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An asymmetric synthesis is a favorable approach for obtaining enantiomerically pure substances, but racemic resolution remains an efficient strategy. This study aims to elucidate the chiral resolution of aromatic amino acids and their elution order using glycopeptides as chiral selectors through molecular docking analysis. Chiral separation experiments were conducted using Vancomycin as a chiral additive in the mobile phase (CMPA) at various concentrations, coupled with an achiral amino column as the stationary phase. The Autodock Vina 1.1.2 software was employed to perform molecular docking simulations between each enantiomer (ligand) and Vancomycin (receptor) to evaluate binding affinities, demonstrate enantiomeric resolution feasibility, and elucidate chiral recognition mechanisms. Utilizing Vancomycin as CMPA at a concentration of 1.5 mM enabled the separation of tryptophan enantiomers with a resolution of 3.98 and tyrosine enantiomers with a resolution of 2.97. However, a poor chiral resolution was observed for phenylalanine and phenylglycine. Molecular docking analysis was employed to elucidate the lack of separation and elution order for tryptophan and tyrosine enantiomers. By calculating the binding energy, docking results were found to be in good agreement with experimental findings, providing insights into the underlying mechanisms governing chiral recognition in this system and the interaction sites. This comprehensive approach clarifies the complex relationship between chiral discrimination and molecular architecture, offering valuable information for creating and improving chiral separation protocols.

The objective of this study is the development of innovative nanocurcumin-based formulations designed for the treatment and prevention of oxidative stress and diabetes. Nanocurcumin was obtained through a micronization process and subsequently encapsulated within biopolymers derived from corn starch and fenugreek mucilage, achieving encapsulation rates of 75% and 85%, respectively. Subsequently, the encapsulated nanocurcumin was utilized in the formulation of sugar-free syrups based on Stevia rebaudiana Bertoni . The stability of the resulting formulations was assessed by monitoring particle size distribution and zeta potential over a 25-day period. Dynamic light scattering (DLS) revealed a particle size of 119.9 nm for the fenugreek mucilage-based syrup (CURF) and 117 nm for the corn starch-based syrup (CURA), with polydispersity indices PDIs of 0.509 and 0.495, respectively. The dissolution rates of the encapsulated nanocurcumin were significantly enhanced, showing a 67% improvement in CURA and a 70% enhancement in CURF compared with crude curcumin (12.82%). Both formulations demonstrated excellent antioxidant activity, as evidenced by polyphenol quantification using the 2.2-diphenyl 1-pycrilhydrazyl (DPPH) assay. In the evaluation of antidiabetic activity conducted on Wistar rats, a substantial reduction in fasting blood sugar levels from 392 to 187 mg/mL was observed. The antioxidant properties of CURF in reducing oxidative stress were clearly demonstrated by a macroscopic observation of the rats' livers, including their color and appearance.

The main objective of this study was to create a mathematical tool that could be used with experimental data to predict the rheological flow behavior of functionalized xanthan gum according to the types of chemical groups grafted onto its backbone. Different rheological and physicochemical analyses were applied to assess six derivatives synthesized via the etherification of xanthan gum by hydrophobic benzylation with benzyl chloride and carboxymethylation with monochloroacetic acid at three (regent/polymer) ratios R equal to 2.4 and 6. Results from the FTIR study verified that xanthan gum had been modified. The degree of substitution (DS) values varying between 0.2 and 2.9 for carboxymethylxanthan gum derivatives were found to be higher than that of hydrophobically modified benzyl xanthan gum for which the DS ranged from 0.5 to 1. The molecular weights of all the derivatives were found to be less than that of xanthan gum for the two types of derivatives, decreasing further as the degree of substitution (DS) increased. However, the benzyl xanthan gum derivatives presented higher molecular weights varying between 1,373,146 (g/mol) and 1,262,227 (g/mol) than carboxymethylxanthan gum derivatives (1,326,722-1,015,544) (g/mol). A shear-thinning behavior was observed in the derivatives, and the derivatives' viscosity was found to decrease with increasing DS. The second objective of this research was to create an ANN model to predict one of the rheological properties (the apparent viscosity). The significance of the ANN model (R 2 = 0.99998 and MSE = 5.95 × 10 -3 ) was validated by comparing experimental results with the predicted ones. The results showed that the model was an efficient tool for predicting rheological flow behavior.

