tipranavir and amprenavir

Protease inhibitors (PIs) are potent competitive inhibitors of the human immunodeficiency virus (HIV) widely used in the treatment of the acquired immune deficiency syndrome (AIDS) and prescribed in combination with other antiretroviral drugs. So far ten PIs were approved by the United States Food and Drug Administration (FDA) for the treatment of HIV infection. In this mini review, quality control methods of each PI are discussed on the basis of analytical techniques published in the literature. Special attention is given to summarize the LC methods described for the analysis of the selected PIs in both drug substances and products with the available literature till date.

Topics: Anti-HIV Agents; Atazanavir Sulfate; Carbamates; Chromatography, Liquid; Darunavir; Drug Contamination; Furans; HIV Protease Inhibitors; Indinavir; Lopinavir; Nelfinavir; Oligopeptides; Organophosphates; Pyridines; Pyrimidinones; Pyrones; Quality Control; Ritonavir; Saquinavir; Sulfonamides

This review deals with clinical applications of compounds that inhibit the action of the protease encoded within the genome of human immunodeficiency virus (HIV). The HIV-protease is essential for viral maturation and represents an important therapeutic target in the fight against AIDS. Following a brief overview of the enzyme structure and function, the article focuses on a number of peptide and non-peptide based HIV-protease inhibitors that are in current clinical use. These drugs are discussed both with respect to their efficacy in treatment of AIDS, and to problems related to insurgence of viral resistance and side effects seen to date in patient populations.

Topics: Acquired Immunodeficiency Syndrome; Anti-HIV Agents; Binding Sites; Carbamates; Clinical Trials as Topic; Computer-Aided Design; Crystallography, X-Ray; Drug Design; Drug Resistance, Microbial; Drug Therapy, Combination; Furans; HIV Protease; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Nelfinavir; Oligopeptides; Pyridines; Pyrones; Randomized Controlled Trials as Topic; Ritonavir; Saquinavir; Sulfonamides

Topics: Carbamates; Drug Resistance; Furans; HIV Protease; HIV Protease Inhibitors; Indinavir; Nelfinavir; Pyridines; Pyrones; Ritonavir; Saquinavir; Structure-Activity Relationship; Sulfonamides

The effect of HIV type-1 (HIV-1) subtype on in vitro susceptibility and virological response to darunavir (DRV) and lopinavir (LPV) was studied using a broad panel of primary isolates, and in recombinant clinical isolates from treatment-naive, HIV-1-infected patients in the Phase III trial, AntiRetroviral Therapy with TMC114 ExaMined In naive Subjects (ARTEMIS).. Patients received DRV/ritonavir (DRV/r) 800/100 mg once daily (n=343) or LPV/ritonavir (LPV/r) 800/200 mg total daily dose (n=346), plus a fixed daily dose of emtricitabine and tenofovir disoproxil fumarate.. DRV demonstrated high antiviral activity against a broad panel of HIV-1 major group (M) and outlier group (O) primary isolates in peripheral blood mononuclear cells, with a median 50% effective concentration (EC(50)) of 0.52 nM. Most (61%) patients in ARTEMIS harboured HIV-1 subtype B; other prevalent subtypes were C (13%) and CRF01_AE (17%); 9% harboured other subtypes. Median EC(50) values (interquartile range) for DRV were 1.79 nM (1.3-2.6) for subtype B, 1.12 nM (0.8-1.4) for C and 1.27 nM (1.0-1.7) for CRF01_AE. Virological response to DRV/r (HIV-1 RNA<50 copies/ml [intent-to-treat, time-to-loss of virological response algorithm]) was 81%, 87% and 85% for patients with subtype B, C and CRF01_AE infections, respectively. Similar results were observed in the LPV/r treatment group.. In vitro susceptibility to DRV was comparable across HIV-1 subtypes in a broad panel of primary isolates and in recombinant clinical isolates. Once daily DRV/r 800/100 mg and LPV/r 800/200 mg were highly effective in ARTEMIS irrespective of the HIV-1 subtype studied, confirming their broad anti-HIV-1 activity.

Topics: Adamantane; Adult; Analysis of Variance; Atazanavir Sulfate; Carbamates; Darunavir; Drug Resistance, Viral; Furans; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Lopinavir; Microbial Sensitivity Tests; Molecular Typing; Nelfinavir; Neuraminidase; Oligopeptides; Pyridines; Pyrimidinones; Pyrones; Saquinavir; Sulfonamides; Viral Load

A fluorogenic substrate for HIV-1 protease was designed and used as the basis for a hypersensitive assay. The substrate exhibits a kcat of 7.4 s(-1), KM of 15 μM, and an increase in fluorescence intensity of 104-fold upon cleavage, thus providing sensitivity that is unmatched in a continuous assay of HIV-1 protease. These properties enabled the enzyme concentration in an activity assay to be reduced to 25 pM, which is close to the Kd value of the protease dimer. By fitting inhibition data to Morrison's equation, Ki values of amprenavir, darunavir, and tipranavir were determined to be 135, 10, and 82 pM, respectively. This assay, which is capable of measuring Ki values as low as 0.25 pM, is well-suited for characterizing the next generation of HIV-1 protease inhibitors.

