Stability of a second-generation cephalosporin veterinary mastitis formulation after electron beam irradiation

Abstract

The objective of this study was to characterize the moisture sorption of magnesium stearate and the morphological changes, if any, resulting from moisture sorption. Six samples of commercial magnesium stearate USP were examined. Moisture sorption isotherms were obtained at 25 degrees C and 5% to 98% relative humidity (RH) using a moisture balance. Changes in crystal form resulting from moisture sorption were determined by x-ray diffraction. There were differences in the shape of the isotherm, reversibility of moisture uptake, and shape of the hysteresis loop in the isotherms of crystalline and amorphous magnesium stearates. The isotherm of crystalline magnesium stearate was almost parallel to the pressure axis until an RH of ~80% was reached, when there was desorption of practically all of the adsorbed water. The isotherm of the amorphous sample was characterized by continuous uptake of water over the entire range of RH. Exposure of amorphous magnesium stearate to RH greater than 70% resulted in the formation of the trihydrate. The trihydrate was converted into the anhydrous form when heated to a temperature of 100 degrees C to 105 degrees C. The trihydrate could be generated by exposing the anhydrate to RH higher than 70%.

Study on gamma and electron beam sterilization of third generation cephalosporins cefdinir and cefixime in solid state

“…It was shown in a study on the effect of b-radiation (e-beam) on penicillin that irradiation at 25 kGy dose with b-radiation did not cause any significant qualitative and quantitative change (Marciniec et al, 2002). Some of the parenteral veterinary cephalosporins irradiated with e-beam were also found to be sufficiently stable (Johns et al, 2003). In a feasibility study performed on cefazolin sodium (a first generation cephalosporin), the color modification was found to be a limitation to radiosterilization (Crucq et al, 2000).…”