The aim of this work was to develop and study nanoemulsions and thermosensitive nanoemulgels of phenytoin and fosphenytoin, in combination, for intranasal administration, with immediate and sustained release profiles. Nanoemulsions were prepared by adding the aqueous phase, containing gelling polymers in the case of nanoemulgels, to emulsion preconcentrates, followed, in the optimized procedure, by premix membrane emulsification. Formulation design and optimization was guided by drug strength, rheological behavior, osmolality, mean droplet size and polydispersity. Fosphenytoin interfered significantly with Carbopol but not with Pluronic's gelation, and allowed to achieve drug strengths equivalent to 22 or 27 mg/g of phenytoin in lead nanoemulsions, and 16.7 mg/g of phenytoin in the lead nanoemulgel. The final selected low viscosity nanoemulsions had an immediate or prolonged fosphenytoin release profile, depending of anhydrous phase proportion (10% or 40%, respectively). The thermosensitive nanoemulgel, with 10% anhydrous phase, showed prolonged drug release. Future studies will establish whether they are more suited for topical effects or therapeutic brain delivery., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Autologous and synthetic bone grafts showed some limitations during their usage in bone tissue regeneration. This is attributed to several drawbacks such as difficulty of finding a donor in addition to the autoimmune rejection. This study aims to fabricate a well-designed biocompatible double-layered structure of highly porous poly(lactic acid)-based electrospun nanofibers (NFs) as scaffolds for bone tissue regeneration. Poly(lactic acid) was chosen to fabricate the main matrix of the NFs scaffold as it is one of the FDA approved and highly recommended biopolymers for biomedical applications owing to its high biodegradability and biocompatibility Each layer is loaded with a different drug (Phenytoin and Sildenafil) to stimulate bone healing process. The solvents and the parameters of electrospinning were manipulated to produce highly porous structures in order to enhance the in-situ biodegradability of the NFs mats as well as the drug release rate. The produced NFs mats were fully characterized morphologically (SEM), chemically (FTIR), physically (DSC) and physicochemically (biodegradability, swellability, porosity and water vapor permeability) as well as studying the drug release profiles of both drugs. Cytotoxicity of the fabricated NFs was tested using fibroblast cells to detect their biocompatibility. Cell adhesion and proliferation were examined using SEM before using the NFs as scaffolds in mice animal model. The efficiency of the developed NFs scaffolds in healing bone fractures was assessed after 14 and 28 days through visual inspection, SEM investigation and bone mineral density assessment. Finally, sections from the bone fracture sites were isolated for histopathological examination. The study revealed the efficiency of the drugs-loaded NFs in enhancing cell adherence, cell proliferation, angiogenesis formation and finally tissue restoration of bone fractures., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Milling beads experience wear upon repeated use. And milling beads made of material that is safe when ingested have not yet been developed. The present report describes the development and characteristics of spherical d-mannitol (SDM) beads, which would be safe when ingested. The model drug phenytoin was dispersed in liquid nitrogen along with SDM and the materials were agitated at high speed. The effects of the amount of beads, agitation speed, and milling time on phenytoin particle size, yield, and bead fractures were investigated using a central composite experimental design. The diameter of milled phenytoin particles decreased significantly as the amount of SDM beads and agitation speed increased. In contrast, no difference was found in the diameter with milling time. Although the fractured SDM ratio increased slightly at higher agitation speeds, the SDM was not broken and was durable enough for milling. This milling technique was applicable not only to phenytoin but also to other drug substances. Bead durability and applicability indicated that SDM can be used as wet milling beads that are considered safe for use if ingested., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The aim of this study is to establish a contamination-free milling method using ice beads instead of conventional hard beads such as metal or ceramics. Ice beads, which melt after the milling process to form water, would solve the contamination issue attributed to bead breakage or abrasion. The technique/method for preparing spherical ice beads of mono-dispersed size ranging from 150 to 3000 μm was newly developed. An oscillation beads milling apparatus was used for pulverization. In the initial stages of ice beads milling, the process is dry, but as time passes, the surface of the ice beads begins to melt, resulting in a transition to wet beads milling. It was found that ice beads are an effective milling media for beads milling, and that milling efficiency is strongly affected by the temperature of the coolant, with the peak efficiency occurring when the temperature was set to -2 °C and ice beads around 1500 μm in diameter were used. The spray-dried powder obtained from suspension after ice beads milling had dissolution improvement equivalent to that obtained after zirconia beads milling, resulting from its spontaneous rapid dispersion into nanosuspension., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The objective of the present study was to understand quality of brand and generic products of phenytoin sodium by in vitro methods. Three commercial products were selected for the study, 1 brand and 2 generics (product-A, product-B, and product-C). Products were repacked in pharmacy vials and stored for 12 weeks at 30°C/75% RH to simulate in-use conditions. The products were examined visually and microscopically for morphologic changes, spectroscopic and diffractometric methods for chemical changes, and dissolution, assay, and impurities for performance evaluation. Capsules content of the product-A turned yellowish to dark orange color from initial white powder, which indicated a possible chemical interaction between lactose and the drug in addition to disproportionation. This was supported by pH, microscopic, spectroscopic, and X-ray diffraction data. Product-A failed to meet United States Pharmacopoeia dissolution specification of 75% in 120 min after 2-weeks whereas product-B and product-C failed at 6-weeks of in-use stability conditions exposure. Furthermore, product-A also failed to meet United States pharmacopoeia assay and impurities specifications in 12 weeks in-use period. In summary, this study indicated salt disproportionation, chemical interactions, and phase transformations of drug and excipients in the commercial products of phenytoin sodium, which may affect the clinical performance of the product., (Copyright © 2019 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.)

