Enhancement of dissolution rate and bioavailability of sulfamethoxazole by complexation with β-cyclodextrin

The purpose of this study was to improve the solubility and dissolution rate of sulfamethoxazole (SMZ) with inclusion compound of β-cyclodextrin (β-CD). The interaction between SMZ and β-CD in solution was studied by the phase-solubility method. The phase-solubility studies revealed the formation of inclusion complexes with poor solubility with an inclusion complex of 1:1 molar ratio and a stability constant of 122.3?M(-1). The solid complexes of SMZ with β-CD were prepared by using kneading and coprecipitation methods. The physical mixture of these chemicals was also prepared for comparison. Inclusion complexation was confirmed by the results from the studies of infrared spectoroscopy (IR) and differential scanning calorimetry (DSC). The effect of water-soluble polymers i.e., polyethylene glycol 20000 and non-ionic surfactants i.e., polysorbate 20 on the complexation of SMZ with β-CD was also investigated by the same methods. The rates of release of the active material from the complexes were determined from dissolution studies using USP XXII paddle method. The formulation, that provided delivery of active material near to the target value in six healthy volunteers and in vivo tests, clearly revealed that the bioavailability of active material was found to be enhanced by preparing ternary mixtures.     

Enhanced solubility and dissolution rate of amiodarone by complexation with β-cyclodextrin through different methods

The aim of this work was to investigate the inclusion complexation between amiodarone (AMD), a practically water insoluble anti arrhythmic agent, and β-cyclodextrin (βCD) in order to improve the solubility and the dissolution rate of the drug, in an attempt to enhance its bioavailability. The complexation was done through different methods: physical mixture (PM), coevaporated (CV), freeze-drying (FD) and spray-drying (SD). The data analysis indicated that the complexes produced by freeze-drying and spray-drying techniques resulted in amorphous samples (data obtained by DSC and XRPD), and showed a possible chemical interaction between OH-βCD group and AMD tertiary amine (visualized by FT-IR). Also, they presented higher thermal stability (demonstrated by TG) and the improvement of the drug dissolution rate.