Online Dissolution Testing of Supplements

Significance of the Topic

Online dissolution testing plays a crucial role in formulation development, quality control, and bioequivalence studies. Traditional manual sampling and offline HPLC analysis are time-consuming and prone to variability. Automating the entire workflow enhances reproducibility, reduces labor, and accelerates data acquisition.

Objectives and Study Overview

This study demonstrates the use of the Nexera™ FV system for fully automated online dissolution testing of dietary supplements. Two model products—vitamin B2 (riboflavin) tablets and α-lipoic acid capsules—were evaluated to compare conventional and automated workflows.

Methodology and Instrumentation

• Nexera FV with two operation modes:
  • Direct injection mode for immediate HPLC analysis
  • Fraction analysis mode for timed vial collection with optional dilution and internal standard addition
• Dissolution tester: NTR-6600AST (TOYAMA SANGYO Co., Ltd.)
• Software: DT-Solution for analytical condition setup and report generation
• Columns: Shim-pack VP-ODS (150 × 4.6 mm I.D., 5 µm)
• Mobile phases:
  • Riboflavin: 10 mmol/L sodium phosphate buffer (pH 2.6)/acetonitrile = 80:20
  • α-Lipoic acid: 10 mmol/L sodium phosphate buffer (pH 2.6)/acetonitrile = 30:70
• Flow rate: 1.0 mL/min; column temp: 40 °C
• Detection wavelengths: UV 210 nm for riboflavin; UV 333 nm for α-lipoic acid
• Sampling schedules:
  • Riboflavin: 5, 10, 15, 20, 30, 45, 60 min
  • α-Lipoic acid: 5, 10, 20, 30, 50, 90, 180, 240 min (sinker used)

Main Results and Discussion

Automated online testing reduced total analysis time from approximately 10.5 h to 7.5 h, achieving a 30 % time savings. The fraction analysis mode enabled HPLC runs during intervals, optimizing throughput. Reproducibility data for a 10 mg/L riboflavin standard over six injections showed retention time RSD = 0.023 % and peak area RSD = 0.036 %. For α-lipoic acid (100 mg/L standard), retention time RSD = 0.027 % and area RSD = 0.21 %. Dissolution profiles were consistent across vessels, with riboflavin RSD < 3 % at all time points and α-lipoic acid showing higher variability at early sampling that stabilized (< 5 %) at later times.

Benefits and Practical Applications

• Fully automated sequence: dissolution sampling, filtration, dilution/internal standard addition, HPLC analysis, and reporting
• Reduced manual intervention minimizes human error and ensures consistent data quality
• Applicable to supplement testing under pharmaceutical-style protocols
• Flexible mode selection allows adaptation to varying analysis durations and sample preparation needs

Future Trends and Potential Applications

Integration with advanced data analytics and cloud-based reporting platforms can enhance real-time monitoring and decision making. Expanding the approach to multi-component and complex dosage forms, as well as coupling with mass spectrometry detectors, will broaden the method’s applicability in pharmaceutical and nutraceutical research.

Conclusion

The Nexera FV online dissolution testing system delivers significant time savings and high reproducibility for supplement analysis. Automation of the sampling-to-report workflow streamlines quality control efforts and supports robust data generation in both research and production environments.

Reference

Shimadzu Corporation. Ultra High Performance Liquid Chromatograph Nexera FV: Online Dissolution Testing of Supplements. Application News, First Edition, October 2021.