Open Science Journal of Pharmacy and Pharmacology 2015; 3(3): 19-27 Published online July 20, 2015 (http://www.openscienceonline.com/journal/osjpp) Excipients Use in Parenteral and Lyophilized Formulation Development Yasir Mehmood 1, 2, * , Umer Farooq 1 1 Faculty of Pharmacy, University of Central Punjab, Lahore, Pakistan 2 Ameer & Adnan Pharmaceuticals (pvt.) Limited, Lahore, Pakistan Email address yasirmehmoodamjad@gmail.com (Y. Mehmood) To cite this article Yasir Mehmood, Umer Farooq. Excipients Use in Parenteral and Lyophilized Formulation Development. Open Science Journal of Pharmacy and Pharmacology. Vol. 3, No. 3, 2015, pp. 19-27. Abstract Excipients are the integral part of pharmaceutical product development to achieve the desired product profile (stability and efficacy). This review deals with understanding of the physicochemical properties of excipients used in parenteral formulation development for solution, suspension and lyophilized drug products. However, in spite of proper excipients selection, judicious use during formulation, manufacturing process based on their critical property that is also important to avoid negative effects such as loss of drug solubility, activity and stability. This paper deals with proper selection of excipients in lyophilized and parenteral drug products which gives high critical temperature, good bulking properties avoiding melt back and collapse with improved dried product appearance. We have also emphasized on appropriate selection of excipients for solution, suspension injectable dosage forms and linking their physiochemical properties with optimum manufacturing method with suitable case studies. This review will highlight various excipients related issues, optimizing product performance with documented references and practical approaches based on scientific justification. The reader will gain better understanding of excipients complexity during stability studies and resolving problems with practical approach. Keywords Excipients, Parenteral, Lyophilized, Suspension, Formulation Development 1. Introduction Excipients are typically the major components in a drug product. Many formulations contain only a small percentage of the active drug molecules. Pharmaceutical excipients or additives are compounds added to the finished drug products to serve a specific function. They are added to increase bulk, aid manufacturing, improve stability, enhance drug delivery and targeting, and modify drug safety or pharmacokinetic profile. Ingredients that are used during drug product manufacturing, but may not be present in the finished drug product are also considered excipients (examples include water for lyophilized products, and inert gases in the head space of containers) (1) . In recent years the “functionality” of excipients in a dosage form (similar to the pharmacological activity of an active pharmaceutical ingredient or drug substance) has been recognized by USP & European Pharmacopoeia. Excipients are traditionally referred to as inactive or inert ingredients to distinguish them from active pharmaceutical ingredients. Excipients may not be as inert as the term inactive suggests. Due to safety issues, several countries have restrictions on the type or amount of excipients that can be included in the formulation of parenteral drug product. For example, in Japan, U.S.A and EU amino mercuric chloride or thiomersal use is prohibited, despite the presence of these excipients in products in other regions (2) . As defined in Ph. Eur. and the British Pharmacopeia (BP), “Parenteral preparations are sterile preparations intended for administration by injection, infusion, or implantation into the human or animal body.” In the present article, only sterile preparations for administration by injection or infusion into the human body will be surveyed (3,4) . Injectable products require a unique formulation strategy. The formulated product must be sterile, pyrogen-free, and, in the case of solution, free of particulate matter. No coloring agent may be