Effect of fatty base components on drug release and drug absorption of diclofenac sodium suppositories

Diclofenac sodium 100 mg suppositories were formulated using a mixture of Witepsol H15, a low melting point fatty base, and Suppocire NBL, a high melting point fatty base, in two different proportions. Their drug release functions were investigated in vitro and in vivo versus Voltaren 100 mg suppositories. The in vitro drug release properties changed by varying the proportions of the two bases. The percentage of released diclofenac sodium rose with the increase of Witepsol H15 at 37degreesC because a higher proportion of the suppositories was melted and allowed a faster release. The in vivo absorption of diclofenac sodium was also found to be influenced by the proportion of Witepsol H15 in the formula. Consequent! v, the formula containing a higher proportion of Witepsol H15 showed bioequivalence with Voltaren while the formula containing the higher proportion of Suppocire NBL did not.