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Diseases that affect the Central Nervous System (CNS) are one of the most exciting challenges of recent years, as they are ubiquitous and affect all ages. Although these disorders show different etiologies, all treatments share the same difficulty represented by the Blood-Brain Barrier (BBB). This barrier acts as a protective system of the delicate cerebral microenvironment, isolating it and making extremely arduous delivering drugs to the brain. To overtake the obstacles provided by the BBB it is essential to explore the changes that affect it, to understand how to exploit these findings in the study and design of innovative brain targeted formulations. Interestingly, the concept of age-related targeting could prove to be a winning choice, as it allows to consider the type of treatment according to the different needs and peculiarities depending on the disease and the age of onset. In this review was considered the prospective contribution of lipid-based formulations, namely Solid Lipid Nanoparticles (SLNs) and Nanostructured Lipid Carriers (NLCs), which have been highlighted as able to overcome some limitations of other innovative approaches, thus representing a promising strategy for the non-invasive specific treatment of CNS-related diseases.

Hypothesis Solid lipid nanoparticles (SLNs), co-encapsulating superparamagnetic iron oxide nanoparticles and sorafenib, have been exploited for magnetic-guided drug delivery to the liver. Two different magnetic configurations, both comprising two small magnets, were under-skin implanted to investigate the effect of the magnetic field topology on the magnetic SLNP accumulation in liver tissues. A preliminary simulation analysis was performed to predict the magnetic field topography for each tested configuration. Experiments SLNs were prepared using a hot homogenization approach and characterized using complementary techniques. Their in vitro biological behavior was assessed in HepG-2 liver cancer cells; wild-type mice were used for the in vivo study. The magnet configuration that resulted in a higher magnetic targeting efficiency was investigated by evaluating the iron content in homogenated murine liver tissues. Findings SLNs, characterized by an average size smaller than 200 nm, retained their superparamagnetic behavior and relevant molecular resonance imaging properties as negative contrast agents. The evaluation of iron accumulation in the liver tissues was consistent with the magnetic induction profile of each magnet configuration, concurring with the results predicted by simulation analysis and obtained by measurements in living mice.

The solubility of bortezomib, a boronic acid, in water and normal saline is often misquoted in the literature. Here we confirm that bortezomib equilibrium solubility in water and normal saline is 0.59 ± 0.07 and 0.52 ± 0.11 mg/mL, respectively. The aqueous solubility is significantly enhanced, 1.92 ± 0.14 and 3.40 ± 0.21 mg/mL, respectively, in the presence of 55 mM and 137 mM D-mannitol in normal saline, as in the commercial formulation, Velcade®, after reconstitution. This is due to reversible ester formation between bortezomib and D-mannitol. Based on the pH-solubility profile curve for bortezomib in the absence of added D-mannitol, bortezomib's pKa value is estimated to be 8.8 ± 0.2. Boric acid, glycine and a combination of the two, used in an alternative formulation to that of Velcade® do not enhance the equilibrium aqueous solubility of bortezomib.

Niclosamide (NCS) is a drug that has been used as an anthelmintic and anti-parasitic drug for about 40 years. Recently, some studies have highlighted its potential in treating various tumors, allowing a repositioning of this drug. Despite its potential, NCS is a Biopharmaceutical Classification System (BCS) Class II drug and is consequently characterized by low aqueous solubility, poor dissolution rate and reduced bioavailability, which limits its applicability. In this work, we utilize a very novel technique, direct powder extrusion (DPE) 3D printing, which overcomes the limitations of previously used techniques (fused deposition modelling, FDM) to achieve direct extrusion of powder mixtures consisting of NCS, hydroxypropyl methylcellulose (HPMC, Affinisol 15 LV), hydroxypropyl-β-cyclodextrin (HP-β-CD) and polyethylene glycol (PEG) 6000. For the first time, direct printing of powder blends containing HP-β-CD was conducted. For all tablets, in vitro dissolution studies showed sustained drug release over 48 h, but for tablets containing HP-β-CD, the release was faster. Solid-state characterization studies showed that during extrusion, the drug lost its crystal structure and was evenly distributed within the polymer matrix. All printed tablets have exhibited good mechanical and physical features and a stability of the drug content for up to 3 months. This innovative printing technique has demonstrated the possibility to produce personalized pharmaceutical forms directly from powders, avoiding the use of filament used by FDM. Graphical abstract

Niclosamide (NCS) is a drug that has been used as an anthelmintic and anti-parasitic active principle for about 40 years. Recently, some studies have highlighted its potential in treating various tumors, allowing a repositioning of this drug. Despite its potential, NCS is a Biopharmaceutical Classification System (BCS) Class II drug, and is consequently characterised by low aqueous solubility, poor dissolution rate and reduced bioavailability, which limits its applicability. In this work, we utilize a very novel technique, Direct Powder Extrusion (DPE) 3D printing, which overcomes the limitations of previously used techniques (Fused Deposition Modelling, FDM) to achieve direct extrusion of pharmaceutical grade powder mixtures consisting of NCS, hydroxypropyl methylcellulose (HPMC, Affinisol 15 LV), hydroxypropyl-b-cyclodextrin (HP-β-CD) and polyethylene glycol (PEG) 6000. For the first time, direct printing of powder blends containing HP-β-CD was explored. For all tablets, in vitro dissolution studies showed sustained drug release over 48 hours, but for tablets containing HP-β-CD, the release was faster. Solid-state characterisation studies showed that during extrusion, the drug lost its crystal structure and was evenly distributed within the polymer matrix. All printed tablets exhibited good mechanical and physical features and guarantee stability of the drug content for up to 3 months. This innovative printing technique has demonstrated the possibility to produce personalised pharmaceutical dosage forms starting directly from powders, avoiding the use of filament used by FDM.

The authors provide a report on the preparation of an extemporaneous liquid formulation of diazepam enema using an alcohol-free base solution for use by both pediatric and adult patients. A solubility study using this base and the chemical stability of the drug in this formulation was performed by using a high-pressure liquid chromatography analytical method. Results of this study showed that the intrinsic solubility of the drug in this liquid base was 6.03 mg/mL ± 0.06 mg/mL and that diazepam was chemically stable when the formulation was stored at 25°C over a period of 3 months.

