An easy to use, low cost colorimetric method to identify the quality and quantity of the tuberculosis (TB) medication, streptomycin was developed. TB is typically treated using a multi-drug regimen comprised of antibiotics such as streptomycin. According to WHO and USAID up to 50% of pharmaceuticals are counterfeit worldwide. The problem intensifies the closer one gets to the point of care. A facile counterfeit detection method, that is specific to only the authentic medication, is essential. Since the 1940s, streptomycin was colorimetrically identified using a 16-hour base hydrolysis process followed by an iron complexation reaction. A tris(maltonato)iron (III) complex was suggested, but not confirmed in the 1940s method. The maltol formation using a base hydrolysis approach was optimized for streptomycin. Monitored using HPLC, the original 16-hour hydrolysis time was reduced to 3 minutes using a heating process and a two-fold reduction in NaOH concentration. A two-fold increase in maltol hydrolysis per mole streptomycin was also achieved. The 2 M HCl acid, used to catalyze the iron complex formation, was eliminated by using iron (II) acetate in place of iron chloride in a capsule delivery system. The new assay system was improved to include fewer steps and to remove caustic solutions thereby making the reaction safer. In conducting optimizations to the 1945 method, we discovered a discrepancy in the 1945 reaction interpretations. HPLC results comparing the 1945 assay products with the known tris(maltonato)iron (III) standard did not match. The solution colors were visually distinct. FTIR and UV-visible Spectroscopic analysis suggested that the 1945 method was not forming the tris(maltonato)iron (III) complex as reported. The safer and optimized assay method, however, does make the tris(maltonato)iron (III) complex. An effective, yet safer and better characterized colorimetric assay for streptomycin was developed.
Library of Congress Subject Headings
Antibiotics--Quality control; Streptomycin--Analysis; Colorimetric analysis
Department, Program, or Center
School of Chemistry and Materials Science (COS)
Foster, MaKayla R., "Drug Quality Assurance to Combat Counterfeit Streptomycin using Facile, Low Cost Colorimetry" (2019). Thesis. Rochester Institute of Technology. Accessed from
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