Vaccines are considered the most economical and effective preventive measure against most deadly infectious diseases. Vaccines help protect around three million lives every year, but hundreds of thousands of lives are lost due to the instability of vaccines. Each vaccine, including (a) live, attenuated bacterial (LAB) vaccines; (b) subunit vaccines; (c) live, attenuated viral vaccines; (d) recombinant vaccines; (e) conjugated polysaccharide vaccines; (f) inactivated viral vaccines; and (g) combination vaccines, has its own stability problems. The inherent lability of vaccines can critically limit their distribution, administration, and efficacy in parts of world where it is difficult to maintain a cold chain. Combination with other vaccines and oral administration may also compromise vaccine stability. Vaccine instability can be caused by light, heat, radiation, changes in the environment, or reactions with the container or with other components in the mixture. Even when optimal conditions are maintained, potency may decline gradually as time passes after production. Successful vaccine stabilization strategies include both empirical efforts to screen and identify appropriate stabilizers and environmental conditions and more rational approaches toward developing an understanding of the causes and mechanisms of vaccine inactivation. Among these, determining the appropriate stabilizer is a critical means of maintaining vaccine potency and efficiency. Such stabilizers stop chemical reactions from occurring in the vaccine and prevent the components from separating from each other or sticking to the vaccine vial during transportation and storage. Over longer time scales of storage, combinations of stabilizers preserved the most vaccine activity.
Common vaccine stabilizers
If a wide variety of vaccine stabilizers could be successfully applied to more vaccines, the public health benefits would be enormous. The main categories of common vaccine stabilizers are as follows.
- Generally, most of the stabilizers found in commercial viral vaccines are considered as safe protein excipients such as human serum albumin and/or gelatin. These rich formulations are required due to the high level of complexity and intrinsic instability of active pharmaceutical ingredient in live-attenuated vaccines and inactivated vaccines, requiring lyophilized formulation, were gelatin plays a decisive stabilization role.
- Amino acids are also an important vaccine stabilizer. Amino acid mixtures are used for increasing protein solubility and stability. There are several reasons for amino acid presence in the vaccine formulations, depending on the amino acid physicochemical characteristics. For example, the histidine has antioxidant and buffering properties, by scavenging HO- radicals in solutions and by controlling pH and stabilizing non-covalent interaction of solid-state proteins. Another interesting amino acid is arginine, which is widely known for preventing protein aggregation by interacting with aromatic and charged protein residues.
- Another important stabilizer group within vaccine formulation are sugars (mono /di/polysaccharides). In fact, approximately one third of therapeutic proteins in the pharmaceutical industry are stabilized in sugar glasses, which demonstrate their wide use as well as proven stabilizing and protective potential. The sucrose and sorbitol are the most mentioned sugar stabilizers in licensed vaccine list.
What we offer
Alfa Chemistry supplies vaccine stabilizers to companies researching vaccines. If you cannot find the vaccine stabilizer you need, please contact us. We also offer product customization according to customer's detailed requirements.
Our products and services are for research use only and cannot be used for any clinical purposes.