Preparation, characterization, and in vivo evaluation of a polymorphic form of valnemulin hydrogen tartrate

We prepared a polymorphic form of valnemulin hydrogen tartrate (Form I) to overcome the instability and irritating odor of valnemulin hydrochloride that affect its use in the production and application of veterinary drugs. The physicochemical properties of Form I were characterized by scanning electron microscopy, X-ray powder diffraction, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The results showed the crystal structure and thermal properties of Form I were very different from those of a commercially available form of valnemulin hydrogen tartrate (Form II). Form I and Form II were more stable than valnemulin hydrochloride after storage under irradiation and high humidity conditions, respectively. The solubility of Form I was 2.6 times that of Form II, and Form I was selected for use in pharmaceutical kinetics experiments in vivo. Compared to valnemulin hydrochloride, after oral administration at a dose of 10 mg/kg in pigs, Form I had similar pharmaceutical kinetic behavior but a slightly higher area under the concentration–time curve from time zero to the last measurable concentration. Consequently, Form I should be suitable for the development of simple formulations and be effective in the clinical application of veterinary drugs.

Preparation and characterization of follwing the national standard anti-Brucella abortus serum, bovine / 生物工程学报

To prepare anti-Brucella abortus serum used for calibrate the agglutination test follwing the national standard, 4 anti-Brucella abortus sera were obtained from 4 cows infected with Brucella abortus naturally. By potency testing, the third serum was selected. Sterility, vaccum degree, residual moisture, uniformity and stability of this standard material were tested and proved to meet the national standard. Referring to the international standard, RBT (Rose-Bengal plate agglutination test), SAT (standard tube agglutination) and CFT (complement fixation test) titers of this standard material were measured to be 1:160 "+" 1:2 400 "++" and 1:800 "++", which are identical with the collaborative assay results. International unit of the standard material is 4 000 IU/mL.