Development and validation of an HPLC-UV method for quantification of elvitegravir and two other new antiretrovirals, dolutegravir and rilpivirine, in the plasma of HIV-positive patients.

Therapeutic drug monitoring may be crucial in selected clinical conditions for the management of HIV infection. In recent years, new antiretrovirals have been introduced and in particular elvitegravir (EVG) is now recommended for first-line and simplification treatment as well as dolutegravir (DTG) and rilpivirine (RPV). The aim of this study was to develop and validate a high-performance liquid chromatography-ultraviolet (HPLC-UV) method for determining EVG and new antiretrovirals DTG and RPV in human plasma. Solid-phase extraction was applied to a 600 µL plasma sample. Chromatographic separation of the three drugs and internal standard was achieved with a gradient of acetonitrile and phosphate buffer on a C18 reverse-phase analytical column with a 20 min analytical run time. EVG and DTG were detected at 265 nm and RPV at 290 nm. Mean intra- and inter-day precisions were < 10%; the mean accuracy was <15%. Extraction recovery ranged between 105 and 82% for the drugs analyzed. Calibration curves were optimized according to the expected ranges of drug concentrations in patients; the coefficient of determination was >0.997 for all drugs. This method allows for monitoring EVG, DTG and RPV in the plasma of HIV-positive patients using HPLC-UV.

Antigiardial activity of novel triazolyl-quinolone-based chalcone derivatives: when oxygen makes the difference.

Giardiasis is a common diarrheal disease worldwide caused by the protozoan parasite Giardia intestinalis. It is urgent to develop novel drugs to treat giardiasis, due to increasing clinical resistance to the gold standard drug metronidazole (MTZ). New potential antiparasitic compounds are usually tested for their killing efficacy against G. intestinalis under anaerobic conditions, in which MTZ is maximally effective. On the other hand, though commonly regarded as an 'anaerobic pathogen,' G. intestinalis is exposed to relatively high O2 levels in vivo, living attached to the mucosa of the proximal small intestine. It is thus important to test the effect of O2 when searching for novel potential antigiardial agents, as outlined in a previous study [Bahadur et al. (2014) Antimicrob. Agents Chemother. 58, 543]. Here, 45 novel chalcone derivatives with triazolyl-quinolone scaffold were synthesized, purified, and characterized by high resolution mass spectrometry, (1)H and (13)C nuclear magnetic resonance and infrared spectroscopy. Efficacy of the compounds against G. intestinalis trophozoites was tested under both anaerobic and microaerobic conditions, and selectivity was assessed in a counter-screen on human epithelial colorectal adenocarcinoma cells. MTZ was used as a positive control in the assays. All the tested compounds proved to be more effective against the parasite in the presence of O2, with the exception of MTZ that was less effective. Under anaerobiosis eighteen compounds were found to be as effective as MTZ or more (up to three to fourfold); the same compounds proved to be up to >100-fold more effective than MTZ under microaerobic conditions. Four of them represent potential candidates for the design of novel antigiardial drugs, being highly selective against Giardia trophozoites. This study further underlines the importance of taking O2 into account when testing novel potential antigiardial compounds.

Sildenafil and bosentan plasma concentrations in a human immunodeficiency virus- infected patient with pulmonary arterial hypertension treated with ritonavir-boosted protease inhibitor.

Sildenafil and bosentan are increasingly used for the treatment of pulmonary arterial hypertension (PAH) in HIV-infected patients. However, concerns exist about pharmacokinetic interactions among sildenafil, bosentan and antiretroviral drugs, including protease inhibitors (PI). We describe here the case of an HIV-infected patient with PAH, who was co-administered bosentan 125 mg twice daily and sildenafil 40 mg three times per day, together with a ritonavir-boosted PI-based antiretroviral therapy; plasma levels of bosentan, sildenafil, N-desmethylsildenafil, and PI were measured. The patient had a sildenafil Cthrough and Cmax of 276.94 ng/mL and 1733.19 ng/mL, respectively. The Cthrough and the Cmax of bosentan were 1546.53 ng/mL and 3365.99 ng/mL, respectively. The patient was able to tolerate as high sildenafil blood concentrations as 10 times those usually requested and did not report any significant adverse reaction to sildenafil during the follow-up period. Therapeutic drug monitoring should be considered during sildenafil therapy in patients concomitantly treated with ritonavir-boosted PI.

Determination of telaprevir in plasma of HCV-infected patients by HPLC-UV.

