Formulation development and evaluation of diclofenac sodium injection using benzyl alcohol (co-solvent), mixed solvency concept

Introduction: Mixed solvency is a concept of solubilization of the material. For producing new formulation, especially in the form of injection it is essential to solubilize the active pharmaceutical ingredients (API) in the solvent and that must be stable throughout the shelf life. Aqueous solubility of raw materials is important for injection formulation, but in some cases if the drug is not soluble in water, oil can be used for drug solubility. In this present investigation, mixed-solvency approach has been applied for the enhancement of aqueous solubility of poorly water-soluble drugs, diclofenac sodium (selected as a model drug). Those drugs that poorly soluble in aqueous media are required fractioned oil to enhance its solubility. In most of the cases to make raw materials soluble in water, solubilizing agent in high concentration (co-solvent and surfactant) are use for drug solubility. But due to high concentration of co-solvent and use of oil can make more painful to inject. In the present study, we formulated the diclofenac sodium injection without using high concentrations of propylene glycol as co-solvent which is used in conventional formulation. Benzyl alcohol is used as preservative in conventional formulation and in this formulation benzyl alcohol uses as co-solvent for diclofenac sodium in aqueous medium and due to this, injection is less painful Yasir Mehmood Affiliations: Faculty of Pharmacy University of Central Punjab, Lahore, Pakistan. Corresponding Author: Yasir Mehmood, Faculty of Pharmacy, University of Central Punjab, Lahore, Pakistan; Ph: +92301-7795575; EMail: [email protected] Received: 12 June 2015 Accepted: 05 August 2015 Published: 12 December 2015 then propylene glycol based injection. At the end, we studied the stability, toxicity, pyrogenicity and isotonicity of the formulated injection. Conclusion: From the various formulation studied, it was found that benzyl alcohol (6– 7% v/v) is good and save solubilizing agent for preparation of injection dosage form of diclofenac sodium. This mixed solvency shall prove definitely a boon for pharmaceutical industries for the development of dosage form of poorly water soluble drugs.