Polarographic study of a benzodiazepinooxazole: Cloxazolam
The polarographic behaviour of 10-chloro-11b-(2-chlorophenyl)-2,3,7,11b-tetrahydrooxazolo[3,2-d][1,4]-benzodiazipine-6(5H)-one (cloxazolam) was studied in the pH range 1–12. Cloxazolam suffers a hydrolysis process, which can be followed by polarography. The reduction processes of cloxazolam and its hydrolysis product are irreversible and their currents are diffusion-controlled. Two polarographic methods have been developed upon the basis of the reduction of both the protonated iminium form (pH 1.45, measurement time: 10 min) and the benzophenone produced in the hydrolysis process (pH 11.75, measurement time: 15 min). The relationship between reduction peak current and concentration is linear up to at least 5.72×10−5 mol/l for both methods. A higher sensitivity was obtained for the method based on the benzophenone reduction (detection limit 5.72×10−8 mol/l; 20 ppb). The methods developed were applied to the determination of cloxazolam in its pharmaceutical formulations (Betavel, 1 mg). The method in alkaline medium was the most adequate for the determination of the compound in tablets, with errors lower than 1%.
KeywordsReduction Peak Hydrolysis Process Drop Mercury Electrode Reduction Peak Current Differential Pulse Polarography
Polarographische Untersuchung eines Benzodiazepinoxazols: Cloxazolam
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