Brief Report: Urine Emtricitabine and Tenofovir Concentrations Provide Markers of Recent Antiretroviral Drug Exposure Among HIV-Negative Men Who Have Sex With Men.

BACKGROUND: Urine provides a minimally invasive specimen that may allow for development of rapid tests to detect antiretroviral drugs and provide opportunities to improve individual adherence. This study sought to determine whether urine could provide a biomarker of adherence for currently approved pre-exposure prophylaxis and HIV treatment regimens. METHODS: Urine and blood were collected from 34 HIV-negative men who have sex with men aged 18-49 years, enrolled in a clinical trial comparing 2 antiretroviral regimens. Specimens were collected 4 and 24 hours after a single oral dose of tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) (n = 10) or tenofovir alafenamide (TAF)/FTC/cobicistat (COBI)/elvitegravir (EVG) (n = 8), or after 4 and 10 days of daily oral TDF/FTC (n = 9) or TAF/FTC/COBI/EVG (n = 7). Tenofovir (TFV), FTC, and EVG were measured by high-performance liquid chromatography-mass spectrometry. RESULTS: Median urine FTC concentrations at 4 and 24 hours were similar between men receiving TDF/FTC (4 hours 147 µg/mL; 24 hours 10 µg/mL) and men receiving TAF/FTC/COBI/EVG (4 hours 333 µg/mL, P = 0.173; 24 hours 13 µg/mL, P = 0.681). Median urine TFV concentrations were lower among men receiving TAF/FTC/COBI/EVG (4 hours 1.2 µg/mL; 24 hours 0.8 µg/mL) compared with men receiving TDF/FTC (4 hours 17 µg/mL, P < 0.001; 24 hours 7 µg/mL, P = 0.001). Urine TFV concentrations remained reduced among men receiving TAF/FTC/COBI/EVG compared with men receiving TDF/FTC after daily dosing. EVG was not consistently measurable in urine. CONCLUSIONS: High urine FTC and TFV concentrations could provide an indication of adherence to daily oral dosing with TDF or TAF-based regimens used for treatment and prevention.

Simultaneous determination and validation of emtricitabine, rilpivirine and tenofovir from biological samples using LC and CE methods.

A combination of antiretroviral agents is frequently used in effective treatment of the human immunodeficiency virus infection. In this study, two different separation methods are presented for the simultaneous determination of emtricitabine, rilpivirine and tenofovir from raw materials and urine samples. Developed liquid chromatography and capillary electrophoresis methods were thoroughly optimized for high analytical performances. Optimization of multiple variables at the same time by performing a minimum number of experiments was achieved by the Box-Behnken design, which is an experimental design in response surface methodology, in capillary electrophoresis. The results of the experimental design ensure minimum analysis time with well-separated analytes. Separation conditions, such as different stationary phases, pH level, organic modifiers and temperatures in liquid chromatography method, were also optimized. In particular, among stationary phases, the core-shell column especially enhanced the effectiveness of separation in liquid chromatography. Both methods were fully validated and applied to real samples. The main advantage of the developed methods is the separation of the drug combination in a short time with high efficiency and without any time-consuming steps.

Two-dimensional LC-MS/MS determination of antiretroviral drugs in rat serum and urine.

A simple, rapid, reliable and highly sensitive on-line two-dimensional reversed-phase liquid chromatography-tandem mass spectrometric (2D-LC/MS/MS) method to determine antiretroviral drugs viz., abacavir (ABC), nevirapine (NVP) and indinavir (IDV) in rat serum and urine was developed and validated. The analytes were extracted on-line from rat serum and urine by a restricted access material (RAM) column and back-flushed into the reversed-phase C18 column for separation by LC. Detection was carried out by ESI-MS/MS. The developed method showed good selectivity, accuracy and precision for quantification of the antiretroviral drugs in rat serum and urine. Quantification limits for abacavir and nevirapine were 4.0 ng ml(-1), whereas for indinavir 4.7 ng ml(-1). The calibration graphs were linear in the range of 4-50 ng ml(-1)for abacavir, nevirapine and indinavir. The method was successfully applied to study the pharmacokinetics of antiretroviral in rats.

A novel probe drug interaction study to investigate the effect of selected antiretroviral combinations on the pharmacokinetics of a single oral dose of maraviroc in HIV-positive subjects.

