Safety and PK Study of Ha44 Gel Under Maximal Use Conditions for Treatment of Head Lice Infestation

Inclusion Criteria: 1. Male or female 2. 6 months to 17 years of age 3. Be in good health, as determined by medical history and physical examination 4. Has an active head lice infestation at screening as determined by an experienced evaluator. An active infestation is defined as the presence of at least 3 live lice. 5. Female subjects must be: * Of non-childbearing potential (no history of menstrual periods, post-hysterectomy, or post-menopausal for at least 2 years) OR, * If of childbearing potential, must have a negative urine pregnancy test prior to treatment and agree to use a highly effective method of contraception from Day 0 through the Day 14 visit. Acceptable methods of contraception include abstinence, vasectomized partner, tubal ligation, combined oral hormonal contraceptive, contraceptive injection, contraceptive patch, or IUD. If a hormonal contraception is the only method, the subject must have been on a stable dose for at least 3 months. 6. The parent/guardian agrees to allow serial blood samples collected from subject for PK analysis during study. 7. Has signed an informed consent and/or assent form (ICF). Exclusion Criteria: 1. Has a condition or illness that, in the opinion of the Investigator, may interfere with the study results. 2. Has current dermatological disease or inflammation on the face, scalp, ears, neck or back, including eczema, atopic dermatitis, alopecia, psoriasis or any other chronic skin disease that, in the opinion of the Investigator, would interfere with the safety or PK evaluation. 3. Had a prior reaction to products containing piperonyl butoxide, pyrethrin, or pyrethrum extract. 4. Has been using hormonal contraception for less than 3 months. 5. Is pregnant or currently nursing. 6. Receiving systemic or topical medication, which in the opinion of the Investigator, may interfere with the study results. 7. Has received an investigational agent within 30 days prior to Day 0.