Absorbance data for 50 samples used to test BSF data for Praziquantel.

Absorbance data for 50 samples used to test BSF data for Praziquantel.</p

Uncertainty parameters for lower and upper boundaries of CAT-A.

Uncertainty parameters for lower and upper boundaries of CAT-A.</p

Credibility threshold sensitivity analysis.

An estimated 30–70% of available medications in low-income countries and conflict states are of low quality or counterfeit. Reasons for this vary but most are rooted in regulatory agencies being poorly equipped to oversee quality of pharmaceutical stocks. This paper presents the development and validation of a method for point-of-care drug stock quality testing in these environs. The method is termed Baseline Spectral Fingerprinting and Sorting (BSF-S). BSF-S leverages the phenomena that all compounds in solution have nearly unique spectral profiles in the UV spectrum. Further, BSF-S recognizes that variations in sample concentrations are introduced when preparing samples in the field. BSF-S compensates for this variability by incorporating the ELECTRE-TRI-B sorting algorithm, which contains parameters that are trained in the laboratory using authentic, proxy low quality and counterfeit samples. The method was validated in a case study using fifty samples that include factually authentic Praziquantel and inauthentic samples prepared in solution by an independent pharmacist. Study researchers were blinded to which solution contained the authentic samples. Each sample was tested by the BSF-S method described in this paper and sorted to authentic or low quality/counterfeit categories with high levels of specificity and sensitivity. In combination with a companion device under development using ultraviolet light emitting diodes, the BSF-S method is intended to be a portable and low-cost method for testing medications for authenticity at or near the point-of-care in low income countries and conflict states.</div

Conceptual illustration of theoretical BSFs for three medications.

Illustration of three samples with transmitted light absorbance plotted at 240, 250, 260 and 270 nm, with the target baseline dilution of 1.0 for 240 nm. Note the absorbance scale is bounded at zero (transparent solution) and 2 (opaque solution).</p

Lower and upper boundaries for Praziquantel CAT-A.

Lower and upper boundaries for Praziquantel CAT-A.</p

Example of potential false positive sorting.

Sample-Y is illustrated with four measures of absorbance, one at each of the four wavelengths in the BSF: two are located in CAT-B, two are located in CAT-C.</p

Absorbance data for 25 samples used to optimize uncertainty parameters.

Absorbance data for 25 samples used to optimize uncertainty parameters.</p

S1 File -

An estimated 30–70% of available medications in low-income countries and conflict states are of low quality or counterfeit. Reasons for this vary but most are rooted in regulatory agencies being poorly equipped to oversee quality of pharmaceutical stocks. This paper presents the development and validation of a method for point-of-care drug stock quality testing in these environs. The method is termed Baseline Spectral Fingerprinting and Sorting (BSF-S). BSF-S leverages the phenomena that all compounds in solution have nearly unique spectral profiles in the UV spectrum. Further, BSF-S recognizes that variations in sample concentrations are introduced when preparing samples in the field. BSF-S compensates for this variability by incorporating the ELECTRE-TRI-B sorting algorithm, which contains parameters that are trained in the laboratory using authentic, proxy low quality and counterfeit samples. The method was validated in a case study using fifty samples that include factually authentic Praziquantel and inauthentic samples prepared in solution by an independent pharmacist. Study researchers were blinded to which solution contained the authentic samples. Each sample was tested by the BSF-S method described in this paper and sorted to authentic or low quality/counterfeit categories with high levels of specificity and sensitivity. In combination with a companion device under development using ultraviolet light emitting diodes, the BSF-S method is intended to be a portable and low-cost method for testing medications for authenticity at or near the point-of-care in low income countries and conflict states.</div

Absorbance data for 15 samples of authentic Praziquantel prepared using simplified procedures.

Variability in resulting concentration of Praziquantel in solution induced variability in subsequent measures of absorbance.</p

Conceptual illustration of category system and sample.

CAT-A, CAT-B and CAT-C boundaries and sorting system are illustrated with a hypothetical Sample-X. Here it can be seen that the spectral fingerprint of Sample-X places the sample within the boundaries of CAT-A which would be assumed an authentic sample of the medication.</p