Telaprevir is a direct acting antiviral agent, used with pegylated interferon and ribavirin for the management of chronic hepatitis C virus (HCV) genotype 1 infection, in patients not responding to therapy with pegylated interferon and ribavirin only. Although 75% of patients achieve a sustained virological response after treatment with telaprevir, adverse drug-drug interactions and undesirable events often occur. Therefore, telaprevir monitoring is pivotal to improve the management of HCV infection. Here, the first High-Performance Liquid Chromatography-Ultraviolet (HPLC-UV) method to quantify telaprevir in human plasma of HCV-genotype 1-infected patients is reported. The volume of the plasma sample was 700 µL. This method involved automated solid-phase extraction with Oasis HLB Cartridge 1 cc (divinylbenzene and N-vinylpyrrolidone). The extracted samples were reconstituted with 150 µL of 60/40 water/acetonitrile. Thirty microliters of these samples was injected into a HPLC-UV system, and the analytes were eluted on a X Terra(®) RP18 column (250 mm × 4.6 mm i.d.) with a particle size of 5 µm. The mobile phase (ammonium acetate buffer, 150 mM, pH 8.0, and methanol:acetonitrile 50:50) was delivered at 1.0 mL/min with linear gradient elution. The total run time for a single analysis was 16 min; telaprevir was detected by UV at 276 and 286 nm. The calibration curve was linear from 312.5 to 20,000 ng/mL (r(2) > 0.996). The absolute recovery of telaprevir ranged between 89 and 93% at concentrations of quality control samples of 800, 4,000, 8,000, and 16,000 ng/mL. Both precision and accuracy were always <15%. The HPLC-UV method reported here: (i) has been validated, (ii) is currently applied to monitor telaprevir in plasma of HCV-infected patients, and (iii) appears useful in a routine laboratory. ,

Determination of P-glycoprotein surface expression and functional ability after in vitro treatment with darunavir or raltegravir in lymphocytes of healthy donors.

It has been shown that P-glycoprotein (P-gp) can greatly affect the cell uptake of antiretroviral drugs, thus hampering their access to HIV-1 replication sites. Lymphocytes are important sites of replication of HIV and target of other drugs, modification on these cells of P-gp could have an effect on pharmacokinetic of antiretrovirals and drug substrates. Blood samples from 16 healthy volunteers were used to determine the expression of P-gp on total, T and T helper lymphocytes after exposure to darunavir, a second generation protease inhibitor, and raltegravir, the first approved integrase inhibitor. Moreover, the effect of the drugs on P-gp functional activity was also studied by the rhodamine-123 efflux test. Darunavir, but not raltegravir, exposure caused a moderate, dose-dependent increment in P-gp expression in total, T and T helper lymphocytes, as demonstrated by the relative frequency of P-gp+ cells and by the amount of P-gp molecules present on cell surface. Functionally, incubation with darunavir led to a marked inhibition of P-gp activity measured by the efflux of rhodamine-123 similar to that observed by verapamil, a specific P-gp inhibitor. Raltegravir was not able to modify the efflux of rhodamine-123 level. Data show that darunavir, unlike raltegravir, may modify the expression and functionality of P-gp on human lymphocytes, thus leading to potential changes in intracellular concentrations of darunavir in patients treated with other drugs substrate of P-gp and vice versa. Our study highlights the need for studies on drug interactions via the P-gp modulation mechanism, especially with the current multi-drug regimens.

Simultaneous determination of lamivudine, lopinavir, ritonavir, and zidovudine concentration in plasma of HIV-infected patients by HPLC-MS/MS.

The nucleoside reverse transcriptase inhibitors lamivudine and zidovudine and the protease inhibitors lopinavir and ritonavir are currently used in anti-human immunodeficiency virus (HIV) therapy. Here, a high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) method, using a hybrid quadrupole time-of-flight mass analyzer, is reported for the simultaneous quantification of lamivudine, lopinavir, ritonavir, and zidovudine in plasma of HIV-infected patients. The volume of plasma sample was 600 µL. Plasma samples were extracted by solid-phase using 1 cc Oasis HLB Cartridge (divinylbenzene and N-vinylpyrrolidone) and evaporated in a water bath under nitrogen stream. The extracted samples were reconstituted with 100-µL methanol. Five microliters of the reconstituted samples were injected into a HPLC-MS/MS apparatus, and the analytes were eluted on a Vydac column (250 × 1.0 mm i.d.) filled with 3-µm C(18) particles. The mobile phase was delivered at 70 µL/min with a linear gradient elution, both acetonitrile and ultrapure water solvents contained 0.2% formic acid. The calibration curves were linear from 0.47 to 20 ng/mL. The absolute recovery ranged between 91 and 107%. The minimal concentration of lamivudine, lopinavir, ritonavir, and zidovudine detectable by HPLC-MS/MS is 0.47, 0.28, 0.30, and 0.66 ng/mL, respectively. The great advantage of the new HPLC-MS/MS method here reported is the possibility to achieve a very high specificity toward the selected anti-HIV drugs, despite the simple and rapid sample preparation. Moreover, this method is easily extendible to the analysis of co-administrated drugs.

