Safety and Pharmacokinetic Study of Oral Morphine Sulfate in Pediatric Subjects

The purpose of this study is to evaluate the tolerability and safety of oral morphine sulfate in the treatment of postoperative pain in different pediatric age groups following multiple-dose administration. To determine multiple-dose pharmacokinetics (PK) of morphine sulfate in pediatric subjects. To compare plasma concentration of morphine sulfate in each age group of pediatric subjects with adult plasma morphine sulfate concentrations.