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Drug formulation and Super Refined™ excipients

Super Refined™ excipients are meticulously processed using our proprietary Super Refined™ purification technology, specifically designed to reduce oxidative impurities such as peroxides, aldehydes, and catalyst residues. This advanced purification significantly reduces potential interactions between excipients and active pharmaceutical ingredients (APIs), enhancing formulation stability and drug efficacy, while minimising cellular irritation and potential allergenicity.

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Super Refined™ Excipients for Drug Formulation

Super Refined excipients are Croda Pharma’s highest purity excipient offering. They go through our proprietary Super Refining™ purification process, which removes polar impurities and oxidative impurities from a wide range of excipients (Croda International Plc, 2025d).

Excipient compatibility in an overall formulation can mean the difference between a failed drug and commercial success. Croda Pharma’s Super Refined™ excipients support drug formulators by ensuring consistent purity and performance across a broad range of excipient chemistries, including (Croda International Plc, 2025d):  

The Super Refined™ range not only meets, but exceeds the stringent requirements of the pharmaceutical industry. Contact our representatives to learn how the Super Refined™ range can help you to develop quality drug formulations.

 

What is Drug Formulation? 

Drug formulation is a multistep process that combines active pharmaceutical ingredients (API) with all other components, known as excipients,  through considering their physicochemical properties to develop a final pharmaceutical product. Excipients, are typically one or more agents that serve different functions for developing the final product. The excipients chosen depend on various factors including the mode of delivery (Afrin & Gupta, 2025).

Specific aspects of a drug’s formulation determine properties of the final product and this can have a direct impact on therapeutic outcomes, treatment adherence and patient quality of life (Afrin & Gupta, 2025). 

Drug formulation development aims to create safe, effective, stable and compliant pharmaceutical products. It bridges the gap between drug discovery and commercialisation (Afrin & Gupta, 2025; Bannigan et al., 2021).

 

The Importance of Excipients in the Drug Formulation Process 

Excipients are an essential element of drug formulation, constituting up to 80-90% of the final product. They play a role in determining the stability, effective administration and delivery of the API. Excipients may also be used to improve the aesthetics of the drug product or facilitate treatment compliance. APIs may also interact physically or chemically with the excipients. Therefore, the selection of appropriate excipients is critical in a drug product (Makkad et al., 2025). 


Applications of Super Refined™ Excipients in Drug Formulation

Topical formulations

Super Refined™ excipient range includes products offering exceptional purity, while improving drug delivery to the epidermis. For instance, Super Refined™ DMI increases the polarity of the upper skin layers to increase the reception of hydrophilic actives within the formulation. Croda Pharma’s Medilan range is engineered to mimic the natural lipids of the skin and offer great therapeutic value for topical formulations (Croda International Plc, 2025d).

Parenteral/Injectable formulations

Parenteral drug delivery demands the highest standards of quality and attention to detail for APIs and excipients. Minimising API degradation is important to the formulation’s integrity and overall efficacy. Super Refined™ excipients such as Super Refined™ Polysorbate 80 and Super Refined™ PEG 400 are suitable for parenteral use and help to minimise API degradation compared to standard compendial grade counterparts (Croda International Plc, 2025c).

Ophthalmic formulations

Oxidative degradation products such as formaldehyde can contribute to cellular irritation. The lower impurity and peroxide profile of Super Refined™ excipients, like the Super Refined Polysorbate 20, reduces the potential for cellular irritation (Croda International Plc, 2025a).

Super Refined™ excipients are also suitable for use in ophthalmic formulations with strict endotoxin concentration guidelines. The refining process yields a reduction in the endotoxin units (EU/ml) of the high-purity excipients, and the products are evaluated using a limulus amoebocyte lysate (LAL) assay (Croda International Plc, 2025a).

Biologics and Biopharma applications

Super Refined™ excipients may support the stability of sensitive biological molecules by minimising aggregation of monoclonal antibodies or other therapeutic proteins. Batch-to-batch consistency conferred by the Super Refined™ process also allows for predictability in the final formulation (Croda International Plc, 2022b).

Oral formulations

Impurities found in commonly used solvents and fillers can lead to moisture-induced crosslinking of gelatine, which is used for capsule formation in self-emulsifying oral drugs such as SEDDS and SMEDDS. This results in hardening of the capsule. The lower impurity profile of Super Refined™ excipients suited for oral use, such as Super Refined PEG 400, can reduce this effect (Croda International Plc, 2025b).

In addition, Super Refined™ excipients improve the patient experience by minimising the taste impact of excipients (Croda International Plc, 2025b). 

FREQUENTLY ASKED QUESTIONS

Explore frequently asked questions about our Super Refined offering

The drug formulation process involves not just the selection of an active pharmaceutical ingredient (API), but also combining it with other suitable ingredients called excipients to create a viable pharmaceutical product. Excipients serve various functions depending on the physical and chemical properties of the API to ensure effective administration and therapeutic outcomes. (Afrin & Gupta, 2025).