The superoxide reductase from the early diverging eukaryote Giardia intestinalis.

Unlike superoxide dismutases (SODs), superoxide reductases (SORs) eliminate superoxide anion (O(2)(•-)) not through its dismutation, but via reduction to hydrogen peroxide (H(2)O(2)) in the presence of an electron donor. The microaerobic protist Giardia intestinalis, responsible for a common intestinal disease in humans, though lacking SOD and other canonical reactive oxygen species-detoxifying systems, is among the very few eukaryotes encoding a SOR yet identified. In this study, the recombinant SOR from Giardia (SOR(Gi)) was purified and characterized by pulse radiolysis and stopped-flow spectrophotometry. The protein, isolated in the reduced state, after oxidation by superoxide or hexachloroiridate(IV), yields a resting species (T(final)) with Fe(3+) ligated to glutamate or hydroxide depending on pH (apparent pK(a)=8.7). Although showing negligible SOD activity, reduced SOR(Gi) reacts with O(2)(•-) with a pH-independent second-order rate constant k(1)=1.0×10(9) M(-1) s(-1) and yields the ferric-(hydro)peroxo intermediate T(1); this in turn rapidly decays to the T(final) state with pH-dependent rates, without populating other detectable intermediates. Immunoblotting assays show that SOR(Gi) is expressed in the disease-causing trophozoite of Giardia. We propose that the superoxide-scavenging activity of SOR in Giardia may promote the survival of this air-sensitive parasite in the fairly aerobic proximal human small intestine during infection.

Marked increase in etravirine and saquinavir plasma concentrations during atovaquone/proguanil prophylaxis.

The case of a 32-year-old Caucasian female with multi-drug resistant HIV-1 subtype B infection treated with a salvage regimen including maraviroc, raltegravir, etravirine and unboosted saquinavir who started atovaquone/proguanil prophylaxis, is reported. The potential interactions between atovaquone/proguanil and these anti-retroviral drugs are investigated. Pharmacokinetic analyses documented a marked increase in etravirine and saquinavir plasma concentrations (+55% and +274%, respectively), but not in raltegravir and maraviroc plasma concentrations. The evidence that atovaquone/proguanil significantly interacts with etravirine and saquinavir, but not with raltegravir and maraviroc, suggests that the mechanism of interaction is related to cytochrome P450.

Multicompartment vectors as novel drug delivery systems: selective activation of Tγδ lymphocytes after zoledronic acid delivery.

Multicompartment nanoscopic carriers can be easily assembled by inducing the aggregation of anionic "hybrid" niosomes by means of cationic biocompatible polyelectrolytes. The resulting vesicle clusters, whose size and overall net charge can be easily controlled by varying the polyelectrolyte-to-particle charge ratio, show an interesting potential for multidrug delivery. In this article we provide strong evidence for their effective use in vitro as multicompartment vectors selectively directed toward monocyte/macrophage cells, showing that the monocyte/macrophage-mediated activation of Tγδ lymphocytes induced by zoledronic acid is enhanced by a factor 10(3) when the zoledronic acid is intracellularly delivered through these carriers. Furthermore, the multicompartment ɛ-polylysine niosome clusters, with their intrinsic selectivity toward macrophages, appear particularly suitable for implementing therapeutic strategies against chronically infected macrophages. FROM THE CLINICAL EDITOR: ɛ-polylysine niosome clusters, with their intrinsic selectivity toward macrophages, offer the potential for multidrug delivery. The effectiveness of aminobisphosphonate zoledronate is demonstrated to enhance the recruitment of Tγδ lymphocytes by macrophages by 2 orders of magnitude, suggesting a new therapeutic strategy for addressing pathologies featuring chronically infected macrophages.

Use of novel antiretroviral agents in rescue regimens: a case of early virological failure to raltegravir.

