This study will find how weight affects the dosing of a drug called dapsone. Currently, the amount of dapsone a patient receives is the same regardless of the patient's weight.

Inclusion Criteria:

• Male and female subjects, age >18 years, of all racial and ethnic origins.
• Non-English speaking Spanish speakers will be included in the study.
• We are recruiting 12 normal or underweight (BMI <25 kg/m2), 12 overweight or obese (BMI 25-40 kg/m2), and 12 extremely obese (BMI > 40 kg/m2) for this study. This index is calculated using the volunteer's height and weight (Formula: weight (lb) / [height (in)]2 x 703). Half of each group will be male; the other half will be female.

Exclusion Criteria:

• Pregnant or nursing or unwilling to use a reliable contraception method during the study. The effects of dapsone on pregnancy are unknown. In addition, the metabolic changes that accompany pregnancy may alter the concentration-time profile of dapsone, so that the pregnancy and post-partum state would be a confounding variable.
• Abnormal liver function tests: transaminases>10 times upper limit of normal, Alkaline phosphatase>5 times upper limit of normal, total bilirubin>5 times upper limit of normal.
• History of allergies to dapsone, sulfones, or sulfonamides.
• Dapsone, sulfones, or sulfonamides are contraindicated for any reason.
• Volunteers unwilling to comply with study procedures.
• Current suspected or documented infection of any kind.
• Volunteers with colon resection, gastric bypass, lap band, or any other conditions inhibiting gastric absorption of drug.
• Current or previous participation within 28 days of enrollment in another research study that involves the use of medication, contrast, or any other compound that may alter blood count and/or blood chemistry (liver function, kidney function or electrolyte balance), unless waved by PI.
• Donation of 450 milliliters (ml) (one unit) of blood or more within 8 weeks (56 days) prior to study enrollment, unless waved by PI.
• Current use of zidovudine, amprenavir, rifabutin, rifapentine, or saquinavir.
• Creatinine clearance < 70 ml/minute (min) as estimated by the Cockcroft-gault equation.

72 hours

Participants were in the Clinical Research Unit under nursing supervision 0-24 hours after the dapsone dose. Research clinic visits occured at 48 and 72 hours after the dapsone dose under supervision of a research coordinator.