Pharmacokinetics and tolerance of repeated oral doses of loxiglumide.

The study was conducted on 6 adult healthy subjects (5 males and 1 female) in order to investigate the pharmacokinetics and tolerance of repeated b.i.d. oral administration for 7 days of tablets containing 400 mg of loxiglumide (CR 1505). The pharmacokinetics of loxiglumide in plasma after the first single dose of 400 mg is characterized by a lag time of 16 +/- 4 min, a rapid invasion (kinv = 10 h-1), a Cmax of 11.9 +/- 5.1 mg/l at tmax of 2.3 +/- 0.8 h, a mean residence time (MRT) of 6.9 +/- 1.1 h and an AUC of 60.6 +/- 16.3 (mg/l) x h. After the last dose of 400 mg the lag time was 17 +/- 6 min, the Cmax 12.7 +/- 3.8 mg/l at tmax of 2.1 +/- 0.8 h, a MRT of 11.0 +/- 1.9 h and an AUC of 109.8 +/- 39.9 (mg/l) x h. The increases of the AUC and of MRT were statistically significant and are probably due to an accumulation of loxiglumide which occurs during the repeated dose course and reaches the steady state within 48 h of repeated administration. Due to this accumulation the Cmax increased by 7%. The increase was not statistically significant or clinically relevant. No dose adjustment seems required during a repeated dose dosing schedule with 400 mg b.i.d. In the urine loxiglumide and 3 metabolites were found, which were called Metabolite (Met.) 11.2, Met. 12.0 and Met. 12.8. Met. 12.0 was the most abundant, accounting for 45% of the loxiglumide related substances excreted in the urine.(ABSTRACT TRUNCATED AT 250 WORDS)

Distribution of tiropramide and metabolites after single intravenous or peroral administration of 14C-tiropramide to the rat.

The study was performed with 14C-tiropramide hydrochloride, i.e. O-(2-diethylamino-ethyl)-N-benzoyl-[DL-(U-14C)tyrosyl]-dipropylamide+ ++ hydrochloride, with a specific activity of 466.16 microCi/mmol. The substance was administered in single intravenous (i.v.) doses of 4 mg/kg to 16 rats (8 males and 8 females) and in single peroral (p.o.) doses of 10 mg/kg to other 16 rats (8 males and 8 females). The radioactivity in plasma, in several organs and tissues and in gastrointestinal contents was measured by scintillometry. After i.v. administration the radioactivity is rapidly found in all investigated organs and tissues and also in the stomach contents. The radioactivity is concentrated in the liver and kidney, and also in other organs, as the pancreas and the salivary glands. After 120 h the radioactivity is small in the organs but still appreciably present in the colon content. The radioactivity crosses the blood-brain barrier. Deep compartments were not found. After p.o. administration the radioactivity is rapidly found in the organs and is particularly concentrated in the liver, showing a rapid absorption from the gastrointestinal tract. Besides the obvious higher concentration of radioactivity in the stomach and small intestine in the initial times after p.o. administration, the distribution and elimination pattern from the organs do not substantially differ from those found after i.v. administration. The distribution pattern found using the scintillographic method were confirmed by an autoradiographic study made on 12 non-pregnant rats (10 males and 2 females) and on 7 rats at the 13th day of pregnancy and 7 rats at the 18th day of pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolism and excretion of 14C-tiropramide after single intravenous or peroral administration to the rat.

The study was performed with 14C-tiropramide hydrochloride, i.e. O-(2-diethylamino-ethyl)-N-benzoyl-[DL-(U-14C)tyrosyl]-dipropylamide+ ++ hydrochloride, with a specific activity of 466.16 microCi/mmol. For the study of pulmonary, urinary and fecal excretion the substance was administered in single intravenous (i.v.) doses of 4 mg/kg to 4 rats (2 males and 2 females) and in single peroral (p.o.) doses of 10 mg/kg to other 4 rats (2 males and 2 females). For the study of biliary excretion 4 mg/kg of 14C-tiropramide hydrochloride were administered in single i.v. doses to 4 rats (2 males and 2 females) anesthetized with urethane and the bile was collected from the choledocus in the 8 h following administration. The radioactivity in the expired CO2, urine feces and bile was measured by scintillometry. The radioactive substances were extracted, separated by TLC and identified by comparison of their Rf values with those of putative metabolites with known chemical structure. The following results were obtained. Radioactivity in the expired CO2: No radioactivity was found, either after i.v. or p.o. administration. Radioactivity in urine: In the 48 h after administration 37% of the i.v. administered radioactivity and 31% of the p.o. administered radioactivity was recovered in the urine. Six basic substances could be identified. In order of decreasing abundance these were CR 1166, CR 1098, tiropramide, CR 1034, CR 1919 and CR 1938. Radioactivity in feces: In the 120 h after administration 60% of the i.v. administered radioactivity and 56% of the p.o. administered radioactivity was recovered in the feces.(ABSTRACT TRUNCATED AT 250 WORDS)

