PENTAGASTRIN

Manufacturing Process

A solution of 3.55 parts of L-tryptophanyl-L-methionyl-L-aspartyl-Lphenylalanine amide trifluoroacetate in 30 parts of dimethylformamide is cooled to 0°C, and 1.01 parts of triethylamine are added. The mixture is stirred while 1.84 parts of N-tert-butyloxycarbonyl-β-alanine 2,4,5trichlorophenyI ester are added at 0°C. The reaction mixture is kept at 0°C for 48 hours and then at 20°-23°C for 24 hours. The mixture is added to a mixture of 100 parts of ice-water, 0.37 part of concentrated hydrochloric acid (SG 1.18), 1.2 parts of acetic acid and 20 parts of ethyl acetate. The mixture is stirred for 15 minutes at 0°-10°C and is then filtered. The solid residue is washed with water and then with ethyl acetate, and is dried at 40°-50°C under reduced pressure. There is thus obtained N-tert-butyloxycarbonyl-βalanyl-L-tryptophanyl-L-methionyl-L-aspartyl-L-phenylalanine amide, MP 213°C with de composition.

Therapeutic Function

Gastrosecretory hormone

Biochem/physiol Actions

CCKB agonist that stimulates gastric acid secretion; anxiogenic.Pentagastrin is an agonist of the cholecystokinin-2 (CCK2) receptor. It helps to increase the excitability of neurons in the basolateral amygdala through the activation of a non-specific cation channel.

Brand name

Peptavlon (Wyeth).

General Description

Pentagastrin (Peptavlon), a physiologicalgastric acid secretagogue, is the synthetic pentapeptide derivative:N-t-butyloxycarbonyl-β-alanyl-L-tryptophyl-L-methionyl-L-aspartyl-L-phenylalanyl amide. It contains theCOOH-terminal tetrapeptide amide (H·Try·Met· Asp·Phe·NH2), which is considered to be the active center ofthe natural gastrins. Accordingly, pentagastrin appears tohave the physiological and pharmacological properties ofthe gastrins, including stimulation of gastric secretion,pepsin secretion, gastric motility, pancreatic secretion ofwater and bicarbonate, pancreatic enzyme secretion, biliaryflow and bicarbonate output, intrinsic factor secretion, andcontraction of the gallbladder.Pentagastrin is indicated as a diagnostic agent to evaluategastric acid secretory function, and it is useful in testing foranacidity in patients with suspected pernicious anemia, atrophicgastritis or gastric carcinoma, hypersecretion in suspectedduodenal ulcer or postoperative stomal ulcers, andZollinger-Ellison tumor.