Influence of humidity on the phase behavior of API/polymer formulations

Recent advances in smart biotechnology: Hydrogels and nanocarriers for tailored bioactive molecules depot

“…In such a case, drug release will begin as soon as an external aqueous fluid diffuses towards the polymeric network and a key step can be represented by the drug dissolution over the water permeating the network. When metastable bioactive molecules like polymorphs, amorphous or nano-crystalline drugs are present in the dry hydrogel, the dissolution process may correlate with recrystallization which leads to the formation of a new, more stable, drug crystallographic organization induced by the contact with the absorbed water [22].…”

Drug Release Kinetics and Mechanism from PLGA Formulations

“…The chemical‐potential‐gradient model was used to study the drug release mechanisms and to correlate and predict the drug release kinetics. As the Perturbed‐Chain Statistical Associating Fluid Theory (PC‐SAFT) has been successfully applied to model the systems containing drugs, electrolytes, and polar components, in this work, it was used to calculate the solubility and activity coefficients of the model drugs. The effects of copolymer composition and molecular weight of PLGA on drug release kinetics and mechanism were investigated.…”

Development of a Predictive Model for the Long-Term Stability Assessment of Drug-In-Adhesive Transdermal Films Using Polar Pressure-Sensitive Adhesives as Carrier/Matrix

“…Different approaches for the prediction of drug crystallization in polymer matrix have already been described for solid dispersion applications only, based on thermodynamic [5][6][7][8][9][10] , kinetic 11 or a combination of thermodynamic and kinetic principles 12 . Typical semi-empirical thermodynamic approaches consisted in using thermal analysis (recrystallization of supersaturated solid dispersions or melting point depression methods) [6][7][8] , water sorption data 8,10 or solubility of API in low molecular weight analogue of polymer 7,8 , to apply either Flory-Huggins or the regular solution theory, which however do not allow for hydrogen bonding interactions.…”

“…Typical semi-empirical thermodynamic approaches consisted in using thermal analysis (recrystallization of supersaturated solid dispersions or melting point depression methods) [6][7][8] , water sorption data 8,10 or solubility of API in low molecular weight analogue of polymer 7,8 , to apply either Flory-Huggins or the regular solution theory, which however do not allow for hydrogen bonding interactions. Alternatively, Prudic et al 9 applied a computational thermodynamic model (PC-SAFT) to solve the water vapor-liquid and API solid-liquid equilibria to predict the impact of water sorption and API crystallization on API (indomethacin and naproxen) and polymer (PVP and poly(vinyl pyrrolidone-co-vinyl acetate)) solid dispersions. used a computational method to estimate the microstructure of API-polymer systems, based on thermodynamic (Flory-Huggins theory), kinetic (Fick's second law of diffusion) and manufacturing (solvent evaporation) considerations to rank the polymers according to their miscibility with the drug (itraconazole).…”

“…A different approach was employed for solid dispersions intended for oral formulation by Prudic et al 9 , which involved modelling and thermal analysis. The authors used a thermodynamic model, Perturbed Chain-Statistical Association Fluid Theory, which determined the residual Helmholtz energy by describing a molecule as a chain of segments and experimental data on binary systems to solve simultaneously vapor-liquid equilibrium of water (moisture) and liquid-solid equilibrium of API (amorphous/crystalline).…”