Tiropramide and metabolites in blood and plasma after intravenous or peroral administration of 14C-tiropramide to the rat.

The study was performed with 14C-tiropramide hydrochloride (O-(2-diethylamino-ethyl)-N-benzoyl-[DL-U-14C-tyrosyl]-dipropyl-amide hydrochloride) with a specific activity of 466.16 muCi/mmol. The substance was administered in single i.v. doses of 4 mg/kg to 18 male and 18 female rats or p.o. doses of 10 mg/kg to 16 male and 16 female rats. The radioactivity in blood and plasma was measured by scintillometry. The radioactive substances were extracted, separated by TLC and identified by comparison of their Rf values with those of putative metabolites with known chemical structure. After i.v. administration the parent substance tiropramide and 5 metabolites were identified in plasma. Tiropramide was the most abundant substance with an AUC equal to 51% of the AUC of total radioactivity. After p.o. administration the parent tiropramide and 5 metabolites were identified. Tiropramide was the most abundant substance till the 1st h. Then the metabolite CR 1098 ((+-)a-benzoylamino-4-(2-ethylamino-ethoxy)-N, N-dipropyl-benzenepropanamide) prevailed. The Cmax of tiropramide was reached at 0.5 h with 1183 nmol/l. The AUC of tiropramide was 19% of the AUC of total radioactivity. It appears that after p.o. administration the biotransformation of tiropramide is more intense than after i.v. administration. The absolute bioavailability of total radioactivity calculated on the ratio between the p.o. and i.v. AUC was 0.67, that of tiropramide was 0.23. The difference between the absolute bioavailability of total radioactivity and that of tiropramide is probably due to a first-pass effect and a more intense biotransformation of the substance after p.o. administration.

Pharmacokinetics of loxiglumide after single intravenous or oral doses in man.

Loxiglumide (D,L-4-(3,4-dichlorobenzoylamino)-5-(N-3-methoxypropyl-pentylam ino)-5-oxo-pentanoic acid, CR 1505) was given intravenously to 8 male healthy volunteers in a single dose of 2 mg/kg body weight (b.w.) or orally in a single dose of 5 mg/kg b.w. Loxiglumide was measured in plasma and in urine by HPLC during 48 h following the administration. After i.v. infusion the plasma levels were consistent with an open two-compartment pharmacokinetic model represented by the equation C (mg/l) = 43.791 x e-2.652 x h + 2.657 x e-0.139 x h. In the urine, besides loxiglumide, two metabolites were found and in the 48 h following the i.v. administration the urinary excretion of loxiglumide and of its metabolites accounted for 11.13% of the administered dose. After oral administration loxiglumide appeared in plasma with a lag time of 14 min, reached the peak 34 min after administration, being eliminated with an initial fast and a terminal slow elimination rate. The plasma levels were consistent with an open two-compartment pharmacokinetic model represented by the equation C (mg/l) = -46.72 x e-8.765 x (h-0.23) + 40.660 x e-1.383 x (h-0.23) + 6.057 x e-0.120 x (h-0.23). In the urine, besides loxiglumide, two metabolites were found and in the 48 h following the oral administration the excretion of loxiglumide and of its metabolites accounted for 7.67% of the administered dose. The absolute bioavailability of loxiglumide was calculated comparing the AUC(0-inf) found after oral and after i.v. administration and was estimated as 0.967, with p = 0.05 fiducial limit of 0.656-1.278.

Identification of metabolites of tiropramide in human urine.

The metabolites of tiropramide were extracted from the urine of healthy volunteers given tiropramide hydrochloride orally. Eight metabolites of tiropramide were found by gas chromatography/mass spectrometry. Three were identified on the basis of their mass spectra, retention times and comparison with synthetic standards. For the others a probable structure is proposed on the basis of their mass spectra.