Although phenytoin is an antiepileptic drug used in the oral treatment of epilepsy, its off-label use as a cutaneous healing agent has been studied in recent years due to the frequent reports of gingival hyperplasia after oral administration. However, the cutaneous topical application of phenytoin should prevent percutaneous skin permeation. Therefore, the aim of this study was to evaluate the in vitro skin permeation/retention and in vivo effects of nanocapsules and nanoemulsions loaded with phenytoin and formulated as chitosan hydrogels on the healing process of cutaneous wounds in rats. The hydrogels had adequate pH values (4.9-5.6) for skin application, drug content of 0.025% (w/w), and non-Newtonian pseudoplastic rheological behaviour. Hydrogels containing nanocapsules and nanoemulsions enabled improved controlled release of phenytoin and adhesion to skin, compared with hydrogels containing non-encapsulated phenytoin. In vitro skin permeation studies showed that phenytoin permeation to the receptor compartment, and consequently the risk of systemic absorption, may be reduced by nanoencapsulation without any change in the in vivo performance of phenytoin in the wound healing process in rats., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The effects of cross-link density and composition on the loading and in vitro dissolution of the drug phenytoin as amorphous solid dispersions in emulsion polymerized poly( N-isopropylacrylamide) (PNIPAm) and poly( N-isopropylacrylamide- co- N, N-dimethylacrylamide) nanogels were investigated near the lower critical solution temperature (LCST). Nanogel size and particle density in phosphate buffered saline were quantified by dynamic light scattering (DLS) and viscometry experiments, while drug-nanogel interactions were revealed by cross peaks in aqueous-state nuclear Overhauser effect spectroscopy measurements. Spray-dried dispersions (SDDs) of drug-loaded PNIPAm nanogel particles ( R ≈ 43 nm) were directly visualized by cryogenic transmission electron microscopy and further quantified by small-angle X-ray scattering during in vitro dissolution. SDD dissolution profiles were highly dependent on the nanogel cross-link density and directly correlated with the state of dispersion of the drug-loaded nanogel particles. A balance between net particle hydrophobicity and hydrophilicity along with the distance in temperature from the LCST are shown to dictate the in vitro dissolution of the amorphous solid dispersions. Solubility enhancement mechanisms disclosed in this study provide essential guidance for the design of effective nanogels for oral drug delivery applications.

Accurate assessment of tablet content uniformity is critical for narrow therapeutic index drugs such as phenytoin sodium. This work presents a near-infrared (NIR)-based analytical method for rapid prediction of content uniformity based on a large number of phenytoin sodium formulation tablets. Calibration tablets were generated through an integrated experimental design by varying formulation and process parameters, and scale of manufacturing. A partial least squares model for individual tablet content was developed based on tablet NIR spectra. The tablet content was obtained from a modified United States Pharmacopeia phenytoin sodium high-performance liquid chromatography assay method. The partial least squares model with 4 latent variables explained 92% of the composition variability and yielded a root mean square error of prediction of 0.48% w/w. The resultant NIR model successfully assayed the composition of tablets manufactured at the pilot scale. For one such batch, bootstrapping was applied to calculate the confidence intervals on the mean, acceptance value, and relative SD for different sample sizes, n = 10, 30, and 100. As the bootstrap sample size increased, the confidence interval on the mean, acceptance value, and relative SD became narrower and symmetric. Such a 'large N' NIR-based process analytical technology method can increase reliability of quality assessments in solid dosage manufacturing., (Published by Elsevier Inc.)

