ABSTRACT
Vaccines available on the market contain various types of antigens, adjuvants, and additives, which in combination provide maximum protection against several infectious diseases. These vaccines might contain live or killed viruses, purified viral proteins, inactivated bacterial toxins, and polysaccharides or purified subunit recombinant proteins. The diverse nature of these antigens requires different excipients to be used to stabilize them for use within their designated shelf life. Because the total vaccine doses used each year globally average several million in number, the selection of an excipient for a vaccine formulation is a serious task having huge implications toward safety, stability, and storage. Also, in recent years, certain preservatives used in some vaccines such as thimerosal have been highlighted for their possible contributions to unwarranted reactogenicity in infants and adults.
