| DOI: 10.29090/psa.2020.01.019.0013 | Pharm Sci Asia 2020; 47(1), 86-96 |
Determination of curcumin stability in various gastrointestinal pH by Arrhenius equation using HPLC methodSakonjan Treesinchai,Tasana Pitaksuteepong,Srisagul Sungthongjeen*
- Department of Pharmaceutical Technology,
Faculty of Pharmaceutical Sciences, Naresuan
University, Phitsanulok-Nakornsawan Road,
Phitsanulok 65000, Thailand
Curcumin is the major bioactive constituent of Curcuma longa L. It has been used for many ailments due to its wide spectrum of pharmacological activities, including antioxidant, anti-inflammatory and anti-microbial activities. Besides its low solubility, curcumin instability is a crucial factor affecting its bioavailability and therapeutic efficacy. This study aimed to investigate the effect of temperature and gastrointestinal (GI) pH on curcumin stability. The Arrhenius equation was used to describe the dependence of the curcumin degradation rate constant on temperature and thus predict curcumin shelf life. HPLC method was validated according to ICH guidelines in terms of linearity, LOD, LOQ and precision. The results revealed that the degradation of curcumin followed first-order kinetics. The degradation rate constant of curcumin increased with increasing media pH. Curcumin was more stable in an acidic condition (0.1 N HCl) than in basic conditions (pH 6.8 and pH 7.4 phosphate buffer). This data is useful to design site-targeted drug delivery systems e.g. a gastroretentive DDS to improve the bioavailability and therapeutic efficacy of curcumin. Curcumin degradation accelerated with increasing temperature. The Arrhenius plot exhibited high linearity over the experimental temperature range (37-80 °C) (r2 = 0.9886-0.9994). The predicted degradation rate and shelf life of curcumin in 0.1 N HCl at room temperature (26 + 2 °C) and body temperature (37 °C) obtained from Arrhenius plot were close to those obtained from actual storage. This indicated that Arrhenius equation appeared reliable for shelf life prediction of curcumin at room temperature.
Keyword:
Curcumin; Stability; HPLC; Gastrointestinal pH; Arrhenius equation
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