Bioequivalence Study Between GR37547 500 Milligrams (mg) Tablet Versus Ciprofloxacin 500 mg Tablet Reference Product in Healthy Adult Subjects

This two-period cross-over study will evaluate bioequivalence of GR37547 (ciprofloxacin 500 mg) tablet versus ciprofloxacin 500 mg reference tablet in healthy adult subjects under fasting conditions. Subjects will receive Treatment A (GR37547 tablet) and Treatment B (ciprofloxacin reference tablet) in crossover manner, separated by a washout period of at least 7 days and not more than 14 days. The total duration of study for each subject will be approximately 5-7 weeks. This study will enroll approximately 26 healthy adult subjects at a single center.


Eligibility Criteria:
Inclusion Criteria:

* Subject must be between 18 and 60 years of age inclusive, at the time of signing the informed consent.
* Healthy, non-smoker, as determined by the investigator or medically qualified designee based on a medical evaluation including medical history, physical examination, laboratory tests, and cardiac monitoring.
* A subject with a clinical abnormality or laboratory parameter(s) which is/are not specifically listed in the inclusion or exclusion criteria, outside the normal reference range for the population being studied may be included only if the investigator in consultation with the Medical Monitor if required,agree and document that the finding is unlikely to introduce additional risk factors and will not interfere with the study procedures.
* Body weight \>=50 kilogram (kg) and body mass index (BMI) within the range 19-30 kg per meter square (kg/m\^2) (inclusive).
* Healthy Male or female subjects: Male subjects: A male subject must agree to use contraception during the treatment period and for at least 5 days, after the last dose of study treatment and refrain from donating sperm during this period; Female subjects: A female subject is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: Not a woman of childbearing potential (WOCBP) OR A WOCBP who agrees to follow the contraceptive guidance during the treatment period and for at least 30 days after the last dose of study treatment.
* The investigator is responsible for ensuring that male and female study subjects understand how to correctly use the methods of contraception.
* Capable of giving signed informed consent.

Exclusion Criteria:

* History or presence of cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematological, neuromuscular, psychiatric, auto-immune or neurological disorders.
* History of convulsions.
* Any other condition that is capable of significantly altering the absorption, metabolism, or elimination of drugs; constituting a risk when taking the study treatment; or interfering with the interpretation of data.
* History of any malignancies or chemotherapy/radiation within the past 5 years excluding treated squamous carcinoma of the skin and adequately excised basal cell carcinoma.
* History of kidney, heart or lung transplants.
* History or presence of rheumatoid arthritis.
* Presence of hypocalcaemia where the serum potassium is \< lower limit of normal (LLN).
* Presence of hypomagnesaemia where the serum magnesium is \< LLN.
* Fasting blood glucose \>=7 millimoles (mmol)/liter (L).
* Serum glucose-6-phosphate dehydrogenase \< LLN.
* Abnormal renal function, as determined by creatinine clearance and considered as clinically significant by the investigator will be excluded.
* Alanine transaminase (ALT) \>1.5x upper limit of normal (ULN).
* Bilirubin \>1.5xULN (isolated bilirubin \>1.5xULN is acceptable if bilirubin is fractionated and direct bilirubin \<35%).
* Current or chronic history of liver disease, or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones).
* Excessive alkalinity of the urine (potential of hydrogen \[pH\] \>=9), as determined on Day -1.
* Abnormal BP as determined by the investigator.
* QT interval corrected for heart rate according to Bazett's formula (QTcB) \>450 milliseconds (msec). Subjects with a known risk of QT prolongation will be excluded. For purposes of data analysis, only QTcB, will be used
* Past or intended use of over-the-counter or prescription medication including herbal medications, within 14 days prior to dosing unless, in the opinion of the investigator and sponsor, the medication will not interfere with the study.
* Where participation in the study would result in loss of blood or blood products in excess of 500 milliliter (mL) within 90 days.
* Exposure to more than 4 new chemical entities within 12 months prior to the first dosing day.
* Current enrolment or past participation within the last 90 days before signing of consent in this or any other clinical study involving an investigational study treatment.
* Presence of Hepatitis B surface antigen (HBsAg) at screening or a Positive Hepatitis C antibody test result at screening.
* Positive pre-study drug/alcohol screen.
* Positive human immunodeficiency virus (HIV) antibody test.
* Regular use of known drugs of abuse.
* Sensitivity to heparin or heparin-induced thrombocytopenia.
* Sensitivity to any of the study treatments, or components thereof, or drug or other allergy including allergy to quinolones that, in the opinion of the investigator or medical monitor, contraindicates participation in the study.
* Regular alcohol consumption within 6 months prior to the study defined as: An average weekly intake of \>21 units for males or \>14 units for females. One unit is equivalent to 8 grams (g) of alcohol: a half-pint (approximately 240 mL) of beer, 1 glass (125 mL) of wine or 1 (25 mL) measure of spirits.
* Urinary cotinine levels indicative of smoking or history or regular use of tobacco or nicotine-containing products within 6 months prior to screening.