Drug stability can be compromised by oxidative impurities and reactive species. Super Refined™ excipients go through a proprietary purification process that reduces these impurities, significantly improving formulation stability and extending shelf life (Croda International Plc, 2025d). 

Combining active pharmaceutical ingredients (APIs) and excipients in a well-considered drug formulation process ensures that the final product is in the best possible state for patient compliance. As APIs can interact physically and chemically with the excipients, careful selection of excipients is important to maintain efficacy and ensure effective dosing. ((Afrin & Gupta, 2025; Makkad et al., 2025)

Croda Pharma’s proprietary purification technology reduces aldehydes, peroxides, and other impurities, which contribute to cellular irritation. Super Refined™ excipients therefore greatly reduce the potential for cellular irritation (Croda International Plc, 2025a).

Super Refined™ excipients are suitable for use in injectable, ophthalmic, nasal, pulmonary, auricular, oral, topical, transdermal, vaginal and rectal formulations (Croda International Plc, 2025d).

Super Refined™ excipients go far beyond compendial standards: they undergo Croda Pharma’s proprietary purification process to reduce oxidative impurities, making them ideal excipients for sensitive formulations (Croda International Plc, 2025d).

Biologic drugs are highly sensitive to oxidative stress, which can cause protein aggregation and a lack of batch-to-batch consistency (Croda International Plc, 2022b).

Injectable and formulations bypass many of the body’s natural protective barriers, such as the gastrointestinal tract and first-pass metabolism. As a result, any impurities present are introduced directly into the bloodstream or tissues (Petrovic et al., 2024), where they can cause adverse reactions (Liu, 2024). Using highly purified excipients like Super Refined™ Polysorbate 20 helps minimise these risks, ensuring better patient safety and enhanced drug stability in parenteral formulations (Croda International Plc, 2025c).

Yes, Super Refined™ excipients are tested for bacterial endotoxins using a limulus amoebocyte lysate (LAL) assay (Croda International Plc, 2025a). 

By reducing oxidative impurities that can initiate degradation pathways, Super Refined™ excipients are known to enhance API stability and extend the shelf life of drug formulations (Croda International Plc, 2025d). 

Yes, Super Refined™ excipients often comply with multiple pharmacopoeias (USP/NF, Ph. Eur., JP, ChP) and are listed in the FDA’s Inactive Ingredient Database (IID) to facilitate global regulatory submissions (Croda International Plc, 2022a). 

Yes, while they are especially valuable in biologics due to their high purity and low impurity profile, Super Refined™ excipients also improve the performance, stability, and sensory attributes of small molecule formulations, including oral and topical products (Croda International Plc, 2025d). 

Super Refined™ excipients come with a certificate of analysis (CoA).  They go through a proprietary purification process that reduces oxidative impurities, conferring various benefits to the resulting formulation such as potential for reduced cellular irritation, improved taste profile and longer shelf-life (Croda International Plc, 2025d).

References:

  1. Afrin, S., & Gupta, V, "Pharmaceutical formulation, In StatPearls", StatPearls Publishing, 28 Apr 2025, View
  2. Bannigan, P., Aldeghi, M., Bao, Z., Häse, F., Aspuru-Guzik, A., & Allen, C, "Machine learning directed drug formulation development. ", Advanced Drug Delivery Reviews, 175(113806), 113806, 28 Apr 2021, View
  3. Croda International Plc., "FDA IID listed products. In Pharma Excipients", Croda Pharma, 28 Apr 2022
  4. Croda International Plc., "Super Refined Polysorbates for biopharma applications.", Croda Pharma, 28 Apr 2022
  5. Croda International Plc., "Pharmaceutical excipients for ophthalmic formulations.", Croda Pharma, 28 Apr 2025
  6. Croda International Plc., "Super refined excipients for oral drug delivery", Croda Pharma, 28 Apr 2025
  7. Croda International Plc., "Super refined excipients for oral drug delivery", Croda Pharma, 28 Apr 2025
  8. Croda International Plc., "Super refined pharmaceutical excipients.", Croda Pharma, 28 Apr 2025
  9. Liu, F., "Safety assessment of drug impurities for patient safety: A comprehensive review. ", Regulatory Toxicology and Pharmacology, 153(105715), 105715, 28 Apr 2024, View
  10. Makkad, S., Sheikh, M., Shende, S., & Jirvankar, P. , "Pharmaceutical excipients: Functions, selection criteria, and emerging trends. ", International Journal of Pharmaceutical Investigation 15(2), 361–376., 28 Apr 2025, View
  11. Petrovic, S., Bita, B., & Barbinta-Patrascu, M.-E, "Nanoformulations in pharmaceutical and biomedical applications: Green perspectives.", International Journal of Molecular Sciences, 25(11), 5842, 28 Apr 2024, View