The purpose of this study is to assess some of the variables determining the aldol-like condensation of pyruvic acid (1), a peroxide scavenger, in aqueous solution to parapyruvic acid and higher oligomers. Its stability is compared to 3 other α-keto carboxylic acids, 2 with sterically hindered methylene groups alpha to the keto functionality (2-3) and phenylglyoxylic acid (4) with no methylene group. High-performance liquid chromatography, nuclear magnetic resonance, and liquid chromatography mass spectroscopy techniques are used in the kinetics and product analyses. 1 condensation is concentration dependent and base catalyzed above pH 7, consistent with the reaction mechanism proceeding through the attack of the fraction of the methylene group, alpha to the keto group, in its anionic form, at the keto group of a second molecule of 1. The major product is confirmed to be parapyruvic acid, but higher-order oligomers are also observed. All 3 of the other α-keto carboxylic acids 2-4 are considerably less reactive, with 4 being completely stable. Stable solutions of 1 can be prepared by the use of relatively dilute solutions maintained at slightly acidic pH values. 1 prevents the oxidation of methionine on addition of hydrogen peroxide.

Indomethacin (IND) is topically administered for the treatment of the anterior segment diseases such as conjunctivitis, uveitis, and inflammation prevention for post-cataract surgery, as well as posterior segment diseases as macular edema. Currently IND is available as 0.1% w/v hydroxypropyl-β-cyclodextrin-based eye drop formulation and its bioavailability is limited by several drawbacks such as the nasolacrimal duct draining, the reflex blinking and the low volume of the conjunctival sac. In this study, chitosan (CS)/sulfobutylether-β-cyclodextrin (SBE-β-CD) based nanoparticles (NPs) with a mean diameter of 340 (±7) nm, a ζ-potential value of +18.3 (±0.5) mV and coated with thiolated low molecular weight hyaluronic acid were formulated to improve both the solubility and the residential time in the conjunctival sac of the loaded drug IND. The NPs were prepared through the ionotropic gelation technique, exploiting the interaction between the positively charged amino group of CS and the negatively charged sulfonic group of SBE-β-CD. The mucoadhesive properties of the NPs were evaluated on chicken trachea and esophagus tissues using a texture analyser. The irritability effects of NPs were disclaimed with Hecam test. The developed coated NPs showed increased residential time in the conjunctival sac, displayed no irritancy or toxicity for local administration, making them an optimal and innovative drug delivery system for the treatment of anterior segment inflammation diseases. On the other hand, the uncoated NPs displayed better permeating properties since they are smaller and could be further exploited for the treatment of posterior segment diseases.

Purpose Translocator protein 18-kDa (TSPO) positron emission tomography (PET) is a valuable tool to detect neuroinflammed areas in a broad spectrum of neurodegenerative diseases. However, the clinical application of second-generation TSPO ligands as biomarkers is limited because of the presence of human rs6971 polymorphism that affects their binding. Here, we describe the ability of a new TSPO ligand, [18F]BS224, to identify abnormal TSPO expression in neuroinflammation independent of the rs6971 polymorphism. Methods An in vitro competitive inhibition assay of BS224 was conducted with [3H]PK 11195 using membrane proteins isolated from 293FT cells expressing TSPO-wild type (WT) or TSPO-mutant A147T (Mut), corresponding to a high-affinity binder (HAB) and low-affinity binder (LAB), respectively. Molecular docking was performed to investigate the interaction of BS224 with the binding sites of rat TSPO-WT and TSPO-Mut. We synthesized a new 18F-labeled imidazopyridine acetamide ([18F]BS224) using boronic acid pinacol ester 6 or iodotoluene tosylate precursor 7, respectively, via aromatic 18F-fluorination. Dynamic PET scanning was performed up to 90 min after the injection of [18F]BS224 to healthy mice, and PET imaging data were obtained to estimate its absorbed doses in organs. To evaluate in vivo TSPO-specific uptake of [18F]BS224, lipopolysaccharide (LPS)-induced inflammatory and ischemic stroke rat models were used. Results BS224 exhibited a high affinity (Ki = 0.51 nM) and selectivity for TSPO. The ratio of IC50 values of BS224 for LAB to that for HAB indicated that the TSPO binding affinity of BS224 has low binding sensitivity to the rs6971 polymorphism and it was comparable to that of PK 11195, which is not sensitive to the polymorphism. Docking simulations showed that the binding mode of BS224 is not affected by the A147T mutation and consequently supported the observed in vitro selectivity of [18F]BS224 regardless of polymorphisms. With optimal radiochemical yield (39 ± 6.8%, decay-corrected) and purity (> 99%), [18F]BS224 provided a clear visible image of the inflammatory lesion with a high signal-to-background ratio in both animal models (BPND = 1.43 ± 0.17 and 1.57 ± 0.37 in the LPS-induced inflammatory and ischemic stroke rat models, respectively) without skull uptake. Conclusion Our results suggest that [18F]BS224 may be a promising TSPO ligand to gauge neuroinflammatory disease-related areas in a broad range of patients irrespective of the common rs6971 polymorphism. Supplementary Information The online version contains supplementary material available at 10.1007/s00259-021-05617-4.

