Formulation Development of Dry Injection for Reconstitution of a Poorly Water Soluble Drug, Candesartan Cilexetil, Using Mixed Solvency Concept and their Evaluations

In this current era of pharmaceutical research, maximum newly invented drugs are found to be very poorly soluble in water. It possess difficulties in various developmental, manufacturing and administrating processes, which lead to the high failure of clinical trials of the drug due to poor pharmacokinetics. Parenteral dosage form could be expected to be an effective tool for avoiding the oral side effects and also achieving maximum bioavailability. Poor solubility of drugs in water is currently biggest challenge and limitation in injectable formulation developments. The prime purpose of any research work should be highly efficient and most effective in the pharmaceutical field to serve the society�s needs by developing a formulation after literature survey and market review. The ultimate objective of this present research was to promote the use of mixed solvency concept by formulating the dry injection of the poorly water soluble drug and to decrease the concentration of individual solubilizers required to produce a substantial increase in solubility and thereby resulting in expected synergistic enhancement of solubility of the drug in water. In the present work, poorly water soluble drug, candesartan cilexetil, was selected as a drug and its dry injection for reconstitution was formulated. Candesartan cilexetil is an anti-hypertensive drug belonging to the category of angiotensin II type 1 (AT1) receptor antagonist (AII-RA). However, it has low aqueous solubility and undergoes extensive hepatic first pass metabolism, leading to poor drug bioavailability (15 %) and therefore, higher doses are required to achieve the desired therapeutic efficacy. (BCS class II: highly permeable and low soluble). In order to get expected synergistic enhancement on solubility, various blends of solubilizers were tried thereby reducing the amount of individual solubilizer employed to achieve the desired solubility enhancement ratio. The successful completion of the research work was there for preparation of stable dry injection for reconstitution of candesartan cilexetil.