Fluorodensitometric evaluation of gentamicin from plasma and urine by high-performance thin-layer chromatography

High-performance thin-layer chromatographic (HPTLC) analysis of gentamicin by in situ fluorodensitometric evaluation of its 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) derivative is presented. The aminoglycoside components separated on silica gel plates using chloroform-methanol-20% ammonium hydroxide (2.4:2.2:1.5, v/v/v) as the mobile phase were reacted with NB-Cl to yield highly fluorescent derivatives. The calibration curves of gentamicin in water, plasma and urine were linear in the range 40-200 ng. The mean values of intercept, slope and correlation coefficient were 16.82 +/- 0.473, 6.83 +/- 0.015 and 0.9968 +/- 0.0017 for standard curves in water, 17.35 +/- 0.375, 6.85 +/- 0.018 and 0.9941 +/- 0.0012 for standard curves in plasma and 14.35 +/- 0.286, 6.86 +/- 0.002 and 0.9933 +/- 0.0011 for standard curves in urine respectively. The analytical technique was validated for within-day and day-to-day variation. The results indicate that HPTLC, coupled with in situ fluorodensitometry, is a reliable and valuable technique for quantitative analysis of the bulk drug gentamicin and gentamicin from urine and plasma.