Current developments of bioanalytical sample preparation techniques in pharmaceuticals

Sample preparation is considered as the bottleneck step in bioanalysis because each biological matrix has its own unique challenges and complexity.Competent sample preparation to extract the desired analytes and remove redundant components is a crucial step in each bioanalytical approach.The matrix effect is a key hurdle in bioanalytical sample preparation,which has gained extensive consideration.Novel sample preparation techniques have advantages over classical techniques in terms of accuracy,automation,ease of sample preparation,storage,and shipment and have become increasingly popular over the past decade.Our objective is to provide a broad outline of current developments in various bioanalytical sample preparation techniques in chromatographic and spectroscopic examinations.In addition,how these techniques have gained considerable attention over the past decade in bioanalytical research is mentioned with preferred examples.Modern trends in bioanalytical sample preparation techniques,including sorbent-based microextraction techniques,are primarily emphasized.

Three new shRNA expression vectors targeting the CYP3A4 coding sequence to inhibit its expression

RNA interference(RNAi)is useful for selective gene silencing.Cytochrome P4503A4(CYP3A4),which metabolizes approximately 50% of drugs in clinical use,plays an important role in drug metabolism.In this study,we aimed to develop a short hairpin RNA(shRNA)to modulate CYP3A4 expression.Three new shRNAs(S1,S2 and S3)were designed to target the coding sequence(CDS)of CYP3A4,cloned into a shRNA expression vector,and tested in different cells.The mixture of three shRNAs produced optimal reduction(55%)in CYP3A4 CDS-luciferase activity in both CHL and HEK293 cells.Endogenous CYP3A4 expression in HepG2 cells was decreased about 50%at both mRNA and protein level after transfection of the mixture of three shRNAs.In contrast,CYP3A5 gene expression was not altered by the shRNAs,supporting the selectivity of CYP3A4 shRNAs.In addition,HepG2 cells transfected with CYP3A4 shRNAs were less sensitive to Ginkgolic acids,whose toxic metabolites are produced by CYP3A4.These results demonstrate that vector-based shRNAs could modulate CYP3A4 expression in cells through their actions on CYP3A4 CDS,and CYP3A4 shRNAs may be utilized to define the role of CYP3A4 in drug metabolism and toxicity.