Development and evaluation of rectal suppository formulation for antidiabetic activity of repaglinide: A comparative study

Diabetes mellitus is a group of metabolic diseases mainly characterized by chronic hyperglycemia. The oral immediate release tablet formulation of Repaglinide (REP) is associated with the sudden hypoglycemia and difficulty in swallowing particularly by pediatric and geriatric patients. These limitations ultimately affect the patient compliance highlighting the need for the development of alternative formulations such as suppositories. The current study was aimed to formulate and evaluate REP suppositories as a potential alternative to inhibit diabetic activity. REP suppositories prepared by molding method were characterized via Fourier Transform Infra-Red spectroscopy and evaluated for various physicochemical parameters including FTIR analysis, disintegration, breaking, liquefaction and dissolution tests. The entrapment efficiency of the formulation was quantified by UV method. In vivo efficacy was assessed using alloxan-induced diabetic rabbits at predetermined time intervals in experimental groups. FTIR analysis confirmed the chemical compatibility of REP and suppository base. Disintegration time was 21 min, while breaking test confirmed that the suppository was able to withstand up to 1.9 kg of applied weight. Liquefaction time and E.E (%) was recorded as 10 min and 88%, respectively. In vitro drug release showed a burst release followed by sustained release up to 3 hrs (34). In vitro evaluation confirmed that the REP suppository formulations met the official standards for physicochemical evaluation, and drug-base interaction. In vivo study showed that the REP suppository caused a significant reduction of blood glucose level in a sustained release manner. Taken together, REP suppository provides the promising antidiabetic activity for a sustained period with improved efficacy as compare to oral tablets. However, further trials are needed to confirm its clinical efficacy and safety in diabetic patients.