Double blind, placebo controlled, ascending multiple (10) oral dose, sequential group study. Twenty-four subjects will complete the study in 3 cohorts (Groups A to C), each group consisting of 8 subjects. Each cohort will consist of 4 male and 4 female subjects. Each subject will be dosed for 10 days and will be on study for approximately 7 weeks. Each subject will participate in one treatment cohort only, residing at the Clinical Research Unit (CRU) from Day -1 (the day before dosing) to Day 15 (120 hours post the last dose). The dose will range between 2 and 10 mg/kg daily, given as either a single daily dose or as two doses divided over the 24-hour dosing period. All subjects will return for a post-study visit 8 to 10 days after the last dose of study medication. Cohorts will be dosed at least at 3 weekly intervals. There will be a review of the safety and pharmacokinetic data of each cohort prior to each dose escalation.
Inclusion Criteria: 1. Subjects will be males or females of any ethnic origin between 18 and 45 years of age and with a body weight of 50-100 kg inclusive. Females of child bearing potential must be established on a reliable form of contraception and have a negative pregnancy test at screening. 2. Subjects must be in good health, as determined by a medical history, physical examination, 12-lead electrocardiogram (ECG) and clinical laboratory evaluations (congenital non haemolytic hyperbilirubinaemia is acceptable). 3. Subjects will have given their written informed consent to participate in the study and to abide by the study restrictions. 4. Subjects must have ophthalmology assessments within the normal limits at screening. This includes normal Meibomian gland function. Exclusion Criteria: 1. Male or female subjects who are not willing to use appropriate contraception during the study and until 3 months after the last dose. 2. Subjects who have received any prescribed systemic or topical medication within 14 days of the dose administration unless in the opinion of the Investigator and the Medical Monitor the medication will not interfere with the study procedures or compromise safety. 3. Subjects who have used any non-prescribed systemic or topical medication (including herbal remedies) within 7 days of the dose administration (with the exception of vitamin/mineral supplements and paracetamol) unless in the opinion of the Investigator and the Medical Monitor the medication will not interfere with the study procedures or compromise safety. 4. Subjects who have received any medications, including St John's Wort, known to chronically alter drug absorption or elimination processes within 30 days of the dose administration unless in the opinion of the Investigator and the Medical Monitor the medication will not interfere with the study procedures or compromise safety. 5. Subjects who are still participating in a clinical study (e.g. attending follow-up visits) or who have participated in a clinical study involving administration of an investigational drug (new chemical or biological entity) in the past 3 months since the last dose. 6. Subjects who have donated any blood, plasma or platelets in the 3 months prior to screening or who have made donations on more than two occasions within the 12 months preceding the dose administration.