Backround: The effect of methadone (MET) during therapy with novel direct-acting antiviral agents is still not fully understood. Currently, no data are available about the influence of MET on ...daclatasvir (DCV) plasma levels in patients affected by chronic hepatitis C (CHC). The aim of this study was to assess the DCV plasma concentrations in patients treated with sofosbuvir (SOF) plus DCV, with or without ribavirin (RBV) and with or without MET.
In this analysis, 47 patients were included, treated consecutively with SOF + DCV ± RBV for 24 weeks, from May to October 2015; 22 (46.8%) received MET substitutive therapy.
We found a significant difference in DCV levels at 2 weeks and 1 month: 150 ng/mL in patients without MET and 313 ng/mL with MET at 2 weeks (p < 0.001), 149 and 279 ng/mL at 1 month (p = 0.006). DCV levels were lower in cirrhotic patients (p < 0.001); among cirrhotic patients we also evidenced higher DCV concentrations in patients receiving MET at 2 weeks, 1 and 2 months (p < 0.001, p = 0.005, and p = 0.031, respectively). In multivariate analysis, the only predictive factor associated with DCV plasma levels was the presence of MET. The reason for this increased DCV exposure is unclear; on the clinical side, we have not observed significant adverse events related to the reduction or increase of MET plasma levels. The administration of MET in patients with advanced fibrosis or cirrhosis leads to an early increase of DCV plasma level without significant clinical effects or toxicity.
Ribavirin-induced hemolytic anemia is the main cause of discontinuation of the combination therapy with alpha-interferon-2b and ribavirin for the treatment of hepatitis C virus (HCV) infection. The ...determination of intracellular ribavirin levels in blood, including the levels of its phosphorylated metabolites, might be useful for predicting ribavirin-induced anemia, which could be caused by the accumulation of these molecules within the erythrocytes. In this work, we simplified and validated a previously developed assay method, to make it suitable for routine monitoring of cellular ribavirin. Whole blood diluted with a five-fold volume of ice-cold distilled underwent a process of acid phosphatase digestion to convert phosphorylated ribavirin metabolites to free ribavirin. The resulting mixture, spiked with an internal standard, was treated with a protein precipitation protocol in acetonitrile, followed by reverse-phase high-performance liquid chromatography analysis. The calibration curve for ribavirin levels in whole blood was linear at concentrations from 625 to 320,000ng/mL (r2=0.998). Accuracy, intra-day and inter-day precision for ribavirin and phosphorylated-ribavirin quality controls were all below 9.0%. We tested this method by monitoring blood ribavirin concentrations in 13 HCV+ patients, receiving alpha interferon-plus ribavirin combination therapy.
First-line nilotinib in chronic myeloid leukemia is more effective than imatinib to achieve early and deep molecular responses, despite poor tolerability or failure observed in one-third of patients. ...The toxicity and efficacy of tyrosine kinase inhibitors might depend on the activity of transmembrane transporters. However, the impact of transporters genes polymorphisms in nilotinib setting is still debated. We investigated the possible correlation between single nucleotide polymorphisms of
(rs683369 c.480C>G) and
(rs1128503 c.1236C>T, rs2032582 c.2677G>T/A, rs1045642 c.3435C>T) and nilotinib efficacy and toxicity in a cohort of 78 patients affected by chronic myeloid leukemia in the context of current clinical practice. The early molecular response was achieved by 81% of patients while 64% of them attained deep molecular response (median time, 26 months). The 36-month event-free survival was 86%, whereas 58% of patients experienced toxicities. Interestingly,
and
polymorphisms alone or in combination did not influence event-free survival or the adverse events rate. Therefore,
n contrast to data obtained in patients treated with imatinib,
and
polymorphisms do not impact on nilotinib efficacy or toxicity. This could be relevant in the choice of the first-line therapy: patients with polymorphisms that negatively condition imatinib efficacy might thus receive nilotinib as first-line therapy.
Measurement of ribavirin plasma levels in HCV-positive patients have been shown to be useful in order to optimise individual ribavirin exposure. Efficacy and toxicity of this drug are shown to be ...concentration-dependant. A simple HPLC-UV method was developed and validated, which has an easy liquid/liquid extraction, sensitive limit of detection, without any interference peaks, reproducible and linear over the range of clinical relevant concentrations. The assay warrants further evaluation as a tool for ribavirin therapeutic drug monitoring in HCV-positive patients.
