FORMULATION AND EVALUATION OF MICROEMULSION-BASED SUBLINGUAL LIQUID CONTAINING VALERIAN ROOT EXTRACT

Objective: The objective of this work was to perform pre-formulation studies, prepare, and optimize microemulsion containing valerian root extract, and evaluate the prepared microemulsion liquid containing valerian root extract. Methods: Valerian roots were subjected to extraction by maceration and percolation methods. The microemulsion formulation was prepared using different concentrations of peanut oil as an oil phase, Tween 20 as a surfactant, and span 80 as a cosurfactant. Pseudoternary phase diagrams were constructed to identify the microemulsion region, and a suitable composition was identified to formulate the microemulsion. The microemulsion was evaluated for viscosity, pH, staining test, globule size, zeta potential, and transmission electron microscopy. Results: The extractive value of valerian root in 70% ethanol was the maximum (27.56±1.95% w/w). Based on the thin-layer chromatography experiment, the reported Rf value for valerenic acid is 0.48. Peanut oil showed the highest solubilization capacity for the drug, i.e., 7.00±0.02 mg/mL. The optimized F4 formulation showed viscosity 110±7.9cP, pH 6.22±2.00, globule size 96.78±10.9, and zeta potential +67.5±1.9. The staining test for the optimized formulation (F4) indicated that the emulsion is an zo/w type of microemulsion. Conclusion: This novel delivery of the drug in the oral cavity may ensure the quick and full release of the drug without interfering with the food, pH, enzymatic degradation, and gastric motility. This formulation containing herbal drug may offer an alternative natural solution for the treatment of insomnia.