Rapid, high throughput protein estimation method for saponin and alhydrogel adjuvanted R21 VLP Malaria vaccine based on intrinsic fluorescence

Aluminum Adjuvants-'Back to the Future'

Aluminum-based adjuvants will continue to be a key component of currently approved and next generation vaccines, including important combination vaccines. The widespread use of aluminum adjuvants is due to their excellent safety profile, which has been established through the use of hundreds of millions of doses in humans over many years. In addition, they are inexpensive, readily available, and are well known and generally accepted by regulatory agencies. Moreover, they offer a very flexible platform, to which many vaccine components can be adsorbed, enabling the preparation of liquid formulations, which typically have a long shelf life under refrigerated conditions. Nevertheless, despite their extensive use, they are perceived as relatively 'weak' vaccine adjuvants. Hence, there have been many attempts to improve their performance, which typically involves co-delivery of immune potentiators, including Toll-like receptor (TLR) agonists. This approach has allowed for the development of improved aluminum adjuvants for inclusion in licensed vaccines against HPV, HBV, and COVID-19, with others likely to follow. This review summarizes the various aluminum salts that are used in vaccines and highlights how they are prepared. We focus on the analytical challenges that remain to allowing the creation of well-characterized formulations, particularly those involving multiple antigens. In addition, we highlight how aluminum is being used to create the next generation of improved adjuvants through the adsorption and delivery of various TLR agonists.

A novel high throughput plate-based method for 2-PE quantification in novel multidose vaccines (R21 malaria, Covishield and Covovax) and combination vaccines (Hexavalent)

Multidose presentation of vaccines is the most preferred choice, for mass immunization particularly during pandemics. WHO also recommends multidose containers of fill finished vaccines for programmatic suitability and global immunizations programmes. However, multidose vaccine presentations requires inclusion of preservatives to prevent contaminations. 2-Phenoxy ethanol (2-PE) is one such preservative which is being used in numerous cosmetics and many vaccines recently. Estimation of 2-PE content in multidose vials is a crucial quality control parameter to ensure in use stability of the vaccines. Presently available conventional methods, have their own limitation in terms of being time consuming, requiring sample extraction, large sample volume requirement etc. Therefore, a robust, simple, high-throughput method with a low turnaround time was required, which can quantitate 2-PE content in the conventional combination vaccines as well as new generation complex VLP based vaccines. In order to address this issue, a novel absorbance-based method has been developed. This novel method specifically detects 2-PE content in Matrix M1 adjuvanted R21 malaria vaccine, nano particle and viral vector based covid vaccines and combination vaccines like Hexavalent vaccine. The method has been validated for parameters such as linearity, accuracy and precision. Importantly, this method works even in presence of high amounts of proteins and residual DNA. Considering the advantages associated with method under study, this method can be used as an important in process or release quality parameter to estimate the 2-PE content in various vaccines containing 2-PE in multidose presentations.