AIMS: Maraviroc (UK-427 857), an antagonist of the CCR5 receptor with potent anti-HIV activity, was recently approved for use in treatment-experienced patients infected with CCR5-tropic HIV-1. The aim of this study was to evaluate the effect of selected commonly used antiretroviral therapy (ART) combinations on the pharmacokinetics of a single oral dose of maraviroc 300 mg in HIV-positive subjects compared with historical controls. METHODS: In this study, four cohorts of HIV-positive patients (n = 8 each) receiving one of the following combination therapies were recruited: cohort 1--efavirenz + Combivir (lamivudine/zidovudine); cohort 2--efavirenz + didanosine + tenofovir; cohort 3--nevirapine + lamivudine + tenofovir; cohort 4--Kaletra (lopinavir/ritonavir) + stavudine + lamivudine. Subjects continued on their prescribed ART and also received a single oral dose of maraviroc 300 mg. Serial blood samples and urine for determination of maraviroc pharmacokinetics were collected over 12 h postdose. Plasma pharmacokinetic parameters from this study were compared with historical data generated in HIV-positive subjects receiving maraviroc monotherapy in a Phase IIa study. RESULTS: A total of 29 subjects were recruited (eight each in cohorts 1-3, and five in cohort 4). The geometric mean ratios for AUC(12) and C(max) for each treatment group compared with maraviroc monotherapy were: 47% and 67% (cohort 1); 48% and 76% (cohort 2); 101% and 154% (cohort 3); and 265% and 180% (cohort 4), respectively. T(max) was similar in all treatment groups. Mean values for renal clearance ranged from 8.2 l h(-1) (cohort 1) to 13.2 l h(-1) (cohort 4). There were no renal clearance data collected in the comparator study. CONCLUSIONS: The results of this study support those previously seen in healthy volunteer studies that showed that efavirenz reduces maraviroc exposure, whereas lopinavir/ritonavir increases maraviroc exposure. These data also suggest that nevirapine does not lead to a clinically significant effect on maraviroc pharmacokinetics.

Litiasis medicamentosa en pacientes Vih+ eb tratamietno con Indinavir / Urinary lithiasis secondary to medication in HIV+patients receiving Indinavir

Objetivo: Los antirretrovirales inhibidores de la proteasa (IP) son fármacos utilizados en el tratamiento de pacientes afectos por el virus de la inmunodeficiencia humana (VIH). Un 20% de la dosis administrada se excreta por el riñón, que en presencia de orina alcalina puede precipitar formando cristales del propio fármaco susceptibles de provocar crisis renoureterales. Métodos: Entre enero del 1998 y junio de 2005 hemos atendido en nuestro centro a 26 pacientes con síntomas de urolitiasis y bajo el tratamiento con antirretrovirales IP. Todos ellos fueron sometidos a exploración física minuciosa, ecografía renoureteral y vesical, urografía intravenosa. Así mismo, se realizó análisis de sangre y anormales y sedimento de orina. Los pacientes fueron tratados ambulatoriamente, salvo aquellos en los que la analgesia con AINEs no fue suficiente para el control del cuadro álgico. Resultados: Todos los pacientes llevaban más de 12 meses de tratamiento con Indinavir. Los 26 pacientes con síntomas de nefrolitiasis representaban un 4% de los sujetos tratados con la dosis recomendada de Crivixan®. La mayoría presentaron dolor en fosa renal casi siempre asociado a microhematuria. De ellos, cinco pacientes requirieron ingreso en nuestra unidad por clínica no controlable de forma ambulatoria. Las pruebas diagnósticas (ecografía y/o UIV) revelaron retraso funcional del riñón (2 casos), ectasia de vía (8 casos) y pequeñas concreciones litiásicas de escasa o nula densidad cálcica (5 casos). El análisis urinario mostró cristaluria sugestiva y un pH alcalino. Todos requirieron tratamiento analgésico e hidratación. En tres casos se redujo la dosis de indinavir, en otro se retiró la medicación y en otro se añadieron 100 mgr de ritonavir. En un caso se intento cateterismo ureteral infructuosamente. La evolución fue satisfactoria en todos ellos. Conclusiones: Es preciso conocer la posibilidad de litiasis medicamentosa en pacientes HIV tratados con IP, si bien, afortunadamente, cada vez se emplean menos. La prevalencia de urolitiasis en los VIH + parece más elevada en función del tiempo de tratamiento con indinavir. Se han observado alteraciones metabólicas en la orina de estos pacientes que contribuyen a una mayor incidencia de litiasis que en la población general (AU)

Objectives: Therapy with protease inhibitors is commonly used in patients infected by human inmunodeficency virus (HIV). 20% of the administered dose is excreted by the kidney, and when alkaline urine is present , indinavir may crystallize forming stones and patients may experience renal colic due to this fact. Methods: Between January 1998 and June 2005, 26 patients receiving antiretroviral treatment with protease inhibitors received care at our hospital because of renal colic or flank pain. All of them underwent physical examination, echography and urography as well as blood and urine analysis. Patients were treated ambulatory excepting those in whom oral analgesics were insufficient to control the pain. Results: All patients had been treated with indinavir for longer than 12 months. They represented 4% of all patients treated with the recommended dose of Crivixan ®. Most of them presented flank pain, associated in most cases to microhaematuria. Five of them required hospitalization because of persistent pain in spite of endovenous analgesia. Imaging tests (echography and urography) showed functional delay of the kidney (2 cases), ureteral stasis (4 cases) and little lithiasic concretions of mild radiologic density (5 cases). Urinalysis revealed suggestive christaluria and alkaline pH. All patients required hidratation and analgesic treatment. In 3 patients indinavir dose was reduced, it was retired in another one, and 100mg of rito-navir were added in another one. Unsuccesfuly ureteral cateterization was tried in one patient. All of them presen-ted symptomatic improvement. Conclusions: We ought to know the capability of indinavir to form urolithiasis in HIV patients treated with protease inhibitors, although its use is decreasing along time. Prevalence of urolithiasis in these patients seems to be higher as length of treatment becomes longer. Metabolic alterations in urine have been proved in these patients, contributing to a higher incidence of lithiasis than in general population (AU)