Optimization of Supercritical Fluid Extraction Parameters for Vitamins D2, D3, and K1 from Pharmaceutical Preparations

Importance of the Topic

Vitamin D2, D3, and K1 play critical roles in human health and are widely incorporated into pharmaceutical supplements. Accurate quantification of these lipophilic vitamins within complex formulations is essential for quality control and compliance with labeling regulations. Supercritical fluid extraction (SFE), using carbon dioxide and modifiers, offers an efficient, solvent-efficient approach to isolate these compounds while minimizing thermal and solvent-related degradation.

Objectives and Study Overview

This study aimed to optimize SFE parameters for the extraction of vitamins D2, D3, and K1 from three commercial pharmaceutical preparations. The research focused on evaluating modifier composition, pressure, temperature, flow rate, and static/dynamic extraction time to maximize recovery yields prior to HPLC-PDA analysis.

Methodology and Instrumentation

The experimental workflow combined static and dynamic SFE using carbon dioxide with alcohol-based modifiers. Ground supplement powders were extracted under various conditions of pressure (150–350 bar), temperature (30–50 °C), flow rate (1–2 mL/min), and modifier composition (pure MeOH or EtOH versus water-rich mixtures). Extracts were directly diluted and analyzed by high-pressure liquid chromatography with photodiode array detection (HPLC-PDA).

Instrumentation Used

• SFE System: Shimadzu Nexera UC with CO2 pump, modifier and make-up pumps, static/dynamic SFE-30A module, backpressure regulator, and fraction collector.
• HPLC-PDA System: Shimadzu Prominence LC-20A with degasser, dual-plunger pumps, autosampler (SIL-20AC), column oven (CTO-20A), and SPD-M30A diode array detector.
• Chromatographic Conditions: Shim-pack GIS C18-P column (25 cm×4.6 mm, 5 µm), isocratic MeOH mobile phase, 1.5 mL/min, 40 °C, detection at 265 nm.

Main Results and Discussion

• Sample S1 (capsule, D3 and K1): Initial methods yielded 0% D3 recovery. Addition of a water-rich modifier (MeOH:H2O or EtOH:H2O, 90:9:1), higher pressure (350 bar), temperature (50 °C), and flow (2 mL/min) increased D3 recovery to 98–99% and K1 to above 90%.
• Sample S2 (tablet, D2): Pure alcohol modifiers led to <15% recovery. Incorporating 10% water enhanced D2 extraction, achieving 77% recovery at 250 bar, 50 °C, and 2 mL/min.
• Sample S3 (tablet, D3): Optimal conditions (250 bar, 50 °C, 1 mL/min, water-rich modifier) yielded 87% D3 recovery, with similar performance using ethanol-based mixtures.

This highlights that extraction efficiency strongly depends on the formulation matrix and requires tailored SFE conditions.

Benefits and Practical Applications

• High recovery rates using environmentally friendly modifiers reduce solvent waste and processing time.
• Optimized SFE enables robust quality control of fat-soluble vitamins in pharmaceutical and nutraceutical products.
• The approach can be integrated into routine analytical workflows for regulatory compliance and batch release testing.

Future Trends and Potential Applications

Future developments may include the coupling of SFE directly with HPLC-MS for enhanced sensitivity, exploration of novel green co-solvents, integration into continuous manufacturing, and application to other lipophilic bioactive compounds. Advances in matrix-specific extraction modeling and real-time monitoring could further streamline analytical protocols.

Conclusion

Optimizing SFE parameters, particularly the use of water-enriched modifiers, pressure, and temperature, significantly improves the extraction of vitamins D2, D3, and K1 from diverse pharmaceutical matrices. The method offers a sustainable, high-throughput alternative for reliable quantification in quality assurance laboratories.

References

1. Melfi MT et al. Simultaneous determination of water- and fat-soluble vitamins in tomato samples and pharmaceuticals by RP-LC-UV. J. Food Comp Analysis, 2018.
2. Abu Saaleek A et al. Salting-out assisted extraction of vitamin D3 coupled with RP-LC for pharmaceutical analysis. Microchemical Journal, 2023.