Purpose Translocator protein 18-kDa (TSPO) positron emission tomography (PET) is a valuable tool to detect neuroinfammed areas in a broad spectrum of neurodegenerative diseases. However, the clinical application of second-generation TSPO ligands as biomarkers is limited because of the presence of human rs6971 polymorphism that afects their binding. Here, we describe the ability of a new TSPO ligand, [ 18F]BS224, to identify abnormal TSPO expression in neuroinfammation independent of the rs6971 polymorphism. Methods An in vitro competitive inhibition assay of BS224 was conducted with [3H]PK 11195 using membrane proteins isolated from 293FT cells expressing TSPO-wild type (WT) or TSPO-mutant A147T (Mut), corresponding to a high-afnity binder (HAB) and low-afnity binder (LAB), respectively. Molecular docking was performed to investigate the interaction of BS224 with the binding sites of rat TSPO-WT and TSPO-Mut. We synthesized a new 18F-labeled imidazopyridine acetamide ([18F]BS224) using boronic acid pinacol ester 6 or iodotoluene tosylate precursor 7, respectively, via aromatic 18F-fuorination. Dynamic PET scanning was performed up to 90 min after the injection of [18F]BS224 to healthy mice, and PET imaging data were obtained to estimate its absorbed doses in organs. To evaluate in vivo TSPO-specifc uptake of [18F] BS224, lipopolysaccharide (LPS)-induced infammatory and ischemic stroke rat models were used. Results BS224 exhibited a high afnity (Ki=0.51 nM) and selectivity for TSPO. The ratio of IC50 values of BS224 for LAB to that for HAB indicated that the TSPO binding afnity of BS224 has low binding sensitivity to the rs6971 polymorphism and it was comparable to that of PK 11195, which is not sensitive to the polymorphism. Docking simulations showed that the binding mode of BS224 is not afected by the A147T mutation and consequently supported the observed in vitro selectivity of [ 18F]BS224 regardless of polymorphisms. With optimal radiochemical yield (39±6.8%, decay-corrected) and purity (>99%), [18F]BS224 provided a clear visible image of the infammatory lesion with a high signal-to-background ratio in both animal models (BPND =1.43±0.17 and 1.57±0.37 in the LPS-induced infammatory and ischemic stroke rat models, respectively) without skull uptake. Conclusion Our results suggest that [ 18F]BS224 may be a promising TSPO ligand to gauge neuroinfammatory disease-related areas in a broad range of patients irrespective of the common rs6971 polymorphism.

P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP) are two transporters expressed in human neural stem/progenitor cells and at the Blood-Brain Barrier (BBB) level with decreased activity in the early stage of Alzheimer’s disease (AD). Both proteins, have a protective role for the embryonic stem cells in the early developmental step, maintaining them in an undifferentiated state, and limit the access of exogenous and endogenous agents to the brain. Recently, MC111 selected from a P-gp/BCRP ligands library was investigated as multitarget strategy for AD treatment, considering its ability to induce the expression and activity of both proteins. However, MC111 clinical use could be limited for the ubiquitous physiological expression of efflux transporters and its moderate toxicity towards endothelial cells. Therefore, a selective MC111 delivery system based on nanostructured lipid carriers (NLC) functionalized with transferrin were developed. The results proved the formation of NLC with average size about 120 nm and high drug encapsulation efficiency (EE% greater than 50). In vitro studies on hCMEC/D3 cells revealed that the MC111 was selectively released by NLC at BBB level and then inducing the activity and expression of BCRP and P-gp, involved in the clearance of amyloid β peptide on brain endothelial cells.

Natural oils that are rich in biologically active polyunsaturated fatty acids have many health benefits but have insufficient bioavailability and may oxidize in the gastrointestinal tract. For these reasons and to improve the handling as well, the possibility of incorporating a natural oil, extracted from Serenoa Repens fruits (SR-oil), in alginate-based beads was investigated. SR-oil has been used from centuries in both traditional and modern medicine for various nutraceutical or therapeutic purposes such as, in both sexes, as a general tonic, for genitourinary problems, to increase sexual vigor, as a diuretic or to treat in male lower urinary tract symptoms and benign prostatic hyperplasia. In this study, alginate-based beads prepared by vibration technology, also known as prilling technique, were explored as SR-oil delivery systems. Twenty-seven different formulations (F1-F27) were produced starting from stable emulsions for the period of the production. The formulations having spheroid shape (sfericity factor0.07), high formulation yield (90%) and high encapsulation efficiency (EE%80) were selected for further characterizations. Gas chromatographic analysis revealed a high loading of lauric acid as principal component of SR-oil allowing to calculate the content of total fatty acids (50%) into the beads. Swelling behavior and release features were also studied at different pH values. The swelling of the beads and their SR-oil release were negligible for the first 2 h in simulated gastric fluid (pH 1.2), and appreciable in simulated intestinal fluid (pH 6.8). The release data were fitted by various equations to define the release kinetic mechanism. In addition, the selected formulation (F16) was stable to the oxidation not only during the formulation process, but also after 3 months of storage at room temperature. In summary, these polynucleate alginate beads, produced by prilling technique, are promising systems for improving the intestinal specific delivery and bioavailability of health-promoting bioactive SR-oil.

Hydroxychloroquine is a well-known anti-malarial and anti-rheumatic drug that has garnered recently unprecedented attention as potential therapeutic agent against virus infections. Hydroxychloroquine sulphate is authorized in the EU as film-coated tablets (i.e. Plaquenil®), which cannot be administered to non-cooperative patients, such as those in intensive care units or, more in general, unable to swallow solid dosage forms. Therefore, the hospital pharmacist must manipulate the solid dosage form for the preparation of suspension, even if it can strongly affect the product quality. In this scenario, it is crucial to offer useful information and advice to assist hospital pharmacists in their activity. The data presented in this article suggest that extemporaneous suspensions of hydroxychloroquine sulphate in oral liquid bases after tablet manipulation are stable for at least 30 days.

Here, polyethylene glycol (PEG)-stabilized solid lipid nanoparticles (SLNs) containing Pt(IV) prodrugs derived from kiteplatin were designed and proposed as novel nanoformulations potentially useful for the treatment of glioblastoma multiforme. Four different Pt(IV) prodrugs were synthesized, starting from kiteplatin by the addition of two carboxylate ligands with different length of the alkyl chains and lipophilicity degree, and embedded in the core of PEG-stabilized SLNs composed of cetyl palmitate. The SLNs were extensively characterized by complementary optical and morphological techniques. The results proved the formation of SLNs characterized by average size under 100 nm and dependence of drug encapsulation efficiency on the lipophilicity degree of the tested Pt(IV) prodrugs. A monolayer of immortalized human cerebral microvascular endothelial cells (hCMEC/D3) was used as in vitro model of blood–brain barrier (BBB) to evaluate the ability of the SLNs to penetrate the BBB. For this purpose, optical traceable SLNs were achieved by co-incorporation of Pt(IV) prodrugs and luminescent carbon dots (C-Dots) in the SLNs. Finally, an in vitro study was performed by using a human glioblastoma cell line (U87), to investigate on the antitumor efficiency of the SLNs and on their improved ability to be cell internalized respect to the free Pt(IV) prodrugs.

