Formulation and characterization of bitter melon (Momordica charantia Linn.) fruit fraction loaded solid lipid nanoparticles

Background: The main active compound of bitter melon (Momordica charantia Linn.) fruit is charantin, which is believed to have important role on antihyperglycemic effect. However, charantin compound has a large molecular weight and is easily hydrolysed when given orally. Therefore, a colloidal drug delivery system, such as solid lipid nanoparticles (SLN), is required to provide a suitable and effective delivery of charantin, which is contained in a bitter melon fraction (BMF). Objective: This study aimed to prepare and evaluate SLN containing BMF with an appropriate characteristic for transdermal delivery. Methods: Bitter melon fruits were extracted with ionic liquid of [BMIM]BF₄ using ultrasound-assisted extraction (UAE) and fractionated with dichloromethane. Four formulas of BMF loaded SLN were prepared with various ratio of BMF to surfactant and various ratio of lipids using high-shear homogenization followed by ultrasonication method. The obtained SLN were characterized, including morphology, particle size distribution, zeta potential, and entrapment efficiency. Furthermore, the stability study of BMF-loaded SLN was also conducted. Results: The result showed that BMF was a dry powder and brownish fraction with a specific smell. The BMF loaded SLN showed a spherical shape with the SLN F1 formula as a selected formula. The SLN F1 showed a particle size (Z-average) of 98.3±1.98 nm, polydispersity index of 0.26±0.01, zeta potential of -39.53±0.15 mV, and entrapment efficiency of 82.96±1.42 %. According to the stability study, it revealed that the BMF loaded SLN F1 had an acceptable stability, which the charantin content in the SLN was 96.52% after 3 months storage at 25°C ± 2°C. Conclusion: The BMF loaded SLN F1 with 1:12 ratio of BMF to surfactant and 1:2 ratio of capric caprylic triglyceride to glyceryl monostearate was selected as the best formula with the appropriate characteristics for transdermal delivery.