This study evaluated the in vivo anticonvulsant effect of a spray-dried powder for reconstitution containing phenytoin-loaded lipid-core nanocapsules. The effect of chitosan coating on redispersibility, gastrointestinal stability, and drug release from nanoparticles was evaluated during the development of the powders. Maltodextrin was used as adjuvant in the spray-drying process. Chitosan coating played an important role in redispersibility, and large particles (>100 μm) were obtained using the highest concentration of solids in the feed. However, after aqueous redispersion, volume-based particle size was reduced to about 1 µm. The release of nanoparticles from the surface of the spherical microagglomerates (roundness index = 0.75) was confirmed by SEM analysis. Powders reconstituted in water recovered partially the nanometric properties of the original suspensions and were stable for 24 h. Phenytoin-loaded chitosan-coated nanocapsules and their redispersed powders have good gastrointestinal stability, and are able to control drug release in simulated gastric and intestinal fluids. Besides that, the reconstituted powder containing chitosan-coated nanocapsules exhibited improved anticonvulsant activity against seizures induced by pilocarpine in mice, compared to the non-encapsulated drug, representing an important approach in anticonvulsant treatments for children and adults., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Phenytoin sodium (PS) is a narrow therapeutic index drug that dictates maintenance of narrow plasma concentration of the drug. This requires a good quality product that meets regulatory specifications throughout shelf-life as well as during the usage period. Quality of the drug product may change if not develop in a scientific fashion which may have ramifications on clinical outcome. The focus of the study was to understand the effect of process variables and storage conditions on the disproportionation and phase transformation of the drug, and dissolution of extended-release capsules of PS. Four formulations were prepared to contain either powder blend or granules of PS with commonly used excipients. The granules were prepared in a high shear mixture by granulating with water, ethanol or mixture thereof. The capsules were stored in pharmacy vials for 4-weeks at 40 °C/75% RH and 30 °C/65% RH. Formulations were characterized by spectroscopies (FTIR, NIR, and chemical imaging), X-ray powder diffraction (XRPD), dissolution and assay. Granules filled capsule did not meet USP dissolution specifications and there was a significant decrease in dissolution on exposure to stability conditions. Dissolution decreased from 77.56 ± 3.83% to 42.34 ± 4.31%, and 63.96 ± 6.12 to 46.53 ± 2.91 in physical mixture and water granulated formulations, respectively, after four weeks exposure at 40 °C/75% RH. Spectroscopic (NIR, FTIR, and chemical imaging) data indicated disproportionation of the drug during the storage period. Moreover, XRPD data explained a decrease in dissolution in the initial granules filled capsules as well as temperature and humidity exposed samples. It indicated the phase transformation of the drug and/or excipients, disproportionation and/or interactions. These changes further accelerated on exposure to stability conditions. In conclusion, our studies indicated the significant effect of process variables and stability conditions on the critical quality attributes of PS extended-release capsule that has the potential impact on the clinical performance of the product., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Phenytoin is a non-sedative barbiturate derivate and has been recently rediscovered as a neuroprotective and retinoprotective compound in patients affected by optic neuritis secondary to multiple sclerosis. However, currently there are still no neuroprotective compounds registered and available in the clinic. We reviewed the literature supporting the retinoprotective properties of phenytoin and analyzed the various approaches and definitions from the first research periods onwards. The retinoprotective role of phenytoin was already known in the 1970s, but only recently has this effect been rediscovered, confirming that it could indeed provide structural protection of the retinal cells., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Light irradiation with high photon flux in the vacuum and far-UV region is known to denature the conformation of biopolymers. Measures are in place at Diamond Light Source B23 beamline for Synchrotron Radiation Circular Dichroism (SRCD) to control and make this effect negligible. However, UV denaturation of proteins can also be exploited as a novel method for assessing biopolymer photostability as well as ligand-binding interactions. Usually, host⁻ligand binding interactions can be assessed monitoring CD changes of the host biopolymer upon ligand addition. The novel method of identifying ligand binding monitoring the change of relative rate of UV denaturation using SRCD is especially important when there are very little or insignificant secondary structure changes of the host protein upon ligand binding. The temperature study, another method used to determine molecular interactions, can often be inconclusive when the thermal effect associated with the displacement of the bound solvent molecules by the ligand is also small, making the determination of the binding interaction inconclusive. Herein we present a review on the UV-denaturation assay as a novel method to determine the relative photostability of protein formulations as well as the screening of ligand-binding interactions using the high photon flux Diamond B23 beamline for SRCD.

