Clinical Monitoring of AIDS Drugs

Scientists from Erasmus Medical Centre in Rotterdam and from UMC in Nijmegen, both in the Netherlands, have joined forces with researchers from the Medical Research Council in Cambridge, UK, to develop an effective technique for measuring antiretroviral drugs in the blood of AIDS patients. They have achieved the accuracy necessary for clinical monitoring of patients undergoing therapy.

Matrix-assisted laser desorption/ionization (Maldi) provides fast throughput and enables sample storage for later reference. However, chemical noise from the matrix interferes with the signal, especially with low-molecular-mass drugs. The team showed that a novel matrix compound called HFMC gives strong signals for seven HIV inhibitors, since its peak light absorption matches the wavelength of the frequency-tripled Nd:YAG laser in the Maldi system.

The researchers used a hydrophobic coating on the target plate to form a well-focused area of crystals and to reduce the measurement time to 2.5 s. By using selected reaction monitoring in a triple quadrupole mass spectrometer, they detected ion transitions particular to the drug compounds and further reduced matrix noise, achieving a mean relative error of 4.6 per cent.

(Analytical Chemistry, 1 July 2008, pp. 4969-4975)