Development and Validation of a High-performance Liquid Chromatography Method with Ultraviolet Detection for the Determination of Flunitrazepam in Human Plasma

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Bela Kiss ◽  
Daniela-Saveta Popa ◽  
Marius Bojita ◽  
Felicia Loghin

A high performance liquid chromatography (HPLC) method was developed and validated for determination of flunitrazepam in human plasma. After a simple liquid-liquid extraction, the analyses were carried out on a ODS column with diode array detection at 330nm. The mobile phase consisted in a mixture of potassium dihydrogene phosphate/acetonitrile (40/60, v/v). The method showed good linearity, accuracy and precision. Advantages of this validated assay include a simple plasma extraction method, short analysis time and good sensitivity (LLOQ = 5ng/mL). The stability data indicated a potential instability of flunitrazepam in plasma at room temperature.

2019 ◽  
Vol 57 (8) ◽  
pp. 724-729 ◽  
Author(s):  
Mahmoud M Sebaiy ◽  
Wafaa S Hassan ◽  
Mostafa E Elhennawy

Abstract A high performance liquid chromatography method had been developed and validated for rapid simultaneous separation and determination of three anti-helicobacter drugs, oxytetracycline (OXY), tinidazole (TIN) and esomeprazole (ESM) in human plasma within 6 minutes. Drugs extraction method from plasma was based on protein precipitation technique. Separation was carried out on a Equisil BDS C18 column (5 μm, 150 × 4.60 mm) using a mobile phase of acetonitrile: 0.025 M KH2PO4 (25: 75, v/v) adjusted to pH 3.50 with ortho-phosphoric acid at ambient temperature. The flow rate was 1 mL/min and maximum absorption was measured using Diode Array (DAD) detector at 285 nm. The retention times of OXY, TIN and ESM were recorded to be 2.68, 3.52 and 5.17 minutes, respectively, indicating a shorter analysis time. Limits of detection were also reported to be 0.10, 0.07 and 0.04 μg/mL for OXY, TIN and ESM, respectively, showing a high degree of the method sensitivity. The method was then validated according to FDA guidelines for the determination of the drugs clinically in human plasma specially regarding pharmacokinetic and bioequivalence studies.


2020 ◽  
Vol 20 (13) ◽  
pp. 1053-1059
Author(s):  
Mahmoud M. Sebaiy ◽  
Noha I. Ziedan

Background: Allergic diseases are considered as the major burden on public health with increased prevalence globally. Histamine H1-receptor antagonists are the foremost commonly used drugs in the treatment of allergic disorders. The target drug in this study, loratadine, belongs to this class of drugs and its biometabolite desloratadine which is also a non-sedating H1 receptor antagonist with anti-histaminic activity being 2.5 to 4 times greater than loratadine. This study aimed to develop and validate a novel isocratic Reversed-phase High-Performance Liquid Chromatography (RP-HPLC) method for rapid and simultaneous separation and determination of loratadine and its metabolite, desloratadine in human plasma. Methods: The drug extraction method from plasma was based on protein precipitation technique. The separation was carried out on a Thermo Scientific BDS Hypersil C18 column (5μm, 250 x 4.60 mm) in a mobile phase of MeOH: 0.025M KH2PO4 adjusted to pH 3.50 using orthophosphoric acid (85: 15, v/v) at an ambient temperature. The flow rate was maintained at 1 mL/min and maximum absorption was measured using the PDA detector at 248 nm. Results: The retention times of loratadine and desloratadine in plasma samples were recorded to be 4.10 and 5.08 minutes, respectively, indicating a short analysis time. Limits of detection were found to be 1.80 and 1.97 ng/mL for loratadine and desloratadine, respectively, showing a high degree of sensitivity of the method. The method was then validated according to FDA guidelines for the determination of the two analytes in human plasma. Conclusion: The results obtained indicate that the proposed method is rapid, sensitive in the nanogram range, accurate, selective, robust and reproducible compared to other reported methods.


2020 ◽  
Vol 10 (9) ◽  
pp. 1581-1587
Author(s):  
Lei Shi ◽  
Chunqi Liang ◽  
Yongzhi Qi

A sulphurous acid thiolysis-HPLC method for the determination of procyanidins in pine bark products was established. The concentration of sulphurous acid is 1.2%, the concentration of benzyl mercaptan is 2%, the reaction temperature is 90 °C, and the reaction time is 60 minutes. Under these conditions, the preservative rates of catechin, epicatechin, epicatechin gallate and their benzyl sulfide derivatives were 89.7%, 86.2%, 95.4%, 63.1%, 64.6% and 73.5%, respectively. According to this study, the calculation method for the procyanidin content determination by the thiolysis-HPLC method was corrected.


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