Recently, we have developed a novel granulation technology to manufacture hollow spherical granules (HSGs) for controlled-release formulations; however, the mechanism of the granulation is still unclear. The aim of this study is to determine the mechanism of the formation of the HSGs using a high shear granulator. Samples of granulated material were collected at various times during granulation and were investigated using scanning electron microscope and X-ray computed tomography. It was observed that the granulation proceeded by drug layering to the polymer, followed by formation of a hollow in the granule. In addition, it was also found that generation of a crack in the adhered drug layer and air flow into the granules might be involved in forming the hollow in the structure. Observation of the granulation of formulations with different types of drugs and polymers indicated that negative pressure in the granules occurred and the granules caved in when the hollow was formed. The hollow-forming speed and the shell density of the hollow granules depended on the particular drug and polymer. Taken together, the granulation mechanism of HSGs was determined and this information will be valuable for HSGs technology development., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Water-soluble polymers with high viscosity are frequently used in the design of sustained-release formulations of poorly water-soluble drugs to enable complete release of the drug in the gastrointestinal tract. Tablets containing matrix granules with a water-soluble polymer are preferred because tablets are easier to handle and the multiple drug-release units of the matrix granules decreases the influences of the physiological environment on the drug. However, matrix granules with a particle size of over 800 μm sometimes cause a content uniformity problem in the tableting process because of the large particle size. An effective method of manufacturing controlled-release matrix granules with a smaller particle size is desired. The aim of this study was to develop tablets containing matrix granules with a smaller size and good controlled-release properties, using phenytoin as a model poorly water-soluble drug. We adapted the recently developed hollow spherical granule granulation technology, using water-soluble polymers with different viscosities. The prepared granules had an average particle size of 300 μm and sharp particle size distribution (relative width: 0.52-0.64). The values for the particle strength of the granules were 1.86-1.97 N/mm 2 , and the dissolution profiles of the granules were not affected by the tableting process. The dissolution profiles and the blood concentration levels of drug released from the granules depended on the viscosity of the polymer contained in the granules. We succeeded in developing the desired controlled-release granules, and this study should be valuable in the development of sustained-release formulations of poorly water-soluble drugs., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The study focused on the analysis of the nature and site of binding of Phenytoin (PHT) -(a model hydrophobic drug) with Bovine Serum Albumin (BSA) (a model protein used as a surrogate for HSA). Interactions with defined amounts of Phenytoin and BSA demonstrated a blue shift (hypsochromic -change in the microenvironment of the tryptophan residue with decrease in the polar environment and more of hydrophobicity) with respect to the albumin protein and a red shift (bathochromic -hydrophobicity and polarity related changes) in the case of the model hydrophobic drug. This shift, albeit lower in magnitude, has been substantiated by a fairly convincing, Phenytoin-mediated quenching of the endogenous fluorophore in BSA. Spectral shifts studied at varying pH, temperatures and incubation periods (at varying concentrations of PHT with a defined/constant BSA concentration) showed no significant differences (data not shown). FTIR analysis provided evidence of the interaction of PHT with BSA with a stretching vibration of 1737.86cm -1 , apart from the vibrations characteristically associated with the amine and carboxyl groups respectively. Our in vitro findings were extended to molecular docking of BSA with PHT (with the different ionized forms of the drug) and the subsequent LIGPLOT-based analysis. In general, a preponderance of hydrophobic interactions was observed. These hydrophobic interactions corroborate the tryptophan-based spectral shifts and the fluorescence quenching data. These results substantiates our hitherto unreported in vitro/in silico experimental flow and provides a basis for screening other hydrophobic drugs in its class., (Copyright © 2017. Published by Elsevier B.V.)

In this work, the effect of saccharin (SAC) addition on the dissolution and supersaturation level of phenytoin (PHT)/Eudragit® E (EUD-E) solid dispersion (SD) at neutral pH was examined. The PHT/EUD-E SD showed a much slower dissolution of PHT compared to the PHT/EUD-E/SAC SD. EUD-E formed a gel layer after the dispersion of the PHT/EUD-E SD into an aqueous medium, resulting in a slow dissolution of PHT. Pre-dissolving SAC in the aqueous medium significantly improved the dissolution of the PHT/EUD-E SD. Solid-state 13 C NMR measurements showed an ionic interaction between the tertiary amino group of EUD-E and the amide group of SAC in the EUD-E gel layer. Consequently, the ionized EUD-E could easily dissolve from the gel layer, promoting PHT dissolution. Solution-state 1 H NMR measurements revealed the presence of ionic interactions between SAC and the amino group of EUD-E in the PHT/EUD-E/SAC solution. In contrast, interactions between PHT and the hydrophobic group of EUD-E strongly inhibited the crystallization of the former from its supersaturated solution. The PHT supersaturated solution was formed from the PHT/EUD-E/SAC SD by the fast dissolution of PHT and the strong crystallization inhibition effect of EUD-E after aqueous dissolution., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Purpose: The U.S. Pharmacopeia defines excipients as substances other than the active pharmaceutic ingredient (API) that are added in a drug delivery system in order to aid in the manufacturing process and enhance stability, bioavailability, safety, effectiveness and delivery of the drug. The 1968 phenytoin intoxication outbreak in Brisbane, Australia, is a classic example of an API-excipient interaction. When administered with CaSO4 the absorption of phenytoin was reduced due to an interaction between the API and the excipient. When CaSO4 was replaced by lactose, the amount of drug absorbed was much higher, resulting in the observed intoxication. It was hypothesized that phenytoin was converted to a calcium salt prior to ingestion. The purpose of this study was to mechanistically investigate the interactions between excipients and phenytoin to confirm the hypothesis of the previous reports., Methods: Titration experiments with phenytoin and calcium salt were performed. Isothermal micro calorimetry was used to determine incompatibilities between excipients, phenytoin and milk. NMR was used to characterize the compounds. Dissolution tests containing CaSO4, lactose or sorbitol as excipients were also performed. Both Canadian and United States of America commercially available capsules were tested with milk and water., Results: The calorimeter results indicate that phenytoin sodium interacts with CaSO4 in aqueous media and the dissolution profile of CaSO4 containing capsules showed a reduced dissolution rate. In addition, phenytoin sodium also interacts with lactose through a Maillard reaction that can occur at body temperature. Likewise, commercial Phenytoin sodium products interacted with milk and the products containing lactose showed browning in water., Conclusion: In Canada and the USA, the reference product contains lactose as an excipient in the formulation, whereas the Canadian generic formulations do not contain lactose. Any clinical relevance of these difference has not been determined. A new incompatibility between phenytoin and lactose has been discovered and an incompatibility with calcium was confirmed, which may have implications in regard to excipients and food effects. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Phenytoin (PHT) is an antiepileptic drug that was reported to exhibit high wound healing activity. Nevertheless, its limited solubility, bioavailability, and inefficient distribution during topical administration limit its use. Therefore, this study aims to develop, characterize nanostructured lipid carriers (NLCs), and evaluate their potential in topical delivery of PHT to improve the drug entrapment efficiency and sustained release. The NLCs were prepared by hot homogenization followed by ultra sonication method using 2 3 factorial design. NLC formulations were characterized regarding their particle size (PS), zeta potential (ZP), entrapment efficiency percent (%EE), surface morphology, physicochemical stability, and in vitro release studies. The optimized NLC (F7) was further incorporated in 1%w/v carbopol gel and then characterized for appearance, pH, viscosity, stability, and in vitro drug release. The prepared NLCs were spherical in shape and possessed an average PS of 121.4-258.2 nm, ZP of (-15.4)-(-32.2) mV, and 55.24-88.80 %EE. Solid-state characterization revealed that the drug is dispersed in an amorphous state with hydrogen bond interaction between the drug and the NLC components. NLC formulations were found to be stable at 25 °C for six months. The stored F7-hydrogel showed insignificant changes in viscosity and drug content (p>.05) up to six months at 25 °C that pave a way for industrial fabrication of efficient PHT products. In vitro release studies showed a sustained release from NLC up to 48 h at pH 7.4 following non-Fickian Higuchi kinetics model. These promising findings encourage the potential use of phenytoin loaded lipid nanoparticles for future topical application.

