00000nam a22000004a 4500 UP-1685675941131387418 Buklod 20240104125015.0 m |o d | ta 240104s2023 xx r |||| u| d PHARM rda eng LG 993.5 2023 P5 A43 Aldeguer, Thea Chariz B. author Simultaneous determination and stability profiling of diphenhydramine and diazepam in human urine using a validated RP-HPLC-QTOF-MS method Thea Chariz B. Aldeguer, Rosalina A. Areola, Vincent Morlie R. Tolentino ; adviser, Joanna V. Toralba,. Manila Department of Pharmacy, College of Pharmacy, University of the Philippines Manila 2023 xv, 158 leaves 23 cm. text rdacontent unmediated rdamedia volume rdacarrier Thesis (Bachelor of Science in Pharmaceutical Sciences)--University of the Philippines Manila, June 2023 Available to the public. Determination of the stability of drug analytes in biological samples and the development of reliable analytical methods for their detection are crucial for accurate analyses. For this research, diphenhydramine (DPH) and diazepam (DZP) stability profiles were investigated following the revalidation of a developed reversed-phase high performance liquid chromatography coupled with high resolution quadrupole time-of-flight mass spectrometry (RP-HPLC-QTOF-MS) method for their simultaneous determination. The method was specific for both drugs and showed acceptable degrees of linearity and accuracy. Intra-day and inter-day precision were satisfactory. The determined range was 15.625-250 ng/mL for DPH and 15.625-200 ng/mL for DZP. No significant matrix effect and carryover effect were obseved for both drugs. Autosampler stability under 4°C showed both drugs were stable for up to 72 hours. For benchtop stability studies, the drugs were only stable up to 1 hour at 20 to 26°C. Freeze-thaw stability studies revealed that both drugs were only stable up to one freeze-thaw cycle. Further qualitative analysis exhibited new fragments and peaks more polar than their parent compounds in both unstable samples of DPH and DZP. In conclusion, the study provides a validated RP-HPLC-QTOF-MS method that can simultaneously quantify DPH and DZP in human urine samples. Findings of the study significantly contribute to a better understanding of the stability of DPH and DZP in human urine. Moreover, it emphasizes the importance of immediate processing of samples and minimizing their exposure to high temperatures to ultimately preserve analyte stability and produce accurate test results and interpretations. Diphenhydramine. Analysis. Diazepam Analysis. High performance liquid chromatography. Drug Stability High-performance liquid chromatography. Areola, Rosalina A. author. Tolentino, Vincent Morlie R. author. Toralba, Joanna V. adviser. FI UP UPMNL PHARM LG 993.5 2023 A43 Thesis