Dissolution Rate of Polymorphs and Two New Pseudopolymorphs of Sulindac

Abstract

This study reports the enhancement of sulindac dissolution rate by using the acetone and chloroform solvated forms. me intrinsic dissolution rates of potymorphs I and II and the influence of crystal habit on the drug dissolution process have also been studied. The dissolution properties were studied by calculating the intrinsic dissolution rate (k) by linear regression analysis from the amount dissolved versus time. The results indicated that the intrinsic dissolution rates of solvates in acetone and chloroform were much higher (k = 0.076 mg min⁻¹cm-², respectively) than those of polymorphs I and II (k = 0.036 mg min⁻¹cm⁻²). However, the dissolution rates of the two solvates were found to be essentially the same and independent of the solvent nature. The intrinsic dissolution rates of form II recrystal-lized in methanol and ethanol differed (k = 0.031 and 0.036 mg min⁻¹cm⁻², respectively), which confirms the influence of crystal habit on sulindac dissolution rate. No significant difference in dissolution profiles were observed between forms I and II, in agreement with the similar values of fusion cemperature (1187 and 183°C respectively.