Pharmacokinetics of a novel oral slow-release form of misoprostol

Forensic Toxicological Aspects of Misoprostol Use in Pharmacological Abortions

The aim of this study was establishment of an UHPLC-QqQ-MS/MS method for the deter-mination of misoprostol acid in biological specimens in cases of pharmacological abortions. Forensic toxicological examination was performed in three different biological samples (whole blood, placenta and fetal liver). The validation parameters of the method were as follows: limit of detection: 25 pg/mL; limit of quantification: 50 pg/mL, coefficient of determination: >0.999 (R2), intra- and interday accuracy and precision: not greater than 13.7%. The recovery and matrix effect were in the range of 88.3−95.1% and from −11.7 to −4.9%, respectively. Toxicological analysis of the mother’s blood (collected two days after pregnancy termination) did not reveal any abortifacients; however, misoprostol acid was found in the placenta (793 pg/g) and fetal liver (309 pg/g). The second case involved a fetus found near a garbage container. The concentration of misoprostol acid in the placenta was 2332 pg/g. In the presented study, an extensive literature review of misoprostol pharmacokinetics studies was performed. To our knowledge, the UHPLC-QqQ-MS/MS technique presented in this paper is the first quantitative method applied for forensic toxicological purposes. In addition, postmortem concentrations of misoprostol acid in miscarried fetuses due to illegal abortions were reported for the first time.

Single-dose pharmacokinetics of orally and rectally administered misoprostol in adult horses

OBJECTIVE

To characterize the pharmacokinetics of a clinically relevant dose of misoprostol administered PO or per rectum (PR) to horses.

ANIMALS

8 healthy adult horses.

PROCEDURES

In a randomized 3-way crossover design, horses received a single dose of misoprostol (5 μg/kg) administered PO (with horses fed and unfed) and PR, with a minimum 3-week washout period separating the experimental conditions. Blood samples were obtained before and at various points after drug administration (total, 24 hours), and plasma concentrations of misoprostol free acid were measured.

RESULTS

Mean maximum plasma concentration of misoprostol was significantly higher in the PR condition (mean ± SD, 967 ± 492 pg/mL) and unfed PO condition (655 ± 259 pg/mL) than in the fed PO condition (352 ± 109 pg/mL). Mean area under the concentration-versus-time curve was significantly lower in the PR condition (219 ± 131 pg•h/mL) than in the unfed (1,072 ± 360 pg•h/mL) and fed (518 ± 301 pg•h/mL) PO conditions. Mean time to maximum concentration was ≤ 30 minutes for all conditions. Mean disappearance half-life was shortest in the PR condition (21 ± 29 minutes), compared with values for the unfed (170 ± 129 minutes) and fed (119 ± 51 minutes) PO conditions. No adverse effects were noted.

CONCLUSIONS AND CLINICAL RELEVANCE

Misoprostol was rapidly absorbed and eliminated regardless of whether administered PO or PR to horses. Rectal administration may be a viable alternative for horses that cannot receive misoprostol PO, but this route may require more frequent administration to maintain therapeutic drug concentrations.

A randomized controlled trial of the safety and efficacy of preoperative rectal misoprostol for prevention of intraoperative and postoperative blood loss at elective cesarean delivery

OBJECTIVE

To assess the safety and efficacy of preoperative rectal misoprostol for the prevention of intraoperative and postoperative blood loss in women undergoing elective cesarean delivery.

METHODS

A single-blind randomized controlled trial of 200 full-term pregnant women scheduled for elective cesarean delivery. Computer-generated randomization allocated women to receive 400 μg rectal misoprostol at urinary catheter insertion plus 400 μg rectally after abdominal closure (preoperative group, n=100) or 800 μg of rectal misoprostol after abdominal closure (postoperative group, n=100). Primary outcome was intraoperative blood loss.

RESULTS

Intraoperative blood loss was significantly lower in the preoperative misoprostol group compared with the postoperative group (528.7 ± 114.8 mL vs 788.6 ± 165.8 mL; P<0.001). Blood loss during the first 24 hours after delivery was also lower in the preoperative group (199.3 ± 84.5 mL vs 302.9 ± 125.6 mL; P<0.001). Fewer women in the preoperative group needed additional uterotonics (7 vs 21; P<0.001). After delivery, the decrease in both hemoglobin and hematocrit levels was significantly less in the preoperative group (-6.8 vs -12.8% and -6.05 vs -17.8%, respectively; P<0.001).

CONCLUSION

Preoperative rectal administration of misoprostol significantly reduced intraoperative and postoperative blood loss during and after elective cesarean delivery. ClinicalTrial.gov ID: NCT03680339. Date of registration 9/2018.

Determination of misoprostol acid in human plasma by liquid chromatography coupled to tandem mass spectrometry

A rapid and sensitive liquid chromatographic/tandem mass spectrometric method for determination of misoprostol acid, the active metabolite of misoprostol, was developed and validated. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a C(18) column. An API 4000 tandem mass spectrometer equipped with Turbo IonSpray ionization source was used as detector and was operated in the negative ion mode. Multiple reaction monitoring using the precursor to product ion combinations of m/z 367-249 and 296-269 was performed to quantify misoprostol acid and the internal standard hydrochlorothiazide, respectively. The method was linear in the concentration range of 10.0-3000 pg mL(-1) using 200 microL plasma. The lower limit of quantification was 10.0 pg mL(-1). The intra- and inter-day relative standard deviation over the entire concentration range was less than 8.3%. Accuracy determined at three concentrations (25.0, 200 and 2700 pg mL(-1) for misoprostol acid) ranged from -0.5 to 1.2% in terms of relative error. Each plasma sample was chromatographed within 3.5 min. The method was successfully used in a pharmacokinetic study of misoprostol in human plasma after an oral administration of 0.6 mg misoprostol.

Review of medical abortion using mifepristone in combination with a prostaglandin analogue

Induced abortion is still a major health problem in the world and the most frequently performed intervention in obstetrics and gynecology with an estimated total of 46 million worldwide each year. Medical abortion with mifepristone and prostaglandin was first introduced in 1988 and is now approved in 31 countries. This combination of drugs has recently been included in the List of Essential Medicines by the World Health Organisation. The present review summarizes the development, physiology and the development of the currently used regimens.