Contact lenses set to dispense prescription drugs

Eye diseases could soon be treated more effectively thanks to the development of soft contact lenses embedded with particles that slowly release drugs directly where they’re needed.

Eye diseases like glaucoma could one day be treated by pharmaceuticals delivered through contact lenses. Chemical engineers from the University of Florida say they’ve been able to make soft contact lenses containing tiny embedded particles that slowly release drugs directly where they’re needed.

‘One of the biggest problems with using eye drops to deliver medication to the eyes is that about 95 percent of the medication goes where it’s not needed,’ said Anuj Chauhan, Ph.D., one of the authors of the study.

Chauhan said that eye drops applied topically mix with tears, which then drain into the nasal cavity and from there, get into the bloodstream and to other organs, where the drugs can cause serious side effects. But drugs contained in a contact lens could be released slowly enough to stay in the eye.

Chauhan and his colleague Derya Gulsen have found a way to encapsulate a drug in nanoparticles, which can then be mixed into the contact lens matrix during manufacturing of the lens.

In theory, the disposable, drug-laden contact lenses could be worn for up to two weeks, steadily delivering a supply of the drug directly to the eye where it’s needed. The same lenses could be used to correct vision while delivering medication. And for a person whose vision doesn’t need to be corrected, the lenses could be made without correction.

Chauhan said the process could also be used to incorporate antibiotics into the matrix of a lens, making an extended-wear lens that would leave its wearer less vulnerable to bacterial infections, which is said to be a chief drawback of such lenses today.

Other researchers have tried getting drugs into contact lenses, either by soaking the lenses in a drug solution or trapping the drug in a hollow cavity between two pieces of lens material. ‘But contact lenses soaked in drug solutions are not very effective at delivering medications for extended periods of time,’ Chauhan said.

‘Our approach allows us great flexibility in designing controlled drug delivery vehicles that can be tailored to different drugs, but are also effective for extended periods of time.’

The lenses are in the very early engineering design stages and have not been tested clinically. ‘We’re in the very preliminary stages of developing this technology right now,’ Chauhan added.