This review provides insight into the use of boric acid as a pharmaceutical, a buffer, and an adjuvant/excipient in pharmaceutical formulations. Boric acid is a Lewis acid with a pKa of 8.92–9.24 that is sensitive to temperature, ionic strength, and concentration. The pKa varies with concentration because of polymerization above 0.02 M. Boric acid reacts reversibly with alcohols, especially 1,2-diols including carbohydrates, with carboxylic acids, thiols, and amines. These esters/adducts, are also Lewis acids with lower pKa values. Boric acid can stabilize some materials while catalyzing the degradation of others. Boric acid is used in various dermal and women's hygiene products because of its mild antibacterial and antifungal activity. In ophthalmic products, it is used as a buffer and in combination with other preservatives to broaden the prservative spectrum. Boric acid has been used reluctantly in parenteral products but appears to be quite safe at low doses. However, at high exposure, toxicity, including death, has been reported in humans, especially in children. Animal toxicities have also been noted, including reductions in male sperm counts. Boric acid is well absorbed on oral dosing. Its biological half-life is about 21 h in humans and has an affinity for some tissues, especially bone.

Treatment of Behçet's syndrome (BS) is aimed at controlling all symptoms of such a complex disorder, ensuring a good quality of life and preventing life-threatening complications. A better understanding of the pathogenic role of different chemokines has improved our knowledge of BS and elicited a more specific use of therapies currently available, minimizing the burden of potential side-effects related to treatment.This work aims to provide a detailed overview of the safety profile for current therapies available in the treatment of BS, focusing on the main side-effects, toxicity and contraindications.The greatest experience in the management of BS has been achieved with the employment of monoclonal anti-tumor necrosis factor antibodies which have been advocated for BS refractory manifestations. Moreover, interleukin-1 inhibitors have proven to be effective as well as safe, despite escalation of their dosage, especially to manage the most severe and difficult-to-treat ocular manifestations. However, general treatment of BS patients remains awkward as protean clinical features may respond differently to the same treatment or even worsen. Therefore, patients' safety for therapies used in BS promotes the implementation of precision medicine, which could help targeting accurately the pathogenetic mechanisms concealed behind specific clinical phenotypes.

Superparamagnetic iron oxide nanoparticles (SPIONs) can be used for the delivery of the anticancer drug Sorafenib, which possesses multikinase inhibitor activity, to specific locations in the body through the application of an external magnetic field. In order to increase the biocompatible and protect the drug, solid lipid NPs (SLN) have been used to contain sorafenib and SPIONs by means of hot homogenization technique using cetyl palmitate as lipid matrix and polyethylene glycol-modified phospholipids (PEG lipids), in order to achieve a PEG-based anti-fouling coating on SLN surface.

Recurrent pericarditis (RP) is a troublesome and debilitating complication of acute pericarditis. Although the etiopathogenesis of this condition remains unknown, an intricate overlap of autoimmune and autoinflammatory pathways has been hypothesized to explain its beginning and recurrence over time. The majority of cases are defined as "idiopathic", reflecting our awkwardness to unravel the intimate mechanisms of RP. Given the possible occurrence of anti-nuclear, anti-heart and anti-intercalated disk antibodies as well as the association with peculiar human leukocyte antigen haplotypes, an autoimmune contribution has been claimed to specify the nature of RP. However, the most innovative pathogenic scenario of RP has been conferred to the innate immune system, mainly involving neutrophils and macrophages that produce a large amount of interleukin (IL)-1 via inflammasome activation. The clinical resemblance of RP with autoinflammatory diseases that may be marked by symptomatic serositis, high fevers and strikingly increased inflammatory parameters further suggests a similar inflammasome-mediated pathogenesis. Aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) remain the mainstay of therapy in RP, whereas colchicine is recommended on top of standard anti-inflammatory therapy, due to its role in inhibiting the IL-1 converting enzyme (caspase 1) within the inflammasome as well as the release of additional pro-inflammatory mediators and reactive oxygen species. With regard to treatment of RP refractory to NSAIDs and colchicine, blockade of IL-1 is the most relevant advance achieved in the last decade: the outstanding effect of the short-acting IL-1 receptor antagonist anakinra has been first recognized in the pediatric population, giving a proof of its practical feasibility. Over a more recent time, a growing experience with anakinra deriving from both large and small studies has further confirmed that RP might be regarded as an IL-1-mediated disease. This review aims to provide a contemporary insight into the mechanisms leading to RP as well as into the most recent literature data showing the beneficial approach originating from IL-1 blockade in this intriguing disorder.

The purpose of this study is to try to identify the etiology and formulation implications of the significant pKa drop in aqueous solution that occurs when boronic acids are reversibly esterified by reaction with alcohols, especially 1,2-diols. Experimental studies have shown that conversion of a boronic acid to a boronic acid ester, both Lewis acids, is accompanied by an increase in the acidity, that is, a lowering of the pKa value in aqueous solution. The drop in pKa value has significant implications for the formulation of boronic acid-based drugs. Specifically, in the presence of 1,2-diols, a ΔpKa, a drop, of about 3 pKa units has been observed for several boronic acids, including boron-based drugs that have demonstrated value as active pharmaceutical ingredients. Boric acid itself shows an even larger drop of about 4 units. Here, electronic structure calculations are used to investigate the origins of this pKa change. Specifically, density functional theory (DFT) is used to predict the ΔpKa for a model boronic acid, methylboronic acid, to two of its esters, the dimethyl ester and the cyclic ester with ethylene glycol. The approach is validated by accurately predicting the experimentally observed increased acidity of the cyclic boronic acid ester relative to the corresponding boronic acid. The origins of the acidity difference are examined in detail. Analysis shows that the primary origin is an electronic effect with a smaller contribution due to the reduced structural flexibility of the boronic ester.

