Key Inclusion Criteria:  Healthy males or healthy females (WoNCBP) aged 18 to 55 years inclusive, with a body mass index 18.5-30kgm2 and body weight less than 50kg. Healthy on the basis of a clinical history, physical examination, electrocardiogram (ECG), vital signs and laboratory tests of blood and urine. Willingness to comply with requirements or the trial, including contraception requirements. Able to give fully informed consent.  Key Exclusion Criteria:  Confirmed current COVID 19 infection before randomisation. Clinical signs and symptoms consistent with COVID 19 (e.g. fever, dry cough, dyspnoea, sore throat, or fatigue) or confirmed infection by appropriate laboratory test within the last 4 weeks prior to Screening or on admission. Suffered from severe course of COVID 19 (ECMO, mechanically ventilated). Receipt of any IMP in a clinical research study within the previous 3 months (or 5 half-lives, whichever is longer) of Screening. Any abnormalities on 12-lead ECG or BP at Screening (as specified). History of any drug or alcohol abuse in the past 2 years. Vital signs outside the normal range for healthy volunteers Clinically significant abnormal biochemistry, haematology, coagulation, or urinalysis Abnormal renal function, hepatic function or history of abnormal hepatic function occurring during treatment with investigational or licensed drugs, which led to permanent discontinuation of treatment. Positive hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (anti HCV), or human immunodeficiency virus (HIV) History of clinically significant cardiovascular, renal, hepatic, chronic respiratory or gastrointestinal disease, neurological or psychiatric disorder, or current hepatic renal dysfunction as judged by the investigator. Risk factor for ischaemic heart disease or cerebrovascular disease. Failure to satisfy, in the Investigator's judgement, the subject's fitness to participate for any other reason, including previous serious adverse reaction or serious hypersensitivity reactions to any drug or formulation excipients administered parenterally or orally. All female subjects must have a negative serum and urine pregnancy test at Screening and admission, respectively.