Effect of Radiation Sterilization on Alprenolol in the Solid State Studied by High-Performance Thin-Layer Chromatography

Abstract

The possibility of radiation sterilization of alprenolol (AL) has been studied. Irradiation of AL in solid form with a 25 kGy beam of electrons caused only an insignificant change in color that became more intense with increasing irradiation dose. Moreover, with increasing dose a decrease in pH, the content of water, and the degree of crystallinity were observed. AL in solid form was radiated with a high-energy electron beam (9.96 MeV) at doses from 25-400 kGy and analyzed by HPTLC using the mobile phase methanol-ammonia 25% (99 + 1, v/v). Densitometric analysis was carried out directly from chromatograms at 270 nm. The applied method was validated and characterized by good precision (RSD = 3.95%); good accuracy (80% level 100.15%, 100% level 99.99%, and 120% level 104.44%); and low LOD (LOD = 0.52 microg/zone and LOQ = 1.55 microg/zone). Chromatograms recorded for samples irradiated at the doses of 25 kGy were unchanged, but at higher doses (100-400 kGy) additional peaks corresponding to the radiodegradation products appeared (Rf = 0.24 and Rf = 0.40). The decrease in the concentration of AL was proportional to the applied radiation dose, and for 400 kGy the concentration of AL was 90.23%. The calculated radiolytic yield of the radiodegradation process was G(-AL) = 7.12 x 10(-7) mol/J.