title: An evaluation of protein assays for quantitative determination of drugs.
abstract: We have evaluated the response of six protein assays [the biuret, Lowry, bicinchoninic acid (BCA), Coomassie Brilliant Blue (CBB), Pyrogallol Red-Molybdate (PRM), and benzethonium chloride (BEC)] to 21 pharmaceutical drugs. The drugs evaluated were analgesics (acetaminophen, aspirin, codeine, methadone, morphine and pethidine), antibiotics (amoxicillin, ampicillin, gentamicin, neomycin, penicillin G and vancomycin), antipsychotics (chlorpromazine, fluphenazine, prochlorperazine, promazine and thioridazine) and water-soluble vitamins (ascorbic acid, niacinamide, pantothenic acid and pyridoxine). The biuret, Lowry and BCA assays responded strongly to most of the drugs tested. The PRM assay gave a sensitive response to the aminoglycoside antibiotics (gentamicin and neomycin) and the antipsychotic drugs. In contrast, the CBB assay showed little response to the aminoglycosides and gave a relatively poor response with the antipsychotics. The BEC assay did not respond significantly to the drugs tested. The response of the protein assays to the drugs was further evaluated by investigating the linearity of the response and the combined response of drug plus protein. The results are discussed with reference to drug interference in protein assays and the development of new methods for the quantification of drugs in protein-free solution.
authors.affiliation: Analytical Biochemistry Group, Sunderland Pharmacy School, School of Health, Natural and Social Sciences, Fleming Building, The University of Sunderland SR1 3RG, Sunderland, UK. kath.williams@sunderland.ac.uk
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Williams
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Arthur
authors.forename: Gillian
authors.initials: G
authors.lastname: Burrell
authors.forename: Fionnuala
authors.initials: F
authors.lastname: Kelly
authors.forename: Darren W
authors.initials: DW
authors.lastname: Phillips
authors.forename: Thomas
authors.initials: T
authors.lastname: Marshall
mesh_terms: D000700:Analgesics / Q000032:analysis; D000900:Anti-Bacterial Agents / Q000032:analysis; D014150:Antipsychotic Agents / Q000032:analysis; D019963:Clinical Chemistry Tests / Q000379:methods* / Q000592:standards; D004347:Drug Interactions; D005069:Evaluation Studies as Topic; D004364:Pharmaceutical Preparations / Q000032:analysis* / Q000592:standards; D011506:Proteins / Q000032:analysis*; D015203:Reproducibility of Results; D014815:Vitamins / Q000032:analysis
chemical_list: D000700:Analgesics; D000900:Anti-Bacterial Agents; D014150:Antipsychotic Agents; D004364:Pharmaceutical Preparations; D011506:Proteins; D014815:Vitamins