Background/aim: To search for new antileukemic agents, the chemical structure of phenytoin was modified. A possible cytotoxic activity of three bromoalkyl phenytoin analogs, methyl 2-(1-(3-bromopropyl)-2,4-dioxo-5,5-diphenylimidazolidin-3-yl) propanoate (PH2), 1-(3-bromopropyl)-3-methyl-5,5-diphenylimidazolidine-2,4-dione (PH3) and 1-(4-bromobutyl)-3-methyl-5,5-diphenylimidazolidine-2,4-dione (PH4) on regulated cell death, the cell cycle and cell ultrastructure was assessed., Materials and Methods: The experiments were performed in vitro on HL-60 and U937 cells, using flow cytometry and electron microscopy methods., Results: Application of PH2, PH3, and PH4 resulted in cell surface exposure of phosphatidylserine and plasma membrane impairment, caspase-8, -9, and -3/7 activation, dissipation of mitochondrial membrane potential, DNA breakage, cell-cycle disturbance and cell ultrastructural changes. In general, PH3 appeared to be the most active against the leukemia cells, and all bromoalkyl hydantoins, PH2-PH4, were more active in HL-60 cells than in U937 cells., Conclusion: The antileukemic activity of the bromoalkyl phenytoin analogs depended on the combination of N-hydantoin substituents and the human cell line used., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

We recently developed coarse-grained (CG) force fields for hydroxypropyl methylcellulose acetate succinate (HPMCAS) polymers and the model drug molecule phenytoin, and a continuum transport model to study the polymer-drug nanostructures presented during a dissolution test after solvation of solid dispersion particles. We model the polymer-drug interactions that contribute to suppression of drug aggregation, release, and crystal growth during the dissolution process, and we take these as indicators of polymer effectiveness. We find that the size and the intermolecular interaction strength of the functional group and the drug loading concentration are the major factors that impact the effectiveness of the polymeric excipient. The hydroxypropyl acetyl group is the most effective functional group, followed by the acetyl group, while the deprotonated succinyl group is the least effective functional group, except that the deprotonated succinyl group at the 6-position is very effective in slowing down the phenytoin crystal growth. Our simulation results thus suggest HPMCAS with higher acetyl and lower succinyl content is more effective in promoting phenytoin solubility in dissolution media, and polymers become less effective when drug loading becomes high (i.e., 50% of the mass of the polymer/drug solid dispersion), agreeing with previous experimental studies. In addition, our transport model indicates that the drug release time from a solid dispersion particle of 2 μm diameter is less than 10 min, correlating well with the experimental time scale for a typical dissolution profile to reach maximum peak concentration. Our modeling effort, therefore, provides new avenues to understand the dissolution behavior of complex HPMCAS-phenytoin solid dispersions and offers a new design tool to optimize the formulation. Moreover, the systematic and robust approach used in our computational models can be extended to other polymeric excipients and drug candidates.

