Excipients, also known as inactive ingredients, play a crucial role in the development and manufacturing of pharmaceutical products, including topical formulations. These ingredients aid in the delivery, stability, and quality of the active pharmaceutical ingredient (API) and can significantly impact the final product. With the growing demand for topical therapeutics, the choice of excipients becomes increasingly important for manufacturers to ensure cost-effectiveness, quality, and commercial success.
The Importance of Excipients in Topical Formulations
Topical formulations, which account for a significant portion of the pharmaceutical industry, require the incorporation of more excipients than other products to deliver their API payload effectively. The market for topical pharmaceuticals was valued at US$95 billion in 2020 and is projected to grow to more than $155 billion by 2028. These formulations often contain a variety of excipients, including polymers, surface active agents, preservatives, and penetration enhancers, which can impact manufacturing processes, product quality, and shelf life.
Common Excipients Used in Topical Formulations
- Polymers: Used to control viscosity and enhance suspension/retention characteristics. Examples include fermented polymers like Xanthan gum, synthetic polymers like hydroxypropyl methylcellulose (HPMC) and hydroxypropyl cellulose (HPC), and natural polymers like acacia and starch.
- Surface Active Agents: Help solubilize APIs in the formulation. Examples include sodium starch glycolate and fatty acids.
- Preservatives: Improve shelf life and microbiological stability. Examples include citric acid and parabens.
- Penetration Enhancers: Promote absorption. Examples include phthalates and other endocrine disrupting chemicals (EDCs).
Challenges in Large-Scale Manufacturing
Manufacturers face several challenges when scaling up production of topical formulations, including:
- Longer Processing Times: Excipients that require more steps to process can add to timelines and costs.
- Material Addition Challenges: Ensuring uniformity in batch and ergonomics can be difficult.
- Matching Process Parameters: Optimizing process parameters from smaller scales to larger commercial batches can be complex.
Selecting Affordable and Safe Excipients
To overcome these challenges, manufacturers must carefully select excipients that meet their formulation needs while ensuring cost-effectiveness and quality. Here are some tips on where to buy and what to avoid:
- Partner with Reputable Suppliers: Ensure that your suppliers provide high-quality, USP-grade excipients to guarantee the safety and efficacy of your products.
- Avoid Obesogens: Some excipients, such as phthalates and parabens, can interfere with hormone function and cause metabolic disorders. Opt for alternatives that do not have these negative effects.
- Custom Compounding: Consider custom compounding to tailor your formulations to specific needs and avoid unwanted ingredients.
Conclusion
The choice of excipients in topical formulations is critical for manufacturing success, quality, and commercial viability. By understanding the functions and challenges associated with different excipients, manufacturers can make informed decisions to ensure the development of high-quality, cost-effective products that meet the growing demand for topical therapeutics.
Pullquote: “Topical formulations are often inherently semi-solid in nature and typically contain more types of excipients than most other finished drug products. Many of these excipients, if specified without due consideration and analysis or formulated improperly, can adversely impact topical drug manufacturing processes.” – Daryl Bassett and David Barnes
Cited Sources:
1. Bassett D, Barnes D, “Excipient Choices and Why They Matter in Topical Formulations”. ONdrugDelivery Online, November 30, 2021.
2. The Compounding Center, “Are Their Inactive Ingredients (Excipients) Safe? The Compounding Center Blog”, March 30, 2021.
3. Jeeva Organic, “Pharmaceutical Excipients That Can Improve Your Products”, January 9, 2023.
4. Amy’s Massage and Wellness, “Excipients — Life is a journey”.
5. American Chemical Society, “What’s that stuff? Excipients – C&EN”, January 7, 2008.
