The purpose of this study is to determine if two formulations of diphenhydramine hydrochloride are bioequivalent.

Subjects were required to observe a ten-hour fast and a one-hour fluid restriction prior to each dosing period.

Subjects were randomized into one of two active treatment groups, received supervised dosing of their treatment with approximately eight ounces of water, and were required to maintain fluid restriction for one hour after treatment. Following the one-hour post-dose fluid restriction, subjects could drink water, but consumer no other food or fluids for four hours post-dose.

Following a seven-day washout period, the comparison treatment was administered according to the same procedure as above.

Inclusion Criteria:

• healthy male and/or female subjects between the ages of 18 and 55 years, inclusive
• approximately 18 to 30 kg/m2 BMI
• total body weight at least 55 kg (121 lbs)
• able to understand and sign the written Informed Consent Form
• willing to follow the protocol requirements and comply with protocol restrictions

Exclusion Criteria:

• pregnant or lactating women
• women of childbearing potential not using acceptable form of contraception 3 months prior to the first dose until completion of follow-up procedures
• history of allergy, sensitivity, and/or idiosyncratic reaction to Benadryl, diphenhydramine hydrochloride, or diphenhydramine citrate
• evidence of clinical, dietary or psychiatric deviation from normal that could increase the risk to the subject or research staff or interfere with the interpretation of study results
• use of licit or illicit drugs
• participated in any other trials within a specified number of days prior to the first dose of the trial treatment