Widespread resistance of Anopheles sp. populations to pyrethroid insecticides has led to the search for sustainable alternatives in the plant kingdom. Among many botanicals, there is great interest in essential oils and their constituents. Many researchers have explored essential oils (EOs) to determine their toxicity and identify repellent molecules that are effective against Anopheles populations. Essential oils are volatile and fragrant substances with an oily consistency typically produced by plants. They contain a variety of volatile molecules such as terpenes and terpenoids, phenol-derived aromatic components and aliphatic components at quite different concentrations with a significant insecticide potential, essentially as ovicidal, larvicidal, adulticidal, repellency, antifeedant, growth and reproduction inhibitors. The current review provides a summary of chemical composition of EOs, their toxicity at different developmental stages (eggs, larvae and adults), their repellent effects against Anopheles populations, for which there is little information available until now. An overview of antagonist and synergistic phenomena between secondary metabolites, the mode of action as well as microencapsulation technologies are also given in this review. Finally, the potential use of EOs as an alternative to current insecticides has been discussed., Competing Interests: The authors declare that they have no competing interests.

Blends of hydroxypropyl methylcellulose acetate succinate (HPMCAS) and dodecyl (C 12 )-tailed poly(N-isopropylacrylamide) (PNIPAm) were systematically explored as a model system to dispense the active ingredient phenytoin by rapid dissolution, followed by the suppression of drug crystallization for an extended period. Dynamic and static light scattering revealed that C 12 -PNIPAm polymers, synthesized by reversible addition-fragmentation chain-transfer polymerization, self-assembled into micelles with dodecyl cores in phosphate-buffered saline (PBS, pH 6.5). A synergistic effect on drug supersaturation was documented during in vitro dissolution tests by varying the blending ratio, with HPMACS primarily aiding in rapid dissolution and PNIPAm maintaining supersaturation. Polarized light and cryogenic transmission electron microscopy experiments revealed that C 12 -PNIPAm micelles maintain drug supersaturation by inhibiting both crystal nucleation and growth. Cross-peaks between the phenyl group of phenytoin and the isopropyl group of C 12 -PNIPAm in 2D 1 H nuclear Overhauser effect (NOESY) spectra confirmed the existence of drug-polymer intermolecular interactions in solution. Phenytoin and polymer diffusion coefficients, measured by diffusion-ordered NMR spectroscopy (DOSY), demonstrated that the drug-polymer association constant increased with increasing local density of the corona chains, coincident with a reduction in C 12 -PNIPAm molecular weight. These findings demonstrate a new strategy for exploiting the versatility of polymer blends through the use of self-assembled micelles in the design of advanced excipients.

We present coarse-grained (CG) force fields for hydroxypropyl-methylcellulose acetate succinate (HPMCAS) polymers and the drug molecule phenytoin using a bead/stiff spring model, with each bead representing a HPMCAS monomer or monomer side group (hydroxypropyl acetyl, acetyl, or succinyl) or a single phenytoin ring. We obtain the bonded and nonbonded interaction parameters in our CG model using the RDFs from atomistic simulations of short HPMCAS model oligomers (20-mer) and atomistic simulations of phenytoin molecules. The nonbonded interactions are modeled using a LJ 12-6 potential, with separate parameters for each monomer substitution type, which allows heterogeneous polymer chains to be modeled. The cross interaction terms between the polymer and phenytoin CG beads are obtained explicitly from atomistic level polymer-phenytoin simulations, rather than from mixing rules. We study the solvation behavior of 50-mer and 100-mer polymer chains and find chain-length-dependent aggregation. We also compare the phenytoin CG force field developed in this work with that in Mandal et al. (Soft Matter, 2016, 12, 8246-8255) and conclude both are suitable for studying the interaction between polymer and drug in solvated solid dispersion formulation, in the absence of drug crystallization. Finally, we present simulations of heterogeneous HPMCAS model polymer chains and phenytoin molecules. Polymer and drug form a complex in a short period of simulation time due to strong intermolecular interactions. Moreover, the protonated polymer chains are more effective than deprotonated ones in inhibiting the drug aggregation in the polymer-drug complex.

