Comparative Assessment of Stabilizers Used for Freeze-Drying T₁/44 Contagious Bovine Pleuropneumonia Vaccine (CBPPV) Produce in Nigeria

The effect of using 85% buffered sucrose solution plus gelatin ("S") as stabilizer and a combination of buffered sucrose/lactalbuminhydrolysate solution in ratio 20:5% (w/w), respectively with gelatin ("L") as stabilizer during freeze-drying process and under varying storage temperature conditions on CBPP vaccine was investigated. It was found that both stabilizers gave good freeze-dried preparation of T1/44 CBPP vaccines. During the process of freeze-drying, there was a total average loss of 4.73 cfu mL 1viable organisms in vaccine with stabilizing medium "L" plus gelatin and an average loss of 5.25 cfu mL 1 viable organisms for vaccine with stabilizing medium "S" plus gelatin. The results favoured the choice of sucrose/lactalbuminhydrolysate plus gelatin stabilizer on viability of T1/44 Mycoplasma mycoides subsp. mycoides during freeze-drying process. Vaccine with stabilizing medium "L" plus gelatin stored at +4 C for 15 months maintained sufficient viable mycoplasma to protect cattle. The vaccine titre dropped from 1.5 109-4.3 107 cfu mL 1, while vaccine with stabilizing medium "S" plus gelatin for the same period dropped from 3.1 109-1.8 107 cfu mL 1. At room temperature of 25 C, the 2 types of vaccines maintained sufficient viable mycoplasma up to 4 months, but detrimental as the titre may drop suddenly when reconstituted for vaccination in the field. Storage of this vaccine at 37 C is not recommended for the same reason stated above.