This is a Phase 2, open-label study to evaluate the PK and safety of HTX-011 in women undergoing a planned C-section.

Inclusion Criteria:

• Is expected, at the time of Screening visit, to deliver a single neonate.
• Is scheduled to undergo a planned C-section surgery with a low transverse skin incision (eg, Pfannenstiel).
• Has American Society of Anesthesiologists (ASA) Physical Status of I, II, or III.
• Agrees to practice abstinence or use double-barrier contraception in the event of sexual activity and commits to the use of an acceptable form of birth control for 30 days after HTX-011 administration.
• Agrees to refrain from the use of breast milk from this pregnancy in any manner.

Exclusion Criteria:

• Has planned to breastfeed her neonate at any time during the 28-day period after HTX-011 administration.
• Has had a prior full-term pregnancy with unsuccessful breast milk expression.
• Has a planned concurrent surgical procedure.
• Has a contraindication or a known or suspected history of hypersensitivity or clinically significant idiosyncratic reaction to required study medications.
• Has been administered bupivacaine within 5 days prior to the scheduled surgery.
• Has been administered any local anesthetic within 72 hours prior to the scheduled surgery.
• Has been administered systemic steroids within 5 half-lives or 10 days prior to administration of study drug.
• Has initiated treatment with study medications within 1 month prior to study drug administration that can impact pain control.
• Has taken any NSAIDs within least 10 days prior to the scheduled surgery.
• Has current significant placental abnormality/complications including, but not limited to, placenta previa or placenta accreta.
• Has a medical condition such that, in the opinion of the Investigator, participating in the study would pose a health risk to the subject or confound the postoperative assessments.
• Has uncontrolled anxiety, psychiatric, or neurological disorder.
• Had a malignancy in the last year, with the exception of nonmetastatic basal cell or squamous cell carcinoma of the skin or localized carcinoma in situ of the cervix.
• Has a known or suspected history of drug abuse, a positive drug screen on the day of surgery, or a recent history of alcohol abuse.
• Previously participated in an HTX-011 study.
• Received an investigational product or device in a clinical trial within 30 days or within 5 elimination half-lives.
• Weight is <50 kg at the time of Screening visit.
• In the Investigator's judgment, subject is likely to have been morbidly obese prior to her pregnancy.