Topic: Various OTHER
Podium Presentation in Room 1 on Thursday at 9:20 (Chair: Richard Van Breemen / Ruben Luo)
In 2018, half a million people developed multidrug-resistant tuberculosis (MDR-TB), which requires at least 9 months of complicated and expensive drug regimens. The current method of measuring adherence to anti-tuberculosis (TB) drugs, analysis of patient plasma, is limited by its ability to only detect recent adherence and the requirement of a phlebotomist and cold chain for sampling and storage. Analyzing hair samples, which contain a longer record of adherence and can be stored at room temperature, avoids these shortcomings. The new anti-TB drug delamanid has yet to be quantified in hair using LC-MS/MS.
The primary objective of this study was to develop an LC-MS/MS method for delamanid, which accumulates in hair at very low concentrations. Therefore, the method also quantifies its metabolite, DM6705.
Two milligrams of patient hair was pulverized, extracted in methanol for two hours, and then the vial was rinsed with water before injection. Delamanid and DM6705 both demonstrated some instability in initial extraction procedures, as has been published elsewhere, and required low temperatures to improve extraction recovery. A gradient elution method, using 0.1% formic acid in water and acetonitrile as mobile phases, eluted delamanid, DM6705, and the internal standard OPC-14714 within 3 minutes, limiting overall analysis time to 5.5 minutes. Samples were quantified on a calibration curve with a linear dynamic range from 3 pg/mg to 2.1 ng/mg for delamanid and 0.03 ng/mg to 21 ng/mg for DM6705.
Linearity for both delamanid and DM6705 was strong. The mean coefficient of determination was 0.997 for delamanid and 0.995 for DM6705. At three quality control levels, mean coefficient of variation of precision was below 10% for delamanid and DM6705, and mean relative error of accuracy was below 15%. To test the method’s quantifiable range, 12 hair samples from patients taking delamanid were analyzed. 11 of the samples had concentrations within the quantifiable range for delamanid and all 12 samples had concentrations within the quantifiable range for DM6705. For delamanid, the minimum concentration in patient hair was 0.9 pg/mg, the maximum concentration was 264 pg/mg, and the median concentration was 11.5 pg/mg. For DM6705, the minimum concentration in patient hair was 0.4 ng/mg, the maximum concentration was 12.0 ng/mg, and the median concentration was 2.7 ng/mg.
Using hair as a matrix to analyze anti-TB drug adherence, clinicians could design better drug regimens because hair lacks some of the shortcomings inherent in analyzing plasma. We demonstrated that delamanid accumulates in hair at very low levels, but its metabolite DM6705 is present at levels approximately 100 times higher. This method will be run alongside our previously published 11-analyte panel to quantify 12 common anti-TB drugs. In 2020, we will analyze delamanid and DM6705 concentrations taken from 84 TB patients over 24 months.
|Grants||yes||National Institute of Allergy and Infectious Diseases|
|Salary||yes||University of California San Francisco|
|Planning to mention or discuss specific products or technology of the company(ies) listed above:||