Effects of Transcutol P on the corneal permeability of drugs and evaluation of its ocular irritation of rabbit eyes.

Our purpose was to explore the use of Transcutol P (Trans) in an ocular drug delivery system. The effect of Trans on the corneal permeability of drugs was investigated in-vitro, using isolated rabbit corneas. The ocular irritation of Trans was also tested in rabbits in-vivo. In the presence of Trans, at a concentration of 0.005-0.03%, the maximum increase in the apparent permeability coefficient (P(app)) was 1.5, 1.5, 3.0 and 3.3 fold for ribavirin, gatifloxacin, levofloxacin hydrochloride and enoxacin, respectively. However, the P(app) value of oxaprozin was reduced in the presence of Trans. The maximum reduction was found to be 2.8 fold at a concentration of 0.03% Trans. The results of the ocular irritation studies showed that Trans was non-irritant at the concentrations studied (0.005-0.03%), while it produced slight irritation at a concentration of 0.05%. It was also found that Trans did not cause any visible ocular damage or abnormal clinical signs involving the cornea, iris or conjunctivae at all concentrations. We concluded that Trans may have potential clinical benefits in improving the ocular drug delivery of hydrophilic compounds.