Pharmaceutical products, particularly those that are aqueous or semi-solid, are susceptible to microbial contamination, which can compromise their safety and efficacy.
For Preservation of Pharmaceutical Products, antimicrobial preservatives are commonly added to formulations.
Types of Antimicrobial Agents Used in Preservation of Pharmaceuticals Products
1. Preservatives:
Parabens (Methylparaben, Propylparaben): Widely used due to their broad-spectrum antimicrobial activity.
Benzalkonium Chloride: Effective against bacteria and fungi; commonly used in ophthalmic and nasal preparations.
Phenol and Chlorocresol: Used in injectable products and antiseptics.
Alcohols (Ethanol, Benzyl Alcohol): Effective against bacteria and fungi; used in oral and topical formulations.
Quaternary Ammonium Compounds (Cetylpyridinium Chloride): Used in mouthwashes and lozenges.
2. Antioxidants:
These protect the product from oxidation, which can indirectly help in maintaining antimicrobial stability.
Examples include Ascorbic Acid and Butylated Hydroxyanisole (BHA).
3. Chelating Agents:
EDTA (Ethylenediaminetetraacetic Acid): Enhances the effectiveness of preservatives by binding metal ions that could otherwise stabilize microbial cell walls.
Mechanism of Action
1. Disruption of Cell Membranes:
Many preservatives, such as alcohols and quaternary ammonium compounds, disrupt microbial cell membranes, leading to cell lysis.
2. Inhibition of Metabolic Pathways:
Parabens and phenolic compounds can interfere with microbial enzyme systems.
3. Oxidative Stress:
Antioxidants can generate reactive oxygen species that damage microbial DNA and proteins.