The need to increase drug absorption caught the eye of drugdelivery researcher Dean Hsieh, who said he intuitivelybelieved a safe enhancement could be found.

While on the faculty at the pharmaceutical department ofRutgers University, Hsieh hit upon a class of substances whoseisolation in the 1920s earned the 1939 Nobel Prize inchemistry for Leopold Ruzicka. These macrocyclic compounds,large rings of nine to 15 carbons, had not been expected toexist. But they later were used in foods and fragrances as a"fixative" for flavors and scents.

Their use on human skin created no irritation, sensitization,photosensitization or mutagenicity, Hsieh said. He quit teachingin 1985 and formed Conrex Pharmaceutical Corp., a privateR&D laboratory, to develop their potential in enhancing drugabsorption. In June 1991, he obtained U.S. Patent No.5,023,252, covering a composition method and use ofmacrocyclic compounds for transdermal and transmembranedelivery of drugs.

His company is preparing an investigational new drugapplication with an unnamed business partner to use thetechnology in a psoriasis cream, which is intended to enhancethe ability of the active ingredient to cross the outer layer ofthe skin, or stratum corneum, without leaving that tissue andentering the bloodstream.

Previous attempts to create such "penetration enhancers"received a bad name after an early compound, Azone, wasfound to be irritating and hazardous.

Conrex is testing its so-called Permeation EnhancementTechnology (PET) in labs in Camden, N.J. Toxicity and kineticstudies have been completed in dog, mouse and guinea pigmodels.

Hsieh said the technology can eventually be applied to crossthe intestine, increasing absorption of slow-release compounds,for instance, and in eye compounds and nasal applications.

Conrex is also exploring PET's utility in nasal applications ofcalcitonin for osteoporosis, said Raphael Wong, companypresident. He added that the company is being "very careful"about toxicity and irritation concerns. Wong is also chiefoperating officer of the Malvern, Pa., company, whose officesare located near several potential biotechnology andpharmaceutical clients. Hsieh is chairman, chief executiveofficer and chief scientific officer.

They figure they will need $6 million to refine and launch PETin a drug delivery market that is estimated to grow to morethan $2 billion by 1997. So far, the company has raised $1million, plus a $500,000 equity stake from initial lenders, Hsiehsaid.

-- Nancy Garcia Associate Editor

(c) 1997 American Health Consultants. All rights reserved.