The vagina has been studied as favorable site for the local and systemic delivery of drugs, for female associated conditions. Vaginal preparations, although generally perceived as safer most still associated with number of problems including frequent dosing and escape causing discomfort to patient. For efficient vaginal delivery of drugs, the delivery system should reside at the site of infection for a prolonged period of time. Present dosage form includes thermosensitive polymers (Poloxamer 127and Poloxamer 188) and pH activated polymers (Chitosan, Carbopol 974 p) for in-situ gel formulation which combines advantages of both gels and solution so that an accurate dose can be administered with ease. These formulations remain in solution state before administration and transforms to gel after administration in to vaginal cavity. Preliminary studies were carried out using different concentrations of various polymers evaluated for their gelling capacity & viscosity in order to identify the compositions suitable for use in the in situ gelling system. Clindamycin HCl was used with varying concentration of P127 and P188 in combination and found that ratio of concentration in %w/v of 23/7 of P127 / P188 is effective for sol-gel transformation at body temperature (37°C). NaCl (0.9%) was added as isotonic agent and HPMC (0.1%) as bioadhesive polymer to provide strength to formulation. Formulations have satisfactory appearance, clarity & drug content in the range 98.1%- 101%. Performed studies and obtained results prove the efficacy of Poloxamer 127/188 combination as Bio-responsive polymer in the formulation of Clindamycin in situ gel system for vaginal application.