Determination of vitamin D3 in pharmaceutical products using salting-out assisted liquid–liquid extraction coupled with reversed phase liquid chromatography

A new method, based on salting-out assisted liquid–liquid extraction (SALLE) coupled with HPLC-UV, has been introduced for the analysis of vitamin D3, cholecalciferol, in different pharmaceutical dosage forms. The developed method has been optimized in terms of chromatographic and extraction parameters. Higher yields were obtained when the SALLE was carried out using 10 mL of acetonitrile and 7.5 g of sodium chloride. The proposed method was validated in terms of selectivity, linearity, accuracy, limit of detection (LOD), limit of quantification (LOQ), robustness, and stability of vitamin D3 in solution. The method was linear with r2 > 0.999 over the range of 100–300 IU.mL−1. Recovery was within 98.80–100.43 % of the nominal vitamin D3 and the relative standard deviation values of the precision study were less than 2.0%. The LOD and LOQ were 3.17 IU.mL−1 and 9.61 IU.mL−1, respectively. Vitamin D3 in different commercial pharmaceutical formulations was analyzed using the developed method and the results were compared to those obtained using the pharmacopeial USP method. Low deviations (0.2–5.9%) between the two methods were obtained, suggesting that the developed method could replace the well-known USP method. The SALLE method proposed in this study offers a simpler and more efficient approach, requires smaller volumes of less toxic organic solvents and significantly reduces the analysis time needed to determine vitamin D3. Consequently, the SALLE method can be a promising alternative to the conventional pharmacopeial method used for vitamin D3 determination in dosage forms as it resolves most of the drawbacks associated with the pharmacopeial method.