Introduction: Rectal suppositories of valproic acid were prepared using different lipophilic excipients: Suppocire NAI, Adeps solidus 50, Adeps solidus 3, Lipex 403, Cacao oleum. Each prepared suppository has been evaluated for various physical parameters like weight variation, disintegration and softening time and crushing (breaking) strength.
Methods: Suppositories were prepared by fusion method. The quantity of active drug (valproic acid) added to the suppositories was 200 mg, thus resulting 1.0 g suppositories. Prepared suppositories were visually inspected. Randomly selected suppositories were cut longitudinally and the surfaces were examined with naked eye. For determination of weight variation, 20 suppositories were weighed and the average weight was determined. Disintegration time, softening time and breaking strength of the prepared suppositories were determined according to the 5th European Pharmacopoeia.
Results: All the suppositories were free from pits, fissures and cracks. All formulas studied were disintegrated in less than 30 minutes. Valproic acid decreased the disintegration time of suppositories. The used excipient also influences the disintegration time, with a greater effect on the F1 formula (Suppocire NAI). After one month of preservation, the disintegration time of all formulas increased, but was less than 30 minutes. The softening time of the suppositories was the largest for the F1 formula (Suppocire NAI). The softening time decreases in the presence of valproic acid. The softening time and breaking strength increased for all formulas after one month.
Conclusions: The prepared suppositories were within the permissible range of physical parameters. The results obtained allow the selection of excipients in order to assure the optimum characteristics for prepared suppositories.