however, there is a lack of data regarding absorption rate. This study aims to determine intraperitoneal chloroprocaine in vivo half-life and assess tolerability in the clinical setting.This prospective, single-center, open-label, cohort, multiple-dose escalation study used data from patients enrolled in the trial between September 2019 and September 2020. The study included patients between the ages of 18 and 50 presenting for a scheduled cesarean section with a Pfannenstiel incision and receiving spinal anesthesia. Language was not an exclusion criterion. Patients were excluded if they received a combined spinal epidural technique, body mass index (BMI) > 40 kg/m 2 , chronic opioid use, American Society of Anesthesiologists (ASA) physical status grade IV or higher, known atypical pseudocholinesterase activity, platelet count <70,000/mL, stage IV kidney disease or worse, infection overlying the lumbar spine, ester local anesthetic allergy, significant hepatic dysfunction, multifetal gestation, or cognitive impairment preventing informed consent. The study participants were divided into 3 cohorts and given varying doses of chloroprocaine solution: cohort one (n = 5) received 1%, cohort 2 (n = 5) received 2%, and cohort 3 (n = 5) received 3%. Blood samples of the patient were obtained before administration and 1, 5, 10, 20, and 30 minutes following dosing. The primary outcome was to define the pharmacokinetic profile, including in vivo halflife, of intraperitoneal chloroprocaine. The secondary outcome was to analyze peak plasma concentration to assess tolerability and determine potential local anesthetic systemic toxicity.A total of 174 patients were eligible for the study and 15 were enrolled and completed the study and follow-up. Those enrolled received the planned intervention. The pharmacokinetic profile of intraperitoneal chloroprocaine had an in vivo half-life of 5.3 minutes (95% CI, 4.0-6.6). The peak plasma concentration was reached 5 minutes following administration in all 3 groups (1% chloroprocaine was 64.8 ng/mL, 2% was 28.7 ng/mL, and 3% was 799.2 ng/mL. Toxicity was not found in any of the 3 study groups.This prospective study of 15 patients found chloroprocaine administered intraperitoneally with a peak plasma concentration of 799.2 ng/mL had a maximum plasma level 5 minutes following administration, no toxicity was reported, and all the patients had a safe level of exposure. The pharmacokinetic profile and tolerability of intraperitoneal chloroprocaine suggest it is safe to continue to administer to women undergoing cesarean delivery. Limitations of the study include small sample size, variability to patient demographics between cohorts, and the fixed nature of the dosage. Future studies should look at larger sample groups adjusting for confounding variables to corroborate findings.