Acid-base properties and solubility of pindolol, diazepam and chlordiazepoxide in SDS micelles

• Type: Article in International Scientific Journal
• Date: 1999

Authors

de Castro, B (Author) FCUP; Domingues, V (Author) Other; Gameiro, P (Author) FCUP; Lima, JLFC (Author) FFUP; Oliveira, A (Author) Other; Reis, S (Author) FFUP

Journal

Title: International Journal of Pharmaceutics

Vol. 187

Pages: 67-75

ISSN: 0378-5173

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 20 Citations

Scopus - 27 Citations

Scientific classification

FOS: Medical and Health sciences > Basic medicine

Other information

Authenticus ID: P-001-39J

DOI: 10.1016/s0378-5173(99)00148-9

Abstract (EN): The effect of sodium dodecyl sulphate (SDS) on the acid-base properties and on the solubility of a beta-blocker (pindolol) and of two benzodiazepines (diazepam and chlordiazepoxide) has been assessed. The study was performed by potentiometric and spectrophotometric determinations of the acidity constants and by spectrophotometric evaluation of the solubilities of the pharmaceutical drugs in aqueous solution and in solutions to which was added SDS with concentrations below and above the critical micelle concentration (cmc), at 25 degrees C and at an ionic strength 0.1 M (NaCl). The effect of the organized assemblies on the pK(a) values was quantified by the application of two theoretical models that differ in the inclusion of ionic exchange between positively charged species in solution. These models have allowed the determination of the binding constants for drug/micelle and yielded values in good agreement with those obtained by the solubility method, and in addition provide a more detailed picture of the effect of drug charge on its partition. The results can be taken to evidence different interaction modes of the drugs with the SDS micelles.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9