Cutaneous minoxidil (MXD) formulations were developed with the intent to reduce the side effects of the cosolvents propylene glycol and ethanol, frequently used in commercial MXD solutions. Completely aqueous alginate-based hydrogels were investigated and MXD aqueous solubility was improved using inclusion complexes with hydroxypropyl-β-cyclodextrin (HP-β-CD) at 2 different molar substitution degree (MS), namely 0.65 and 0.85. HP-β-CD MS 0.65 was selected for its improved solubilizing ability toward MXD. At concentration of 39% w/v, this cyclodextrin increased the intrinsic aqueous solubility of MXD of about 22-fold. The calculated complexation constant was 2309 ± 20 M −1 , and the inclusion process was spontaneous and enthalpically driven. Nuclear magnetic resonance studies (Job plot, 1 H, 2D correlations spectroscopy, nuclear overhauser effect spectroscopy, and rotating-frame overhauser enhancement spectroscopy) confirmed the stoichiometry 1:1 between MXD and HP-β-CD providing information about the exact geometry of the inclusion complex. Rheological and in vitro release studies performed on the formulation loaded with MXD 3.5% w/w proved that the inclusion complex increased the viscosity of the hydrogel modulating the release of the free drug. Furthermore, the hydrogel formulation facilitate MXD to permeate into the skin and did not damage epidermis, suggesting that these completely aqueous MXD delivery systems can be proposed as alternative formulations to commercial solutions.

Solid lipid nanoparticles (SLNs) can combine the advantages of different colloidal carriers and prevent some of their disadvantages. The production of nanoparticles by means of microfluidics represents a successful platform for industrial scale-up of nanoparticle manufacture in a reproducible way. The realisation of a microfluidic technique to obtain SLNs in a continuous and reproducible manner encouraged us to create surface functionalised SLNs for targeted drug release using the same procedure. A tumor homing peptide, iRGD, owning a cryptic C-end Rule (CendR) motif is responsible for neuropilin-1 (NRP-1) binding and for triggering extravasation and tumor penetration of the peptide. In this study, the Paclitaxel loaded-SLNs produced by microfluidics were functionalized with the iRGD peptide. The SLNs proved to be stable in aqueous medium andwere characterized by a Z-average under 150 nm, a polydispersity index below 0.2, a zeta-potential between -20 and -35 mV and a drug encapsulation efficiency around 40%. Moreover, in vitro cytotoxic effects and cellular uptake have been assessed using 2D and 3D tumour models of U87 glioblastoma cell lines. Overall, these results demonstrate that the surface functionalization of SLNs with iRGD allow better cellular uptake and cytotoxicity ability.

Purified Glycogen (PG) is a highly hyper branched carbohydrate, characterized by high water solubility and very moderate increase in viscosity. The dendrimeric structure of PG, appropriately functionalized, makes it an alternative to current synthetic gene delivery agents. The present study explores the preparation of purified glycogen polycationic derivatives (PGPDs), developed and characterized starting from a single step reaction between PG and N,N-dialkylamino alkyl halides. Subsequently PGPDs were used for the complexation of a model siRNA nucleic acid, a transfection reagent siRNA and a fluorescein-labelled dsRNA oligomer. PGPDs-siRNA complexes were fully characterized by agarose gel electrophoresis and their efficacy was assessed by both confocal microscopy and transfection assays on breast and renal cancer cells. Results proved that PGPDs-siRNA complexes were efficient and not cytotoxic, maintaining their spherical and dendrimeric structure and, particularly, were able to effectively transfect the target cells by releasing the siRNA.

Many modern therapeutic approaches are based on precise diagnostic evidence, where imaging procedures play an essential role. To date, in the diagnostic field, a plethora of agents have been investigated to increase the selectivity and sensitivity of diagnosis. However, the most common drawbacks of conventional imaging agents reside in their non-specificity, short imaging time, instability, and toxicity. Moreover, routinely used diagnostic agents have low molecular weights and consequently a rapid clearance and renal excretion, and this represents a limitation if long-lasting imaging analyses are to be conducted. Thus, the development of new agents for in vivo diagnostics requires not only a deep knowledge of the physical principles of the imaging techniques and of the physiopathological aspects of the disease but also of the relative pharmaceutical and biopharmaceutical requirements. In this scenario, skills in pharmaceutical technology have become highly indispensable in order to respond to these needs. This review specifically aims to collect examples of newly developed diagnostic agents connoting the importance of an appropriate formulation study for the realization of effective products. Within the context of pharmaceutical technology research in Italy, several groups have developed and patented promising agents for fluorescence and radioactive imaging, the most relevant of which are described hereafter.

Budesonide (BUD) is used as first choice therapy for the treatment of allergic rhinitis, a chronic allergic-immune condition with an increased incidence in the pediatric population. The main problem of BUD nasal formulations is related to its poor aqueous solubility (S0 = 5.03·10-5 M), sometimes compensated by the administration of high doses of the drug. The ability of thiolated hydroxypropyl-β-cyclodextrin (HP- β -CD-SH, 100 mM) to increase the water solubility of BUD (SHP- β-CD-SH = 10.9·10-3 M) more than pristine hydroxypropyl- β -cyclodextrin (HP- β-CD, SHP- β-CD = 4.3·10-3 M) has been previously demonstrated. Considering that S-protected thiomers have the advantage of increasing the stability of thiols over a wide pH range prolonging their residence time at the target site, 2-mercapto-nicotinic acid (MNA) was used in this study to protect the free thiol groups on HP- β -CD-SH generating the corresponding S-protected cyclodextrin (HP-β-CD-MNA). Besides, given the increased stability and processability of HP-β-CD-MNA, mucoadhesive microparticles (MPs) were prepared via spray-drying of aqueous solutions of the inclusion complex HP-β-CD-MNA/BUD. MPs were morphologically and dimensionally homogeneous exhibiting an average diameter of 3.24 ± 0.57 µm. Over time these MPs formed larger aggregates with an average diameter of 10–50 μm, suitable for the design of intranasal delivery systems. Differential scanning calorimetry analyses revealed the absence of crystalline BUD from spray-dried complexes. Dissolution studies shown that spray-dried MPs dissolved quickly and the complexed drug was completely solubilized within the first 20 min of the dissolution process. Cell viability assay indicated that spray-dried complexes are safe. In vitro mucoadhesion studies on freshly excised porcine nasal mucosa showed a 1.4- and 2.3-fold prolonged mucosal residence time of HP- β -CD-SH/BUD and HP-β-CD-MNA/BUD in comparison to the unmodified cyclodextrin (CD), respectively. Rheological behaviour of spray-dried MPs complexes/mucus mixtures confirmed the results of the mucoadhesion studies, as the dynamic viscosity of the spray-dried inclusion complexes HP-β-CD-SH/BUD and HP-β-CD-MNA/BUD was 1.1-fold and 2.4 fold increased in comparison to the unmodified HP-β-CD/BUD complex. According to these results, MPs comprising HP- β -CD-MNA/BUD might be a promising tool for nasal delivery of poorly water-soluble corticosteroids such as BUD.

