Intervention: Diclofenac diethylamine
Trial phase: Phase 3
SMILES: CCNCC.O=C(O)Cc1ccccc1Nc1c(Cl)cccc1Cl
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: Accepts Healthy Volunteers
Participants at risk: 151
Group description: The participants were instructed to apply approximately 2 g DDEA 1.16% gel topically with the fingertips to both sides of affected ankle which corresponds to a region of approximately 200 cm^2 for approximately 1 minute in the morning, at noon, in the late afternoon, and in the late evening for 7 days. The very first dose was applied at the study center.
Eligibility criteria:
Inclusion Criteria:

Participant provision of a signed and dated informed consent document indicating that the participant has been informed of all pertinent aspects of the study before any assessment will be performed.
A participant who is willing and able to comply with scheduled visits, treatment plan and other study procedures.
A participant with acute sprain of the lateral ankle on one side only, Grade I-II.
A participant who had pain-on-movement greater than or equal to (>=) 50 mm on a 100 mm VAS.
A participant with injury within the past 24 hours before randomization.
Participant had not taken pain medication within the 24 hours that precedes randomization.Treatment by rest, ice, compression, or elevation (RICE) is authorized prior to randomization. Stable daily doses of acetylsalicylic acid (less than or equal to [<=] 162 mg) taken for at least 30 days prior to the first dose of study medication for non-analgesic reasons may be continued for the duration of the study.
A participant in good general and mental health with, in the opinion of the investigator or medically qualified designee with no clinically significant/relevant abnormalities in medical history or upon physical examination, or condition, that would impact the participant's safety, wellbeing or the outcome of the study, if they were to participate in the study, or affect the individual's ability to understand and follow study procedures and requirements.
Female participant of childbearing potential and at risk for pregnancy must agree to use a highly effective method of contraception throughout the study and for 14 days after the last dose of assigned treatment.

Exclusion Criteria:

A participant with Grade I-III sprain of the affected ankle during the past 3 months.
A participant with Grade II-III sprain, any other significant injury (such as fracture or torn ligament), or surgery (except for skin or nails) of the affected ankle or foot during the past 6 months.
A participant with pain or instability in the affected ankle attributable to previous ankle sprain or any other trauma.
A participant with ankle sprain attributable to a known disease affecting the ligaments, such as ligament hyperlaxity due to connective tissue diseases (e.g. Marfan's syndrome, Down's syndrome, Ehlers-Danlos syndrome).
A participant who has any skin lesion or wound in the area to be treated.
A participant who intent to undergo surgery during time of participation.
A participant who is an employee of the investigational site, either directly involved in the conduct of the study or a member of their immediate family; or an employee of the investigational site otherwise supervised by the investigator; or, a GSK CH employee directly involved in the conduct of the study or a member of their immediate family.
A participant with,in the opinion of the investigator or medically qualified designee, an acute or chronic medical, including other current acute or chronic pain conditions, or psychiatric condition or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator or medically qualified designee, would make the participant inappropriate for entry into this study.
A participant who is a pregnant female.
A participant who is a breastfeeding female.
A participant with known or suspected intolerance or hypersensitivity to the study materials (or closely related compounds) or any of their stated ingredients.
A participant who, in the opinion of the investigator or medically qualified designee, should not participate in the study.
A participant unwilling or unable to comply with the Lifestyle Considerations below: a) No special requirement for food and drink prior to safety laboratory evaluations. b) Participants will abstain from caffeine-containing products for 12 hours prior to study visit days (except screening/randomization visit). c) Participants will abstain from strenuous exercise (e.g. heavy lifting, weight training, calisthenics, aerobics) for the duration of the study. Walking at a normal pace will be permitted.
A participant who has made use of prescription, non-prescription, or dietary supplements, containing NSAIDs, COX-2 inhibitors and other analgesic treatments within 7 days or 5 half-lives, whichever is longer, prior to the first dose of investigational product and during the study.
A participant with topical analgesics or anti-inflammatory treatment over the previous 30 days in the area to be treated in the study period.
A participant with evidence of clinically significant laboratory abnormality caused by renal disease (Serum creatinine >=1.5 times the upper limit of normal [ULN]), hepatic disease (ALT or AST >= 2 times the ULN), or subject with allergic disease at screening that may increase the risk associated with study participation.
A participant with history of regular alcohol consumption exceeding 14 drinks per week (1 drink = 5 ounces [150 milliliter {mL}] of wine or 12 ounces [360 mL] of beer or 1.5 ounces [45 mL] of hard liquor) within 6 months of Screening.
A participant who has received treatment with an investigational drug within 30 days (or as determined by the local requirement) or 5 half-lives preceding the first dose of investigational product (whichever is longer).
A participant who has previously been enrolled in this study.
A participant with any physical impairment that would influence the study's efficacy evaluations, in particular POM and the ankle joint function, such as : peripheral or central neurological disease, significant back pain, symptomatic osteoarthritis of the hips, knees or feet, or any painful conditions of the lower extremities (e.g. painful nail, wound, corn, or wart).