Biotechnology products for therapeutic use include a very diverse range of products. Some products are intended to mimic the human counterpart, whereas others are intended to differ from the human counterpart and may be analogues, chemically modified (e.g. pegylated) or novel products (e.g. single chain or fragment antibody products, gene transfer vectors, tissue engineered products). Most of these products are regulated as medicinal products; however the regulatory status of others such as some cell therapies and tissue: organ based products differs globally and falls within the borderline between the practice of medicine, medicinal devices and medicinal products.
Biotechnology derived pharmaceuticals may be derived from a variety of expression systems such as E. coli., yeast, mammalian , insects or plant cells, transgenic animals or other organism. The expressed protein or gene may have the identical amino acid or nucleotide sequence as the human endogenous form, or may be intentionally different in sequence to confer some technical advantages such as optimized pharmacokinectics or pharmacodynamics profile. The glycosylation pattern of protein products is likely to differ from the endogenous human form due to the different glycosylation preferences of the expression system used. Furthermore, intentional post translational modifications or alteration may be made such as pegylation. It is important for the toxicologist to be aware of the nature of the product to be tested in terms of primary, secondary and tertiary structure and any post translational modifications such as glycosylation status, particularly as these may be altered if the manufacturing system is modified.

Author: Rajshri Nagar