Misoprostol: a prostaglandin E1 analog with antisecretory and cytoprotective properties

Gastrointestinal Permeation Enhancers for the Development of Oral Peptide Pharmaceuticals

Recently, two oral-administered peptide pharmaceuticals, semaglutide and octreotide, have been developed and are considered as a breakthrough in peptide and protein drug delivery system development. In 2019, the Food and Drug Administration (FDA) approved an oral dosage form of semaglutide developed by Novo Nordisk (Rybelsus^®) for the treatment of type 2 diabetes. Subsequently, the octreotide capsule (Mycapssa^®), developed through Chiasma's Transient Permeation Enhancer (TPE) technology, also received FDA approval in 2020 for the treatment of acromegaly. These two oral peptide products have been a significant success; however, a major obstacle to their oral delivery remains the poor permeability of peptides through the intestinal epithelium. Therefore, gastrointestinal permeation enhancers are of great relevance for the development of subsequent oral peptide products. Sodium salcaprozate (SNAC) and sodium caprylate (C8) have been used as gastrointestinal permeation enhancers for semaglutide and octreotide, respectively. Herein, we briefly review two approved products, Rybelsus^® and Mycapssa^®, and discuss the permeation properties of SNAC and medium chain fatty acids, sodium caprate (C10) and C8, focusing on Eligen technology using SNAC, TPE technology using C8, and gastrointestinal permeation enhancement technology (GIPET) using C10.

In Vivo Gastroprotective and Antidepressant Effects of Iridoids, Verbascoside and Tenuifloroside from Castilleja tenuiflora Benth

Stress is an important factor in the etiology of some illnesses such as gastric ulcers and depression. Castilleja tenuiflora Benth. (Orobanchaceae) is used in Mexican traditional medicine for the treatment of gastrointestinal diseases and nervous disorders. Previous studies indicated that organic extracts from C. tenuiflora had gastroprotective effects and antidepressant activity. In this study, we aimed to evaluate the gastroprotective and antidepressant activity of fractions and isolated compounds from the methanolic extract (MECt) of C. tenuiflora in stressed mice. Chromatographic fractionation of MECt produced four fractions (FCt-1, FCt-2, CFt-3, and FCt-4) as well as four bioactive compounds which were identified using TLC, HPLC and NMR analyses. The cold restraint stress (CRS)-induced gastric ulcer model followed by the tail suspension test and the forced swim test were used to evaluate the gastroprotective effect and antidepressant activity of the extract fractions. FCt-2 and FCt-3 at 100 mg/kg had significant gastroprotective and antidepressant effects. All isolated compounds (verbascoside, teniufloroside and mixture geniposide/ musseanoside) displayed gastroprotective effects and antidepressant activity at 1 or 2 mg/kg. The above results allow us to conclude that these polyphenols and iridoids from C. tenuiflora are responsible for the gastroprotective and antidepressant effects.

The effect of dosing interval on the efficacy of misoprostol in the prevention of aspirin-induced gastric injury

The effect of twice-daily administration of misoprostol on aspirin-induced gastric injury was evaluated. Twenty-four random-source dogs were divided into groups that received aspirin and misoprostol as follows: group I, aspirin 25 mg/kg PO q8h and placebo PO q8h; group II, aspirin 25 mg/kg PO q8h and misoprostol 3 microg/kg PO q8h; group III, aspirin 25 mg/kg PO q8h, misoprostol 3 microg/kg PO q12h, and placebo PO q24h; and group IV, aspirin 25 mg/kg PO q8h, misoprostol 3 microg/kg PO q24h, and placebo PO q12h for 28 days. Gastroscopy was performed on days -9, 5, 14, and 28. Visible lesions were scored on a scale of 1 (mucosal hemorrhage) to 11 (perforating ulcer). No difference in total score was identified between groups I and IV on any day. Median total scores for groups II and III were significantly (P < or = .05) lower compared to groups I and IV on day 5. Group III had a significantly lower score (P < or = .05) than groups I, II, and IV on day 28. This study suggests that misoprostol 3 microg/kg PO q12h is as effective as misoprostol 3 microg/kg PO q8h in preventing aspirin-induced gastric injury in this model. However, misoprostol 3 microg/ kg PO q8h was less effective in preventing aspirin-induced gastric injury on days 14 and 28 than in previous studies. No difference among numbers of dog-days of vomiting, diarrhea, or anorexia was detected among groups.

Diclofenac/misoprostol. A review of its pharmacology and therapeutic efficacy in painful inflammatory conditions

Diclofenac is a well established nonsteroidal anti-inflammatory drug (NSAID) used in the treatment of a variety of painful inflammatory conditions. Although generally well tolerated, diclofenac, like other NSAIDs, is associated with gastrointestinal adverse effects which infrequently can be serious and/or life-threatening. Misoprostol, a prostaglandin E1 analogue, reduces the incidence of NSAID related ulcers, both gastric and duodenal. The lack of conclusive pharmacoeconomic data for misoprostol and the widespread use of NSAIDs makes routine administration of misoprostol difficult to justify for all NSAID users. However, it appears to be an economically warranted approach in the elderly, who are at particularly high risk for NSAID-related gastrointestinal complications. The fixed combination of diclofenac 50mg and misoprostol 200 micrograms administered 2 to 3 times daily for 4 to 12 weeks has shown equivalent therapeutic efficacy to diclofenac (alone or combined with placebo), piroxicam and naproxen, and was slightly more effective than ibuprofen in clinical studies in patients with a variety of painful inflammatory conditions. No significant differences in therapeutic efficacy were noted between elderly (aged > or = 65 years) and younger patients in these studies. Gastrointestinal adverse events are common with diclofenac and misoprostol, administered alone or in combination. Diarrhoea (presumably attributable to the misoprostol component) appears to be more frequent in diclofenac/misoprostol recipients than in those receiving diclofenac alone or combined with placebo. However, diclofenac/misoprostol recipients had significantly fewer gastroduodenal ulcers at the end of treatment relative to patients receiving comparators in clinical trials. In addition, the types and incidences of adverse events are similar in elderly and younger patients. Routine ulcer prophylaxis with misoprostol in all NSAID users is not warranted from a pharmacoeconomic viewpoint. In common with other fixed combination products, dosage flexibility is somewhat compromised with diclofenac/misoprostol. However, once drug dosages are determined in the individual patient, the fixed combination of diclofenac and misoprostol offers the potential for increased patient convenience and possibly patient compliance, and lower drug acquisition costs than those of the individual drugs used together. Thus, it should be considered a useful treatment option in appropriately selected patients with a high risk for serious NSAID-related gastrointestinal complications who require NSAID therapy.