Lower than expected maraviroc concentrations in cerebrospinal fluid exceed the wild-type CC chemokine receptor 5-tropic HIV-1 50% inhibitory concentration.

To measure maraviroc total cerebrospinal fluid (CSF) concentrations and compare them with total and unbound plasma concentrations. Total maraviroc was measured by reverse-phase high-performance liquid chromatography with tandem mass spectrometry, whereas ultrafiltration was used for unbound maraviroc. Maraviroc was detected in all nine CSF/plasma pairs with a median CSF total concentration of 2.4 ng/ml. CSF concentrations exceeded the 50% inhibitory concentration of wild-type CC chemokine receptor 5-tropic HIV-1 in all specimens. CSF concentrations are lower than expected based on plasma concentrations and physicochemical characteristics. Unbound maraviroc plasma concentrations may be informative in estimating concentrations in CSF.

An LC-MS-MS method for quantitative determination of maraviroc (UK-427,857) in human plasma, urine and cerebrospinal fluid.

Maraviroc is a first-in-class CCR5 antagonist that shows potent anti-HIV-1 activity in vitro and in vivo and is well tolerated in both healthy volunteers and HIV-1-infected patients. The method for determination of maraviroc (UK-427,857) and its major metabolite (UK-408,027) in human plasma consists of a protein-precipitation procedure and analysis by liquid chromatography/tandem mass spectrometry using positive ion TurboIonSpray® ionization and multiple reaction monitoring. The assay has been validated over a concentration range of 0.500-500 ng/mL for both analytes. The determinations of maraviroc in human cerebrospinal fluid (0.500-500 ng/mL) and in urine (5.00-5000 ng/mL) have also been validated but do not include measurement of the metabolite. The validations included extraction recovery, intra-assay and inter-assay precision and accuracy, stability of stock and spiking solutions, freeze-thaw stability, matrix stability, processed-extract stability, and evaluation of potential interferences from selected medications in plasma or urine.

Maraviroc concentrations in cerebrospinal fluid in HIV-infected patients.

OBJECTIVE: To determine maraviroc (MVC) concentrations in cerebrospinal fluid (CSF) in HIV-infected patients. METHODS: Twelve CCR5+ HIV-1 adult antiretroviral-experienced patients receiving MVC-containing regimens for at least 1 month were enrolled. Both CSF and blood samples were taken around 12 hours after the last MVC dose. liquid chromatography tandem mass spectrometry was used to determine MVC concentrations, and HIV-1 viral load was determined by real-time polymerase chain reaction, (LOD, 40 copies/mL). RESULTS: Twelve blood and 12 CSF samples were collected. Median CD4 count was 281(120-759) cells per microliter, and median HIV-1 viral load was <40 copies per milliliter. Median time on MVC was 13.5 weeks (4-60). Nucleoside analogues (tenofovir/didanosine) were given in only 1 case. Median MVC concentrations in plasma were 124.75 (7.3-517) ng/mL. In all except one, CSF sample-receiving an erroneous MVC dose while taking concomitantly nevirapine-MVC concentrations [2.58 (<0.5-7.22) ng/mL] were within the EC(90) range (0.06-10.70). Median MVC CSF: plasma ratio was 0.022 (0.004-0.17), and when the free MVC plasma concentration was used, 0.094 (2.58-27.44). CSF viral load was <40 copies per milliliter in all 9 patients with undetectable plasma viral load. CONCLUSIONS: MVC achieves concentrations within the EC(90) range in CSF. All patients with undetectable plasma viral load although receiving nucleoside-sparing regimens including new drugs showed viral suppression in CSF.

Cerebrospinal fluid maraviroc concentrations in HIV-1 infected patients.

In order to assess the penetration of maraviroc to the central nervous system, we measured maraviroc concentrations in cerebrospinal fluid (CSF) and plasma. Concentrations were determined by liquid chromatography tandem mass spectrometry (lower limit of quantitation 1.25 ng/ml) in seven paired CSF and plasma samples. The median plasma maraviroc concentration was 94.9 ng/ml (range 21.4-478.0) and the median CSF concentration was 3.63 ng/ml (range 1.83-12.2). CSF samples exceeded the median EC90 for maraviroc (0.57 ng/ml) by at least three-fold. The CSF levels of maraviroc found in this study likely contribute to viral suppression in the CSF.

Sensitive gas chromatographic-mass spectrometric method for the determination of gacyclidine in rat plasma and spinal cord dialyzates.

A sensitive gas chromatographic-mass spectrometric (GC-MS) procedure is described for the selective determination of gacyclidine (a non-competitive N-methyl-D-aspartate antagonist) in rat plasma and spinal cord dialyzates. It involves a single-step liquid-liquid extraction of plasma samples and dialyzates with hexane (pH 8.0) and the use of phencyclidine as an internal standard. The compounds were separated on a GC capillary column and specifically detected by MS in the selected-ion monitoring mode. Gacyclidine and its internal standard were monitored by using the fragment ions at m/z 206 and 200, respectively. The method was accurate and reproducible (intra- and inter-day reproducibility < 12%) with a limit of quantification of 1.6 ng ml-1 using 100 microliters plasma of dialyzate samples. The calibration curves for rat plasma and Ringer's solution were linear (r2 > 0.996) over a range from 1.6 to 200 ng ml-1. The extraction efficiency was close to 100%. This simple and rapid assay (total run time < 10 min) was validated for a pilot pharmacokinetic study in healthy rats after intravenous injection of a bolus dose of gacyclidine (2.5 mg kg-1).