Comparative efficacy of chemical stabilizers on the thermostabilization of a novel live attenuated buffalopox vaccine M.S. Siva Sankar, V. Bhanuprakash *, 1 , G. Venkatesan, D.P. Bora 2 , M. Prabhu 3 , R. Yogisharadhya 4 Division of Virology, ICAR- Indian Veterinary Research Institute, Mukteswar Campus, Nainital [District], Uttarakhand 263 138, India article info Article history: Received 13 January 2017 Received in revised form 6 July 2017 Accepted 8 July 2017 Available online xxx Keywords: Buffalopox vaccine Diluents Stabilizers Thermostability abstract In the present investigation, the thermostability of a live attenuated buffalopox vaccine prepared with an indigenous baffalopox virus isolate (BPXV Vij/96) and freeze-dried under conventional lyophilizing conditions is described. Three different stabilizer combinations like LS (lactalbumin hydralysate þ sucrose), LHT (lactalbumin hydralysate þ Trehalose dihydrate) and TAA (Trehalose dihydrate þ L- Alanine þ L-Histidine) were used to prepare the vaccine. The study indicated that the LS stabilizer was found to be the stabilizer of choice followed by LHT and TAA for buffalopox vaccine at all temperatures studied. The presence of stabilizers has beneficial influence in preserving the keeping quality of the vaccine. Further, among the diluents used to reconstitute the freeze-dried buffalopox vaccine, double distilled water, 0.85% normal saline solution and phosphate buffer saline were the choice of diluents in that order. However, 1M MgSO 4 did not perform well at higher temperatures. Investigation suggests for using LS as a stabilizer for freeze-drying and any of the three diluents except 1MgSO 4 for reconstitution of buffalopox vaccine. © 2017 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved. 1. Introduction Buffalopox affects buffaloes and rarely cows and humans [1e4]. The disease causes local and generalized pox lesions including mastitits in milch animals. In draught animals, it reduces the working capacity of the animal [1]. The disease has been reported from India, Pakistan, Egypt, Nepal and Bangladesh [1]. Pox-like- infections caused by Vaccinia virus (VACV) - like agents', namely Cantagalo [5] and Aracatuba [6] have been reported from Brazil. The disease is important due to its economic and public health impact. The causative agent is buffalopox virus (BPXV) belongs to Orthopoxvirus (OPV) genus of Chordopoxvirinae subfamily and the Poxviridae family. Buffalopox is difficult to control in countries where the disease is endemic. In such circumstances, the choice of control is vacci- nation. In this direction, a Vero cell attenuated buffalopox vaccine using indigenous buffalopox virus (BPXV Vij/96) has been devel- oped in the authors' laboratory (Indian Patent filed). Like any other vaccines, attenuated buffalopox vaccine is no exception in thermo- instability. The vaccine requires cold-chain for storage and trans- port. As a result, the cost of production and transportation are high and users' expenses are unavoidable, especially in developing countries like India. Therefore, evaluation of stability of the vaccine is a requisite in order to maintain the efficacy of the vaccine, which is normally affected due to temperature and other factors. Stable viral vaccines are efficacious. The stability of the vaccine depends on heat sensitivity of the virus, nature of stabilizer, the pH of the vaccine and the vaccine vial. Among the extrinsic factors, temperature has great influence on the quality of a vaccine. A lot of emphasis has been given on the vaccine quality studies performed under real storage conditions, in real-time, and other relevant environmental factors. It is a requirement to have vaccine stability data prior clinical trial of a vaccine as the stability of the vaccine ensures its shelf-life [7e9]. Further, each host is expected to receive a recommended dose depending on the vaccine. It is known that * Corresponding author. E-mail address: bhanu6467@gmail.com (V. Bhanuprakash). 1 Present address: FMD Laboratory, ICAR- Indan Veterinary Research Institute, H A Farm, Hebbal, Bengaluru 560 024, Karnataka, India. 2 Present address: Department of Microbiology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati 781 022, Assam, India. 3 Present address: Sheep Breeding Research Station, Sandynallah 643 237, Tamil Nadu Veterinary and Animal Science University, The Nilgiris District, Tamil Nadu, India. 4 Present address: National Institute of Veterinary Epidemiology and Disease Informatics, Yelahanka, Bengaluru, 560064, Karnataka, India. Contents lists available at ScienceDirect Biologicals journal homepage: www.elsevier.com/locate/biologicals http://dx.doi.org/10.1016/j.biologicals.2017.07.002 1045-1056/© 2017 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved. Biologicals xxx (2017) 1e7 Please cite this article in press as: Siva Sankar MS, et al., Comparative efficacy of chemical stabilizers on the thermostabilization of a novel live attenuated buffalopox vaccine, Biologicals (2017), http://dx.doi.org/10.1016/j.biologicals.2017.07.002