Safety and Tolerability of Preservative-free Polyhexamethylene Biguanide (PHMB) Ophthalmic Solution in Healthy Subjects

Inclusion Criteria: * able and willing to give informed consent. * man or woman of any race and 18 to 55 years of age, inclusive. * Body Mass Index of 20-30 kg/m2 * willing and able to attend required study visits. * bilateral visual acuity \>6/10. * intraocular pressure (IOP) of 14-21 mmHg. * ophthalmologic examination without abnormalities. * medical history without major pathology. * laboratory test results without deviations from the normal range. * female subjects of childbearing potential with negative urine pregnancy test and using effective contraception during the study. Exclusion Criteria: * presence of bacterial ocular infections. * presence of any concomitant ocular pathology. * performing activities likely to result in an irritated conjunctiva during the study (including heavy alcohol intake, swimming in chlorinated water and heavy smoking). * contact lenses wearing . * ocular surface fluorescein staining score \>3. * use of topical or systemic antibiotics, antihistamines, decongestants and non-steroidal anti-inflammatory agents as well as steroids within 7 days before screening. * known or suspected allergy to biguanides or intolerance to any other ingredient of the test treatments. * ocular surgery performed within 12 months before screening. * participation in another clinical study in the preceding 30 days. * one functional eye. * pregnancy or breastfeeding. * use of recreational drugs.