DEVELOPMENT OF SULFAMETHOXAZOLE-TRIMETHOPRIM SPHEROIDAL GRANULES - FACTORS AFFECTING DRUG RELEASE INVITRO

In the present study spheroidal granules of sulphamethoxazole (SMZ) and trimethoprim (TMP) were produced by the process of wet granulation of powders in a rotating pan with concomitant addition of a binder solution. Initially, preliminary trials were performed. In order to estimate the effect of binder, disintegrant and glidant on the dissolution rates of SMZ and TMP spheres a 2(3) factorial design was developed. After the correct formulation was obtained, SMZ and TMP spheres of pre-determined size fractions were encapsulated in a 5:1 weight ratio (400 mg SMZ and 80 mg TMP), and dissolution rates of active ingredients were examined against a commercially available product. Before encapsulation, TMP spheres were coated with Eudragit E 12.5% solution, in order to avoid interaction between SMZ and TMP molecules, which would probably produce a 1:1 molecular compound, as reported in the literature (Giordano et al., 1977).