Quantitation of curcuminoid contents, dissolution profile, and volatile oil content of turmeric capsules produced at some secondary government hospitals

The aim of this work was to validate the simple and rapid isocratic reversed phase-high performance liquid chromatography using a C-18 column for the determination of curcuminoid contents, dissolution profile, and volatile oil content of turmeric capsules produced at three secondary government hospitals. The validated reversed phase-high performance liquid chromatography method for three curcuminoids (bisdemethoxycurcumin, demethoxycurcumin, and curcumin) had a good linearity (R(2) > 0.9990), accuracy (% recovery was 99.96–101.14%, 97.42–102.23%, and 98.01–99.12% for bisdemethoxycurcumin, demethoxycurcumin, and curcumin, respectively), precision (% relative standard deviation < 2% and < 5% for intraday and interday precision, respectively), including limit of detection, limit of quantitation, and system suitability. We found that turmeric capsules had a higher content of curcumin than bisdemethoxycurcumin and demethoxycurcumin. The total curcuminoid contents of all lots ranged from 12.02%w/w to 14.36%w/w. Dissolution profiles of curcuminoids were fitted with Higuchi model. Moreover, volatile oil content, determined using the hydrodistillation method, ranged from 7.00%v/w to 8.00%v/w. In conclusion, all nine lots of turmeric capsules from three secondary government hospitals met the standard criteria of the Thai Herbal Pharmacopoeia in the topic of curcuminoid contents, dissolution, and volatile oil content.