Design And Development of Sublingual Films Incorporating R-HCL And Vitamin D-Loaded NLCS

The present study focused on the formulation and evaluation of a microemulsion-based gel for the enhanced transdermal delivery of Trimebutine maleate hydrochloride (TPHCl). Microemulsions were prepared using an optimized combination of oil, surfactant, and co-surfactant, and were converted into gel using Carbopol® 934P. The optimized microemulsion exhibited a globule size of 52.37 nm, polydispersity index of 0.273, and zeta potential of −19.62 mV, indicating uniformity and stability. The microemulsion gel exhibited pseudoplastic rheological behavior and showed improved Spreadability and viscosity suitable for topical application. In vitro drug release studies revealed that the microemulsion gel released 92.46% of the drug within 8 hours, significantly higher compared to 65.43% from the plain gel. Drug permeation was enhanced by increasing water content and reducing oil and Smix concentrations. FTIR analysis confirmed no drug–excipient interactions. A strong Level A IVIVC was established with a correlation coefficient (R²) of 0.9731, suggesting a reliable predictive relationship between in vitro release and in vivo absorption. Stability studies conducted over 3 months showed that formulations stored at 4 ± 2°C remained more stable than those at 40 ± 2°C/75 ± 5% RH, with only minimal changes in physicochemical parameters like particle size, zeta potential, drug content, and viscosity. In conclusion, the developed microemulsion gel demonstrated excellent physical stability, enhanced drug release, and favorable characteristics, making it a promising vehicle for the transdermal delivery of TPHCl.