Dissolution of Two-Component Solids

Dissolution Kinetics of Three‐Component Compressed Solid Mixtures with Largely Different Solubilities: Flaking Spheres

“…Minute particles of drug powder may flake out from the solid surface, as mentioned before, resulting in an increased effective surface area and the faster dissolution rates than those predicted. 1,4,7,10,11 In contrast, the observed dissolution rates were found to be slower than those predicted by the model in the vicinity of critical compositions, which were also observed by former investigators. 1,4,7,8 This deviation was explained on the basis of small local variation (nonhomogeneity at the microlevel) for physical mixtures compared with homogeneous melts of components.…”

“…1 Early pharmaceutical studies of the dissolution of two-component systems were reported for mixtures of weak acids-tribasic sodium phosphate 2 and salicylic acid-polyvinylpyrrolidone. 3 Diffusion models have also been proposed to depict the dissolution of nondisintegrating polyphase mixtures containing two noninteracting components and complexing components.…”

“…4 This approach has also been applied to mixtures of polymorphs, 5 as well as to noninteracting compressed mixtures of aspirin-salicylic acid, aspirin-phenacetin, and phenacetin-caffeine, and to interacting solids of aspirin-caffeine. 1 A general mathematical model describing dissolution rates of a nondisintegrating sphere composed of any number of components has been proposed along with experimental cases to support the model for two-and three-component spheres, two-component interacting spheres, and threecomponent spheres with two interacting components. 6 The dissolution behaviors of ethylparaben, phenacetin, and salicylamide, 7 as well as benzoic acid, salicylic acid, and salicylamide, 8 from three-component nondisintegrating compressed spheres at 13 various compositions were studied under sink conditions and described by the film diffusion model.…”

“…Moreover, some deviations on the faster experimental dissolution rates than the predicted rates were observed, particularly at high mass fraction ratio of the more soluble component, both in noninteracting and interacting systems, which were attributed to flaking of the surface component. 1,4,7,10,11 Because most freely soluble additives are usually incorporated into compressed solids of poorly water soluble drugs to facilitate dissolution of prime particles, it is of interest to investigate the dissolution behaviors of such solid mixtures theoretically. The purpose of this study was therefore to develop a suitable dissolution model for three-component solid mixtures with largely different solubilities as well as to compare the experimental dissolution rates of each of the components with those predicted by the model.…”

Release behavior of alkyl-p-aminobenzoate ester–PVP solid dispersions

“…Physical models have been developed and tested rigorously to describe the simultaneous diffusion and fast equilibria for two-and threecomponent systems. [52][53][54][55][56] These models serve as the basic foundation for the traditional approach (SMH) for drug release from solid dispersions. In these models, the dissolution of each component is assumed to be a diffusion controlled process and the dissolution surface is assumed as non- (A or B) can be calculated.…”