The purpose of this study was to synthesize and characterize a novel thiolated glycogen, so-named S-preactivated thiolated glycogen, as a mucosal drug delivery systems and the assessment of its mucoadhesive properties. In this regard, glycogen-cysteine and glycogen-cysteine-2-mercaptonicotinic acid conjugates were synthesized. Glycogen was activated by an oxidative ring opening with sodium periodate resulting in reactive aldehyde groups to which cysteine was bound via reductive amination. The obtained thiolated polymer displayed 2203.09±200μmol thiol groups per gram polymer. In a second step, the thiol moieties of thiolated glycogen were protected by disulfide bond formation with the thiolated aromatic residue 2-mercaptonicotinic acid (2MNA). In vitro screening of mucoadhesive properties was performed on porcine intestinal mucosa using different methods. In particular, in terms of rheology investigations of mucus/polymer mixtures, the S-preactivated thiolated glycogen showed a 4.7-fold increase in dynamic viscosity over a time period of 5h, in comparison to mucus/Simulated Intestinal Fluid control. The S-preactivated polymer remained attached on freshly excised porcine mucosa for 45h. Analogous results were obtained with tensile studies demonstrating a 2.7-fold increase in maximum detachment force and 3.1- fold increase in total work of adhesion for the S-preactivated polymer compared to unmodified glycogen. Moreover, water-uptake studies showed an over 4h continuing weight gain for the S-preactivated polymer, whereas disintegration took place for the unmodified polymer within the first hour. Furthermore, even in the highest tested concentration of 2mg/ml the new conjugates did not show any cytotoxicity on Caco-2 cell monolayer using an MTT assay. According to these results, S-preactivated glycogen represents a promising type of mucoadhesive polymers useful for the development of various mucosal drug delivery systems.

The neurotransmitter dopamine (DA) was covalently linked to oxazepam (OXA), a well-known positive allosteric modulator of γ-aminobutyric acid type-A (GABAA) receptor, through a carbamate linkage (4) or a succinic spacer (6). These conjugates were synthesized with the aim of improving the delivery of DA into the brain and enhancing GABAergic transmission, which may be useful for the long-term treatment of Parkinson disease (PD). Structure-based permeability properties, in vitro stability and blood-brain barrier (BBB) permeability studies led to identify the OXA-DA carbamate conjugate 4a as the compound better combining sufficient stability and ability to cross BBB. Finally, in vivo microdialysis experiments in freely-moving rats demonstrated that 4a (20 mg/kg, i.p.) significantly increases extracellular DA levels into striatum, with a peak (more than 15-fold increase over the baseline) at about 80 min after a single administration. The stability and delivery data proved that 4a may be a promising candidate...

An interesting mitochondrial biomarker is the 18-kDa mitochondrial translocator protein (TSPO). Decades of study have shown that this protein plays an important role in a wide range of cellular functions, including opening of the mitochondrial permeability transition pore as well as programmed cell death and proliferation. Variations in TSPO expression have been correlated to different diseases, from tumors to endocrine and neurological disorders. TSPO has therefore become an appealing target for both early diagnosis and selective mitochondrial drug delivery. The number of structurally different TSPO ligands examined has increased over time, highlighting the scientific community's growing understanding of the roles of TSPO in normal and pathological conditions. However, only few TSPO ligands are characterized by the presence of groups that are potentially derivatizable; therefore only few such ligands are well suited for the preparation of targeted prodrugs or nanocarriers able to deliver therapeutics and/or diagnostic agents to mitochondria. This review provides an overview of the very few examples of drug delivery systems characterized by moieties that target TSPO.

The anticancer agent, carfilzomib, has a unique α-keto-epoxide warhead. The model α-keto-epoxide, N-((S)-1-((R)-2-methyloxiran-2-yl)-1-oxo-3-phenylpropan-2-yl)pivalamide (1), along with a few of its degradation products was synthesized and studied. The kinetics of hydrolysis and identification of some of the degradation products of 1 were performed at pH values 2, 4, 5, 7, and 8 at 25°C, 40°C, and 60°C and followed by HPLC and liquid chromatography-mass spectroscopy, respectively. 1 degraded independent of pH between pH values 4-7 but showed some acid catalysis at pH 2 and base catalysis at pH 8. Energy of activation, Ea, values progressed from 16.8 ± 0.1 at pH 2 to 20.3 ± 0.1 kcal/mole at pH 8. The major initial degradation products in the pH range 4-5 were the S,R diol (hydrolysis of the epoxide), and S,R chlorohydrin (in the presence of chloride ions). At pH 7-8, the major products were the R,R diastereomer and the S,R and R,R diols. At pH 2, additional unidentified products were seen with relative retention times of 0.28, 0.30, 0.33, and 0.35 and masses equivalent to the diols. The study of 1 provides insight into the degradation of future drugs that use an α-keto-epoxide functional group.

The purpose of this study was to determine the aqueous solubility of a model phenyl boronic acid, 4-methoxybenzeneboronic acid, as a function of pH both in the absence and in the presence of varying D-mannitol concentration. Solid isolated D-mannitol esters were characterized by differential scanning calorimetry, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray studies, and the boronic acid-to-D-mannitol ratio was quantified by HPLC. Hydrolysis of the monoester was studied using UV spectral differences between the monoester and the parent boronic acid. Two D-mannitol esters of 4-methoxybenzeneboronic acid were isolated. The triboronate ester was very insoluble whereas a symmetrical monoboronate monohydrate was also less soluble than the parent. Both esters were crystalline. The monoboronate monohydrate was, however, more soluble than the parent at alkaline pH values due to its lower pKa value (6.53) compared to the parent acid (9.41). Hydrolysis of the monoboronate was extremely fast when even small amount of water was added to dry acetonitrile solutions of the ester. The hydrolysis was buffer concentration dependent and apparent pH sensitive with hydrolysis accelerated by acid. Implications affecting the formulation of future boronic acid drugs are discussed.

