Simultaneous determination of some pharmaceuticals in hospital effluents Using HPLC with UV and fluorescence detectors

The development and validation of an HPLC/UV/Fluorescence [FL] detection method is described, which enables the measurement of the most consumed pharmaceuticals [methotrexate, caffeine, diclofenac, glimepiride and ibuprofen] in Jordanian hospital effluents. Separation was done on a RP-C8 column at a flow rate of 1 ml/min using 1:1 H2O/acetonitrile with 0.1% trifluoroacetic acid. The samples [200 ml each] were extracted and cleaned-up on C18 cartridges. Correlation coefficients of the pharmaceuticals calibration were higher than 0.997 using a UV detector and 0.996 using a fluorescence detector for methotrexate. Recoveries were ranged from 87% to 108.3%

Intravitreal injection of methotrexate in an experimental rabbit model: Determination of pharmacokinetics.

Purpose: To investigate the pharmacokinetics of intravitreally administered methotrexate. Materials and Methods: Twenty-one New Zealand white rabbits were used in the study. The pharmacokinetics of intravitreally injected 800 μg/0.1 ml of methotrexate was investigated. Intravitreal concentration of the drug was measured at seven different times, in six eyes at each occasion, on a total of 42 eyes of 21 rabbits from a period of 30 minutes to 72 hours. Results: The volume of distribution was calculated as 1.33 ml following intravitreal injection of 800 μg methotrexate. Vitreous concentrations of the drug were found to be decreasing related to the specific mathematical equation; drug concentration= 1426.73 e-0.1182(time) and remained over effective dose by 81 hours with a half life of 5.9 hours. Conclusions: These findings evidenced those vitreous levels of methotrexate at various time intervals after 800 μg intravitreal injections which formulated a mathematical equation for calculation of vitreous level of the drug at each hour.