Rapid detection of corticosteroids in herbal medicines sold in Tanzania

Abstract

Adulteration of herbal medicines with corticosteroid drugs poses risk to health of consumers. The broad-spectrum drugs including dexamethasone and prednisolone which were mostly used during Corona virus disease (COVID-19) era have been reported as common adulterants in herbal medicines. The increase of herbal medicine market in Tanzania calls for optimization of simple and rapid method for detection of corticosteroids adulterants in these drugs. Four hundred and twenty-three archived herbal samples were analysed using optimized Thin Layer Chromatographic (TLC) method. Retention factor value and visualization reagent were used for confirmation of adulterants in herbal medicines. Results report that 28.13% of all analysed herbal samples were adulterated while 71.87% of all samples no corticosteroid adulterant found. Among herbal samples found with corticosteroids, 87.39% had one adulterant while 12.61% contained at least two adulterants. The optimal concentration for visualization reagent is using equal volume of 3 mol/dm3 sodium hydroxide and 0.625 mg/mL of tetrazolium blue chloride while the limit of detection was 0.26 mg/ml for prednisolone and 2.62 mg/ml for dexamethasone. A rapid method for the detection of dexamethasone and prednisolone in herbal medicines was developed and optimized to determine the presence of these corticosteroids in herbal samples. The method is recommended for use before confirmatory test such as liquid chromatography connected to tandem mass spectrometry (LC-MS/MS).