59-05-032 Proceeding

73 Proceedings of the Princess Maha Chakri Sirindhorn Congress and 15%RSD, respectively. The percentage recoveries of lorazepam, alprazolam, diazepam and midazolam were 90.10-91.12, 91.26-96.116, 92.38-94.72 and 93.33-97.33%, respectively which were in the acceptable range. Intra-day and inter-day precision of 4 BDZs was less than 2.202 as shown in Table 1. Table 1 Validation parameter of lorazepam, alprazolam, diazepam and midazolam in plasma sample Drugs (µg/ml) r 2 % recovery %RSD (n = 6) Intra-day Inter-day Lorazepam 0.0104 2.08 52.10 1.0000 91.12 90.88 90.10 0.06 0.23 1.43 0.08 0.88 1.10 Alprazolam 0.0103 2.56 10.30 0.9990 91.26 94.14 96.12 0.24 0.97 1.08 0.42 1.44 0.94 Diazepam 0.0100 3.03 15.10 0.9994 95.99 94.72 92.38 0.24 1.20 0.54 0.36 1.12 1.59 Midazolam 0.0412 0.51 1.50 0.9991 93.33 96.08 97.33 1.11 1.87 1.74 1.47 0.20 2.20 5) Stability All of spiked plasma sample were stored at room temperature, freeze-thaw and -20°C were analyzed. The results showed that the drugs were detected under these storage conditions throughout the study period. The percentage recoveries of freeze-thaw, short-term stability and long-term stability were in the range of 80.82-84.90, 90.99-97.64 and 86.67-91.06% (Table 2). Even though, no significant difference was shown by these three conditions but the suggestion of the storage condition from the result of this study should be kept at room temperature for at least for 24 hr. and at -20°C for at least 1 week.