The effect of 2-hydroxypropyl-ß-cyclodextrin on the solubility,stability and dissolution rate of famotidine

Abstract

Famotidine was found to form an inclusion complex with 2-hydroxypropyl-ß-cyclodextrin (HPCD). Phase-solubility diagram was classified as type A_L with a stability constant for complex formation (K_st) of 100.50 M¹ at pH 7.4. Famotidine undergoes specific acid catalysis in strongly acidic solutions. Addition of HPCD to these solutions decreased the rate of drug degradation. The rate constant for degradation of complexed famotidine (k_c) and K_st were estimated from the relationship between the observed rate constant for overall drug degradation (K_obs) and HPCD concentration. An increase in ionization of famotidine resulted in a decrease in the magnitude of K_st. The dissolution rate of the prepared complex was significantly greater than that of the pure drug.