Field-adapted method for high-performance thin-layer chromatographic detection and estimation of chloroquine and desethylchloroquine in urine.

A high-performance thin-layer chromatographic (HPTLC) method which can be used in remote field locations lacking electricity has been developed for selective and sensitive detection and estimation of chloroquine (Cq), desethylchloroquine (DECq) and two other antimalarial compounds in urine. The method requires a single extraction step and has a detection limit of 0.25 micrograms/ml for both Cq and DECq. The HPTLC method was coupled with a colorimetric field assay for Cq and metabolites in urine and a field-interfaced, laboratory-based, high-performance liquid chromatographic assay of Cq and DECq in finger-stick blood to survey antimalarial drug use practices in Esmeraldas Province in northwestern Ecuador. Fourteen of 66 patients from whom urine samples were obtained were found to have detectable Cq and DECq. Results of the three assays are compared for these individuals, and the role of the HPTLC method in field studies is assessed.