The skin’s protective barrier is impermeable to most compounds, making it a challenging conduit for drug delivery. Finding a solution to this problem is attractive because, unlike the intravenous route, the delivery of therapeutics through the skin is non-invasive and bypasses the digestive system, which can improve patient compliance. 

“This is the reason delivery of therapeutic molecules through the skin has gained tremendous scientific attention over the years,” says bioinformation scientist Ankur Gautam of the CSIR-Institute of Microbial Technology in India. 

Gautam and his colleagues have found that a peptide (a compound of linked amino acids) they had previously revealed to have cell-penetrating properties, can also deliver therapeutic cargo across the membranes of cancer cells. 

The peptide, called IMT-P8, belongs to a family of cell-penetrating peptides (CPPs) that have an inherent ability to pass through biological membranes without causing significant damage. They are also capable of transporting a variety of cargoes, such as small molecules, peptides, proteins, nucleic acids and nanoparticles, into the cell.  

Their most exciting finding, says Gautam, was discovering that, in mice, IMT-P8 could also cross the stratum corneum, the outermost dead-cell layer of skin. 

This finding suggests that, in the future, IMT-P8 could be a potential candidate to deliver various drug formulations for the treatment of local skin infections. 

Gautam notes that the study is preliminary and the topical delivery of therapeutics using small peptides is still in its infancy. 

“Our study is a step forward in this direction. We believe that, in the future, many other potential CPPs will be evaluated for their topical ability to deliver therapeutics,” he says. 

Many more steps need to be taken before the findings can be translated to humans. “We have tested IMT-P8 on mouse skin and we plan to evaluate the potential of IMT-P8 on human skin biopsy samples.” 

The research team is also planning to design different formulations of IMT-P8 to improve its penetration and delivery capability.

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