Solubilization of tropicamide by hydroxypropyl-beta-cyclodextrin and water-soluble polymers: in vitro/in vivo studies.
Int J Pharm
; 213(1-2): 75-81, 2001 Feb 01.
Article
em En
| MEDLINE
| ID: mdl-11165095
ABSTRACT
1% (w/v) aqueous solutions of tropicamide (TR), a poorly water-soluble mydriatic-cycloplegic drug, are usually obtained by adjusting the pH to approximately 5.0, at the expense, however, of ocular tolerance and bioavailability. The capacity of hydroxypropyl-beta-cyclodextrin (HP-beta-CD) to solubilize TR in pH 7.4 0.02 M phosphate buffer was investigated in the absence and presence of hydrophilic polymers (PVP, CMC and HPMC). Approximately 3.5% (w/v) HP-beta-CD was required to solubilize 1% (w/v) TR in pH 7.4 buffer at room temperature. The required amount was reduced to 0.9% (w/v) by heating at 120 degrees C in the presence of 0.1% (w/v) HPMC. Mydriatic activity tests in rabbits showed an improved bioavailability and maximal mydriatic response for two CD formulations, with and without HPMC, when compared to standard 1% (w/v) TR eyedrops, buffered at pH 5.0. The improved in vivo behaviour of the CD formulations are likely due to their physiological pH, resulting in a reduced irritant effect, although an effect of HP-beta-CD on corneal permeability cannot be dismissed a priori.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tropicamida
/
Ciclodextrinas
/
Beta-Ciclodextrinas
/
Midriáticos
Limite:
Animals
Idioma:
En
Revista:
Int J Pharm
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Itália
País de publicação:
HOLANDA
/
HOLLAND
/
NETHERLANDS
/
NL
/
PAISES BAJOS
/
THE NETHERLANDS