Twenty-seven healthy, non-smoking, non-obese, male and female volunteers at least 18 years of age will be randomly assigned in crossover fashion to receive each of three dosing regimens in sequence with a 7 day washout period between dosing periods. In each of the three dosing periods, after a fast of at least 10 hours, subjects will receive one dose of one of the three test products (treatment A - quinine sulfate capsules 324 mg, treatment B - quinine sulphate tablets 300 mg, treatment C - quinine sulfate capsules 324 mg administered thirty minutes after the initiation of a standardized, high-fat breakfast). Subjects will fast for 4 hours after dosing. Blood samples will be drawn from all participants before dosing and for 48 hours post-dose at times sufficient to adequately define the pharmacokinetics of quinine sulfate under fed and fasting conditions and quinine sulphate under fasting conditions. Sitting blood pressure and heart rate will be obtained prior to dosing and at 1, 2, 4 and 12 hours post-dose and upon completion of the study. An electrocardiogram will be recorded at check-in and at 2, 4, 6, 12, and 24 hours post-dose. Subjects will be monitored throughout their participation in the study for adverse reactions.