59-05-032 Proceeding

74 Proceedings of the Princess Maha Chakri Sirindhorn Congress Table 2 Stability testing of lorazepam, alprazolam, diazepamandmidazolam in plasma samples Drugs (µg/ml) Freshly sample Freeze -thaw Short term Long term Lorazepam 0.0104 95.83 ±1.59 83.14 ±1.63 95.68 ±0.88 90.02 ±2.10 52.10 94.46 ±0.08 81.06 ±0.02 96.28 ±0.06 90.63 ±0.03 Alprazolam 0.0103 93.99 ±1.67 84.90 ±2.84 91.86 ±1.82 91.24 ±1.56 10.30 96.07 ±0.07 83.69 ±0.06 90.99 ±0.03 89.29 ±0.04 Diazepam 0.0100 98.00 ±2.36 82.99 ±1.41 97.64 ±1.92 94.88 ±1.56 15.10 98.66 ±0.04 82.90 ±2.84 96.68 ±0.02 91.06 ±0.04 Midazolam 0.0412 100.15 ±2.59 80.82 ±1.82 95.334 ±0.59 86.67 ±1.43 1.50 99.68 ±0.09 83.81 ±0.02 93.696 ±0.02 87.86 ±0.09 IV. Conclusions The development and validated method for quantization of lorazepam, alprazolam, diazepamandmidazolam in plasma sample in this study was compatible to recommended criteria of Bioanalytical Method Validation of the US FDA, (2001). The isocratic separation containing 10 mMphosphate buffer, pH5.8, acetonitrile andmethanol (58:20:22) asmobile phase demonstrated a high effective and low cost method since it used a simple one step, whichwas presented acceptable value of extraction. Moreover this analysis method had a greater selectivity and specificity. The LOD and LOQ and linearity range is covering the therapeutic concentrations of 4 BZDs [16]. The 4 BZDs and internal standard were separated within 35 minutes and resolution more than 2.98. Percentage of recovery was greater than 90% and relative standard deviation (% RSD) lower than 2.84 within acceptable value. This analytical method could be applied for the analysis of 4 BZDs which are frequently used in the case of drug-facilitated crime.