Effects of Hydroxypropyl-ß-cyclodextrin on the Chemical Stability of a Naphthoquinone in Aqueous Solutions

LINARES MARCELA AND LONGHI MARCELA

PHARMAZIE

Govi-Verlag

Lugar: Eschborn, Germany; Año: 2003 vol. 58 p. 33 - 37

0031-7144

2-hydroxy-N-(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinone-4-imine (1), an antibacterial agent, was shown to form inclusion complexes with HP-ß-CD in aqueous solution. In the present work the kinetics of 1 degradation in aqueous buffer solution was investigated as a function of pH (2.34-3.95), HP-ß-CD concentration (0%-28% (w/v)) and temperature (60-90 ºC). A second-order derivative spectroscopic methodology was developed for the kinetic investigations. The degradation showed to follow pseudo-first-order kinetics. Also, an specific acid catalysis was found and the introduction of up to 28 % (w/v) HP-ß-CD to the reaction medium did not change this kinetic behaviour. The obtained results indicated that HP-ß-CD stabilises 1 against degradation in aqueous solutions.