In situ gel containing Bimatoprost solid lipid nanoparticles for ocular delivery: In-vitro and ex-vivo evaluation

Present study was conducted to develop a novel Bimatoprost (BIM) nanoparticles loaded pH-sensitive in-situ gel for the treatment of glaucoma. BIM loaded solid lipid nanoparticles were prepared by high shear homogenization followed by probe sonication method. Glyceryl Monostearate (GMS) was used as solid lipid and Tween 80 as surfactant. Optimization of nanoformulation was done by 3(2) full factorial design using Design Expert Software 11.0.5. GMS and Tween 80 concentrations were the independent variables and particle size, PDI, zeta potential (ZP) and % entrapment efficiency (EE) were dependent variables. The optimized BIM loaded nanoparticles batch (BIM-SLN4) was further incorporated into carbopol 941 to form nanoparticles loaded in situ gel (SLN-ISG). A total of 5 batches (SLN-ISG1-SLN-ISG5) were prepared by varying the concentration of carbopol 941 from 0.05% w/v to 0.25%w/v. SLN-ISG3 was selected as optimized batch based on its gelling capacity and viscosity. In-vitro and ex-vivo studies of BIM-SLN4, SLN-ISG3 showed drug release for a prolonged period of time. HET-CAM test revealed that the formulation is non-irritant and thus can be well tolerated when instilled in the eye. Histopathological studies also revealed no signs of tissue damage. Thus, SLN-ISG can offer improved management of glaucoma.