Temperature and pH Triggered Insitu Hydrogel of Doxycycline for the Treatment of Chlamydial Conjunctivitis

The present investigation describes the formulation and characterization of ophthalmic in situ hydrogelfor sustained delivery of doxycycline (DOX) that is frequently used to treat chlymydial conjunctivitis.Insitu hydrogel were prepared using thermo-reversible gelling polymer, Pluronic F 127 (PF127) and PHsensitive and viscosity enhancer polymer Carbopol 940 (CP940). Because of high concentration (20 to25%w/v) of PF127 polymer required for insitu gelation causes irritation to the eye. So, to reduce thisconcentration, an attempt was made to combine the PF127 with CP940 showing a pH triggered sol-geltransition by pH of tear fluid. Different batches were prepared of varying concentrations of CP940 (0.1-0.3%) with PF127 (12%-18%) using DOX 2%w/v. Pluronic F68 (PF68) with 2% and 4% concentrationwere mixed to obtain a hydrogel with an appropriate gelation temperature. The formulations wereoptimized by the viscosity measurement and in vitro gelation study. Selected formulations wereevaluated for in vitro drug release study using Franz diffusion cell and indicated sustain drug releaseover a period of 10 h. Stability testing at 80C and 400C and effect of sterilization and were on drugcontent, pH and clarity were also evaluated. The prepared formulation could reduce not only theconcentration of individual polymers but also the side effects without compromising the in vitro gellingcapacity. This formulation of Doxycycline insitu hydrogel represents potentially effective ophthalmicdelivery system for the treatment of chlaymydial conjunctivitis.