Characterizing the Impact of Chitosan on the Nucleation and Crystal Growth of Ritonavir from Supersaturated Solutions

Modification of physicochemical properties of chitosan to improve its pharmaceutical and agrochemical potential applications

Chitosan has received much more attention as a functional biopolymer with applications in pharmaceuticals, agricultural, drug delivery systems and cosmetics. The objectives of present investigation were to carry out modification of chitosan for enhancement of aqueous solubility, which will impart increased solubility and dissolution rate of poorly soluble drug itraconazole (ITZ) and also evaluate the modified chitosan for soyabean seed germination studies. The modification of chitosan was accomplished through the antisolvent precipitation method; employing five carboxylic acids. The resulting products were assessed for changes in molecular weight, degree of deacetylation, solubility and solid state characterization. Subsequently, the modified chitosan was complexed with itraconazole using the co-grinding technique. The prepared formulations were evaluated for solubility, FTIR (Fourier-transform infrared spectroscopy), PXRD (Powder X-ray diffraction), in-vitro dissolution studies. Furthermore the effect of modified chitosan has been evaluated on soybean seed germination. Results demonstrated that, modified chitosan improves self and solubility of itraconazole by six folds. As there was increased degree of deacetylation of chitosan leads to improvement in solubility. The results of FTIR showed the slight shifting of peaks in co-grind formulations of itraconazole. Formulations showed reduction in crystallinity of drug which leads to enhancement in dissolution rate as compared to pure itraconazole. Retention of property of seed germination was observed with modified chitosan at optimum concentration of 3 % w/v, with benefit of enhanced aqueous solubility of chitosan. This positive result paves the way for the advancement of pharmaceutical and agrochemical products employing derivatives of chitosan.

Elucidation of Molecular Interactions Between Drug-Polymer in Amorphous Solid Dispersion by a Computational Approach Using Molecular Dynamics Simulations

Introduction

Amorphous drug dispersion is frequently used to enhance the solubility and dissolution of poorly water-soluble drugs, thereby improving their oral bioavailability. The dispersion of these drugs into polymer matrix can inhibit their recrystallization. The inter-molecular interactions between drug and polymer plays a role in the improvement of the dissolution rate, solubility, and physical stability of drug.

Aim

This study aims to investigate the formation and interactions of ritonavir (RTV)/poloxamer (PLX) amorphous formulation using a computational approach via molecular dynamics (MD) simulations, which mimicked solvent evaporation and melt-quenching method.

Methods

TheRoot Mean Square Deviation (RMSD) value, Root Mean Square Fluctuation (RMSF), Radial Distribution Function (RDF), Radius of Gyration (Rg), Solvent Accessible Surface Area (SASA), and hydrogen bond interactions were analyzed to determine interaction mechanisms between RTV and PLX in amorphous solid dispersion.

Results

The pi-alkyl bonds between RTV and PLX were formed after simulations of solvent evaporation, while the hydrogen bond interactions of RTV-PLX was observed during melt method simulations. These results indicate the successful formulation of amorphous solid dispersion (ASD) from RTV and PLX. The RMSD values obtained from the solvent evaporation, melt-cooling-A, melt-cooling-B, and melt-cooling-C methods were 3.33 Å, 1.97 Å, 1.30 Å, and 1.29 Å, respectively, while the average RMSF values were 2.65 Å, 1.04 Å, 1.05 Å, and 1.07 Å, respectively. This indicates that the suppression of translational motion of RTV from the melt method can be stronger than solvent evaporation caused by the intermolecular interactions of RTV-PLX.

Conclusion

MD simulations helped in understanding the formation and interaction mechanisms of ASD formulations that were difficult to detect by experimental approaches.

Advancing Drug Delivery Paradigms: Polyvinyl Pyrolidone (PVP)-Based Amorphous Solid Dispersion for Enhanced Physicochemical Properties and Therapeutic Efficacy

BACKGROUND

The current challenge in drug development lies in addressing the physicochemical issues that lead to low drug effectiveness. Solubility, a crucial physicochemical parameter, greatly influences various biopharmaceutical aspects of a drug, including dissolution rate, absorption, and bioavailability. Amorphous solid dispersion (ASD) has emerged as a widely explored approach to enhance drug solubility.

OBJECTIVE

The objective of this review is to discuss and summarize the development of polyvinylpyrrolidone (PVP)-based amorphous solid dispersion in improving the physicochemical properties of drugs, with a focus on the use of PVP as a novel approach.

METHODOLOGY

This review was conducted by examining relevant journals obtained from databases such as Scopus, PubMed, and Google Scholar, since 2018. The inclusion and exclusion criteria were applied to select suitable articles.

RESULTS

This study demonstrated the versatility and efficacy of PVP in enhancing the solubility and bioavailability of poorly soluble drugs. Diverse preparation methods, including solvent evaporation, melt quenching, electrospinning, coprecipitation, and ball milling are discussed for the production of ASDs with tailored characteristics.

CONCLUSION

PVP-based ASDs could offer significant advantages in the formulation strategies, stability, and performance of poorly soluble drugs to enhance their overall bioavailability. The diverse methodologies and findings presented in this review will pave the way for further advancements in the development of effective and tailored amorphous solid dispersions.