PREPARATION OF DIAZEPAM RECTAL GEL USING CELLULOSE POLYMERS

Diazepam is a long-acting benzodiazepine with anticonvulsant, anxiolytic, sedative muscle relaxant properties and it is the most widely used drug for treatment of insomnia, convulsions, and status epilepticus. Considering the advantages of rectal administration of diazepam, the objective of our study was to formulate and evaluate rectal hydrogels containing diazepam as a drug substance in combination with suitable co-solvents and preservatives. Hydroxypropylmethyl cellulose (HPMC) gels containing 5 mg diazepam in a 2.5 mL rectal gel, manifested good quality in respect to physicochemical parameters (pH value, drug content and viscosity). Three types of formulation containing benzoate buffer, phosphate buffer and without buffer were prepared and evaluated. Different physicochemical parameters were investigated. Diazepam content in different formulations was in the range of 96 to 103 % which had less than 5% error. pH determination from all formulations did not change significantly during 60 days of preparation. Prepared gels showed good antimicrobial efficiency. Viscosity determination showed that viscosity of formulation No. 3 (without buffer) was highest among all formulations. Formulation containing water (without buffer) was the best formulation, because its shelf-life was 458 days at refrigerator condition and its pH was 6.5 which is in the acceptable range.