Dose Response Study of a Topical Formulation of Nitroglycerin for the Treatment of Raynaud's Phenomenon

It is the intention of this protocol to study, in a controlled manner, the response of fingers of patients with Raynaud's phenomenon to two dosage strengths of a fast acting topical formulation of Nitroglycerin, MQX-503. Patients may have moderate to severe primary Raynaud's phenomenon or Raynaud's phenomenon secondary to autoimmune diseases such as scleroderma. Quantitative changes in blood flow in the fingers of the non-dominant hand will be measured after the clinical induction of constriction of blood vessels by exposure to local cold temperatures. Secondarily, the quantitative reduction in skin temperature recovery time and symptoms of pain, tingling and numbness associated with Raynaud's phenomenon will be evaluated using a patient hand symptom analog assessment score. The frequency and severity of adverse events associated with MQX-503 will be assessed.