Biomedical subjects

Jinglin Zhong

Publications and source records attributed to Jinglin Zhong.

3 recordsLinked to original sources

PubMed2006

A practical approach to optimization and validation of a HPLC assay for analysis of polyribosyl-ribitol phosphate in complex combination vaccines.

The use of multi-factor statistical experimental design methodology minimized the vaccine material and laboratory resources required for optimization and validation of an HPLC assay for quantitation of depolymerized and total PRP. Components of the assay selected for optimization were adjuvant dissolution, ultracentrifuge conditions including ultracentrifuge model, sample diluent, mobile phase and column oven temperature. Previous experience has shown these components of the assay to be most troublesome and therefore required optimization prior to validation. Specificity, linearity, precision, accuracy and ruggedness were confirmed through a validation of the optimized assay. The validation also established the assay to be stability indicating, by showing that changes to the integrity of the PRP-OMPC conjugate could be detected.

Chromatography, High Pressure Liquid↗

PubMed2005

An automated homogeneous method for quantifying polysorbate using fluorescence polarization.

An automated fluorescence polarization (FP) assay has been developed for the quantitation of polysorbate in bioprocess samples. Using the lipophilic probe 5-dodecanoylaminofluorescein (DAF), polysorbate concentrations above the critical micelle concentration can be quantified by the FP increase that results when DAF inserts into the detergent micelles. The specificity, accuracy, and precision of this assay were defined for samples obtained from vaccine purification processes. Spike recoveries were 98-106% for purified products and 110-120% for crude process intermediates. The coefficients of variation for intra- and interassay precision were less than 9 and 14%, respectively. Because of the operational simplicity of the assay, all of the assay steps from sample preparation to data reduction were automated on a Tecan liquid-handling workstation. The combination of a rapid assay and an automated format makes this method well suited to the routine analysis of samples from trial purification processes which are carried out during the development of a vaccine or therapeutic protein. This method should be adaptable for the quantitation of other detergents into which DAF will insert.

Automation↗

PubMed2003

Monitoring the stability of human vaccines.

Postmarketing stability studies of vaccines that tend to be close to their clinical specification at the end of the expiration dating period may require enhanced annual monitoring. In addition, an early assessment of product stability prior to completion of each individual study is desired. However, predictive measures of individual lots may produce early indication of failure. In many cases, these prove to be false alarms. For such products, continued product quality after marketing should, therefore, depend less on evaluating individual observations or individual lot projections, and more on assuring that the underlying stability profile of the product as a whole has not changed. We propose a monitoring procedure and an index of the average quality of vaccine lots currently on the market. We explore the statistical properties of the index for several experimental designs for sampling of marketed lots, and we describe an optimality property of the index.

Drug Stability↗