Percolative Transport and Cluster Diffusion Near and Below the Percolation Threshold of a Porous Polymeric Matrix

Abstract

A model describing transport near and below the percolation threshold in matrices composed of two phases, polymer and drug, was developed. The percolation model developed accounts for diffusion within the porous structure and through the inert, insoluble polymeric amorphous regions of the matrix. The low percolation threshold and subsequently high coordination was concluded to be due to the biphasic classical porous and nonclassical polymeric diffusional transport mechanisms associated with the system studied.

Rational Estimation of the Optimum Amount of Non‐Fibrous Disintegrant Applying Percolation Theory for Binary fast Disintegrating Formulation

“…In recently published works, the application of percolation theory was expanded to investigation of key properties of pharmaceutical compacts,10–18 taking into account complex interactions of different processes involved in disintegration of complex multi‐particulate system. It is well known that heterogeneous ensembles like pharmaceutical formulations for solid dosage forms represent disordered particulate systems where it is necessary to take into account a geometrical description,19 that is, a topological modeling.…”

An emerging terpolymeric nanoparticle pore former as an internal recrystallization inhibitor of celecoxib in controlled release amorphous solid dispersion beads: Experimental studies and molecular dynamics analysis

“…According to percolation theory, a higher concentration of pore former would increase the probability of forming sufficient interconnections of permeable channels to span the pathway along the membrane for drug to transport. For small molecules such as our model drug, CEL, percolation thresholds upwards of ∼9% w / w have been estimated in porous polymer matrices, where pore forming materials with smaller size can function at lower thresholds 45 , 46 . Since TPN is dispersible on a finer scale, does not leach, and can swell significantly upon contact with water ( Fig.…”

“…The issue of supersaturation and precipitation is especially problematic at lower pore former concentrations, where a lack of interconnections ( i.e. , failure to percolate) to form continuous channels could result in isolated, ill-defined passageways and further impede drug release 34 , 45 .…”

A dissolution‐diffusion model for the TAXUS™ drug‐eluting stent with surface burst estimated from continuum percolation

“…In more recent models, the particle dissolution is treated as a homogeneous source term within the diffusion equation 3, 9. Furthermore, extensive work has been done relating drug release from dispersed systems to computational percolation theory [Refs 10–13. and references therein].…”