Tetracycline (TCH), oxytetracycline (OTCH) and chlortetraculine (CTCH) determination using a flow injection potentiometric system

• Type: Article in International Scientific Journal
• Date: 1998

Authors

Couto, CMCM (Author) Other; Lima, JLFC (Author) Other; Montenegro, MCBSM (Author) FFUP; Reis, S (Author) FFUP

Journal

Title: Journal de Pharmacie de Belgique

Vol. 53

Final page: 176

ISSN: 0047-2166

Publisher: Algemene Pharmaceutische Bond

Indexing

ISI Web of Knowledge

Scopus - 0 Citations

Other information

Authenticus ID: P-007-GE4

Abstract (EN): Tetracycline (TC) family members are extensively used in human and veterinary therapy due to their broad-spectrum antibiotic properties. The large number of potential binding sites in its hydronaphtacene skeleton, allow these molecules to readily form metal complexes in solution, which permits its indirect determination (1). This work reports tetracycline, oxytetracycline and chlortetracycline determination taking advantage of the operational characteristics of potentiometric flow injection analysis (2). The detector used was a homogeneous crystalline CuS/Ag2S (1:1) double membrane tubular electrode with increased sensitivity (3), that monitored the Cu(II) decrease in the reagent solution, due to its complexation with TC. The proposed system, after optimization, allowed TC determination in a 50 ppm - 4.9×104 ppm concentration range, accomplishing 150 to 200 samples h-1. Analysis of the available pharmaceutical preparations by FIA showed a good agreement between the proposed method and UV spectrophotometry (4), with 2% precision and with a Cu(II) consumption less than 13 ¿g determination-1. The work also reports the determination of the acidity constants of TC and the stability constants of the binary Cu(II) - TC complexes. Formation constants were potentiometrically determined with a glass electrode at 25 ± 0.4 °C and ¿ = 0.1 mol L-1 (NaCl) and experimental titrations were analysed using Superquad and Best computer programs.

Language: English

Type (Professor's evaluation): Scientific