Effect of hexadecyltrimethylammonium bromide-based microemulsions on the rate of decomposition of the beta-lactam antibiotic cephaclor


Autoria(s): Oliveira, Anselmo Gomes de; Scarpa, Maria Virgínia; Chaimovich, Hernan
Contribuinte(s)

Universidade Estadual Paulista (UNESP)

Data(s)

20/05/2014

20/05/2014

01/05/1997

Resumo

Microemulsions of hexadecyltrimethylammonium bromide (HTAB)/n-butanol/hexadecane/water catalyze the intramolecular degradation of cephaclor. The rate increase is a sensitive function of the microemulsion volume fraction and salt concentration. The effects of microemulsions, analyzed quantitatively using a pseudophase ion-exchange model, assumed that the extent of ion dissociation from the microemulsions varies with volume fraction. Comparison of micellar and microemulsion effects on the same reaction shows that microemulsions are less effective catalysts. Acceleration decreased significantly by increasing the relative proportion of n-butanol ratio in microemulsions and by addition of n-butanol in HTAB micelles. Comparison of the activation parameters of the reaction in aqueous solution, microemulsions, and micelles suggests that catalysis by both aggregates is driven mainly by entropic contributions.

Formato

616-620

Identificador

http://dx.doi.org/10.1021/js9602599

Journal of Pharmaceutical Sciences. Washington: Amer Pharmaceutical Assn, v. 86, n. 5, p. 616-620, 1997.

0022-3549

http://hdl.handle.net/11449/130652

10.1021/js9602599

WOS:A1997WX10100015

2-s2.0-0030974139

Idioma(s)

eng

Publicador

Amer Pharmaceutical Assn

Relação

Journal of Pharmaceutical Sciences

Direitos

closedAccess

Palavras-Chave #Butanol #Cefaclor #Cetrimide #Hexadecane #Dissociation #Drug decomposition #Drug degradation #Drug solubility #Entropy #Ion exchange #Microemulsion #Molecular dynamics #Catalysis #Cefaclor #Cephalosporins #Cetrimonium Compounds #Emulsions #Kinetics #Thermodynamics
Tipo

info:eu-repo/semantics/article