The purposes of this study are to evaluate the safety and tolerability and to model the single-dose pharmacokinetic profile of diclofenac capsules low dose and high dose in children ages 6 to <17 years experiencing mild to moderate acute postoperative pain.

Inclusion Criteria:

• Body weight ≥18 kilograms.
• Mild to moderate acute pain requiring treatment with analgesic medication.
• Willing to have blood samples taken for PK sampling using an indwelling catheter.
• Must be able to swallow capsules and can tolerate oral medication.
• For females: is not of reproductive potential (defined as premenarchal) or is practicing an acceptable method of birth control

Exclusion Criteria:

• Severe acute pain
• Chronic analgesic or glucocorticoid use for any condition within 6 months before dosing with study drug.
• Emergency surgery
• History of allergic reaction, hypersensitivity, or clinically significant intolerance to diclofenac, aspirin, codeine, acetaminophen, or any NSAID
• History of peptic ulcer disease or a GI event (eg, perforation, obstruction, or bleed) within 6 months before screening
• Current use of any medication that may cause a clinically significant drug interaction when co-administered with diclofenac
• Current use of any medication that might affect the pharmacokinetics of diclofenac
• History of bleeding disorders .
• Developmental delay or behavioral problems that would make it difficult to assess pain.
• Impaired liver function
• Clinically significant renal or cardiovascular disease
• Any medical condition that compromises ability to swallow, absorb, metabolize, or excrete the study drug
• Previously received any investigational product or device within 30 days before Screening or scheduled to receive an investigational device or another investigational drug (other than that in this study) during the course of this study.
• Previous participation in this clinical study or currently taking diclofenac.