Physical Stability and Release Profile of Compounded Gabapentin Containing Pluronic Lecithin Organogel for Neuropathic Pain Management.

The objective of this study was to evaluate the physical stability and drug-release profile of gabapentin from different compounded formulations of Pluronic lecithin organogel containing gabapentin, thus confirming the stability of the preparations. Eight different formulations of compounded Pluronic lecithin organogel containing gabapentin alone or gabapentin in combination with other drugs were prepared using the cold incorporation method. Organoleptic properties, pH values, rheology, and gelation temperature were studied at 1, 7, and 14 days after preparation. The release of gabapentin out of Pluronic lecithin organogel was measured by diffusion across cellulose membranes (0.45 um) in the Franz diffusion cell system. The organoleptic properties were constant during the stability study in all formulations. The values of pH varied depending on the formulation, with slight increases after the the 7th day of the study. Gelation temperature, rheology, and drug release of gabapentin out of Pluronic lecithin organogel were remarkably dependent on the nature of combination in formulations during the time of assay. Formulations of Pluronic lecithin organogel containing only gabapentin or gabapentin with another drug were physically stable for 14 days. However, 3- and 4-combined drug formulations demonstrated an altered pseudoplastic behavior and instability during the study period.