Formulation of Tinidazole Rectal Suppositories

Abstract

Tinidazole was prepared as a suppository dosage form that could be used rectally in an attempt to render the drug available systemically by a route other than oral route, thus overcoming the side effects of the drug on the gastrointestinal tract. Also such dosage form could replace the intravenous administration whenever it is inconvenient.The influence of the type of suppository base and added surfactants on the physical properties and drug release was studied using lipophilic bases (witepsole H-15, witepsole H-35) and water soluble bases [mixtures of polyethylene glycols PEG 6000:400:200 (30:35:35) and PEG 4000:1000 (30:70)].The results showed a good release of tinidazole from PEG bases compared to lipophilic bases because of the interaction between the drug and triglycerides of the lipophilic bases. Also the non ionic surfactants increase the release of tinidazole from witepsole H-15 base containing suppository and the increase was greater for span 80 than tween 80.Also the influence of temperature and storage period on the physical properties and release was investigated by storing the prepared suppositories at 4˚C and 25˚C for 1, 15, 30 and 45 days. The results appeared that the temperature of storage affect the release of tinidazole from witepsole H-15, but had no effect on physical properties of the suppositories. While the storage period at both temperatures had some effects on the physical properties. On the other hand, temperature of storage affects the physical properties of polyethylene glycol suppositories and release of the drug, in contrast to the period of storage, which had no effect.The expiration date of tinidazole in formula containing polyethylene glycol 4000:1000 (30:70) was found to be about 3.3 years.