The purpose this study is to evaluate the safety and toleration of PF-03049423 following multiple dose administration as an oral solution to healthy young adult volunteers and healthy elderly volunteers. The study will also evaluate the pharmacokinetics of PF-03049423 after multiple dose administration to healthy young adult volunteers and healthy elderly volunteers. The study will also explore the relationship between blood pressure (supine and standing) and PF-03049423 concentration.

The purpose of the investigation is to evaluate the safety and tolerability of an investigational new drug, PF-03049423, when dosed for two weeks in both healthy younger and healthy older subjects.

Inclusion Criteria:

• Healthy persons, male or female.
• For the healthy young adult cohort, subjects must be 18 to 50 years old, inclusive.
• For the healthy elderly adult cohort, subjects must be 51 to 99 years old, inclusive.
• Body Mass Index (BMI) of 18 to 35; and a total body weight >50 kg (110 lbs)

Exclusion Criteria:

• Subjects with clinically significant medical conditions.
• Women of non-child bearing potential.
• Subjects with a known medical history of hearing loss/disability or nonarteritic ischemic optic neuropathy.
• A positive urine drug screen.