Evaluation of Herbonanoceutical Formulations of Tamoenju (Hibiscus surattensis L.) Leaf Extract

Tamoenju (Hibiscus surattensis L.) is a natural ingredient with antioxidant activity and potential applications in complementary therapy for diabetes mellitus and associated complications. Herbonanoceutical preparations in the form of self-nano-emulsifying drug delivery system (SNEDDS) are well-known for increasing solubility and optimizing pharmacological activity. Therefore, this study is aimed at evaluating the herbonanoceutical formulations of tamoenju leaf extract for its physicochemical characteristics, and stability. Tamoenju leaves were extracted by maceration in 96% ethanol. The extract was subjected to solubility test in oil, surfactant, and cosurfactant. Herbonanoceutical formulations of tamoenju leaf extract (SNASET) were prepared using eight different formulae (F1 – F8) containing different concentrations of oils, surfactants, and cosurfactants. Oil:surfactant+cosurfactant ratio 1:9 was used in all the formulae. The formulations were analysed for their physicochemical characteristics and stability. The parameters evaluated include; transmittance, dispersibility, particle size, zeta potential, polydispersity index, pH, viscosity, robustness, and thermodynamic stability. The results showed that three of the formulae; F1 (tween 80:propylene glycol, 2:1), F2 (tween 80:propylene glycol, 3:1), and F7 (Cremophor RH:PEG 400, 1:1) produced the most optimal formulations based on the physicochemical characteristics and stability. F1, F2, and F7 had the following values for particle size (32.22 nm, 8.49 nm, 19.33 nm), transmittance (99.95-99.98%), polydispersibility index (0.1550, 0.1051, 0.1630), pH (5.11, 7.97, 5.46), viscosity (372 cP, 440 cP, 1116 cP), respectively. The three formulations met grade A criteria for dispersibility, and were thermodynamically stable. The study has successfully formulated tamoenju leaves extract into herbonanoceutical formulations that may find potential application as natural health products.