Vol. 8, Issue 4 (2019)

Author(s):
Mousumi Bora, Sahzad, Sunil Shebannavar, TVS Rao and GS Reddy

Abstract:
Lactalbumin hydrolysate-sucrose (LS) as base formulations are commonly used as stabilizers for lyophilization of live viral vaccines. In the present study, the effect of gelatin hydrolysate along with LS (Stabilizer A) on the pellet profile and stability of lyophilized Peste-des-petits ruminants’ virus (PPRV) and Sheep pox (SPV) vaccines and gelatin hydrolysate, sodium glutamate and LS (Stabilizer B) on pellet profile and stability of Goatpox vaccine (GPV) have been assessed. Both the stabilizers along with LS as base formulations, were found to be effective with respect to consistence cake appearance, texture and dissolution time of ≤ 10±5 seconds of the lyophilized pellet. The vaccines with modified stabilizers were also tested for their efficacy in stabilizing lyophilized PPRV, SPV and GPV vaccines under real time (5±3 ℃) and accelerated storage conditions (25±1 ℃ and 36±1 ℃). Both the stabilizer formulations were found to be effective in extending the shelf-lives of vaccines up to at least 15.82, 21.55 and 13.32 days for PPRV, SPV and GPV vaccines respectively, at 36±1 ℃. At 25±1 ℃, SPV vaccine maintained a superior shelf-life (35.65 days) when to compared to PPRV (26.51 days) and GPV vaccine (28.1 days). All the vaccine batches maintained the minimum infectious titre in their lyophilized form (2.5 log₁₀CCID₅₀/dose for PPR and 3 log₁₀CCID₅₀/dose for SPV and GPV) at the end of 6 months of exposure period under real time conditions (5±3 ℃) thus providing an estimated shelf-life of at-least two years based on regression analysis. Thus, the stability evaluation of vaccines in the present study revealed that these vaccines can be effectively used for mass immunization programs in tropical field situations or during temperature excursion due to cold chain failures by delivering the required recommended dose in animals as they are found to be stable both at ambient as well as higher temperatures.