Modified high-performance liquid chromatography technique for detection of vancomycin in human vitreous

To standardize the technique and methodology for estimating the level of vancomycin in human vitreous using a modified high-performance liquid chromatographic method.

Sample preparation involved spiking the vitreous with known quantities of the drug followed by a brief treatment with 30% trichloroacetic acid. Samples were analyzed on a C18 reverse-phase column using a mobile phase of 50 mM phosphate buffer (pH 4.0) and 10% acetonitrile.

Vancomycin was detected at 198 nm. It showed a retention time of 2.2 min in the vitreous. A linear increase in the area under the peak corresponding to the drug was observed with increase in concentration of vancomycin in the vitreous. The method was applied to detect the vancomycin levels in vitreous of 5 patients with exogenous endophthalmitis, 24-48 h after intravitreal injection of vancomycin 1 mg/0.1 ml. The mean concentration of vancomycin in these samples was 120.022 +/- 59.87 microg/ml (43.859-179.09 microg/ml). The present technique allowed a quantification limit of 1 microg/ml.

This technique is suitable to estimate vancomycin levels in human vitreous in a variety of clinical and experimental studies. It has the added advantages of being less expensive, simple and rapid.