Lorazepam analysis using liquid chromatography: improved sensitivity for single-dose pharmacokinetic studies

Determination of lorazepam in plasma from children by high-performance liquid chromatography with UV detection

“…Previously published GC methods for the quantification of LZP and/or conjugated glucuronide metabolites in biological matter (whole blood, plasma/serum urine, or brain) include GC-ECD [19][20][21][22]45]; GC-NPD [19,23]; GC-MS [25,26] and GC-MS/NICI [27,28] or GC-MS/SIM [24,28,30]. Several HPLC methods with UV or diode array detection [31][32][33][34][35][36][37][38][39][40][41]43] and mass spectrometric detection [43] have also been reported. Although GC methods are more sensitive (with lower limits of quantification ≤2 ng/ml [28,43]) than HPLC methods for measuring LZP, they involve lengthy sample clean-up procedures, and require derivatization steps [25,26,30] to increase the volatility of LZP, which is thermally unstable under GC conditions [22,46].…”

“…These methods include gas chromatography (GC) with electroncapture detection (GC-ECD) [19][20][21][22], nitrogen-phosphorus detection (GC-NPD) [19,23], mass spectrometry (GC-MS) [24][25][26], and GC with negative ion chemical ionization MS (GC-MS/NICI) [27,28] or selected ion monitoring MS (GC-MS/SIM) [28][29][30]. High-performance liquid chromatography (HPLC) methods for quantification of LZP in biological fluids have also been reported, with the choice of detectors, including UV (HPLC-UV) or diode array detector (HPLC-DAD) [31][32][33][34][35][36][37][38][39][40][41][42], and mass spectrometric detection [43]. However, most of these methods have various limitations, including time-consuming sample clean-up and/or derivatization steps [25,26,30]; use of large sample volumes (≥1 ml) [19,21,24,26,29,31,36,41]; inadequate sensitivity [31,32]; and use of expensive solid phase extraction cartridges [25,[34][35]…”

“…High-performance liquid chromatography (HPLC) methods for quantification of LZP in biological fluids have also been reported, with the choice of detectors, including UV (HPLC-UV) or diode array detector (HPLC-DAD) [31][32][33][34][35][36][37][38][39][40][41][42], and mass spectrometric detection [43]. However, most of these methods have various limitations, including time-consuming sample clean-up and/or derivatization steps [25,26,30]; use of large sample volumes (≥1 ml) [19,21,24,26,29,31,36,41]; inadequate sensitivity [31,32]; and use of expensive solid phase extraction cartridges [25,[34][35][36]. Though the combination of HPLC with MS offers the advantage of the separation power of HPLC with the sensitivity and specificity of MS for analysis of LZP, the technique is expensive and involves expensive equipment, which is not affordable for most nonresearch laboratories, particularly those in resource-poor countries.…”

Development and Validation of Related Compounds Method for Lorazepam Tablets by Reverse Phase UPLC

“…There were few methods proposed for estimation of LP such as HPLC [6,7], by GC [8], by FTIR [9], by Luminescence [10] and in plasma [11][12][13]. There was one method proposed for Lorazepam related compounds by HPLC [14], this method has higher runtime with higher mobile phase volume and more over it is not a stability indicating.…”

Analysis of lorazepam in rat brain using liquid/liquid and solid‐phase extraction in combination with high performance liquid chromatography

“…A number of liquid chromatography methods have been described for quantitation of lorazepam in plasma (Walmsley a n d Chasseaud, 1981; Egan a n d Abernethy, 1986; G u n a w a n a n d Treirnan, 1988) a n d in liver (Osselton et a/., 1977), b u t n o n e have been reported for determination of lorazepam in nanogram quantities in brain. Gas chromatography methods have been described f o r lorazepam determination in brain tissue (Lanzoni et al, 1979;,Lister et al, 1983).…”