**Brief Summary**

This study aimed to develop and conduct a preliminary clinical evaluation of a novel weight-adjusted gelatin-based diclofenac potassium medicated lollipop for the management of postoperative pain following adenotonsillectomy in children. The formulation was designed to improve analgesic adherence by providing a palatable and child-friendly dosage form suitable for oral transmucosal administration. Fifty paediatric patients aged 4 to 12 years undergoing elective adenotonsillectomy received one of three weight-adjusted diclofenac potassium lollipop doses (15 mg, 20 mg, or 30 mg) every 8 hours during the first 24 postoperative hours. The study assessed postoperative pain intensity, product acceptability, rescue analgesic use, and safety. In parallel, the formulation underwent pharmaceutical characterization, including physicochemical and microbiological quality evaluation.

This prospective single-arm pilot study evaluated a newly developed gelatin-based diclofenac potassium medicated lollipop intended for postoperative pain management after paediatric adenotonsillectomy. The pharmaceutical formulation was optimized through iterative development and characterized by physicochemical testing, content uniformity analysis, and microbiological quality assessment according to pharmacopeial standards.

Children aged 4 to 12 years undergoing elective adenotonsillectomy received weight-adjusted diclofenac potassium lollipops (15 mg, 20 mg, or 30 mg) administered every 8 hours during the first 24 postoperative hours. Pain intensity was assessed before and after each dose using age-appropriate validated pain scales. Secondary evaluations included product acceptability, requirement for rescue analgesia, and occurrence of adverse events.

The study was designed as an exploratory pilot investigation to assess the feasibility, pharmaceutical performance, preliminary clinical effectiveness, and safety of this novel paediatric drug-delivery platform, providing the basis for future randomized controlled trials and pharmacokinetic evaluation.

Inclusion Criteria:

• Children aged 4 to 12 years.
• Scheduled for elective adenotonsillectomy under general anaesthesia.
• American Society of Anesthesiologists (ASA) physical status I or II.
• Ability to tolerate oral administration of the medicated lollipop after surgery.
• Written informed consent obtained from a parent or legal guardian.

Exclusion Criteria:

• Known hypersensitivity or contraindication to diclofenac or other non-steroidal anti-inflammatory drugs.
• History of asthma precipitated by NSAIDs.
• Active gastrointestinal ulcer disease or gastrointestinal bleeding.
• Significant hepatic, renal, cardiovascular, or coagulation disorders.
• Severe developmental delay or neurological conditions preventing reliable pain assessment.
• Requirement for postoperative intensive care admission.
• Refusal of participation by the patient or parent/legal guardian.

Individual participant data will not be publicly shared because the study involves paediatric participants and contains potentially identifiable clinical information. Data may be made available upon reasonable request to the corresponding author, subject to institutional approval and applicable ethical and privacy regulations.