Providing sustained release for a wide variety of pharmaceutical ingredients, Henkel's pioneering new PROLOC technology looks poised to revolutionise transmucosal drug delivery. Dr Graeme Roan, business development manager for pressure-sensitive adhesives, discusses its exciting range of applications.
One way to resolve this challenge is through dermal administration, which gives a fairly even diffusion and a constant dose; however, this approach brings a different set of problems - absorption becomes more difficult and is confined to a smaller range of molecules.
A pioneering new delivery method promises to bypass these hurdles. Henkel's proprietary PROLOC technology - bioadhesives for transmucosal drug delivery - allows therapeutic agents to be delivered at various absorption sites. Essentially, the drug adheres to the mucosal surface, delivers the ingredient over a period of hours and then erodes in its entirety. Unlike other forms of mucosal delivery, there is no adhesive backing surface to be removed once the tablet has dissolved.
"With transdermal patches or films, stuck on the outside of the skin, there's a limit to the types of drugs you can deliver," says Dr Graeme Roan, business development manager for pressure sensitive adhesives at Henkel. "But because PROLOC works in the mucosa - for example, the tissue inside the mouth - the surface is much more porous and opens up another layer of materials that can be delivered through the skin."
Many people, Roan concedes, are surprised to find Henkel mentioned in a pharmaceutical context. The company boasts a broad portfolio, and is known for manufacturing laundry, detergent, cosmetic and toiletry products. But Henkel is also the world's leading adhesives company, and one important business area is adhesives for drug delivery patches.
"We don't make the active pharmaceutical materials for these patches - we make the adhesives," explains Roan. "PROLOC is something different - a powdered mixture of amylopectin and a carbomer that can be blended with actives and then processed into various delivery forms."
The powder, which can be converted into a film or a compressed tablet, is compatible with a wide range of materials and can be loaded with high volumes of active ingredient. Once converted into its final form, it sticks to the mucosa within seconds - buccal, vaginal, ocular and intranasal surfaces all provide potential delivery sites.
PROLOC is ideally suited both to topical and systemic delivery; for example, eye infections can be treated locally using a bioadhesive ocular minitablet. This provides far greater bioavailability than eye drops, with sustained drug release occurring in the tear film over the course of several hours. The same is true in the mouth, with PROLOC suited to mouth ulcers and other local ailments.
"You can also use buccal delivery for something more systemic," points out Roan. "You can deliver peptides, proteins, all manner of materials to treat really any condition at all, because it dissolves through the buccal tissue into the body."
The veterinary market too is expected to benefit. Because PROLOC becomes intensely sticky once dampened, it cannot be removed easily. This bodes well for buccal delivery in canines - they will not be able to dislodge the tablet, however hard they try to do so with their tongue.
With trials underway at present, full clinical applicability is expected in a matter of months.
"We have some literature that outlines various smallscale trials, but have two larger studies going on right now," says Roan.
"Certainly by early next year at the latest we're going to have some attractive clinical data to share. There's a really broad range of possibilities, and people are very excited about that."
