How drug preservatives help to increase the shelf life of tablets

How drug preservatives help to increase the shelf life of tablets

Preservatives play a critical role in medications like acetaminophen, insulin, and cough syrup to restrict microbial contamination. But do you know they play an extremely important role in increasing tablet shelf life?

However, the FDA meticulously studies and regulates the use of preservatives in food and drugs. These preservatives typically come under the category of "inactive ingredients" within medications and drugs. The agency's Inactive Ingredients Database furnishes details regarding inactive ingredients found in FDA-sanctioned drug products.

Role of FDA in preservative usage

The incorporation of preservatives into products, particularly those with higher water content, should prevent alteration and degradation by microorganisms during storage. Additionally, manufacturers use various ingredients in formulating the desired dosage form of a drug substance. Some of these agents are used to attain the intended physical and chemical attributes of the product or to enhance its appearance, scent, and flavor.

As per the FDA regulations, each added ingredient should not surpass the minimum amount necessary to achieve its intended effect, should not compromise the bioavailability, therapeutic effectiveness, or safety of the official preparation, and should not interfere with the analysis and tests required for assessing compliance with pharmacopeial standards.

Why are drug preservatives essential?

Drug preservatives play a crucial role in increasing the shelf life of tablets by preventing microbial growth and degradation of the active pharmaceutical ingredients (APIs). Two main reasons why they are important in any drug formulation:

Microbial protection: Tablets are susceptible to contamination by bacteria, fungi, and other microorganisms. It can affect at any stage of manufacturing, storage, and distribution. Drug preservatives inhibit the growth of these microorganisms, thereby preventing spoilage and maintaining the integrity of the tablets over time. Common preservatives like parabens, benzalkonium chloride, and chlorhexidine are effective against a wide range of microorganisms.

They ensure the stability and safety of the tablets.

Antioxidant properties: Some drug preservatives also possess antioxidant properties, which protect the APIs and other tablet excipients from oxidative degradation. Oxidation reactions can lead to the formation of degradation products. They can compromise the potency and efficacy of the drug. Antioxidant preservatives like essential oils, ascorbic acid, and sodium metabisulfite scavenge free radicals to inhibit oxidative reactions. That is how they extend the shelf life of the tablets.

3 Commonly used drug preservatives:

Thymol: Thymol is a natural compound found in thyme and other plants. It possesses strong antimicrobial properties. That is why it is one of the most popular drug preservatives. Thymol inhibits the growth of bacteria, fungi, and other microorganisms. It plays a key role in extending the shelf life of drugs.

Menthol: Menthol is a compound extracted from mint oils, particularly peppermint and spearmint. It is commonly used in drugs and pharmaceutical products for its cooling properties. However, Menthol also acts as a preservative that maintains the stability of cough syrups, herbal formulations, and topical creams.


Extending the shelf life of medications could potentially alleviate medication shortages and have a bigger impact on society in general. Some of the best pharmaceutical preservatives include thymol, menthol, and potassium sorbate.

With evidence indicating that medications can remain stable for longer periods, pharmacy managers would gain greater flexibility in avoiding shortages and mitigating the higher costs associated with medications in short supply. Among the 15 medications identified by SLEP as performing well in shelf life extension, 12 (80%) have experienced shortages since 2013.

Prolonging the expiration dates of these medications could offer relief to healthcare providers, pharmacists, and patients during periods of scarcity. Moreover, extending shelf life may also yield positive environmental outcomes.

If you are looking for any drug preservatives or pharmaceutical synthetic flavoring agents, make sure you contact SBBLG. They also deal with cosmetic preservatives and other flavors to cater to diverse industries.