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Researcher Expect barriers in development of drug eluting contact lens
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Clinicians should expect challenges associated with the development of drug elution via contact lenses, a speaker at the British Contact Lens Association Conference said.
Noel A. Brennan, MScOptom, PhD, FAAO, a clinical research fellow and leader of the Developing Eye Platform in Design R&D at Johnson & Johnson Vision Care, said that the mechanisms for controlled release of ocular drugs is not the only area that must be researched.
Other factors need to be explored, such as the consistency a drug must be to cross the cornea and whether or not the drug delivered in such a mode can reach the back of the eye, he said.
Dr. Brennan also noted the lack of understanding that still exists surrounding the mechanisms themselves. Research still needs to be done to determine how soluble the drugs are within lens polymers, what their release kinetics are, what would constitute a toxic dose and what would be the minimum therapeutic dose.
Contact lenses designed for drug delivery also have significant regulatory and industry hurdles, he said. They have been classified by the U.S. Food and Drug Administration as “combination products,” and because it is neither a medical device nor a pharmaceutical solution, the path for this type of product has been difficult to determine, he said.
The combination products also pose difficulties in the industry. Manufacturers need to determine if these products are worth the effort, a largely skeptical endeavor for many companies, particularly in the current global economic environment, he said.
Funding priorities are another hurdle for drug eluting contact lenses, according to Dr. Brennan.
At present, with growing concern about macular degeneration and macular edema related to diabetes, the industry is more focused on treating the back of the eye, which drug eluting contact lenses typically do not reach very well, he said.
Lastly, the drug eluting contact lenses face hurdles in practicality once the developmental hurdles are conquered. Practical applications, including whether the lenses should be sold in pharmacies or by eye care professionals, who will be responsible for patient instruction and determining the best fitting technique considering the need for proper drug release, must be determined before widespread distribution can occur, he said.
Dr. Brennan concluded by saying that while he was confident the lenses would eventually make it to market, the delays in their development and eventual application are complex and far-reaching.
The conference was held in Birmingham, U.K., in May. – by Daniel R. Morgan