[Determination of methoxsalen in pharmaceutical dosage forms using capillary gas chromatography]

ABSTRACT

An analytical method based on capillary gas chromatography with flame ionization detector [GC-FID] was developed for the direct analysis of Methoxsalen [8-MOP] without derivative reaction, in pure and pharmaceutical dosage forms using Caffeine as internal standard. The 8-MOP and Caffeine [IS] were dissolved in chloroform and chromatographed on a TRB-5 column [30m x 0.25 mm, 0.25 micro m], the temperature of GC oven was as follows initial temperature was 130 [degree sign] C, held for 1 min, increased to 230 [degree sign] C at 20 [degree sign]C/ min, and held for 5 min, and then increased to 250 [degree sign] C at 10 [degree sign] C/ min with a final hold of 2 min.. with nitrogen as carrier gas with flow rate 3 mL/min and FID detection. The injector port temperature was maintained at 280 [degree sign]C, with split ratio 1100, and detector temperature was maintained at 300 [degree sign]C. The method had a chromatographic total run time of 12 min. The retention times were about 6.8 and 5.7 min for 8-MOP and IS, respectively. Results of assay and recovery studies were statistically evaluated for its accuracy and precision. The calibration graph of peak area ratio was rectilinear in the concentration range 10-400 micro g/mL of 8- MOP, with a relative standard deviation not exceeds 2.12%. The limit of detection was 1.5 micro g/mL, and the limit of quantitation was 5 micro g/mL. Correlation coefficient [R[2]] of the regression equation was greater than 0.999. No interference from any components of pharmaceutical dosage forms was observed