The purpose of this study is to characterize the pharmacokinetic (PK) profile of a single dose of EXPAREL (133 mg/10 mL) administered intraoperatively per normal infiltration for prolonged analgesia in 12 adult subjects undergoing tonsillectomy with or without removal of the adenoids.

Blood samples for bupivacaine PK analysis will be obtained from subjects at baseline (within 30 minutes prior to EXPAREL infiltration), 15 minutes, 30 minutes, and 1, 2, 4, 8, 12, 24, 36, 48, and 72 hours after the beginning of EXPAREL infiltration, and on Day 7.

Inclusion Criteria:

• Male or female, ≥18 years of age at the Screening Visit.
• Subjects undergoing tonsillectomy with or without removal of the adenoids.
• Able and willing to comply with all study visits and procedures.
• Willing and capable of providing written informed consent.

Exclusion Criteria:

• History of hypersensitivity or idiosyncratic reaction to amide-type local anesthetics.
• Received any investigational drug within 30 days prior to EXPAREL administration, and/or has planned administration of another investigational product or procedure while participating in this study.
• Currently pregnant, nursing, or planning to become pregnant during the study or within 1 month after EXPAREL administration. Female subjects must be surgically sterile, at least 2 years postmenopausal, or using an acceptable method of birth control. If of childbearing potential, must have a documented negative pregnancy test within 24 hours before EXPAREL administration.
• Subjects with significant medical conditions or laboratory results that, in the opinion of the Investigator, indicate an increased vulnerability to EXPAREL and/or procedures, or cause inability to comply with the study requirements.

11 participants received 133 mg/10 mL EXPAREL following protocol amendment subsequent to 1 participant receiving 266 mg/20 mL EXPAREL according to the original protocol.