Preparation of a poloxamers based in situ thermosensitive gel containing chloramphenicol for ophthalmic use

Purpose To prepare a poloxamers based in situ thermosensitive gel containing chloramphenicol for ophthalmic use and to establish its quality control method.Methods The in situ thermosensitive gel of chloramphenicol was prepared with poloxamer 407(P407) and poloxamer 188(P188) as thermosensitive material,and the formulation was optimized by determining solution-gelation conversion temperature.The content of chloramphenicol was determined by ultraviolet spectrophotometry.Results The gelation temperature of in situ thermosensitive gel of chloramphenicol formulations was lowered as the P407 concentration increased.As the P188 concentration increased gradually the gelation temperature initially increased to maximum,and then decreased.The gelation temperature all increased after simulated tear fluid(STF) dilution.The fitted equation was established for the gelation temperature with the concentration of poloxamer solutions after being diluted by STF.An optimized formulation by Design-Expert soft was freely flowing liquid at 29.5 ℃ and it converts to a firm gel at 34.6 ℃ after STF diluted.Conclusion In situ thermosensitive gel satisfied the requirement for ophthalmic application and showed a great potential in ophthalmic application.