Study on the inclusion interactions of berberine hydrochloride and cucurbit[7] by spectrofluorimetry

The inclusion interaction between berberine hydrochloride (BRH) and cucurbit[7] (CB[7]) has been studied by spectrofluorimetry. The result showed that CB[7] interaction with BRH to form a stable inclusion complex with an association constant of 9.57 × 104 L/mol and the fluorescence intensity of the complex was enhanced in 17 times higher than that of the studied drug itself. Based on the significant enhancement of fluorescence intensity of BRH in inclusion complex, a spetrofluorimetric method with high sensitivity and selectivity was developed for the determination of BRH in aqueous solution. The linear range of the method was 3.2–2 × 103 ng/mL with a detection limit of 1.1 ng/mL. The proposed procedure could be applied successfully to determination of BRH remained in pharmaceutical dosage forms, spiked human plasma and urine with satisfactory results.