Preparation, characterization, and pharmaceutical application of linear dextrins. III. Drug release from fatty suppository bases containing amylodextrin.

Drug release from fatty suppository bases containing a solid dispersion of diazepam with amylodextrin or a complex of prednisolone with amylodextrin was analyzed in a flow-through model. Being present as a suspension in the fatty base, particles of complex or solid dispersion are transported to the lipid-water interface by sedimentation. After entering the aqueous phase they partially dissolve. The suppositories showed increased drug release compared with the corresponding suppositories containing drug only. Because of the partial solubility of amylodextrin, drug release was lower than the release from drug-cyclodextrin complexes. Use of the soluble fraction of amylodextrin for both the solid dispersion and the complex further enhanced drug release, but it was still below that of drug-cyclodextrin complexes.