Phenytoin (PHT), valproic acid, and modern antiepileptic drugs (AEDs), eg, remacemide, loreclezole, and safinamide, are only effective within a maximum of 70%-80% of epileptic patients, and in many cases the clinical use of AEDs is restricted by their side effects. Therefore, a continuous need remains to discover innovative chemical entities for the development of active and safer AEDs. Ligands targeting central histamine H 3 receptors (H 3 Rs) for epilepsy might be a promising therapeutic approach. To determine the potential of H 3 Rs ligands as new AEDs, we recently reported that no anticonvulsant effects were observed for the ( S )-2-(4-(3-(piperidin-1-yl)propoxy)benzylamino)propanamide ( 1 ). In continuation of our research, we asked whether anticonvulsant differences in activities will be observed for its R -enantiomer, namely, ( R )-2-(4-(3-(piperidin-1-yl)propoxy)benzylamino)propaneamide ( 2 ) and analogs thereof, in maximum electroshock (MES)-, pentylenetetrazole (PTZ)-, and strychnine (STR)-induced convulsion models in rats having PHT and valproic acid (VPA) as reference AEDs. Unlike the S -enantiomer ( 1 ), the results show that animals pretreated intraperitoneally (ip) with the R -enantiomer 2 (10 mg/kg) were moderately protected in MES and STR induced models, whereas proconvulsant effect was observed for the same ligand in PTZ-induced convulsion models. However, animals pretreated with intraperitoneal doses of 5, 10, or 15 mg/kg of structurally bulkier ( R )-enantiomer ( 3 ), in which 3-piperidinopropan-1-ol in ligand 2 was replaced by (4-(3-(piperidin-1-yl)propoxy)phenyl)methanol, and its ( S )-enantiomer ( 4 ) significantly and in a dose-dependent manner reduced convulsions or exhibited full protection in MES and PTZ convulsions model, respectively. Interestingly, the protective effects observed for the ( R )-enantiomer ( 3 ) in MES model were significantly greater than those of the standard H 3 R inverse agonist/antagonist pitolisant, comparable with those observed for PHT, and reversed when rats were pretreated with the selective H 3 R agonist R -(α)-methyl-histamine. Comparisons of the observed antagonistic in vitro affinities among the ligands 1 - 6 revealed profound stereoselectivity at human H 3 Rs with varying preferences for this receptor subtype. Moreover, the in vivo anticonvulsant effects observed in this study for ligands 1 - 6 showed stereoselectivity in different convulsion models in male adult rats., Competing Interests: The authors report no conflicts of interest in this work.

We describe a systematic coarse-graining method to study crystallization and predict possible polymorphs of small organic molecules. In this method, a coarse-grained (CG) force field is obtained by inverse-Boltzmann iteration from the radial distribution function of atomistic simulations of the known crystal. With the force field obtained by this method, we show that CG simulations of the drug phenytoin predict growth of a crystalline slab from a melt of phenytoin, allowing determination of the fastest-growing surface, as well as giving the correct lattice parameters and crystal morphology. By applying meta-dynamics to the coarse-grained model, a new crystalline form of phenytoin (monoclinic, space group P2 1 ) was predicted which is different from the experimentally known crystal structure (orthorhombic, space group Pna2 1 ). Atomistic simulations and quantum calculations then showed the polymorph to be meta-stable at ambient temperature and pressure, and thermodynamically more stable than the conventional orthorhombic crystal at high pressure. The results suggest an efficient route to study crystal growth of small organic molecules that could also be useful for identification of possible polymorphs as well.

Background: 5,5-Diphenylhydantoin (Phenytoin) is a well-known anticonvulsant and antiarrhythmic drug which may cause unwanted side effects. In order to avoid the adverse effects of phenytoin, especially on the central nervous and cardiovascular systems, two small series of amine derivatives (Mannich bases) and amide ones were designed containing β-tetralinohydantoin system. In preliminary studies, some of arylpiperazinylmethyl derivatives with a β-tetralinohydantoin moiety were effective in screening anticonvulsant tests in mice., Methods: These new amine and amide derivatives of β-tetralinohydantoin were evaluated in standard anticonvulsant screens (maximal electroshock (MES) or pentylenetetrazole (scPTZ) seizure tests) and their neurotoxicity was assessed in standardized rotarod tests. Additionally, due to structural features (a hydantoin ring), influence on antiarrhythmic activity, electrocardiogram components and blood pressure was tested in rats., Results: The new N-Mannich bases were effective in maximal electroshock or pentylenetetrazole seizures screens; and the most interesting compound 4 (1-{[4-(1-phenyethyl)-piperazin-1-yl]methyl}-3',4'-dihydro-1'H,2H,5H-spiro[imidazolidine-4,2'-naphthalene]-2,5-dione) displayed anticonvulsant activity in both the aforementioned tests. Furthermore, compound 6, an amide derivative of β-tetralinohydantoin, displayed significant antiarrhythmic activity in a barium chloride-induced arrhythmia model (ED50 16.3mg/kg), but it was devoid of anticonvulsant protection. None of the tested compounds affected the electrocardiogram components or blood pressure in normotensive rats., Conclusion: All new N-Mannich bases containing the β-tetralinohydantoin system and 1-phenylalkylpiperazine were classified to Anticonvulsant Screening Program 1st class. In contrast, our results suggested that the introduction of an amide bond in the alkyl side chain of the β-tetralinohydantoin system abolished the anticonvulsant activity, but not the antiarrhythmic one. However, further studies are required for a definitive conclusion., (Copyright © 2016 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.)

