Contact High: Lenses That Deliver Drugs
Scientists have come up with a new contact that would could deliver drugs for problems such a dry eyes and glaucoma. For years the only real treatment option for many conditions concerning the eyes have been using eye drops. These drops are inefficient in both delivery and making sure the patient is using the drugs. According to doctors only about 7% at most of the medication in drops actually make into the eye. Also, only about 40% of patients regularly take the drops due to the irritation it can bring.
The idea of drug dispensing contacts has been around for quite sometime although it was only until recently that a good consistent contact has been made.“The main way our lens differs is that it can provide large amounts of drug released at constant rates for long periods of time, which previous discoveries have not been able to do,” said drug-delivery researcher Daniel Kohane of Harvard Medical School, who co-authored the paper published in the July issue of Investigative Ophthalmology & Visual Science. Past lenses have only been able to release a small amount of drug over a long period of time, or a substantial amount of drug for a day or two, he said.
Their design is much different than past designs. Most past designs involved mixing the drug into the hydrogel the contacts are made of. This design proved unusable due to its lack of control on releasing the drug. Others used nanoparticles but also proved ineffective. The new design places the drug between two lens. The drug is literally sandwiched between the lens.
To make the lens they use a polymer called PLGA dissolved in a organic solvent and add the drug. After the solvent evaporates what is left is coated with PHEMA, a polymer used in contact lenses.hs
These materials were chosen because they are FDA approved for use. “Both the polymer film and pHEMA have some influence over slowing diffusion of the medication,” said ophthalmologist Joseph Ciolino of the Massachusetts Eye and Ear Infirmary, a co-author on the study. “So we can change the rate of drug release depending on the ratio of polymer to drug, and depending on the molecular weight of the polymer we use.”
It is still being tested but it looks promising right now. I thought this article was interesting. Many people, including myself, use contact lenses and anyone who has seen an optometrist knows the irritation from eye drops. This could a real good alternative for people with serious conditions like glaucoma.
http://www.wired.com/wiredscience/2009/07/druglens/
The idea of drug dispensing contacts has been around for quite sometime although it was only until recently that a good consistent contact has been made.“The main way our lens differs is that it can provide large amounts of drug released at constant rates for long periods of time, which previous discoveries have not been able to do,” said drug-delivery researcher Daniel Kohane of Harvard Medical School, who co-authored the paper published in the July issue of Investigative Ophthalmology & Visual Science. Past lenses have only been able to release a small amount of drug over a long period of time, or a substantial amount of drug for a day or two, he said.
Their design is much different than past designs. Most past designs involved mixing the drug into the hydrogel the contacts are made of. This design proved unusable due to its lack of control on releasing the drug. Others used nanoparticles but also proved ineffective. The new design places the drug between two lens. The drug is literally sandwiched between the lens.
To make the lens they use a polymer called PLGA dissolved in a organic solvent and add the drug. After the solvent evaporates what is left is coated with PHEMA, a polymer used in contact lenses.hs
These materials were chosen because they are FDA approved for use. “Both the polymer film and pHEMA have some influence over slowing diffusion of the medication,” said ophthalmologist Joseph Ciolino of the Massachusetts Eye and Ear Infirmary, a co-author on the study. “So we can change the rate of drug release depending on the ratio of polymer to drug, and depending on the molecular weight of the polymer we use.”
It is still being tested but it looks promising right now. I thought this article was interesting. Many people, including myself, use contact lenses and anyone who has seen an optometrist knows the irritation from eye drops. This could a real good alternative for people with serious conditions like glaucoma.
http://www.wired.com/wiredscience/2009/07/druglens/
posted by Ronnie Newton at 1:31 PM
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