Cytochrome P450 3A4 (CYP3A4), the major phase I drug metabolizing enzyme in humans, and the MDR1 gene product P-glycoprotein (P-gp) are present at high concentrations in villus tip enterocytes of the small intestine and share a significant overlap in substrate specificity. A large body of research both in vitro and in vivo has established metabolism by intestinal CYP3A4 as a major determinant of the systemic bioavailability of orally administered drugs. More recently it has been recognized that drug extrusion by intestinal P-gp can both reduce drug absorption and modulate the effects of inhibitors and inducers of CYP3A-mediated metabolism. There is relatively little data regarding the effects of CYP3A and P-gp on peptide drugs; however, studies with the cyclic peptide immunosuppresant cyclosporine as well as peptidomimetics such as the HIV-protease inhibitor saquinavir (Invirase) and a new cysteine protease inhibitor K02 (Morpholine-Urea-Phe-Hphe-Vinyl sulfone; Axys Pharmaceuticals) provide some insight into the impact of these systems on the oral absorption of peptides.
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http://dx.doi.org/10.1021/js980082d | DOI Listing |
J Tissue Eng
January 2025
Engineering Research Center of Pulmonary and Critical Care Medicine Technology and Device (Ministry of Education), Tianjin Institutes of Health Science, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China.
The development of advanced models for assessing liver toxicity and drug responses is crucial for personalized medicine and preclinical drug development. 3D bioprinting technology provides opportunities to create human liver models that are suitable for conducting high-throughput screening for liver toxicity. In this study, we fabricated a humanized liver model using human-induced hepatocytes (hiHeps) derived from human fibroblasts via a rapid and efficient reprogramming process.
View Article and Find Full Text PDFClin Pract Epidemiol Ment Health
December 2024
Laboratory of Panic and Respiration, Instituto de Psiquiatria, Universidade Federal do Rio de Janeiro (UFRJ). Rio de Janeiro, RJ, Brazil.
Background: Many pharmacological treatments are considered effective in the treatment of panic disorder (PD), however, about 20 to 40% of the patients have treatment-resistant PD. Pharmacogenetics could explain why some patients are treatment-resistant.
Objective: Our objective was to gather preliminary data on the clinical usefulness of pharmacogenetic testing in this disorder.
Toxicol Mech Methods
January 2025
Department of Pharmacology, Shri Vishnu College of Pharmacy, Vishnupur, Bhimavaram, Andhra Pradesh, India-534202.
The harmful by-product of paracetamol is known as N-Acetyl-p-benzoquinoneimine, (NAPQI). When paracetamol is given at therapeutic dosages or in excess, it undergoes Phase I metabolism in the liver via Cytochrome P-450 2E1 (CYP2E1), and then it produces NAPQI. Previous studies reported that a non-ionic surfactant known as Brij 35 (Polyoxyethylene lauryl ether) has been shown to be an effective inhibitor of CYP2E1 and P-glycoprotein (P-gp).
View Article and Find Full Text PDFCurr Drug Metab
January 2025
College of Pharmacy, Dalian Medical University, Liaoning Dalian, China.
Background: Human cytochrome P450 1B1 (CYP1B1) is an extrahepatic enzyme that is overexpressed in many tumors and is associated with tumor development and acquired resistance. Few studies have reported that anthraquinone compounds have inhibitory activity against the CYP1B1 enzyme. Cassiae semen (Leguminosae) is a well-known traditional Chinese medicine containing more than 70 compounds.
View Article and Find Full Text PDFJ Clin Endocrinol Metab
January 2025
Division of Pediatric Endocrinology, Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX 75390, USA.
Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease that manifests clinically in varying forms depending on the degree of enzyme deficiency. CAH is most commonly caused by 21-hydroxylase deficiency (21OHD) due to mutations in the CYP21A2 gene. Whereas there is a spectrum of disease severity, 21OHD is generally categorized into 3 forms.
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