A Phase 2, Open Label, Pharmacokinetic (PK) Study of TLC599 in Subjects With Osteoarthritis of the Knee

Study Criteria for Patients with OA of the Knee (Cohort G1-G9) Inclusion Criteria: * Age 45 or older, non or moderate smokers, body mass index (BMI) ≤ 40.0 kg/m2. * Knee OA symptoms with confirmed mild to moderate OA. * Study knee OA severity grade 1-3 (Kellgren-Lawrence). * Agree to use contraception Exclusion Criteria: * Clinically significant (CS) abnormalities (physical, lab, hepatitis B/C, HIV, electrocardiogram \[ECG\], vital sign or unstable illness). * Positive urine drug screen, tuberculosis (TB) test; significant alcohol/drug abuse * Allergic reactions to TLC599, its components, related drugs or cosyntropin. * History of autoimmune disease, immunodeficiency diseases, treated malignancy, CS opportunistic infection, tuberculosis, infective arthritis or concurrent knee infection * Intra-articular bleeding in study knee. * Skin issues at injection site or hindrance to knee joint penetration. * Blood coagulation disorders. * Stroke or myocardial infarction * Poorly controlled hypertension or vital sign abnormalities. * Interfering conditions with dosing, visits, or compliance or refusal of synovial fluid collection. * Medication: Strong/moderate Cytochrome P450 (CYP) 3A/3A4 inhibitors/inducers, prescription meds, over-the-counter (OTC)/natural health products, meds affecting platelet function, depot injection/implant, IA corticosteroid, hyaluronic acid, or other injection in study knee, impact on endogenous steroid levels, systemic corticosteroids, live attenuated vaccine, chemotherapeutic/immunosuppressant use for inflammatory diseases. * Plasma donation or significant blood loss. * Pregnancy, breastfeeding, or planning to be pregnant/breastfeed * Serious local/systemic infection or symptomatic viral/bacterial infection * Severe OA (grade 4) in non-study knee (Kellgren-Lawrence). * Recent surgery, scheduled knee replacement or lower limb amputation. * Known/adrenal insufficiency risk. * Recent participation in other study research Study Criteria for Healthy Subjects (Cohort G10) Inclusion Criteria: * Age 18-45, non-smokers, BMI 18.5-25 kg/m2, body weight ≥ 50.0 kg (males) or ≥ 45.0 kg (females). * Healthy with no CS illness/surgery within 4 weeks or CS medical history. * Agree to use contraception * No new tattoos/body piercings at the injection site until the study ends. Exclusion Criteria: * CS abnormal physical, ECG or vital sign findings. * Known/adrenal insufficiency risk. * Abnormal lab results (HBV, HCV, HIV, TB). * Positive pregnancy test or lactating; positive urine drug screen or cotinine test. * Significant alcohol/drug abuse or positive alcohol test. * Significant drug allergies or allergic reactions to DSP, dexamethasone, cosyntropin, natural adrenocorticotropic hormone (ACTH), or other related drugs. * History/presence of conditions including CS opportunistic infection, serious local/systemic infection, autoimmune, blood, heart, vascular, respiratory, lung, skin, liver, gallbladder, retinopathy, neuromuscular, cancer, kidney, diabetes, severe allergic reactions, or others that would preclude participation. * Fever * Active/latent tuberculosis or symptomatic viral/bacterial infection * Medication: Depot injection/implant, vaccine, drug known to induce or inhibit CYP3A4 metabolism, prescription meds, OTC/natural health products. * Consumption of specified fruits. * Recent participation in other study research * Plasma donation or significant blood loss. * Reasons preventing study participation