Evaluation of Factors to Decrease Plasma Concentration of an HIV Protease Inhibitor, Saquinavir in Ethanol-Treated Rats

Abstract

The mid-1990s, HIV protease inhibitors (PIs) have been largely responsible for recent successful results in the treatment of HIV infected patients.1) A combination use of two kinds of reverse transcriptase inhibitors and an HIV protease inhibitor, highly active anti-retrovial therapy (HAART), has been found to be a better therapy than either drug alone in reducing HIV RNA levels and increasing CD4 cell counts. 2)On the other hand, a systematic review about alcohol use and HIV pharmacotherapy by Kresina et al. reported that alcohol consumption by persons infected with HIV is one of important medical management issues, because alcohol consumption is a risk factor for poor medication adherence and can modify liver drug metabolism.3) They also concluded that research areas that are of particular importance for HIV therapy is clarifying the relationships and interactions among alcohol metabolism, HIV drug metabolism and pharmacogenetics.3) However, there had been no study on pharmacokinetic interaction between alcohol and HIV drugs.In our previous reports, 4,5) we recognized that bioavailability of saquinavir (SQV), a potent protease inhibitor, after oral administration was retarded during alcohol consumption both in HIV-infected patients and ethanol-treated rats. The bioavailability of SQV after oral administration alone to rats treated with 15% ethanol solution for 14 d (Day 14 rats) decreased significantly by 51% as compared to non treated (NT) rats. 5) Moreover, total body clearance of SQV after intravenous administration alone to the Day 14 rats increased slightly by 30% as compared to the NT rats. 5) Although most alcoholic beverages contain 0.13 to 0.5% isopentanols that inhibit CYP3A, 6) it has been well known that the greater part of constituent of alcohol beverages, ethanol, induces mainly CYP2E1. Since SQV is one of PIs to be used for HAART therapy and is mainly metabolized via CYP3A4, 7) a room to clarify the reason that ethanol decreases the bioavailability of SQV after oral administration has been remained. In this study, to solve this contradiction that we observed in both clinical practice and ethanol-treated rats, the factors to decrease the bioavailability of SQV during ethanol consumption were evaluated. Where, we focused on the metabolism of SQV via CYP enzymes, the efflux pump; P-glycoprotein (Pgp) and the phase II metabolism in ethanol-treated rats. MATERIALS AND METHODSChemicals SQV was kindly supplied by HoffmanLaRoche Inc. (Nutley, NJ, U.S.A.). Rhodamine 123 (Rho123), ketoconazole (KCZ), cyclosporin A (CsA), Glucose-6-phosphate (G6P), G6P dehydrogenase (G6PDH) and nicotineamide adenosine dinucleotide phosphate (NADP) were obtained from Sigma Chemicals (St. Louis, MO, U.S.A.). Testosterone, 1-naphtol, 4-methylumbelliferone (4-MU) and 1-chloro-2,4-dinitrobenzene (CDNB) were purchased from Nacalai tesque (Kyoto, Japan). Ethanol and all other reagents used were of analytical grade and were used without further purification.Preparation of Ethanol-Treated Rats Male Wistar rats of about 8-9 weeks ol...

Alcohol consumption effect on antiretroviral therapy and HIV-1 pathogenesis: role of cytochrome P450 isozymes

“…Nonetheless, this is an important finding in context with the report that alcohol is known to increase the toxicity and reduce the efficacy of HAART in HIV-1-infected individuals [26,28,86-88]. More specifically, the studies from Flexner and colleagues [88] and Shibata and colleagues [89,90] have shown that alcohol can increase the metabolism and decrease the bioavailability of PI and NNRTI, resulting in decreased efficacy. The presence of multiple PI and/or NNRTI in HAART regimen, in which PI also act as CYP3A4 inhibitors, make alcohol–CYP3A4–PI interactions complex.…”

“…The PIs used in the HAART regimen are expected to interact with alcohol thereby altering their metabolism and antiviral activity, especially in HIV-infected monocytes/macrophages [82,87,89,90]. Thus, HIV-infected individuals who consume alcohol and take PIs are not only affected by decreased drug efficacy, but are also at high risk for deleterious alcohol–PI interactions leading to drug toxicity.…”

In Vivo Effects of Cyclosporin A and Ketoconazole on the Pharmacokinetics of Representative Substrates for P-Glycoprotein and Cytochrome P450 (CYP) 3A in Rats

“…We previously reported that pretreatment of the jejunal loop with 25 mM KCZ or 10 mM CsA did not alter CYP3A or Pgp function in the liver. 23) Yasuda et al reported that KCZ inhibited human CYP3A4 metabolism with a K i of approximately 0.02 to 5 mM (0.01-2.7 mg/ml) and increased Pgp-mediated cellular accumulation of substrates with a K i ranging from 3 to 25 mM (1.5-13.5 mg/ml). 24) In addition, Augustijns et al reported that the Pgp function was inhibited in the presence of CsA ranging from 5 to 10 mM in Caco-2 cells.…”

Relationship between Excretion Clearance of Rhodamine 123 and P-Glycoprotein (Pgp) Expression Induced by Representative Pgp Inducers

“…[2][3][4][5] The fluorescent dye Rho123 has been extensively used as an index of Pgp-mediated transport in rodents and tissue cultured models. 8,[14][15][16][17][18] Several transporters other than expressed in the rat intestinal tract, for example, multridrug resistance associated protein (MRP), organic cation transporters (OCTs) and breast cancer resistance protein (BCRP). Dogan et al 23) studied the relationship between MRP1 expression and transport of 3 fluorescent dyes calcein acetoxymethyl ester (calcein-AM), carboxyfluorecein diacetate (CFDA) and Rho123 in combination with the MRP1 modulators cyclosporine A, probenecid and MK571, using 11 cell lines with different levels of MRP1 expression.…”

“…The total body clearance of Rho123 (CL tot ) was calculated by D/AUC 0-∞ , where D represents the intravenous dose of Rho123. According to our previous reports, 16,18) the excretion clearances of Rho123 from the systemic circulation to the intestinal lumen (CL ex,int ), bile duct (CL ex,bile ) and urine (CL ex,urine ) after intravenous administration was calculated by dividing the average of the total amount of Rho123 excreted into the intestinal lumen, bile duct or urine by the average of AUC last .…”