Topics: Carbamates; Darunavir; Fluorescence; Fluorescent Dyes; Furans; HIV Infections; HIV Protease; HIV Protease Inhibitors; HIV-1; Humans; Kinetics; Pyridines; Pyrones; Sulfonamides

Malaria and HIV infection are both very common in many developing countries. With the increasing availability of therapy for HIV infection, it was of interest to determine whether antiretroviral drugs exert antimalarial effects. We therefore tested the in vitro activity of 19 antiretroviral drugs against the W2 and 3D7 strains of Plasmodium falciparum at concentrations up to 50 μM. None of 5 tested nucleoside reverse transcriptase inhibitors demonstrated activity. Two nonnucleoside reverse transcriptase inhibitors, efavirenz (mean 50% inhibitory concentration [IC(50)] of 22 to 30 μM against the two strains) and etravirine (3.1 to 3.4 μM), were active; nevirapine was not active. Also active were the fusion inhibitor enfuvirtide (6.2 to 7.9 μM) and the entry inhibitor maraviroc (15 to 21 μM). Raltegravir was not active. However, for all active drugs mentioned above, the IC(50)s were considerably greater than the concentrations achieved with standard dosing. The effects most likely to be clinically relevant were with HIV protease inhibitors. Of the tested compounds, activity was seen with lopinavir (2.7 to 2.9 μM), atazanavir (3.3 to 13.0 μM), saquinavir (5.0 to 12.1 μM), nelfinavir (6.5 to 12.1 μM), ritonavir (9.5 to 10.9 μM), tipranavir (15.5 to 22.3 μM), and amprenavir (28.1 to 40.8) but not darunavir. Lopinavir was active at levels well below those achieved with standard dosing of coformulated lopinavir-ritonavir. Lopinavir also demonstrated modest synergy with the antimalarial lumefantrine (mean fractional inhibitory concentration index of 0.66 for W2 and 0.53 for 3D7). Prior data showed that lopinavir-ritonavir also extends the pharmacokinetic exposure of lumefantrine. Thus, when used to treat HIV infection, lopinavir-ritonavir may have clinically relevant antimalarial activity and also enhance the activity of antimalarials.

Topics: Alkynes; Animals; Anti-Retroviral Agents; Antimalarials; Benzoxazines; Carbamates; Cyclopropanes; Darunavir; Furans; Lopinavir; Nelfinavir; Nevirapine; Plasmodium falciparum; Pyridines; Pyrones; Ritonavir; Saquinavir; Sulfonamides

Patterns of HIV-1 protease inhibitor (PI) resistance-associated mutations (RAMs) and effects on PI susceptibility associated with the L76V mutation were studied in a large database. Of 20,501 sequences with ≥1 PI RAM, 3.2% contained L76V; L76V was alone in 0.04%. Common partner mutations included M46I, I54V, V82A, I84V, and L90M. L76V was associated with a 2- to 6-fold decrease in susceptibility to lopinavir, darunavir, amprenavir, and indinavir and a 7- to 8-fold increase in susceptibility to atazanavir and saquinavir.

Topics: Antiviral Agents; Carbamates; Darunavir; Furans; HIV Protease; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Mutation; Pyrimidinones; Sulfonamides

