Kaustubh Tambwekar

Development Pharmaceutics of Microbicide Formulations. Part I: Preformulation Considerations and Challenges

Microbicides, the compounds and formulations that can prevent transmission of sexually transmitted diseases (STDs)/HIV are being pursued actively as a promising AIDS intervention. The drug development chain for a topical microbicide differs significantly from that of any systemic or topical compound/formulation regarding to time line, cost, activities, and milestones. This is in part because of the lack of standard in vitro models to assess efficacy, and complex ethical issues in clinical trials of microbicides. Several factors, including changes in the physiology of the cervix and vagina with age and menstrual cycle, intercourse, as well as leakage of the formulation from the vagina may affect their design, development, and performance. Selection and development of optimal microbicide delivery systems (gel/cream, pessary, film, tablet, foam, etc.), their inactive ingredients, manufacturing details, and packaging system are dependent on the properties of active drug, or their preformulation parameters (PP). The PP of the active drug substance needs to be evaluated in initial stages of drug discovery and development so that the most suitable delivery system can be selected. Some PP of microbicide agents include physical state, organoleptic properties (color, odor, appearance, taste, etc.), molecular weight, aqueous solubility, hygroscopicity, acidity/alkalinity, permeability and absorption characteristics, stability in solid/solution state, and inherent bioadhesiveness. Thus, a well-coordinated, planned, and implemented preformulation program can help in not only accelerating microbicide formulation development, but also to minimize unforeseen failures in subsequent stages of the development. The objective of this review is to highlight the significance of PP, suggesting a systematic preformulation program.

A validated high performance liquid chromatographic method for analysis of nicotine in pure form and from formulations.

A reverse phase HPLC method using C18 column has been developed for the quantitative estimation of nicotine in the bulk material and formulations (extended release and immediate release dosage forms). The method is specific to nicotine (RT approximately 4.64 min, asymmetry approximately 1.75), and can resolve analyte peak from excipient interferences. It is linear (coefficient of variation approximately 0.9993), accurate (average recovery approximately 100%), and passed all the system suitability requirements. Applicability of the method was evaluated in analysis of drug-excipient compatibility samples, commercial dosage form (such as nicotine gum) and two novel in-house formulations.

Survey of vaginal formulations available on the Indian market: physicochemical characterization of selected products

SummaryThe vagina is a potential site for the local and systemic delivery of drugs. Presently, significant attention is given to the development of vaginal formulations (‘microbicides’) that prevent sexual acquisition of acquired immunodeficiency syndrome (AIDS) and other sexually transmitted diseases. Acceptability of vaginal dosage forms may vary among women from different geographical and socioeconomic backgrounds. Therefore, in the drug development process, selection of an appropriate dosage form is crucial for consumer acceptance and use. The primary objective of this study was to survey vaginal preparations available in the Indian market to determine the types of products that are most frequently used by Indian women. In addition, this survey provides information about the active ingredients and dosage forms of these products. The physicochemical properties of selected products were compared in order to help formulation scientists to design vaginal formulations with desired properties. Indian vaginal products are available in several different dosage forms. Tablets are marketed most frequently (38%), followed by gels (15%) and creams (15%). The evaluated products varied greatly in their physicochemical properties such as colour, pH, disintegration, viscosity, osmotic pressure and bioadhesive properties. The information can serve as reference on vaginal products in the Indian market and to aid in the development of new vaginal formulations, especially for India and other tropical countries.