Abstract:
Abstract.
Carrying out chemical analysis of antimalarials to detect low-quality medications before they reach a patient
is a costly venture. Here, we show that a library of chemical color tests embedded on a paper card can presumptively
identify formulations corresponding to very low quality antimalarial drugs. The presence or absence of chloroquine (CQ),
doxycycline (DOX), quinine, sulfadoxine, pyrimethamine, and primaquine antimalarial medications, in addition to fillers
used in low-quality pharmaceuticals, are indicated by patterns of colors that are generated on the test cards. Test card
sensitivity for detection of these pure components ranges from 90% to 100% with no false positives in the absence of
pharmaceutical. The color intensities from reactions characteristic of CQ or DOX allowed visual detection of formula-
tions of these medications cut with 60% or 100% filler, although samples cut with 30% filler could not be reliably
detected colorimetrically. However, the addition of unexpected fillers, even in 30% quantities, or substitute pharmaceu-
ticals, could sometimes be detected by other color reactions on the test cards. Tests are simple and inexpensive enough to
be carried out in clinics, pharmacies, and ports of entry and could provide a screening method to presumptively indicate
very low quality medicines throughout the supply chain.