The importance of the active site region aspartyl residues 25 and 29 of the mature HIV-1 protease (PR) for the binding of five clinical and three experimental protease inhibitors [symmetric cyclic urea inhibitor DMP323, nonhydrolyzable substrate analog (RPB) and the generic aspartic protease inhibitor acetyl-pepstatin (Ac-PEP)] was assessed by differential scanning calorimetry. DeltaT(m) values, defined as the difference in T(m) for a given protein in the presence and absence of inhibitor, for PR with DRV, ATV, SQV, RTV, APV, DMP323, RPB, and Ac-PEP are 22.4, 20.8, 19.3, 15.6, 14.3, 14.7, 8.7, and 6.5 degrees C, respectively. Binding of APV and Ac-PEP is most sensitive to the D25N mutation, as shown by DeltaT(m) ratios [DeltaT(m)(PR)/DeltaT(m)(PR(D25N))] of 35.8 and 16.3, respectively, whereas binding of DMP323 and RPB (DeltaT(m) ratios of 1-2) is least affected. Binding of the substrate-like inhibitors RPB and Ac-PEP is nearly abolished (DeltaT(m)(PR)/DeltaT(m)(PR(D29N)) > or = 44) by the D29N mutation, whereas this mutation only moderately affects binding of the smaller inhibitors (DeltaT(m) ratios of 1.4-2.2). Of the nine FDA-approved clinical HIV-1 protease inhibitors screened, APV, RTV, and DRV competitively inhibit porcine pepsin with K(i) values of 0.3, 0.6, and 2.14 microM, respectively. DSC results were consistent with this relatively weak binding of APV (DeltaT(m) 2.7 degrees C) compared with the tight binding of Ac-PEP (DeltaT(m) > or = 17 degrees C). Comparison of superimposed structures of the PR/APV complex with those of PR/Ac-PEP and pepsin/pepstatin A complexes suggests a role for Asp215, Asp32, and Ser219 in pepsin, equivalent to Asp25, Asp25', and Asp29 in PR in the binding and stabilization of the pepsin/APV complex.

Topics: Atazanavir Sulfate; Binding Sites; Binding, Competitive; Calorimetry, Differential Scanning; Carbamates; Crystallography, X-Ray; Darunavir; Furans; HIV Protease; HIV Protease Inhibitors; Humans; Indinavir; Kinetics; Lopinavir; Models, Molecular; Molecular Structure; Mutation; Nelfinavir; Oligopeptides; Pepsin A; Protein Binding; Protein Structure, Tertiary; Pyridines; Pyrimidinones; Pyrones; Ritonavir; Saquinavir; Sulfonamides

Most HPLC-UV methods for therapeutic drug monitoring of anti-HIV drugs have long run times, which reduce their applicability for high-throughput analysis. We developed an ultra-performance liquid chromatography (UPLC)-diode array detection method for the simultaneous quantification of the HIV-protease inhibitors (PIs) amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, and tipranavir (TPV), and the nonnucleoside reverse transcriptase inhibitors (NNRTIs) efavirenz and nevirapine.. Solid-phase extraction of 1 mL plasma was performed with Waters HLB cartridges. After 3 wash steps, we eluted the drugs with methanol, evaporated the alcohol, and reconstituted the residue with 50 microL methanol. We injected a 4-microL volume into the UPLC system (Waters ACQUITY UPLC BEH C8 column maintained at 60 degrees C) and used a linear gradient of 50 mmol/L ammonium acetate and 50 mmol/L formic acid in water versus acetonitrile to achieve chromatographic separation of the drugs and internal standard (A-86093). Three wavelengths (215, 240, and 260 nm) were monitored.. All drugs were eluted within 15 min. Calibration curves with concentrations of 0.025-10 mg/L (1.875-75 mg/L for TPV) showed coefficients of determination (r(2)) between 0.993 and 0.999. The lower limits of quantification were well below the trough concentrations reported in the literature. Inter- and intraassay CVs and the deviations between the nominal and measured concentrations were <15%. The method was validated by successful participation in an international interlaboratory QC program.. This method allows fast and simultaneous quantification of all commercially available PIs and NNRTIs for therapeutic drug monitoring.

Topics: Alkynes; Atazanavir Sulfate; Benzoxazines; Carbamates; Chromatography, High Pressure Liquid; Cyclopropanes; Furans; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Nelfinavir; Nevirapine; Oligopeptides; Pyridines; Pyrimidinones; Pyrones; Reproducibility of Results; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Sensitivity and Specificity; Solid Phase Extraction; Sulfonamides

Human immunodeficiency virus type 2 (HIV-2) contains numerous natural polymorphisms in its protease (PR) gene that are implicated in drug resistance in the case of HIV-1. This study evaluated emergent PR resistance in HIV-2. Three HIV-2 isolates were selected for resistance to amprenavir (APV), nelfinavir (NFV), indinavir (IDV), and tipranavir (TPV) in cell culture. Genotypic analysis determined the time to the appearance of protease inhibitor (PI)-associated mutations compared to HIV-1. Phenotypic drug susceptibility assays were used to determine the levels of drug resistance. Within 10 to 15 weeks of serial passage, three major mutations--I54M, I82F, and L90M--arose in HIV-2 viral cultures exposed to APV, NFV, and IDV, whereas I82L was selected with TPV. After 25 weeks, other cultures had developed I50V and I84V mutations. In contrast, no major PI mutations were selected in HIV-1 over this period except for D30N in the context of NFV selective pressure. The baseline phenotypes of wild-type HIV-2 isolates were in the range observed for HIV-1, except for APV and NFV for which a lower degree of sensitivity was seen. The acquisition of the I54M, I84V, L90M, and L99F mutations resulted in multi-PI-resistant viruses, conferring 10-fold to more than 100-fold resistance. Of note, we observed a 62A/99F mutational motif that conferred high-level resistance to PIs, as well as novel secondary mutations, including 6F, 12A, and 21K. Thus, natural polymorphisms in HIV-2 may facilitate the selection of PI resistance. The increasing incidence of such polymorphisms in drug-naive HIV-1- and HIV-2-infected persons is of concern.

