RESUMEN
Nalidixic acid was formulated in suppository form using Witepsol H15, Witepsol E15, Novata 75, cocoa butter and polyethylene glycol as bases. The prepared suppositories were evaluated using the following tests: Uniformity of weight and content, disintegration time, differential scanning calorimetry and kinetics of release. The effect of type and concentration of the nonionic surfactants, viz. Tween 80, 60 and 20, Myrj 51 and 53, Brij 58 and 35 and 35 on the rate of drug release from Witepsol H15 was studied. It is worthy to note that maximum release rate [mg%/hour] obtained from plain base [Witepsol H15] was 4.5 while, addition of 10% Tween 80 to this base increased the release rate to 19.36 mg%/hour. The microbiological potency of the suggested formula [90% Witepsol H15 and 10% Tween 80] which was determined using agar diffusion method, showed a marked inhibitory effect on the tested standard strains of Gram positive and negative microorganisms