An evaluation of the efficacy of injectable microencapsulated vitamin B12 in increasing and maintaining the serum and liver vitamin B12 concentrations of lambs

Aim. To develop a long-acting Vitamin B-12 injection to prevent Co deficiency in sheep. Methods. Formulations of microencapsulated Vitamin B-12 in lactide-glycolide polymers were injected intramuscularly or subcutaneously into the anterior neck region of groups of 10 lambs and their efficacy determined from changes in serum and liver Vitamin B-12 concentrations. Results. The 95:5 lactide glycolide and the 100 lactide formulations containing more than 12.5% Vitamin B-12 w/w significantly increased and maintained serum Vitamin B-12 concentrations for at least 210 days as well as liver Vitamin B-12 concentrations in treated lambs when compared with untreated controls. Conclusions. Injections of microencapsulated Vitamin B-12 in lactide/glycolide copolymers are able to increase and maintain the Vitamin B-12 status of lambs for at least 210 days. Clinical significance. Another option for the prevention of Co deficiency in sheep is now available using a long acting injectable Vitamin B-12.