A stability-indicating assay and the preformulation characteristics of the radiosensitizer, 1,2,4-benzotriazin-3-amine 1,4-dioxide.

A stability-indicating LC assay was developed for the analysis of 1,2,4-benzotriazin-3-amine 1,4-dioxide and applied to the preformulation characterization of the drug. The dissociation constants of the drug were determined using UV-vis spectrophotometry. The LC method was used to determine the aqueous stability of the drug under a variety of accelerated conditions, its solubility in a variety of pharmaceutical solvents and its octan-1-ol-water partition coefficient. The preformulation data were used to develop three prototype aqueous formulations of the drug at a concentration of 0.5 mg ml-1 in 5% Dextrose Injection USP, phosphate buffer (pH 7.4) and phosphate buffered mannitol. The 3-month stability of those formulations at room temperature was demonstrated.

Characterization of sulphoalkyl ether derivatives of beta-cyclodextrin by capillary electrophoresis with indirect UV detection.

A capillary electrophoresis method which characterizes the degrees of substitution of heterogeneous sulphoalkyl ether beta-cyclodextrin derivatives is described. The separation is based on the different electrophoretic mobilities observed from changes in the overall charge of the molecule as a result of substitution. Individual peaks of the electropherogram then provide a measure of each degree of substitution of the present beta-cyclodextrin. Detection of these beta-cyclodextrin derivatives is performed by indirect UV detection.