This work aimed to formulate xanthan gum microspheres for the encapsulation of metformin hydrochloride, according to the process of ionotropic gelation. The obtained microparticles, based on various fractions of xanthan gum (0.5-1.25), were subjected to different physico-chemical tests and a drug release study. Microspheres with an average size varying between 110.96 μm and 208.27 μm were obtained. Encapsulation efficiency reached 93.11% at a 1.25% biopolymer concentration. The swelling study showed a swelling rate reaching 29.8% in the gastric medium (pH 1.2) and 360% in the intestinal medium (pH 6.8). The drug release studies showed complete metformin hydrochloride release from the beads, especially those prepared from xanthan gum at the concentration of 1.25%, in intestinal medium at 90.00% after 6 h. However, limited and insignificant drug release was observed within the gastric medium (32.50%). The dissolution profiles showed sustained release kinetics.

This research reported on the synthesis and the evaluation of new octenyl succinate (OS) kappa-carrageenan (KC) esterified derivatives (KC-OS). Two derivatives were synthesized using microwave (KC-OSMM) and conventional heating (KC-OSCM). The FT-IR and 1 H NMR demonstrated the KC-OS esters formation with a higher degree of substitution for KC-OSMM (0.85) than KC-OSCM (0.62). The SEM testing showed the non-deteriorated morphology of KC after modification. The amphiphilic properties and surface activity of KC-OSs investigated by the conductivity method confirmed the formation of self-assembled aggregates beyond a critical aggregation concentration of 0.08% for KC-OSMM and 0.12% for KC-OSCM. Stable oil-in-water emulsions were formulated based on KC-OSs at the concentrations of 0.75% and 1%. Lower globule sizes were observed for KC-OSMM emulsions at 0.75% (12.30 μm) and 1% (08.86 μm), compared to KC-OSCM at 0.75% (32.75 μm) and 1% (19.6 μm). All results demonstrated that microwave synthesis resulted in obtaining novel derivatives with superior properties., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

New amphiphilic derivatives of kappa-carrageenan (KC) were synthesized by hydrophobic modification with octyl chloride. Two different methods based on microwave and conventional heating were used. All KC derivatives (KCRs) were characterized by different techniques. The FT-IR and 1 HNMR studies demonstrated that the octyl groups were effectively grafted onto KC backbone and confirmed that the derivative KCRMM, obtained by microwave heating, presented a higher degree of substitution (DS = 0.77) compared to KCRCM (0.45). The amphiphilic character investigation also revealed that KCRMM exhibited a lower critical aggregation concentration (CAC) value of 0.13% w/v than KCRCM (0.15%). Furthermore, KCRs greatly improved the stability of oil/water emulsions as the droplet size decreased with increasing DS. Unlike the conventional heating method, novel derivatives with a higher DS, greater amphiphilic character, and an improved emulsifying power were obtained by microwave-assisted synthesis. These derivatives could potentially be used in food, cosmetics, or as excipients in pharmaceutics., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this work, topical matrix patches of diclofenac sodium (DS) were formulated by the solvent casting method using different ratios of chitosan (CTS) and kappa carrageenan (KC). Propylene glycol and tween 80 were used as a plasticizer and permeation enhancer, respectively. The drug matrix film was cast on a polyvinyl alcohol backing membrane. All the patches were evaluated for their physicochemical characteristics (thickness, folding endurance, flatness, drug content, tensile strength, bioadhesion, moisture content, and moisture uptake), along with their in vitro release and in vitro skin permeation studies. Franz diffusion cells were used to conduct the in vitro permeation studies. The artificial neural network (ANN) model was applied to simultaneously predict the DS release and the ex vitro skin permeation kinetics. The formulated patches showed good physicochemical properties. Out of all the studied patches, F6 presented sustained permeation in 32 h and was selected as the best formulation. The ANN model accurately predicted both the kinetic release and the skin permeability of DS from each formulation. This performance was demonstrated by the obtained R 2  = 0.9994 and R 2  = 0.9798 for release and permeation kinetics modeling, respectively, with root mean square error (RMSE) = 3.46 × 10 -5 .

This paper addressed the application of deacetylated xanthan (XGDS) and chitosan (CTS) as a mixture blend forming hydrophilic matrices for Tramadol (TD) sustained release tablets. XGDSs derivatives were obtained by alkaline treatment of xanthan gum (XG) with various degrees of deacetylation (DD). The obtained products were characterized in terms of structural, thermal and physicochemical properties. Different tablet formulations containing CTS/XGDSs were prepared by direct compression method and compared to CTS/XG tablets. Flow properties of powder mixtures and pharmaceutical characteristics were evaluated. The dissolution test of TD was realized under simulated gastric and intestinal conditions to achieve drug release more than 24 h. All developed tablets were found conforming to standard evaluation tests. It was shown that CTS/XGDSs matrices ensure a slower release of TD in comparison with CTS/XG based formulations. Meanwhile, increasing DD resulted in a decrease of drug release. In addition, TD release from XGDS matrices was faster at pH (6.8) than at acidic pH (1.2). The matrix tablets based on CTS/XGDS4 (DD = 98.08%) were selected as the best candidates compared to the other systems in prolonging drug release. The optimal formulation was found to release 99.99% of TD after 24 h following a non-Fickian type., Competing Interests: The authors declared that there is no conflict of interest., (© 2019 The Authors.)

