Aromatic Carboxylate Ions Stabilize Proteins Against Preservative Degradation
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Solution Overview
Problem
Proteins in aqueous formulations are unstable in the presence of preservatives, particularly aromatic preservatives like phenol or m-cresol, leading to degradation and loss of activity, especially at ambient temperatures, due to chemical and physical instability issues.
Innovation Solution
Incorporating aromatic carboxylate ions, such as benzoate ions, into the formulation at a pH at least 1 unit greater than the pKa of benzoic acid to stabilize proteins and reduce degradation caused by phenolic preservatives, thereby maintaining protein integrity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aromatic preservatives like phenol or m-cresol are added to prevent bacterial growth, then microbial protection is improved, but protein stability deteriorates due to chemical and physical degradation
Solution Approach 1:
The patent introduces aromatic carboxylate ions (such as benzoate ions) as intermediary substances that mediate between the aromatic preservative and the protein. These ions interact with the aromatic preservative to form complexes, thereby reducing the direct harmful interaction between the preservative and the protein while maintaining the preservative's antimicrobial effectiveness.
2Stability of the object's composition
If storage temperature is reduced to improve protein stability, then protein degradation is reduced, but storage and handling complexity increases
Solution Approach 1:
The patent changes the chemical parameters of the formulation by introducing aromatic carboxylate ions, which fundamentally alters the interaction dynamics between the preservative and protein. This parameter change allows the system to maintain protein stability at higher temperatures, effectively shifting the temperature-stability relationship without requiring complex storage infrastructure.
3Stability of the object's composition
If aromatic carboxylate ions are added to stabilize proteins, then protein stability is improved, but formulation complexity increases
Solution Approach 1:
The aromatic carboxylate ions serve multiple functions simultaneously: they stabilize the protein against aromatic preservative-induced degradation, maintain preservative efficacy against microorganisms, and can contribute to the overall buffering capacity of the formulation. This multi-functionality reduces the need for additional separate additives.
Data Source
AI summary
The invention relates to the discovery that the addition of aromatic carboxylate ions inhibit protein instability caused by aromatic preservatives. Thus, the invention relates to compositions, preferably aqueous compositions, comprising a protein, an aromatic preservative and aromatic carboxylate ions. The proteins remain stable and suitable for storage at ambient temperatures or lower, even in aqueous form. Preferably, the aqueous composition comprises a protein, a phenolic preservative and benzoate ions, wherein the pH of the composition is at least 1 unit greater than the pKa of benzoic acid. The invention also provides methods of reducing protein degradation by aromatic preservatives in an aqueous formulation of a protein susceptible to such degradation, comprising the step of adding aromatic carboxylate ions to the formulation wherein the formulation is maintained at a pH that is at least 1 unit greater than the pKa of the corresponding aromatic carboxylic acid.