Dg. Musson et al., STABILIZATION OF AQUEOUS THYMOXAMINE USING DIMETHYL-BETA-CYCLODEXTRIN, International journal of pharmaceutics, 99(2-3), 1993, pp. 85-92
Moxisylyte (or thymoxamine) is an alpha-adrenoceptor blocking agent us
ed to reverse mydriasis. The drug molecule has an ester moiety which i
s vulnerable to acid and base catalyzed hydrolysis. Long-term storage
of the drug at room temperature has not been possible because of this
hydrolysis. An accelerated, stability-indicating assay was developed t
o study the hydrolysis and modify the formulation for room temperature
storage (instead of refrigeration). Stability studies with pH variati
on and with beta-cyclodextrins resulted in a formulation with dimethyl
-beta-cyclodextrin at pH 5.0. All other available beta-cyclodextrins e
ither accelerated the hydrolysis or had little effect.