In the present study, we investigated the drug release behavior from cellulose derivative (CD) matrices in the oral form of tablets. We used the adaptive neural-fuzzy inference system (ANFIS) to predict the best formulation parameters to get the perfect sustained drug delivery using ibuprofen (IB) as a model drug. The different formulations were prepared with different CDs, namely CMC, HEC, HPC, HPMC, and MC. The amount of the active ingredient varied between 20 and 50%. The flow properties of the powder mixtures were evaluated for their angle of repose, compressibility index, and Hausner ratio, while the tablets were evaluated for weight uniformity, hardness, friability, drug content, disintegration time, and release ratio. All tablet formulations presented acceptable pharmacotechnical properties. In general, the results showed that the drug release rate increases with an increase in the loaded drug. Kinetic studies using the Korsmeyer-Peppas equation showed that different drug release mechanisms were involved in controlling the drug dissolution from tablets. The drug release mechanism was influenced by the gel layer strength of the CDs formed in the dissolution medium. The mean dissolution time (MDT) was determined and the highest MDT value was obtained for the HPMC formulations. Moreover, HPMC exhibited release profiles adequate for sustained release formulations for over 14 h. The intelligent model based on the experimental data was used to predict the effect of the polymer's nature, the amount of the active ingredient, and the kinetic release profile and rate (R 2  = 0.9999 and RMSE = 5.7 × 10 -3 ). The ANFIS model developed in this work could accurately model the relationship between IB release behavior and tablet formulation parameters. The proposed model was able to successfully describe this phenomenon and can be considered an efficient tool with predictive capabilities that is useful for the designing and testing of new dosage systems based on polymers.

The purpose of this study was to develop suitable matrix-type transdermal drug delivery systems of Ketotifen fumarate (KF) as antiasthmatic drugs. Chitosan-alginate polyelectrolyte complex (PEC) films were used as drug release regulators for KF. Antihistaminic films with variable PEC compositions were prepared using different ratios of chitosan (CTS) to sodium alginate (ALG). Propylene glycol (PG) was used as plasticizer; Tween 80 (T 80 ) and Span 20 (S 20 ) were used as permeability enhancers. Nine formulations were obtained by film casting method and characterized in terms of weight uniformity, thickness, folding endurance, moisture lost, and moisture absorption. In addition, drug release and permeation through rat abdominal skin mounted in Franz cell were investigated. All formulations were found to be suitable in terms of physicochemical characteristics, and there was no significant interaction between the used drug and polymers. It was noticed that when T 20 is used as permeation enhancer, a satisfactory drug release pattern was found where 99.88% of drug was released and an amount of 2.121 mg/cm 2 of KF was permeated after 24 h. For the optimal formulation, a permeability coefficient of 14.00 ± 0.001 cm h -1 and a latency time of 0.35 ± 0.02 h were found. The in-vitro analysis showed controlled release profile which was fitted by Korsmeyer-Peppas model (R 2  = 0.998). The obtained results suggested that new controlled release transdermal formulations of asthmatic drugs could be suitably designed as an alternative to the common forms.

The aim of this work was to synthesize a carboxymethylated xanthan (CMXG) via an etherification reaction between different ratios (2, 4, and 6) of xanthan gum (XG) and monochloroacetic acid (MCAA) using the Williamson synthesis method. The synthetized products were characterized in terms of their physico-chemical and rheological properties. Both FTIR and proton nuclear magnetic resonance (H(1) NMR) analyses confirmed the grafting of carboxymethyl groups on xanthan hydroxyl groups. The obtained results demonstrated that the degree of substitution was proportional to the chloroacetic acid and xanthan gum ratios. The obtained carboxymethyl derivatives presented greater hydrophilicity and lower molecular weights with increasing degrees of substitution than native xanthan gum. The rheological study revealed that the viscosity of the CMXG derivatives decreased with the degree of substitution and with the conservation of the shear-thinning and weak gel behaviours. The flow curves suggested the existence of two different populations of particles consisting of CMXG particles with a smaller average size and a second population formed by the residual fractions of native XG particles. It was also found that the elastic modulus of XG was largely higher than that of the CMXG derivatives and decreased with increasing DS. For the CMXG derivatives, two regions of viscoelastic behaviour were observed, which were separated by a crossover point corresponding to the critical frequency and relaxation time, i.e., the time required for stress relaxation., (Copyright © 2016 Elsevier Ltd. All rights reserved.)