Topics: Amino Acid Sequence; Carbamates; Drug Resistance, Viral; Furans; HIV Protease; HIV Protease Inhibitors; HIV-1; HIV-2; Humans; Indinavir; Molecular Sequence Data; Mutation; Nelfinavir; Polymorphism, Genetic; Pyridines; Pyrones; Sulfonamides

An accurate, sensitive and simple reverse-phase (RP) high-performance liquid chromatography (HPLC) assay has been developed and validated for the simultaneous quantitative determination of tipranavir with nine other antiretroviral drugs in plasma. A liquid-liquid extraction of the drugs in tert-butylmethylether (TBME) from 200 microL of plasma is followed by a reversed phase gradient HPLC assay with UV detection at 210 nm. The standard curve for the drug was linear in the range of 80-80,000 ng/mL for tipranavir; 10-10,000 ng/mL for nevirapine, indinavir, efavirenz, and saquinavir; and 25-10,000 ng/mL for amprenavir, atazanavir, ritonavir, lopinavir, and nelfinavir. The regression coefficient (r(2)) was greater than 0.998 for all analytes. This method has been fully validated and shown to be specific, accurate and precise. Due to an excellent extraction procedure giving good recovery and a clean baseline, this method is simple, rapid, accurate and provides excellent resolution and peak shape for all analytes. Thus this method is very suitable for therapeutic drug monitoring.

Topics: Alkynes; Anti-HIV Agents; Atazanavir Sulfate; Benzoxazines; Carbamates; Chromatography, High Pressure Liquid; Cyclopropanes; Drug Stability; Furans; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Molecular Structure; Nelfinavir; Nevirapine; Oligopeptides; Oxazines; Pyridines; Pyrimidinones; Pyrones; Reproducibility of Results; Ritonavir; Saquinavir; Sensitivity and Specificity; Spectrophotometry, Ultraviolet; Sulfonamides; Time Factors

Despite the increasing number of antiretroviral compounds, the number of useful drug regimens is limited owing to the high frequency of cross-resistance.. We studied in vitro two-drug combinations using three protease inhibitors (PIs), tipranavir, amprenavir and lopinavir, on isolates (003 and 004) derived from patients with resistance to multiple PIs compared with the drug-susceptible isolate 14aPre in peripheral blood mononuclear cells. Drug interactions were determined by median dose-effect analysis, with the combination index calculated at several inhibitory concentrations (IC).. In 14aPre experiments, the combination tipranavir + lopinavir demonstrated synergy at low concentrations (IC(50)), an additive effect at IC(75) and antagonism at IC(90)-IC(95); tipranavir + amprenavir were antagonistic at all concentrations except IC(95), where they were synergic; and the lopinavir + amprenavir combination was always antagonistic. In 003 and 004 infections, tipranavir + lopinavir and tipranavir + amprenavir combinations were antagonistic, and lopinavir + amprenavir were synergic, at all concentrations, with the exception of being additive at IC(95).. Our in vitro experiments did not show any advantage in combining second generation PIs as a therapeutic strategy in naive or multi-treatment failure subjects, with the exception of tipranavir + amprenavir at IC(95) in infections by a wild-type isolate.

Topics: Carbamates; Drug Resistance, Viral; Enzyme-Linked Immunosorbent Assay; Furans; Genotype; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Lopinavir; Pyridines; Pyrimidinones; Pyrones; RNA, Viral; Sulfonamides

Pharmaceutical companies are on the brink of offering HIV clinicians new drugs designed to work specifically against drug-resistant strains of the virus. Several already approved drugs can also be effective against resistant strains. For instance, amprenavir is currently available and has a smaller degree of susceptibility to protease inhibitor (PI)-resistant strains than the other four PIs on the market. Also, DAPD, a dioxolane purine nucleoside reverse transcriptase inhibitor (NRTI), shows in vitro activity against drug-resistant strains of HIV. Information on Lamivudine and tipranavir is also presented.

Topics: Anti-HIV Agents; Carbamates; Dioxolanes; Drug Resistance, Microbial; Drug Therapy, Combination; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lamivudine; Purine Nucleosides; Pyridines; Pyrones; Sulfonamides