Liquid chromatography-tandem mass spectrometry analysis of delamanid and its metabolite in human cerebrospinal fluid using protein precipitation and on-line solid-phase extraction.

The penetration of the antituberculosis drug delamanid into the central nervous system is not established. The distribution of delamanid and its major metabolite, DM-6705, into the cerebrospinal fluid requires investigation. A liquid chromatography-tandem mass spectrometry method for the quantification of delamanid and DM-6705 in human cerebrospinal fluid was developed and validated. The calibration range for both analytes was 0.300 - 30.0 ng/mL. The deuterium-labelled analogue of delamanid (delamanid-d4) and OPC-14714 were used as internal standards for delamanid and DM-6705, respectively. Samples were processed by protein precipitation followed by on-line solid-phase extraction and high-performance liquid chromatography on an Agilent 1260 HPLC system. A Phenomenex Gemini-NX C18 (5.0 µm, 50 mm × 2.0 mm) analytical column was used for on-line solid-phase extraction, and a Waters Xterra MS C18 (5.0 µm, 100 mm × 2.1 mm) analytical column for chromatographic separation using gradient elution, at a flow rate of 300 µL/min. The total run time was 7.5 min. Analytes were detected by multiple reaction monitoring on an AB Sciex 5500 triple quadrupole mass spectrometer at unit mass resolution, with electrospray ionization in the positive mode. Accuracy and precision were assessed over three independent validation batches. Extraction recoveries were more than 98% and were consistent across the analytical range. Both analytes in CSF exhibited non-specific adsorption to polypropylene tubes. The method was used to analyse cerebrospinal fluid samples from patients with pulmonary tuberculosis in an exploratory pharmacokinetic study.

Evaluation of adherence measures of antiretroviral prophylaxis in HIV exposed infants in the first 6 weeks of life.

BACKGROUND: Adherence to an antiretroviral regimen is imperative for treatment success in both HIV infected adults and children. Likewise, adherence to antiretroviral prophylaxis is critical in HIV prevention. Studies on pediatric adherence are limited, particularly the prophylactic use of antiretroviral drugs and treatment adherence in very young infants. The HIV Prevention Trials Network (HPTN) 046 study (Clinical Trial Registration NCT00074412) determined the safety and efficacy of an extended regimen of nevirapine suspension in infants born to HIV-1 infected women for the prevention of vertical HIV transmission during breastfeeding. As per protocol, adherence to nevirapine prophylaxis was measured by maternal verbal reports. In addition, the pharmacy assessed the unused returned suspension. The aim of this sub-study was to determine the reliability of maternal verbal reports in measuring adherence to antiretroviral prophylaxis in infants in the first 6 weeks of life and evaluating the unused returned nevirapine as an alternative method of measuring adherence. METHODS: Maternal verbal reports and pharmacy returns indicative of "missed < 2 doses" were evaluated against a plasma nevirapine concentration of >100 ng/ml in a subgroup of infants at 2, 5 and 6 weeks of age. Plasma nevirapine concentration of >100 ng/ml was used as a marker of adherence (10 times the in vitro IC50 against HIV). RESULTS: Adherence was 87.7% (maternal verbal report) and 71.3% (unused returned medication), as compared to 85.6% by plasma nevirapine concentration. Evaluated against plasma nevirapine concentration <100 ng/ml, the sensitivity and specificity of maternal verbal reports to detect a missed dose in the last 3 days were 75% and 78% (p = 0.03) respectively. Overall, among infants who were classified as adherent based on missed doses by maternal verbal reports and unused returned medication, 88.4% and 87.4% of infants attained a nevirapine concentration above 100 ng/ml respectively. CONCLUSION: Maternal verbal reports are a reliable measure of adherence to infant antiretroviral prophylaxis in the first 6 weeks of life and could be useful in assessing adherence to antiretroviral treatment in infants younger than 6 weeks. In the absence of resources or expertise to determine plasma drug concentration, we would recommend random assessments of unused returned medication.