The determination of ofloxacin in human skin tissue by high-performance liquid chromatography and correlation between skin tissue concentration and serum level of ofloxacin.

A simple high-performance liquid chromatographic (HPLC) assay was developed for the measurement of ofloxacin in skin tissue, and the correlation between serum levels and skin tissue levels of ofloxacin was determined. The homogenized skin samples were directly introduced into an HPLC system after filtering through a Molcut II membrane filter to remove proteins. The filtrate was concentration on a pre-column using a phenyl-stationary phase and was then introduced to an analytical column using an ODS-stationary phase by column-switching techniques. Ofloxacin and lomefloxacin as an internal standard were detected by UV absorbance at 300 nm. Determination was possible for ofloxacin over the concentrated range 250-3000 ng (g skin tissue)-1; the limit of detection was 100 ng g-1. The absolute recovery of ofloxacin added to skin tissue homogenate was over 72% with a coefficient of variation of less than 4.1%. This method is applied to determination of skin tissue level of ofloxacin in patients after treatment with ofloxacin. The correlation between serum levels and skin tissue levels of ofloxacin was determined for 30 patients after oral administration of ofloxacin. Good correlation was obtained and the coefficient of correlation was 0.84.