Assay protein pharmaceuticals

Protein concentration is the most fundamental and one of the most important analytical end-points for a protein pharmaceutical. It is used for dosage determination, as a basis for specific biological activity calculations, to normalize sample concentrations for many release assays, to establish process yields, and it can be stability-indicating. 

Of primary concern is consistency of dosing at all stages of development, from animal toxicology studies through clinical trials and on to the commercial market. The dosage for most protein pharmaceuticals is based on mass of protein delivered. Therefore, having a precise, routine protein assay is paramount for... 

Latex agglutination immunoassays are easily formatted into simple kits which can provide yes/no and semiquantitative estimates of antigen (or antibody) in a sample. The first such assay was developed in 1957 for rheumatoid factor (15) and assays are on the market for the deterrnination of many species of bacteria, fungi. Mycoplasma, parasites, ckettsia, and vimses, as well as for the deterrnination of autoimmune disease, hormones (qv), dmgs (see Pharmaceuticals), and blood proteins (16). Latex agglutination is also the basis of many home pregnancy tests. 

Current analytical methods have difficulty detecting picogram levels of nucleic acids, particularly when high levels of other biopolymers (e.g., proteins) are present. The most widely used assay method employed by the pharmaceutical industry involves a nick translation DNA hybridization method (1). This assay offers high sensitivity and selectivity but has a number of drawbacks. 

Additional assays used in early pharmaceutical property profiles usually include plasma protein binding, individual cytochrome P450 assays, stability in the presence of serum, production of metabolites likely to be involved in covalent binding to biomolecules, and interaction with efflux pumps ... 

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