Antiretroviral treatment is generally highly effective in controlling HIV replication in the central nervous system (CNS), although resistance associated mutations may be locally selected 1. Drug ...passage into the CNS is known to be variable, being influenced by several parameters such as protein binding, molecular weight, lipophilicity, ionization, as well as by the presence of membrane transporters. According to a recently defined CNS drug penetration/effectiveness score, which was found to be associated to a significantly lower risk of viral replication in the cerebrospinal fluid (CSF), tenofovir and emtricitabine are classified as drugs with poor and good penetration, respectively 2. However, a high inter-individual variability of drug passage was recorded in pharmacokinetic studies. In this setting, the possible role of disrupted blood-brain barrier (BBB) deserves consideration, as altered BBB has been frequently reported in asymptomatic HIV-positive patients (2-22%) and in up to 100% of those with HIV-associated encephalitis 3,4. In other neurological diseases 5, drug penetration into CSF is known to be significantly affected by disruption of BBB, but only limited evidence of this is available in case of HIV-infected patients receiving antiretroviral treatment 6.
A simple method for the quantification of tipranavir, the first non-peptidic HIV protease inhibitor, was developed and validated. Quinoxaline, as internal standard, was added to 50
μl of plasma ...before a liquid–liquid extraction by 600
μl of protein precipitation solution. The extracts were diluted before being injected in the chromatographic system. Chromatographic separation was made on a C18 column using potassium phosphate buffer (pH 3.2) and acetonitrile with gradient. Detection was performed by an UV detector at 260
nm. Relative error at three control quality concentrations ranged from −1.81 to 1.72%. Intra-day (CV%) and inter-day (CV%) precision ranged from 0.94 to 2.55% and from 3.07 to 4.24%, respectively. LOQ and LOD were 0.090
μg/ml and 0.035
μg/ml, respectively. Mean recovery was 87.1%
±
2.4%. Calibration curve was linear up to 180
μg/ml. Concentration range when optimized (0.703–180
μg/ml) proved to be adequate to measure tipranavir concentration in HIV-1-positive patients, therefore this method could be suitable for therapeutic drug monitoring of this drug.
A new solid-phase extraction (SPE) method has been developed and validated on a liquid chromatography (LC) coupled with a mass spectrometer for the determination of plasma concentrations of tenofovir ...(TNF) and emtricitabine (FTC) in HIV infected patients. Chromatographic separation was achieved with a gradient (acetonitrile and water with formic acid 0.05%) on an Atlantis 4.6 mm × 150 mm, reversed phase analytical column. Detection of TNF, FTC, and internal standard (IS) was achieved by electrospray ionization mass spectrometry (ESI-MS) in the positive ion mode. Calibration ranged from 15.6 to 4000 ng/mL for TNF and 11.7 to 3000 ng/mL for FTC. Plasma was analyzed, and the limit of quantitation was 15.6 ng/mL for TNF and 11.7 ng/mL for FTC; limit of detection was 2 ng/mL for TNF and 1.5 ng/mL for FTC. Mean recovery of TNF, FTC, and IS were 46.5% relative standard deviation (RSD): 8.8% and 88.8% (RSD: 1.0%), and 81.7% (RSD: 3.1%), respectively. The method did not show any significant interference with antiretrovirals or other concomitant drugs administered to patients, and no significant “matrix effects” were observed. The method was applied for the determination of antiretroviral plasma concentration of HIV-positive patients treated with FTC and/or TNF, in combination with various other antiretrovirals.
In the treatment of bone infections, a major determinant of the clinical response is the active drug concentration at the infected site. Because of the high prevalence of meticillin ...(methicillin)-resistant staphylococci and enterococci, glycopeptides are widely used for the treatment of bone and joint infections, but data on their penetration into human bone are lacking. The aim of our study was to measure vancomycin and teicoplanin concentrations in infected human bone under steady-state conditions and verify their relationship with inflammatory markers, patient demographic characteristics and pharmacodynamic microbiological markers.
