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Updated: Jan 9, 2026
A Semi-Automated and Reproducible Biological-Based Method to Quantify Calcium Deposition In Vitro
Published on: June 2, 2022
Development and Validation of a Green Analytical Method for Calcium Determination in Pharmaceuticals Using Curcumin:
Nim Bahadur Dangi1, Hemraj Sharma2, Hari Prasad Sapkota3
1Pharmaceutical Sciences Program, School of Health and Allied Sciences, Pokhara University, Lekhnath, Nepal.
Background:
Reliable determination of calcium in pharmaceuticals is crucial for quality control, yet conventional methods often rely on synthetic chelating agents such as EDTA, which raise environmental and safety concerns. Curcumin, the principal polyphenolic compound in Curcuma longa (turmeric), exhibits strong metal-chelating properties through its β-diketone structure. This study explores the use of curcumin as a natural and sustainable chelating agent for the spectrophotometric determination of calcium in pharmaceutical formulations.
Method:
Curcumin was extracted from turmeric rhizomes collected from different altitudes in Nepal using ethanol and was allowed to form a stable color complex with various calcium-containing drugs, such as calcium gluconate, calcium lactate, and calcium docusate. The method was optimized by adjusting reagent volume, pH, and buffer volume. Validation was carried out according to ICH guidelines, evaluating linearity, precision, accuracy, and robustness. The environmental impact was assessed using Green Analytical Procedure Index, Analytical Eco-Scale, and AGREES tools. The Click Analytical Chemistry Index was used to analyze overall sustainability, while the Carbon Footprint Reduction Index was applied to evaluate the prime environmental impact of the already developed analytical laboratory procedures.
Results:
The highest curcumin yield was from the Kaski region. The optimized method produced a stable yellow-orange complex with maximum absorbance at 430 nm. It demonstrated high precision (%RSD < 2%), accuracy (recovery: 101.63% and 102.01%), and robustness with a stable reaction lasting up to 4 h. The environmental assessment confirmed its sustainability and eco-friendliness, with a very good score reflecting minimal solvent use and no hazardous waste.
Conclusions:
This study successfully developed a green, cost-effective, and reliable method for calcium analysis in pharmaceutical products using curcumin as a natural reagent. Its simplicity and environmental sustainability make it a promising alternative to conventional techniques for calcium analysis.
