Peptide injectables. Greater formulation confidence.

GLP-1 peptide therapeutics such as semaglutide, tirzepatide and liraglutide are highly sensitive to excipient quality and impurity profile. Reactive impurities such as aldehydes, peroxides and trace metals can accelerate degradation, increase impurity formation and compromise long-term peptide stability.

Croda brings together Super Refined™ purification, high purity excipient technologies and formulation expertise to help teams support peptide stability, reduce impurity-driven risk and improve confidence from early formulation challenge through to delivery.

Supporting stability where peptides are under pressure

Peptide formulations can be vulnerable to degradation pathways linked to oxidation, aggregation and excipient-related impurities. Croda’s Super Refined™ excipients are designed to minimise reactive impurities and deliver consistent, tightly controlled impurity profiles. For GLP-1 peptide formulation development, this can help support:

• Peptide stability
• Improved API recovery
• Reduced impurity-driven degradation
• Controlled impurity profiles
• Batch-to-batch consistency
• Greater confidence in formulation performance over time

Data-led support for GLP-1 formulation decisions

Croda has generated formulation data across commercially relevant GLP-1 peptides including semaglutide, tirzepatide and liraglutide. This data helps show how Super Refined™ Propylene Glycol and Super Refined™ Benzyl Alcohol can support API recovery, reduce impurity formation and help formulation teams make more informed excipient choices for peptide injectable applications. For teams working in diabetes and obesity, this creates a clearer link between formulation challenge, excipient purity and development confidence.

Helping address peptide degradation and impurity-related risk

Excipient purity can have a direct impact on peptide formulation stability. Super Refined™ Propylene Glycol is designed to remove oxidative impurities that can affect drug and formulation stability. In semaglutide studies, it maintained high API recovery over 90 days and showed negligible impurity formation compared with standard compendial grade.

Super Refined™ Benzyl Alcohol is purified to reduce benzaldehyde impurities that can negatively impact API and formulation stability. In tirzepatide studies, it delivered stronger API recovery than standard benzyl alcohol, helping demonstrate the value of tighter impurity control in peptide formulation.

Excipient combinations for GLP-1 peptide APIs

Some peptide formulations require carefully selected excipients to help manage stability, impurity formation and long-term performance. Croda can help formulation teams explore excipient options for GLP-1 peptide APIs including: