Alpha-Lipoic Acid and Cyanocobalamin Co-Loaded Nanoemulsions: Development, Characterization, and Evaluation of Stability

Purpose This study aimed to prepare a suitable formulation and perform in vitro characterization studies for oral use by exploiting the synergistic effect of alpha-lipoic acid (ALA) and cyanocobalamin (Vit B-12) for the treatment and prophylaxis of various diseases such as diabetic neuropathy, peripheral neuropathy, and neurological disorders. Methods Nanoemulsions were prepared using different oils (castor oil (CO) and sunflower oil (SO)) and agitation methods (magnetic stirring and ultraturrax). The effects of experimental parameters on droplet size, polydispersity index, zeta potential, encapsulation efficiency, and release rate properties of nanoemulsions were investigated. The physical and chemical stability of formulations at various temperatures (30 degrees C, 50 degrees C, and 70 degrees C) and pH values (1.2, 4.5, 6.8, and 7.4) were also evaluated. Results An HPLC method, enabling the simultaneous determination of ALA and Vit B-12, has been successfully developed with a correlation coefficient value of 0.9999 for both analytes. The best results were obtained by CO and magnetic stirring in terms of colloidal properties for either plain (P-C-NE) or ALA-Vit B-12 co-loaded (C-NE) nanoemulsions. The C-NE had better stability under different conditions, higher encapsulation efficiency (ALA-93.80%, Vit B-12-110.65%), and release percentage. Conclusion As a result, this study demonstrated that nanoemulsions containing ALA and Vit B-12 can be successfully produced and are stable at different temperatures and pH values.