Colorimetric Determination of Propofol in Bulk form, Dosage Form and Biological Fluids

Propofol is coupled with 2, 6-dichloroquinone-4-chlorimide (DCQ) in a reaction buffered at pH 9.6 to give a colored product having an analytically useful maximum at 635 nm. The factors affecting the color generation were optimized and incorporated in the procedure. The reacted propofol has a molar absorptivity of 3.9 × 10 −4 L mol −1 cm −1 , and Beer's law is obeyed for concentrations 1-5 μg ml −1 with detection limit 0.25 μg ml −1 . The method was found applicable to biological fluids (plasma and urine) spiked with propofol at concentration levels 1-5 μg ml −1 for plasma and 1-5 μg 0.5 ml −1 urine (less sensitivity is obtained with urine volumes above 0.5 ml) with detection limits 0.28 μg ml −1 for plasma and 0.4 μg 0.5 ml −1 urine. The average recovery for the commercial preparation (1% w/v propofol emulsion intravenous injection for infusion) was 99.54% with an RSD of 1.05%. The method was validated by an adopted HPLC method. The results obtained by the HPLC method for the commercial preparation were statistically compared with the proposed method and evaluated at the 95% confidence limits.