The purpose of the study is to determine whether Diltiazem Hydrochloride 2% Cream will cause irritation to skin on the back of healthy volunteers after repeated application over 21-days.

The primary objective of this study will be to determine the potential of Diltiazem Hydrochloride 2% Cream to cause irritation after repeated topical application to the healthy skin of humans under controlled conditions.

In addition, safety will be assessed by evaluation of any adverse events (AEs) reported during the study.

Inclusion Criteria:

• Are healthy males or females (to be confirmed by medical history)
• Are 18 years of age or older
• In the case of females of childbearing potential, are using an acceptable form of birth control (oral/implant/injectable/transdermal contraceptives, intrauterine device, condom with spermicide, diaphragm with spermicide, abstinence, partner's vasectomy). Abstinence or vasectomies are acceptable if the female subject agrees to implement one of the other acceptable methods of birth control if her lifestyle/partner changes
• If a female of childbearing potential, have a negative urine pregnancy test (UPT) at Screening, and are willing to submit to a pregnancy test at end of study (EOS)
• Are free of any systemic or dermatologic disorder, which, in the opinion of the investigator, will interfere with the study results or increase the risk of adverse events
• Are of any skin type or race, providing the skin pigmentation will allow discernment of erythema
• Complete a Medical Screening form as well as a Medical Personal History form
• Read, understand, and provide signed informed consent

Exclusion Criteria:

• Have sick sinus syndrome except in the presence of a functioning ventricular pacemaker (confirmed via medical history
• Have second-or third-degree AV block except in the presence of a functioning ventricular pacemaker (confirmed via medical history)
• Have hypotension (less than 90 mm Hg systolic, determined by performing vital signs)
• Have acute myocardial infarction and pulmonary congestion documented by x-ray (confirmed via medical history)
• Have any visible skin disease at the application site which, in the opinion of the investigative personnel, will interfere with the evaluation of the test site reaction
• Are not willing to refrain from using systemic/topical analgesics such as aspirin (81 mg daily aspirin will be allowed), Aleve, Motrin, Advil, or Nuprin for 72 hours prior to Day 1 and during the study (occasional use of acetaminophen will be permitted)
• Are using systemic/topical corticosteroids for 3 weeks prior to and during the study, or systemic/topical antihistamines for 72 hours prior to Day 1 and during the study
• Are using medication which, in the opinion of the investigative personnel, will interfere with the study results, including anti-inflammatory medications
• Are unwilling or unable to refrain from the use of sunscreens, cosmetics, creams, ointments, lotions, or similar products on the back during the study
• Have psoriasis and/or active atopic dermatitis/eczema
• Are females who are pregnant, plan to become pregnant during the study, or are breast-feeding a child
• Have a known sensitivity to constituents present in the material being evaluated
• Have damaged skin in or around the test sites, including sunburn, excessively deep tans, uneven skin tones, tattoos, scars, excessive hair, numerous freckles, or other disfigurations of the test site
• Have received treatment for any type of internal cancer within 5 years prior to study entry
• Have a history of, or are currently being treated for skin cancer
• Are currently participating in any clinical testing
• Have any known sensitivity to adhesives
• Have received any investigational treatment(s) within 4 weeks prior to study entry