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Optimization of Extraction Conditions and HPTLC - UV Method for Determination of Quinine in Different Extracts of Cinchona species Bark

Himanshu Misra, Bhupendra K. Mehta and Dharam C. Jain

1 Green Technology Department, Ipca Laboratories Limited, Ratlam – 457 002, Madhya Pradesh , India .

2 School of Studies in Chemistry & Biochemistry, Vikram University , Ujjain – 456 010, Madhya Pradesh , India .

Abstract: A simple, precise and accurate high-performance thin-layer chromatographic method has been established for quantitative determination of quinine. Conditions were also optimized for best possible extraction of quinine via varying concentrations of diethyl amine in different solvents (n-hexane, chloroform, ethyl acetate and methanol) for maximum recovery of quinine. Methanol modified with 20 % DEA found to be best for highest possible recovery of target analyte quinine. Chromatographic separation of quinine was performed on silica gel 60 F 254 HPTLC plates with ethyl acetate : diethyl amine in the proportion 88 : 12 (v/v), as mobile phase. The determination was carried out using the densitometric absorbance mode at 236 nm. Quinine response was found to be linear over the range 4–24 μg spot −1. The HPTLC method was evaluated in terms of specificity, precision, reproducibility, LOD – LOQ and robustness. Beside these parameters, number of theoretical plates and flow constant were also included as a part of validation.

Keywords: Cinchona spp. ; Rubiaceae ; bark ; quinine ; HPTLC determination.