The translocator protein 18 kDa (TSPO) is mainly located in outer membrane of mitochondria and results highly expressed in a variety of tumor including breast, colon, prostate, ovarian and brain (such as glioblastoma). Glioblastoma multiforme (GBM) is the most common and lethal type of primary brain tumor. Although GBM patients had currently available therapies, the median survival is14 months. Complete surgical resection of GBM is critical to improve GBM treatment. In this study, we performed the one-step synthesis of water-dispersible ultra-small iron oxide nanoparticles (USPIONs) and combine them with an imidazopyridine based TSPO ligand and a fluorescent dye. The optical and structural characteristics of TSPO targeted-USPIONs were properly evaluated at each step of preparation demonstrating the high colloidal stability in physiological media and the ability to preserve the relevant optical properties in the NIR region. The cellular uptake in TSPO expressing cells was assessed by confocal microscopy. The TSPO selectivity was confirmed in vivo by competition studies with the TSPO ligand PK 11195. In vivo fluorescence imaging of U87-MG xenograft models were performed to highlight the great potential of the new NIR imaging nanosystem for diagnosis and successful delineation of GBM.

New scientific findings have recently shown that dasatinib (DAS), the first-choice oral drug in the treatment of chronic myeloid leukemia (CML) for adult patients who are resistant or intolerant to imatinib, is also potentially useful in the paediatric age. Moreover, recent preclinical evidences suggest that this drug could be useful for the treatment of Duchenne muscular dystrophy, since it targets cSrc tyrosin kinase. Based on these considerations, the purpose of this work was to use the strategy of complexation with hydroxypropyl-&beta, cyclodextrin (HP-&beta, CD) in order to obtain an aqueous preparation of DAS, which is characterized by a low water solubility (6.49 &times, 10&minus, 4 mg/mL). Complexation studies demonstrated that HP-&beta, CD is able to form a stable host-guest inclusion complex with DAS with a 1:1 apparent formation constant of 922.13 M&minus, 1, as also demonstrated by the Job&rsquo, s plot, with an increase in DAS aqueous solubility of about 21 times in the presence of 6% w/v of HP-&beta, CD (0.014 mg/mL). The inclusion complex has been prepared in the solid state by lyophilization and characterized by Fourier Transform Infrared (FT-IR), Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetry (DSC) techniques, and its dissolution profile was studied at different pH values. Moreover, in view of potential use of DAS for Duchenne muscular dystrophy, the cytotoxic effect of the inclusion complex has been assessed on C2C12 cells, a murine muscle satellite cell line. In parallel, a one-week oral treatment was performed in wild type C57Bl/6J mice to test both palatability and the exposure levels of the new oral formulation of the compound. In conclusion, this new inclusion complex could allow the development of a liquid and solvent free formulation to be administered both orally and parenterally, especially in the case of an administration in paediatric age.

The determination of the acid-base dissociation constants, and thus the pKa values, of α-keto acids such as pyruvic acid is complex because of the existence of these acids in their hydrated and nonhydrated or oxo state. Equilibria involved in the hydration and dehydration of the α-keto group of pyruvic acid and three other α-keto acids, 3-methyl-2-oxobutanoic acid, 4-methyl-2-oxopentanoic acid, and 2-oxo-2-phenylacetic acid, were investigated by proton and carbon nuclear magnetic resonance spectrometry, at constant ionic strength, 0.15, and 25 °C. Dissociation constants for the oxo (pKa(oxo)) and hydrated (pKa(hyd)) acids of each compound were estimated from the change in the degree of hydration with changes in pH and directly from the changes in chemical shifts of various hydrogen and carbons nuclei with pH. α-Keto acids showed greater hydration in their acidic forms than their carboxylate forms. The degree of hydration was sensitive to steric and electronic/resonance factors. As expected, the oxo forms of the acids were stronger acids compared with their hydrated analogs, and their dissociation constants were also sensitive to steric and electronic factors.

The purpose of this work was to probe the rate and mechanism of rapid decarboxylation of pyruvic acid in the presence of hydrogen peroxide (H2O2) to acetic acid and carbon dioxide over the pH range 2-9 at 25 °C, utilizing UV spectrophotometry, high performance liquid chromatography (HPLC), and proton and carbon nuclear magnetic resonance spectrometry ((1)H, (13)C-NMR). Changes in UV absorbance at 220 nm were used to determine the kinetics as the reaction was too fast to follow by HPLC or NMR in much of the pH range. The rate constants for the reaction were determined in the presence of molar excess of H2O2 resulting in pseudo first-order kinetics. No buffer catalysis was observed. The calculated second-order rate constants for the reaction followed a sigmoidal shape with pH-independent regions below pH 3 and above pH 7 but increased between pH 4 and 6. Between pH 4 and 9, the results were in agreement with a change from rate-determining nucleophilic attack of the deprotonated peroxide species, HOO(-), on the α-carbonyl group followed by rapid decarboxylation at pH values below 6 to rate-determining decarboxylation above pH 7. The addition of H2O2 to ethyl pyruvate was also characterized.

The development of medicines designed for children can be challenging since this distinct patient population requires specific needs. A formulation designed for paediatric patients must consider the following aspects: patient population variability; dose flexibility; route of administration; patient compliance; drug and excipient tolerability. The purpose of this Special Issue entitled “Paediatric Formulation: Design and Development” is to provide an update on both state-of-the-art methodology and operational challenges in the design and development of paediatric formulations. It aims at re-evaluating what is needed for more progress in the design and development of age-appropriate treatments for paediatric diseases, focusing on: formulation development; drug delivery design; efficacy, safety, and tolerability of drugs and excipients. This editorial, briefly, summarizes the objects of nine original research and review papers published in this Special Issue.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, with poor outcomes largely due to its unique microenvironment, which is responsible for the low response to drugs and drug-resistance phenomena. This clinical need led us to explore new therapeutic approaches for systemic PDAC treatment by the utilization of two newly synthesized biphenylnicotinamide derivatives, PTA73 and PTA34, with remarkable antitumor activity in an in vitro PDAC model. Given their poor water solubility, inclusion complexes of PTA34 and PTA73 in Hydroxy-Propil-&beta, Cyclodextrin (HP-&beta, CD) were prepared in solution and at the solid state. Complexation studies demonstrated that HP-&beta, CD is able to form stable host&ndash, guest inclusion complexes with PTA34 and PTA73, characterized by a 1:1 apparent formation constant of 503.9 M&minus, 1 and 369.2 M&minus, 1, respectively (also demonstrated by the Job plot), and by an increase in aqueous solubility of about 150 times (from 1.95 &micro, g/mL to 292.5 &micro, g/mL) and 106 times (from 7.16 &micro, g/mL to 762.5 &micro, g/mL), in the presence of 45% w/v of HP-&beta, CD, respectively. In vitro studies confirmed the high antitumor activity of the complexed PTA34 and PTA73 towards PDAC cells, the strong G2/M phase arrest followed by induction of apoptosis, and thus their eligibility for PDAC therapy.