Background: GFAP is the major intermediate filament protein in mature astrocytes. Its increased expression and aggregation was firstly associated to Alexander's disease, and successively in different neurological diseases including scrapie, Alzheimer's and Creutzfeld-Jacob diseases. Recently, ceftriaxone a multi-potent β-lactam antibiotic able to overcome the blood-brain barrier, successfully eliminated the cellular toxic effects of misfolded mutated GFAP, similarly to phenytoin sodium, in a cellular model of Alexander's disease and inhibited α-synuclein aggregation protecting PC12 cells from the exposure to 6-hydroxydopamine., Methods: In this study, synchrotron radiation circular dichroism spectroscopy has been used to obtain structural information about the GFAP-ceftriaxone (phenytoin) interactions, while computational methods allowed the identification of the relevant putative binding site of either ceftriaxone or phenytoin on the dimer structure of GFAP, permitting to rationalize the spectroscopic experimental results., Results: We found that GFAP exhibited enhanced stability upon the addition of two equivalents of each ligands with ceftriaxone imparting a more spontaneous interactions and a more ordered complex system than phenytoin., Conclusions: SRCD data and MD models indicate a stronger protective effect of ceftriaxone in neurological disorders characterized by an increased production and polymerization of GFAP., General Significance: This result, in addition to our previous works in which we documented that ceftriaxone interacts with α-synuclein inhibiting its pathological aggregation and that a cyclical treatment with this molecule in a patient with adult-onset Alexander's disease halted, and partly reversed, the progression of neurodegeneration, suggests the possibility of a chaperone-like effect of ceftriaxone on protein involved in specific neurodegenerative diseases., (Copyright © 2016 Diamond Light Source Ltd. Published by Elsevier B.V. All rights reserved.)

Anticonvulsants can increase the risk of developing neurotoxicity in infants; however, the underlying mechanism has not been elucidated to date. Thyroxine [3,5,3',5'-l-tetraiodothyronine (T4)] plays crucial roles in the development of the central nervous system. In this study, we hypothesized that induction of UDP-glucuronosyltransferase 1A1 (UGT1A1)-an enzyme involved in the metabolism of T4-by anticonvulsants would reduce serum T4 levels and cause neurodevelopmental toxicity. Exposure of mice to phenytoin during both the prenatal and postnatal periods significantly induced UGT1A1 and decreased serum T4 levels on postnatal day 14. In the phenytoin-treated mice, the mRNA levels of synaptophysin and synapsin I in the hippocampus were lower than those in the control mice. The thickness of the external granule cell layer was greater in phenytoin-treated mice, indicating that induction of UGT1A1 during the perinatal period caused neurodevelopmental disorders. Exposure to phenytoin during only the postnatal period also caused these neurodevelopmental disorders. A T4 replacement attenuated the increase in thickness of the external granule cell layer, indicating that the reduced T4 was specifically associated with the phenytoin-induced neurodevelopmental disorder. In addition, these neurodevelopmental disorders were also found in the carbamazepine- and pregnenolone-16-α-carbonitrile-treated mice. Our study is the first to indicate that UGT1A1 can control neurodevelopment by regulating serum T4 levels., (Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.)

There is an increasing interest in the intranasal delivery of central nervous system-active drugs due to the existence of a direct nose-to-brain connection. However, poor solubility limits the amount of drug that can be administered within an aqueous solution. In the present work, the objectives were to develop an ex vivo bioconversion/permeability evaluation method and to study the ex vivo bioconversion of the hydrophilic phosphate ester prodrug fosphenytoin (FOS) to the active drug phenytoin (PHT) and their comparative nasal permeation. Bioconversion/permeability studies were performed in excised porcine nasal mucosa mounted in Ussing chambers. The physical integrity of the tissues was evaluated by measurement of the transepithelial electrical resistance (TEER). The simultaneous quantitative assay of FOS, PHT and its major metabolite, 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH) was developed and validated according to international guidelines using a liquid chromatography analytical method. The FOS bioconversion rate and PHT and FOS apparent permeability coefficients (Papp) were determined at different time points. FOS bioconversion was also qualitatively investigated in human nasal mucus. The developed liquid chromatography method combines a fast and inexpensive sample preparation with inactivation of the enzymatic metabolism of the prodrug during sample manipulation and storage. It was linear, precise, accurate, and presented a high analyte recovery. FOS was converted ex vivo to PHT but the metabolite HPPH was not detected. The bioconversion rate increased with FOS concentration and with time, which suggests a diffusion-limited process. FOS was also converted to its active drug by human nasal mucus. A novel mathematical data analysis method was developed to reduce the bias introduced by variable mucosal TEER in the permeability results. At comparable FOS and PHT concentrations the ln(Papp(PHT)) of both compounds showed little difference, which indicates that the use of a hydrophilic and charged prodrug did not hinder overall drug permeation. At the highest tested FOS concentration it was possible to quantify FOS in the receiver chambers, meaning that at a sufficiently high concentration the FOS permeation rate overcame its bioconversion rate. The ln(Papp(PHT)) tended to similar equilibrium values as the assay progressed, but with higher FOS concentrations that equilibrium was attained faster. Acidic pH reduced the permeability of both PHT and FOS. The developed bioconversion/permeability evaluation method will constitute an important tool to select the most promising formulations before proceeding to in vivo studies. Importantly, it allowed the demonstration of phosphatase activity and FOS bioconversion in nasal mucosa, as well as the prodrug's nasal permeation potential. Furthermore, this study demonstrates the possibility of formulating phosphate prodrugs of poorly soluble central nervous system-active drugs as a strategy to increase the solubilized drug doses administered through the nasal route., (Copyright © 2016 Elsevier B.V. All rights reserved.)