A preparation method for long-acting veterinary compound doxycycline hydrochloride injection it is to carry out according to the following steps: get suitable quantity of water add chelating agent make to dissolve or suspendible add again antioxidant make to dissolve after add doxycycline hydrochloride stir be warming up to 60-80 ℃ chelating 2-3 hour standby.Separately get compound organic solvent be heated to 80 ℃-100 ℃ add sulfamonomethoxine make to dissolve.Mix above-mentioned two liquid with ethanolamine regulate pH value to 5.0-7.0 add water to full dose filter subpackage sterilizing packing obtains.Advantage of the present invention is: (1) preparation chelating degree is high steady quality; (2) prolongation of effect agent gets final product hydrotropy again can prolongation of effect make by after normal dose single administration and effective drug duration can reach 72 hours; (3) preparation antimicrobial spectrum augmentation antibacterial efficacy strengthens clinical efficacy is significantly better than folk prescription doxycycline hydrochloride injection can be widely used in respiratory tract urogenital tract gastrointestinal tract or the mixed infection of the initiations such as various antibacterials mycoplasma chlamydia and toxoplasma of animal.(4) preparation production technique is stable.

暂无附图