Twenty-seven adult orthopaedic patients undergoing surgical debridement for septic pseudoarthrosis of the tibia and receiving either intravenous vancomycin (Vancocina) 1 g twice daily) or teicoplanin (Targosid) 10 mg/kg/day) were studied from January 2004 to January 2008. Plasma and bone specimens were simultaneously collected during surgery for pharmacokinetic and microbiological assays at a variable interval after antimicrobial administration. Bone samples were dissected into cortical and cancellous bone, cleaned of soft tissues, crushed and eluted into phosphate buffer. Necrotic samples and sequestra were not analysed.Plasma and bone antimicrobial concentrations were measured by a validated method of high-performance liquid chromatography with UV detection, and bone/plasma concentration ratios were calculated. Cortical and cancellous bone area under the concentration-time curve (AUC) over 24 hours (AUC(24)) values were measured by the linear-log trapezoidal rule, using WinNonlin) software, and were compared with the minimum inhibitory concentrations (MICs) of the infecting agents.
For vancomycin, the mean +/- SD concentrations were 2.66 +/- 1.2 mg/L in cortical bone and 11.53 +/- 7.8 mg/L in cancellous bone (corresponding to 20.67% and 89.39% of intraoperative plasma concentrations), and the mean +/- SD tissue AUC(24) values were 55.15 +/- 25.26 h . mg/L for cortical bone and 299.16 +/- 299.54 h . mg/L for cancellous bone. For teicoplanin, the mean +/- SD concentrations were 2.01 +/- 1.7 and 7.51 +/- 7.0 mg/L in cortical and cancellous bone, respectively (12.35% and 48.6% of intraoperative plasma concentrations), and the mean +/- SD teicoplanin tissue AUC(24) values were 34.08 +/- 23.6 h . mg/L and 155.17 +/- 132.8 h . mg/L for cortical bone and cancellous bone, respectively. The mean vancomycin AUC(24)/MIC ratios were 215.02 for plasma, 47.14 for cortical bone and 268.95 for cancellous bone. The mean teicoplanin AUC(24)/MIC ratios were 336.48, 36.27 and 197.21 for plasma, cortical bone and cancellous bone, respectively.
Bone penetration of both glycopeptides ranged from poor (<15%) to satisfactory (15-30%) in the cortical compartment, while it was far higher into the highly vascularized cancellous tissue. Vancomycin bone penetration was slightly higher than with teicoplanin, but the difference was not statistically significant. Higher bone concentrations were observed with higher inflammatory markers, possibly as a result of increased vascularization and vascular permeability under inflammatory conditions. Bone concentrations over the MIC and AUC/MIC ratios suggested that both glycopeptides achieve a satisfactory pharmacokinetic exposure in the cancellous bone, as far as Gram-positive pathogens are concerned. On the other hand, cortical bone exposure was suboptimal in most patients. Furthermore, as antimicrobial penetration may be affected by impaired blood supply, the role of radical surgical removal of purulent and necrotic tissues appears to be essential in order to shorten treatment duration and to reduce the risk of treatment failure.
Background We aimed to compare the steady-state pharmacokinetic parameters and tolerability of Triomune 40® (stavudine 40 mg, lamivudine 150 mg and nevirapine 200 mg) and branded formulations of ...these drugs in HIV-infected Ugandans. Methods This includes a randomized, open-label, cross-over study of HIV-infected patients stable on therapy for 1 month. Patients were randomized to generic or branded formulation. Plasma pharmacokinetics were assessed after 1 month. The following day, alternate formulation was administered, and 1 month later, drug pharmacokinetics were re-assessed. Plasma pharmacokinetics were determined using HPLC–UV detection. Similarity between steady-state pharmacokinetic parameters was assessed using the US Food and Drug Administration standards for bioequivalency testing. Tolerability was assessed using questionnaires. Results Sixteen (10 females) patients completed the study. Median (IQR) age, weight and CD4 count were 37 (33.7–40) years, 65 (63.4–66) kg and 292 (220.7–344.5) cells/mm3, respectively. All patients received co-trimoxazole. The geometric mean ratio (90% CI) for stavudine, lamivudine and nevirapine was 0.92 (0.78–1.08), 1.11 (0.95–1.30) and 0.84 (0.64–1.11), respectively, for Cmax, and 0.83 (0.70–0.97), 1.06 (0.94–1.20) and 0.88 (0.71–1.10), respectively, for AUC. Stavudine plasma concentrations were significantly lower for the generic formulation. Pharmacokinetic parameter inter-individual variability ranged from 29% to 99%. There were no differences in tolerability for the two formulations. Conclusions Pharmacokinetic profiles of generic and branded drugs were similar. Differences particularly with regard to stavudine were demonstrated. Surveillance of the quality of generic antiretroviral drugs in the target populations is needed. Capacity building for pharmacokinetic research in resource-limited settings is a priority.
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