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Stability of protein drugs

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Name: MD. Zahirul IslamRoll:333

Batch:12th World University Of Bangladesh

Dept. Of Pharmacy

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Stability of protein drugs

A biopharmaceutical, also known as a biological medical product, biological, or biologic, is any pharmaceutical drug product manufactured in, extracted from, or semi synthesized from biological sources are called protein drugs.

Protein drugs

Protein stability is the net balance of forces, which determine whether a protein will be in its native folded conformation or a denatured state.

Protein stability normally refers to the physical (thermodynamic) stability, not the chemical stability

Stability of Protein

Irreversible protein aggregation is problematic in the biotechnology industry, where aggregation is encountered throughout the lifetime of a therapeutic protein, including during refolding, purification, sterilization, shipping, and storage processes. The purpose of the current review is to provide a fundamental understanding of the mechanisms by which proteins aggregate and by which varying solution conditions, such as temperature, pH, salt type, salt concentration, cosolutes, preservatives, and surfactants, affect this process.

Physical stability of protein

Chemical stability involves loss of integrity due to bond cleavage.◦deamination of asparagine and/or glutamine

residues, ◦hydrolysis of the peptide bond of Asp residues at

low pH, ◦oxidation of Met at high temperature, ◦elimination of disulfide bonds ◦disulfide interchange at neutral pH

Other processes include thiol-catalyzed disulfide interchange and oxidation of cysteine residues.

Chemical Stability of protein

Denaturation of proteins involves the disruption and possible destruction of both the secondary and tertiary structures. Since denaturation reactions are not strong enough to break the peptide bonds, the primary structure (sequence of amino acids) remains the same after a denaturation process.

Denaturation of proteins

The process by which proteins or complementary strands of nucleic acids re-form their native conformations. [From renature, to undergo renaturation : re- + (de)nature.]

Renaturation of protein

Proteins consist of combinations of amino acids. Body proteins include structural proteins, enzymes, hormones and antibodies. The shape of an enzyme allows it to speed up a biological reaction.

hormonal enzyme of protein

Heat will destroy what is called the tertiary structure (the 3D structure) of protein, these are the helices, folds, etc. 

It results in a very random appearing, tangled molecule. Structure gives the protein a function, and most biologically active proteins are enzymes, they catalyze reactions or create other molecules. But not after heating. That is why heat kills bacteria - it destroys the structure and function of its enzymes. 

Egg white actually turns white when it is denatured. Beef turns brown.

effect of heat on protein

Residual moisture content has a significant impact on the solid-state stability of biopharmaceutical products. Protein degradation due to residual moisture is minimal at or below the monolayer level of hydration owing to low availability of water and limited dynamic activity of the protein. However, residual moisture content beyond a monolayer generally results in increased rates of decomposition due to the enhanced conformational flexibility of the protein and the ability of the less tightly bound water to mobilize reactants.

Effect of Moisture on protein

Four types of attractive interactions determine the shape and stability of a protein. The two that pH changes affect are salt bridges (a) and hydrogen bonding (b). Salt bridges are ionic bonds between positively and negatively charged side chains of amino acids.

Effects on pH of proteins

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