The objectives of this study are to evaluate the adhesion performance and pharmacokinetics of ZTlido (lidocaine topical system) 1.8% during swimming, showering, and under normal conditions.

In this Phase 1, open-label, three-period crossover study, 24 healthy, adult male and female subjects are randomized to 1 of 3 treatment sequences. During each treatment period, subjects have one lidocaine topical system applied to their back for 12 hours with a 4-day washout between treatments. In each treatment period, the subject will either swim (Treatment A), shower (Treatment B), or refrain from these activities (Treatment C) while wearing the topical system. Blood samples for lidocaine PK will be collected pre-dose until 24 hours. Adhesion will be monitored throughout the wear time and skin irritation will be assessed the topical system is removed.

Key Inclusion Criteria:

• Must be healthy based on medical history, laboratory work, and physical exam
• Body mass index ranging between 18.0-30.0 kg/m2, inclusive
• Capable of unaided swimming
• If childbearing potential, use of acceptable form of birth control
• In case of females of childbearing potential, have a negative serum pregnancy

Key Exclusion Criteria:

• Allergy or known hypersensitivity to lidocaine, amide-type local anesthetics or any component of the product formulation
• Any major medical illness 3 months prior or any significant history or ongoing chronic medical illness affecting the major body systems, including the skin
• Subjects with conditions that might affect application of the product or its adhesive properties (including psoriasis, eczema, atopic dermatitis, damaged or irritated epidermal layer, and excessive hair or oil on the skin)
• Use of antiarrhymthic drugs (such as tocainide and mexiletine) and local anesthetics within 14 days prior to product application.
• History of addiction, abuse, or misuse of any drug
• Use of nicotine-containing products within 30 days