Talk by Dr. Marya Lieberman on "No HPLC? No problem! Detection of substandard beta lactam antibiotics with a paper analytical devices"
16 Jan 2018
Seminar Room #350
Talk by Dr. Marya Lieberman on "No HPLC? No problem! Detection of substandard beta lactam antibiotics with a paper analytical devices"
Abstract
Beta lactam antibiotics make up a significant fraction of the
anti-infective market, but poor quality products cause bad clinical
outcomes and contribute to development of resistant pathogens.
Underdosing can result from degradation, repackaging, sloppy or
negligent manufacturing, or outright falsification. In response to the
unacceptable levels of substandard beta lactam antibiotics found in
our 2013-2015 sample pool in Kenya, we developed an inexpensive
paper analytical device, or PAD, to detect beta lactam antibiotic pills
that contain less than 90% of the stated API. A sample of the antibiotic
undergoes base hydrolysis to form free thiol groups, which are then
oxidized with excess iodine. The remaining iodine is back-titrated on
the PAD by thiosulfate. The test takes about 30 minutes and can be
done in a laboratory equipped with a centigram balance. The accuracy
and precision of the paper test card assay were measured for ampicillin
and amoxycillin tablets, and the results were compared with an HPLC assay.
The quantitative accuracy for the PAD was 4-5% with intermediate precision
between three analysts of 2%. The paper cards correctly categorized
85-90% of a representative sample pool of good and bad quality antibiotics
(n = 80 for amoxicillin, n = 56 for ampicillin). The PAD could be used as a
quick screening method for monitoring post-market antibiotic quality.
I will discuss some of the opportunities and problems that arose as we
tried to take this technology out of the lab and into the world.