In patients with virological failure during highly active antiretroviral therapy (HAART) and drug resistance, guidelines recommend the achievement of maximal virological suppression by the use of a new regimen with at least 2 active drugs. We describe the clinical outcome of a heavily antiretroviral-experienced patient who experienced early failure to raltegravir.

Transplacental transfer of antiretroviral drugs and newborn birth weight in HIV-infected pregnant women.

Although it is well known that antiretroviral drugs (ARVs) across the placenta in different extents, few data are available concerning the impact of the transplacental passage of ARVs on newborn outcome. The aim of this study is to evaluate the transplacental diffusion of ARVs and the clinical assessment of the newborn. Mother and cord lopinavir, nelfinavir, atazanavir and nevirapine plasma levels were determined by high-performance liquid chromatography. Newborn gestational age, weight, and Apgar score were recorded. Cord-to-mother ratio (C:M) was calculated to estimate the placental passage of ARVs. Preterm birth was defined as delivery at <37 weeks of gestation and low birth weight was defined as a birth weight of <2500g. Twenty-six HIV-infected pregnant women were enrolled. Nevirapine presented the highest C:M ratio (0.60 +/- 0.19), the C:M ratio of nelfinavir and atazanavir was 0.37 +/- 0.38 and 0.20 +/- 0.14, respectively. The lopinavir level in the cord was undetectable. The observed prevalence rate of neonatal low birth weight and preterm delivery was 19,2% (n = 5) and 15.4% (n = 4), respectively. A significant linear regression analysis was reported between the C:M ratio and newborn birth weight (p = 0.01). Although the role of highly active antiretroviral therapy (HAART) in preventing mother-to-child transmission is indisputable, these data indicate a pharmacological rationale to the association between birth weight and highly active antiretroviral therapy during pregnancy.

Identification of clinically relevant yeast species by DNA sequence analysis of the D2 variable region of the 25-28S rRNA gene.

Clinically relevant yeasts are conventionally identified by a combination of phenotypic tests, which occasionally provide ambiguous results for atypical isolates or uncommon species. In this study, we evaluate a direct polymerase chain reaction-sequencing method, which exploits sequence divergence in the hypervariable D2 region of the large subunit of the 25-28S ribosomal RNA (rRNA) gene for identification of facultative pathogenic asco- and basidiomycota. A panel of 53 yeasts, including 40 clinical isolates and 13 reference strains representative of some clinically relevant taxa, was investigated by combining standard phenotypic tests with commercial identification systems (RapID, API 20C AUX), and results were compared with the taxonomic allocations inferred by D2 sequence analysis. Species-level resolution was achieved for almost all (52/53) strains by combining internet-based D2 sequence homology (BLAST and FASTA) searches in free-access synchronised databases with phylogenetic analysis. The phylogenetic information carried by the short D2 sequence substantiates a pattern of molecular evolution, which is similar to that inferred from analysis of the larger D1/D2 region, and consistent with previously published 25-28S rRNA phylogenetic architectures of facultative pathogenic yeast, including recently identified species. Inconsistency between conventional and molecular identification results was observed for 11/53 strains, likely on account of the ambiguous interpretation of phenotypic tests.

Levels of interleukin-15 in plasma may predict a favorable outcome of structured treatment interruption in patients with chronic human immunodeficiency virus infection.

Structured treatment interruption (STI) may help to alleviate the problems associated with long-term antiretroviral therapy (ART) in human immunodeficiency virus (HIV)-infected patients. We analyzed the role that baseline levels of cytokines in plasma play as markers of a favorable outcome of STI. Two groups of patients were defined: STI responders and STI nonresponders. STI responders showed a higher baseline concentration of interleukin (IL)-15 in plasma than did STI nonresponders and showed lower levels of tumor necrosis factor (TNF)-alpha during STI. No differences were observed in levels of IL-2, IL-7, or interferon-alpha in plasma. Our data show that (1) levels of TNF-alpha in plasma correlate with HIV viremia and (2) monitoring baseline levels of IL-15 in plasma allows for the identification of a favorable outcome of STI.

Identification of early secretory antigen target-6 epitopes for the immunodiagnosis of active tuberculosis.

