This study will identify how much (if any) drug is absorbed from the skin of subjects with acne vulgaris after topical application of SB204.

This is a single-center, double-blind, randomized, 2 period cross-over study to be conducted in 18 subjects (18 years of age and above) each of whom will receive SB204 8% and Vehicle Gel. Subjects who satisfy the entry criteria will be randomized to SB204 8% or Vehicle Gel in a 1:1 ratio for the first treatment period. Study drug will be applied to the face, upper chest, upper back and shoulders (approximately 17% BSA) twice daily on Days 1- 4 approximately 12 hours apart. On Day 5, the study drug will be applied to the same areas only once, in the morning. Pharmacokinetic (PK) profiling will be performed on Day 1 and Day 5. After a wash out period, subjects will be treated with the alternate product and undergo similar treatment and assessments. The primary assessment is the pharmacokinetic profile of nitrate and silicon as markers for systemic exposure to nitric oxide (nitrate) and NVN1000 (silicon) after topical application of SB204 8% to approximately 17% of the total body surface area.

Inclusion Criteria:

• Male and female subjects with an acne severity of moderate or severe and a minimum of 20 inflammatory and 20 non-inflammatory lesions on the face, trunk and shoulders
• 18 years of age and older

Exclusion Criteria:

• Any subject with skin disorders of an acute or chronic nature including psoriasis, eczema, tinea versicolor, etc.
• Subjects who smoke or use tobacco products
• Subjects with methemoglobin level greater than 2% at Screening or Baseline by pulse co-oximeter.
• Subjects with a previous history of methemoglobinemia
• Subjects being treated with nitrates or any drug associated with methemoglobinemia
• Subjects with a known history of HIV, hepatitis, or other blood-borne pathogens.