Spectrophotometric determination of penicillamine and carbocisteine based on formation of metal complexes

• Published in: Farmaco (Società chimica italiana : 1989) 2004-06, Vol.59 (6), p.493-503
• Main Authors: Walash, M.I, El-Brashy, A.M, E.-S. Metwally, M, Abdelal, A.A
• Format: Article
• Language: English
• Subjects: Acetates - chemistry; Borates - chemistry; Capsules - analysis; Capsules - chemistry; Carbocisteine; Carbocysteine - chemistry; Carbocysteine - isolation & purification; Complexation; Data Interpretation, Statistical; Dosage forms; Drug Stability; Hydrogen-Ion Concentration; Hydroxides - chemical synthesis; Ions; Macromolecular Substances - chemistry; Metals, Heavy - chemistry; Metals, Heavy - classification; Metals, Heavy - pharmacokinetics; Molecular Structure; Organometallic Compounds - chemical synthesis; Organometallic Compounds - isolation & purification; Penicillamine; Penicillamine - chemistry; Penicillamine - isolation & purification; Spectrophometric; Spectrum Analysis - methods; Spectrum Analysis - trends; Time Factors; Turkey
• ISSN: 0014-827X; 1879-0569
• DOI: 10.1016/j.farmac.2003.11.016

A simple spectrophotometric method was developed for the determination of penicillamine and carbocisteine. The method depends on complexation of penicillamine with Ni, Co and Pb ions in acetate buffer pH of 6.3, 6.5 and 5.3, respectively, and carbocisteine with Cu and Ni ions in borate buffer pH of 6.7; 1–70 μg/ml of these drugs could be determined by measuring the absorbance of each complex at its specific λ max. The results obtained are in good agreement with those obtained using the official methods. The proposed method was successfully applied for the determination of these compounds in their dosage forms. Also, the molar ratio and stability constant of the metal complexes were calculated and a proposal of the reaction pathway was postulated.