Abstract
N-[(3-fluorophenyl)methyl]glycyl-N-{3-[((3-aminophenyl)sulfonyl)- 2-(aminophenyl)amino]-(1S,2S)-2-hydroxy-1-(phenylmethyl)propyl}- 3-methyl-l-valinamide (DPC 681, DPC1) on oral coadministration with ritonavir (RTV) in rats caused a significant increase in systemic exposure to DPC. Following a single oral dose of [14C]DPC with and without RTV pretreatment in rats, and subsequent analysis of whole-body sections, prepared at 1 and 7 or 8 h postdose, using whole-body autoradiography showed an increase in radioactivity in tissues (e.g., brain, and testes) upon coadministration. The distribution of radioactivity in the brain parenchyma and ventricles was different, such that the concentration of radioactivity was greater in cerebrospinal fluid (CSF) than in central nervous system. Thus, the use of CSF concentration of the total radioactivity as a surrogate for brain penetration would result in an overestimation. DPC was determined to be metabolized prominently by rCYP3A4. The increased tissue exposure to DPC in rats could largely be attributed to inhibition of CYP3A1/2 by RTV. DPC was also a good substrate for P-glycoprotein (Pgp), with Kmof 4 μM and Vmax of 13 pmol/min. The Pgp-mediated transport of DPC across Caco-2 cells was readily saturated at ≥10 μM and was inhibited significantly by RTV at 5 to 10 μM. The data above and the reported RTV concentrations suggested that both the Pgp and CYP3A4 inhibition by RTV may play a significant role in enhancing the systemic and tissue exposure to DPC in humans.
Footnotes
-
↵1 Current Address: E. G. Solon, Quest Pharmaceuticals Services, Inc., Delaware Technology Park, 3 Innovation Way, Suite 240, Newark, DE 19711. E-mail:eric.g.solon{at}questpharm.com
- Abbreviations used are::
- HIV
- human immunodeficiency virus
- RTV
- ritonavir
- Pgp
- P-glycoprotein
- CNS
- central nervous system
- QWBA
- quantitative whole-body autoradiography
- DPC
- N-[(3-fluorophenyl)methyl]glycyl-N-{3-[((3-aminophenyl)sulfonyl)-2-(aminophenyl)amino]-(1S,2S)-2-hydroxy-1-(phenylmethyl)propyl}-3-methyl-l-valinamide
- GF120918
- N-(4-[2-(1,2,3,4-tetrahydro-6,7-dimethoxy-2-isoquinolinyl)ethyl]-phenyl)-9,10-dihydro-5-methoxy-9-oxo-4-acridine carboxamide
- HPLC
- high performance liquid chromatography
- IP
- imaging plates
- AUC
- area under the curve
- Received February 21, 2002.
- Accepted July 22, 2002.
- The American Society for Pharmacology and Experimental Therapeutics
DMD articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|