Combining PEGylation with Cell-Penetrating Peptides: Review of a Dual Drug Delivery Strategy

Many drugs fail because they are broken down too quickly by enzymes or cannot get inside cells where they need to work. PEGylation addresses the first problem by shielding molecules from degradation and kidney clearance. CPPs address the second by ferrying cargo across cell membranes.

However, CPPs themselves are peptides and suffer from rapid degradation. PEGylating CPPs can protect them while preserving their cell-penetrating ability.

The review covers PEGylated CPP formulations used in drug delivery for cancer, gene therapy, protein delivery, and other biomedical applications. It discusses the trade-offs between PEG chain length, CPP type, and overall delivery efficiency.

Drug delivery is often the bottleneck in getting effective therapies to patients. Combining two proven strategies (PEGylation and CPPs) into a single system is a practical approach that is already being applied across multiple therapeutic areas.

Understanding how to balance PEG shielding with CPP activity is critical for designing the next generation of peptide-based drug delivery systems.

As a review, this does not present new data. The field moves quickly, and formulations described may have been superseded by newer approaches since publication.

The review notes that PEG can sometimes interfere with CPP function, and optimizing the balance is still an active area of research.