The early secretory antigenic target (ESAT)-6 purified protein and peptides from Mycobacterium tuberculosis were evaluated as antigens for the immunodiagnosis of tuberculosis (TB). Because the control of TB requires improved diagnostic procedures, efforts have increased to identify Mycobacterium tuberculosis-specific epitopes for the immunodiagnosis of active TB and to discriminate between active and latent states of infection. Two multiepitopic peptides from ESAT-6 protein were selected by computational analysis. Patients with active TB (7 HIV(+) and 20 HIV(-)) and control patients (17 HIV(+) and 28 HIV(-)) were enrolled. Enzyme-linked immunospot assay analysis for interferon-g expression by peripheral blood mononuclear cells was quantified after stimulation with selected ESAT-6 peptides, purified protein derivative, or the intact ESAT-6 protein. During active TB, 20 of 27 patients responded in vitro to ESAT-6 peptides and 23 of 27 patients to purified protein derivative. None of the controls without active TB, including individuals with latent TB infection, recognized ESAT-6 peptides. By contrast, latently infected individuals did respond in vitro to both intact ESAT-6 protein and purified protein derivative. Thus, high T-cell response frequencies to ESAT-6 peptides are present only during active TB and can be used to discriminate between active and latent forms of infection.

Analysis of the dynamics of cryoaggregation by light-scattering spectrometry.

Cryoglobulins are proteins that precipitate at temperatures below 37 degrees C. Cold-induced precipitation of proteins may occur in vivo secondary to several important diseases, and lead to pathological manifestations involving different organs. Cryoprecipitation may be observed in vitro by exposing serum samples, supposed to contain cryoglobulins, to low temperatures, but this needs several days to occur. Protein-protein interactions leading to cryoprecipitation are still poorly understood and the knowledge of the underlying mechanism may be relevant to the understanding of the onset of pathological manifestations. Using light-scattering spectrometry, we studied cryoprecipitation occurring in vitro at different temperatures and cryoglobulin concentrations. We describe the kinetics of the cold-induced precipitation of mixed cryoglobulins, measured as increase in turbidity. The plots obtained demonstrate that the cryoprecipitation did not occur as a single-step reaction, but consisted of four distinct phases where both temperature and cryoglobulin concentration affected the immune complexes formation. Light scatter spectrometry may provide a simple, sensitive and rapid method for the detection of cryoglobulins.

Influence of age and autoimmunity on liver disease in HCV-associated type II mixed cryoglobulinemia.

It has been suggested that hepatitis C virus (HCV) infected patients with type II mixed cryoglobulinemia have less extensive liver damage than patients without cryoglobulinemia. We retrospectively evaluated 35 patients with type II mixed cryoglobulinemia associated with HCV infection, seeking for factors associated with normal alanine aminotransferase (ALT) values. The presence of anti-GOR and of other autoantibodies, including the recently described anti-LAG-3.1, was specifically investigated. Fifty-four percent of patients had anti-GOR, 46% anti-LAG-3.1, 40% anti-smooth muscle, 17% anti-nuclear, and 11% anti-liver-kidney microsome 1 antibodies. Anti-GOR was significantly (p = 0.037) associated with anti-LAG-3.1 but not with other autoantibodies. Persistently abnormal ALT levels were observed in 54% of patients. By univariate analyses, abnormal ALT was significantly associated with anti-GOR positivity (p = 0.018) and younger age (p = 0.03). Multivariate regression analysis confirmed that these variables were independently associated with abnormal ALT. Our data suggest that the presence of autoimmune manifestations as well as unidentified age-related host factor(s) may protect from liver injury in HCV-associated cryoglobulinemia.

Lack of CD27-CD45RA-V gamma 9V delta 2+ T cell effectors in immunocompromised hosts and during active pulmonary tuberculosis.

In humans, the circulating pool of mycobacteria-reactive Vgamma9Vdelta2+ T cells is expanded with age and may contribute to Mycobacterium tuberculosis immunosurveillance. We observed that two subsets of Vgamma9Vdelta2+ T cells could be identified on the basis of CD27 expression in immunocompetent adults, showing that functionally differentiated gammadelta T cells have lost CD27 expression. In contrast, the CD27-CD45RA-Vgamma9Vdelta2+ T cell subset of effector cells was absent in cord blood cells from healthy newborns and lacking in the peripheral blood from HIV-infected patients. Moreover, circulating Vgamma9Vdelta2+ T cell effectors were significantly reduced in patients with acute pulmonary tuberculosis, resulting in a reduced frequency of IFN-gamma-producing cells after stimulation with nonpeptidic mycobacterial ligands. These observations indicate that monitoring and boosting gammadelta T cell effectors could be clinically relevant both in immunocompromised hosts and during active tuberculosis disease.