Glaucoma is an eye disease in which the pressure inside the eye is too high, which causes damage to the optic nerve and can result in blindness. Treatment usually involves drugs that lower this pressure, such as brimonidine tartrate (BT). These drugs are applied in the form of eye drops, which have to be used two or three times a day. This frequent need for application causes many patients to skip doses. In addition, only about 5 % of the active compound actually reaches the target tissue when eye drops are used.

Hu Yang, Virginia Commonwealth University, Richmond, USA, and colleagues have developed dendrimer-based nanofibers which can be applied to the eye in dry form, where they dissolve quickly and can deliver a drug. The team modified polyamidoamine (PAMAM) dendrimers by conjugating them with methoxy polyethylene glycol (mPEG). Then they used electrospinning to combine these dendrimers with poly(ethylene oxide) and BT into nanofiber mats.

The researchers tested the drug delivery properties and eye tolerance of the nanofiber mats in rats. They compared the results to regular BT eye drops and found that the mats were similarly safe and effective in a single application and dissolved rapidly. However, after three weeks of continued use, the dendrimer accumulated in the eye and the drug’s efficacy was significantly improved. According to the team, there could be another reason for the improved results: In contrast to eyedrops, the dry application of the nanofiber mats makes it easier to actually get all of the drug into the eye without loss, which could be especially useful for pediatricians or veterinarians.

• Fast Dissolving Dendrimer Nanofiber Mats as Alternative to Eye Drops for More Efficient Antiglaucoma Drug Delivery,
  Michael G. Lancina, Sudha Singh, Uday B. Kompella, Shahid Husain, Hu Yang,
  ACS Biomater. Sci. Eng. 2017.
  DOI: 10.1021/acsbiomaterials.7b00319