This is a multicenter, dose-ranging study including adult male and female subjects (>= 18 years old) with symptomatic Oral Lichen Planus (OLP). A total of approximately 24 subjects will be enrolled at approximately eight (8) study sites in the United States. This study will evaluate the safety, tolerability and efficacy of LP-10 at 0.25 mg, 0.5 mg and 1.0 mg of tacrolimus.The study consists of screening, treatment and follow-up phases. The treatment phase includes 10 mL LP-10 oral rinse for 3 minutes twice a day for 4 weeks. The follow-up phase includes one post-treatment visit 2 weeks after the last oral LP-10 dose.

Inclusion Criteria:

• Provide written informed consent
• Male or female ≥ 18 years of age
• Oral biopsy performed within the last 10 years before the Screening Visit demonstrating OLP and/or oral lichenoid mucositis in the absence of cancer or dysplasia
• Moderate OLP based on an OLP Investigator Global Assessment (IGA) score of ≥ 3
• OLP Pain and Sensitivity Numerical Rating Scale (NRS) score of ≥ 3
• Patients taking prescription oral steroid or rinse treatment(s) at the time of the Screening Visit agree to stop treatment for the duration of the trial and to undergo a 4-week washout period
• Willing and capable of understanding and complying with all requirements of the protocol, including proper completion of the self-administered questionnaires
• Willing to avoid live vaccines while enrolled in the trial
• Patients of child-bearing potential must have a negative pregnancy test and agree to undergo pregnancy testing at each study visit. (unless patient has undergone a bilateral tubal ligation or hysterectomy and/or is post-menopausal as defined by the absence of menses for at least 12 months)
• Patients of child-bearing potential and male participants with a female partner of child-bearing potential, agree to use a reliable method of contraception (condoms and/or oral contraceptives) for the duration of the trial and for 10 days thereafter

Exclusion Criteria:

• Hyperkalemia
• Chronic kidney disease
• Long QT syndrome
• History of oral cavity or oropharyngeal cancers
• Active cancer
• Uncontrolled hypertension (i.e., > 145 mm/Hg systolic or > 95 mmHg diastolic)
• Patients who failed tacrolimus treatment for OLP in the past
• Patient who is currently or has previously participated in another oral cavity therapeutic or device study within 3 months of screening and has not returned to baseline
• History of oral cavity infection (bacterial, viral or fungal) within 3 months prior to screening
• Pregnant or lactating
• Active bleeding peptic ulcer disease
• Known allergy to liposomes and/or egg yolk and/or tacrolimus
• Evidence of renal impairment (creatinine > 2 × the upper limit of normal at Visit 1), hepatic impairment (AST or ALT > 3 × the upper limit of normal at Visit 1), clinically significant cardiovascular, respiratory, or psychiatric diseases per investigator's judgment
• Patients currently taking magnesium and aluminum-hydroxide antacids or metoclopramide
• Patients currently taking aminoglycosides, ganciclovir, amphotericin B, cisplatin, nucleotide reverse transcriptase inhibitors, and protease inhibitors
• The presence of any clinically significant systemic disease or condition that in the opinion of the investigator would make the patient unsuitable for the study