The purpose of this study was to develop a new solid paediatric formulation for propranolol hydrochloride (PR). This drug is used to treat various paediatric diseases, and recently received clearance to treat haemangioma. However, PR has a bitter salty taste that does not facilitate high rates of compliance among children, especially in liquid formulations. In addition, the solid formulations are designed for adults and often their dosage is not suitable for children that require a flexible dose based on their weight. Therefore, matrix microbeads of EUDRAGIT® E PO containing PR were manufactured to overcome these limitations. Nine different samples were prepared using the prilling-congealing technique with high yield. Using 2 nozzles, 300 and 450 μm (code n), the diameters obtained of microbeads (from 333 to 699 μm) were homogenous and appropriate to be swallowed by children. In this study, the ratio drug:matrix for the microbeads was also examined in detail: 1:25 (F1), 1:15 (F2) and 1:10 (F3) in aqueous and tert-butyl alcohol/aqueous (code t) media. Most of the examined microbeads were characterized by high percentage of encapsulation efficiency (22–100%) and drug loading (22–77 mg of drug per g of matrix) effective for the administration of low and high doses of PR. SEM analysis revealed a matrix with a radial or a spongy structure, with numerous pores that generated soft floating microbeads in aqueous solution. Release studies confirmed a low release and dissolution of the drug in artificial saliva, mainly F1n > F1 > F2nt, and a prompt dissolution in simulated gastric media. Finally, electronic tongue measurements revealed the ability of these formulations to mask the bitter drug taste, especially for the sample with a ratio 1:25 (F1n and F1). These samples were chemically and physically stable for six months. In conclusion, the projected microbeads F1, and F1n reached the goal of the study, and could be proposed as new solid oral formulations dedicated to use by children.

Budesonide (BUD) is a low water soluble (S0 = 5.028·10−5 M) corticosteroid used as preferred therapy for the treatment of Eosinophilic Esophagitis (EoE), a chronic allergic-immune condition with an increased incidence in the paediatric population. Currently there are no commercial medicines indicated for EoE, and, therefore, in the hospital pharmacy the BUD is extemporaneously formulated as viscous oral suspension at the initial dose of 1–2 mg per day for children, highlighting the need of a mucoadhesive drug delivery system (MDDS) that adheres to the site of action and prolongs the therapeutic activity of the administered drug. Considering the ability of hydroxypropyl-β-cyclodextrin (HP-β-CD, 100 mM) to increase the water solubility of BUD (SHP-β-CD = 4.3·10−3 M; K1:1 = 861.11 M−1), a mucoadhesive thiolated HP-β-CD (HP-β-CD-SH) was synthesized and characterized by mass spectroscopy, 1H- and 13C NMR techniques. Phase-solubility studies demonstrated the capability of HP-β-CD-SH (100 mM) to form a reversible water soluble inclusion complex with BUD (SHP-β-CD-SH = 10.9·10−3 M; K1:1 = 2013.52 M−1), which increases its permanence on the target site as proved by mucoadhesive studies on porcine oesophagus mucosa. HP-β-CD-SH might be a useful MDDS for the pharmacist to prepare BUD oral liquid formulations at the recommended doses, with pH values below 5, which guarantee the chemical stability of the new mucoadhesive excipient.

This work describes S-preactivated N-acetylcysteine (NAC)- and glutathione (GSH)-glycol chitosan (GC) polymer conjugates engineered as potential mucoadhesive platform. Preactivated thiomers (GC-NAC-MNA, GC-GSH-MNA) were synthesized by bond formation between GC-NAC or GC-GSH and 2-mercaptonicotinic acid (MNA) used as ligand. The presence of protected thiol moieties on this new class of thiolated GC made them not subject to oxidation. The structural modifications of the resulting derivatives were confirmed by proton Nuclear Magnetic Resonance (1H NMR) and Size Exclusion Chromatography (SEC). The conjugates displayed 91.2% and 90.1% of S-preactivation for GC-NAC-MNA and GC-GSH-MNA, respectively. The polymers were tested in ex-vivo and in vitro for their mucoadhesive properties and toxicity. The results showed that the preactivation of GC-NAC and GC-GSH increased their mucoadhesive abilities compared to their thiolated precursors by 1.4-, 4.4-fold in time of adhesion evaluated using rotating cylinder method, 1.6-, 1.5-fold in total work of adhesion (TWA) and 2.0-, 1.3-fold in maximum detachment force (MDA) determined using tensile studies, respectively. Moreover, water-uptake studies showed an improved in weight indicating water-uptake strongly dependent on derivations, before erosion occurred, whereas disintegration took place for the thiolated polymers within the first hour. The S-preactivated modification did not affect the cell viability of Caco2 cells exposed to the polymers. The release of the model drug sodium naproxen from tablets prepared with a lyophilized mixture of drug and polymer was studied via dissolution apparatus revealing that the preactivation on GC-GSH and GC-NAC involves a slowdown in the drug release rate. The results shown that the novel preactivated thiolated GC-derivatives can be considered promising excipients for the development of mucoadhesive drug delivery systems.

This chapter presents an outline of the recent available information regarding safety, toxicity, and efficacy of nano drug delivery systems. Of particular importance is the evaluation of several key factors to design nontoxic and effective nanoformulations. Among them, we focus on nanostructure materials and synthesis methods, mechanisms of interactions with biological systems, treatment of nanoparticles, manufacture impurities, and nanostability. Emphasis is given to in silico, in vitro, and in vivo models used to assess and predict the toxicity of these new formulations. Additionally, some examples of in vitro and in vivo studies of specific nanoderivatives are also presented in this chapter.

The purpose of this study is to try to identify the etiology and formulation implications of the significant pK