Delivering drugs directly

US scientists have developed a method of administering medication in which the drug delivery system is the drug itself.

The problem of efficiently delivering drugs, especially those that are hydrophobic, to tumours or other disease sites has long challenged scientists to develop innovative delivery systems that keep these drugs intact until reaching their targets.

Scientists in the University at Buffalo‘s (UB) Institute for Lasers, Photonics and Biophotonics and Roswell Park Cancer Institute (RPCI) have developed a solution in which the delivery system is the drug itself.

The drug delivery system consists of 100 nanometre crystals of a hydrophobic drug, HPPH, (2-devinyl-2-(1′-hexyloxyethyl) pyropheophorbide), a photosensitiser currently in Phase I/II human clinical trials at RPCI for treating various types of cancer.

The UB researchers found that the nanocrystals of HPPH were taken up by tumors in vivo, with efficacy comparable to conventional, surfactant-based delivery systems.

The nanocrystals present a major advantage over methods of delivery involving other carriers, according to chemistry professor Paras Prasad.

Because other delivery systems commonly used with HPPH and many other drugs, especially those containing surfactants, may add to the toxicity in the body, they have been considered imperfect solutions.

‘Unlike formulations that require separate delivery systems, once this drug is approved, no additional approvals will be needed,’ said Prasad.

The UB/RPCI team is exploring the use of the same technique for delivering other hydrophobic drugs, including those used in chemotherapy.