MAD Study to Assess the Safety, Tolerability, PKs and Efficacy of YJ001 for Spray Use in Patients With DPNP

Inclusion Criteria: * Male or female, between the ages of 18 to 80 years at screening, both inclusive. * Subjects voluntarily consenting for participation in the study and having signed informed consent document. Subjects are required to understand verbal and/or written English or any other language in which a certified translation of the informed consent is available. * Body mass index (BMI) between 19 to 42 kg/m2 (both inclusive) at screening, calculated as weight (kg)/height2 (m2). Subjects must have two feet. Each foot must have five digits. Each foot must have at least total surface area of 450 cm2 measured from below the ankle to the toes including both dorsum and plantar areas. * The subject is diagnosed with Type 1 or Type 2 diabetes, and has a history of DPNP for at least 3 months based on participant report or medical history. * The subject should have a glycemic control that has been optimized and has been stable for at least 3 months prior to randomization. The subject has used a stable regimen of antidiabetic agents (oral) and/or insulin for at least 3 months before screening. * Glycated hemoglobin (HbA1c) ≤ 10% at screening. * Participants who have a weekly mean score of at least 4 based upon the daily mean scores using 11-point Numeric Rating Scale (NRS) in the daily diary (rated twice daily, once in the morning and the other in the evening) from Day -7 through Day 1 (should be calculated from records 7 days immediately prior to study drug administration). * Males must not donate sperm until 90 days after last dose of study drug and must be willing to use a condom during heterosexual activity for up to 90 days after the application of the study drug. * Females must be either postmenopausal for at least 1 year, surgically sterile (bilateral tubal ligation \[including clip, cauterization methods and coil\], bilateral oophorectomy or hysterectomy, and needs to be confirmed follicle-stimulating hormone \[FSH\] level \&amp;gt;40 IU/L), or of childbearing potential either practicing true abstinence or practicing 2 effective means of contraception for at least 4 weeks prior to randomization, and until 28 days after study drug administration: 1. Intrauterine device (IUD) or IUD hormone-releasing system. 2. Combined estrogen and progestogen containing hormonal contraception (oral, intravaginal, or transdermal) associated with inhibition of ovulation. 3. Progesterone-only hormonal contraception (oral, injectable, implantable) associated with inhibition of ovulation. 4. Intrauterine hormone-releasing system. 5. Double-barrier method (condoms, contraceptive sponge, diaphragm, or vaginal ring with spermicide). * Able and willing to comply with all study requirements. Exclusion Criteria: * Current participation in another investigational drug or device study or treated with an investigational drug within 30 days or 5 half-lives, whichever is longer, before dosing. * History of clinically significant drug, food allergy, skin allergy, or sensitivity to drugs of the same class (e.g., 5-aminosalicylic acid, sulfasalazine, and salicylates) or known hypersensitivity to YJ001 or any of its components. * History of asthma. Adults with history of benign (resolved) childhood asthma may be included. * Any subject who suffers severe peripheral vascular disease (e.g., intermittent claudication) at screening, and is not suitable to be involved in the study as per investigator evaluation. * Any subject who suffers severe cardiovascular and cerebrovascular disease (e.g., severe arrhythmia, heart failure, myocardial infarction, unstable angina pectoris, atherosclerosis, stroke, sequela of stroke, etc.), severe gastrointestinal tract disease or other serious disease (e.g., cancer) which, in the opinion of the Investigator, would prevent the subject from fully participating in the study. * Any subject who suffers chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) or multifocal motor neuropathy (MMN). * Any subject who has a history of moderate to severe depression, obvious neurological or mental disorder not related to neuropathic pain but may interfere with rating of pain, as well as poly neuropathy, numbness, feeling of pins and needles and weakness in extremities, other serious pain cannot be clearly differentiated from or conditions that may interfere with rating of neuropathic pain. Subjects with weakness but w/o sensory complaints may be included. * Any other medical, psychological, or social condition which, in the opinion of the Investigator, would prevent the subject from fully participating in the study, would represent a concern for study compliance, or would constitute a safety concern to the subject. * Any subject who has suffered one or more severe hypoglycemia event (defined as neurofunctional hypoglycemia that needs third-party assistance) within 6 months prior to screening. * Pain scores \< 3 on the NRS over twice during the one-week run-in period. * Any subject with unstable or poorly controlled abnormality in blood pressure or lipid (blood pressure ≥ 160 mmHg/95 mmHg, total cholesterol ≥ 6.2 mmol/L, and/or triglyceride ≥ 6.3 mmol/L) at screening. * Any subject with abnormal renal function, estimated glomerular filtration rate (eGFR)\<60 mL/min/1.73 m2. eGFR=186×Scr\^-1.154×Age\^-0.203×(0.742 for Female) * Any subject with abnormal liver function, liver enzymes (alanine aminotransferase \[ALT\] and aspartate aminotransferase \[AST\]) greater than 2 times upper limit of normal. * Consumed 8 units or more of alcoholic beverages per week for women or 15 units or more of alcoholic beverages per week for men at any time in the 6 months before dosing (1 unit of ethanol is equivalent to 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of spirits) or history of drug or alcohol abuse within the 6 months before dosing or evidence of such abuse as indicated by inquiry, medical history or the laboratory assays conducted during screening. Any subject who has past histo