Pharmacological properties of lorglumide as a member of a new class of cholecystokinin antagonists.

Derivatives of 5-(dipentylamino)-5-oxo-pentanoic acid are a new class of non-peptide cholecystokinin (CCK) antagonists. The most potent compound, D,L-4-(3,4-dichlorobenzoylamino)-5-(dipentylamino)-5-oxo-pen tanoic acid (lorglumide, CR 1409), has a great affinity for the pancreatic CCK receptors and is a competitive, specific and potent CCK antagonist on the smooth muscles of the gall bladder and ileum of the guinea pig and on the CCK-induced amylase secretion of isolated pancreatic acini. In vivo lorglumide antagonizes the contraction of the gall bladder of the guinea pig and of the dog provoked by i.v. CCK-8 or ceruletide (caerulein). It antagonizes the satiety effect of CCK-8 in the rat and is protective against ceruletide-, taurocholate- and diet-induced pancreatitis. Lorglumide is therefore a useful pharmacological tool to study the functions of CCK. For its pharmacological properties, its relatively low toxicity and because it is active also after oral administration, lorglumide is a candidate for diagnostic or therapeutic use in man when an involvement of CCK is suspected.

Anticholecystokinin activities of loxiglumide.

The anticholecystokinin activities of loxiglumide, (D,L-4-(3,4-dichloro-benzoylamino)-5-(N-3-methoxypropyl-pentylamino++ +)-5-oxo- pentanoic acid, CR 1505) are described. Loxiglumide antagonizes in vivo the contractions of the gall bladder of guinea pig induced or mediated by cholecystokinin-8 (CCK-8) (i.v. ED50 = 0.24 mumol/kg), the emptying of the gall bladder of the mouse induced by CCK-8 (i.v. ED50 = 29 mumol/kg, oral ED50 = 42 mumol/kg), the retardation of gastric emptying of the rat induced by CCK-8 (i.p. ED50 = 13 mumol/kg), the retardation of the pyloric transit in the mouse induced by CCK-8 (i.v. ED50 = 3.7 mumol/kg, oral ED50 = 11 mumol/kg), the hypermotility of the ileum of the rabbit induced by CCK-8 (i.v. ED50 = 1.2 mumol/kg) and the contractions of the gall bladder of the non-anesthetized dog induced by caerulein (i.v. ED50 ca. 11 mumol/kg). Loxiglumide also antagonizes the satiety behaviour of the rat elicited by CCK-8 (i.p. ED50 = 0.65 mumol/kg) and the exocrine pancreatic hypersecretion in the anaesthetized dog induced by CCK-8 (i.v. ED50 ca. 0.35 mumol/kg). Loxiglumide has a simple, non-polypeptidic chemical structure and is active after parenteral and after oral administration.

Loxiglumide protects against experimental pancreatitis.

Loxiglumide (D,L-4-(3,4-dichloro-benzoylamino)- 5-(N-3-methoxypropyl-pentylamino)-5-oxo-pentanoic acid, CR 1505) is a derivative of pentanoic acid and belongs to a newly discovered class of agents with cholecystokinin antagonistic activities. Loxiglumide has preventive effects on different types of experimental pancreatitis, induced e.g. by ceruletide (i.p. ED50 ca. 9 mumol/kg), by intrapancreatic taurocholate (i.p. ED50 ca. 80 mumol/kg) or by choline-deficient ethionine-supplemented diet (i.p. ED50 ca. 45 mumol/kg). Loxiglumide has a simple, non-polypeptidic chemical structure and may be a candidate for clinical investigations in man, e.g. for pancreatitis.

Pharmacokinetics and metabolism of [14C]-proglumetacin after oral administration in the rat.

The pharmacokinetics and metabolism of 1H-indole-3-acetic acid, 1-(4-chlorobenzoyl)-5-methoxy-2-methyl 2-[4-[3-[[4-(benzoylamino)-5-(dipropylamino)-1, 5-dioxopentyl]oxy]propyl]-1-piperazinyl]ethyl ester (+/-) (proglumetacin, CR 604), 14C-labelled in position C-2 of the indolic moiety, was studied in male and female rats after oral administration. The radioactivity is slowly absorbed from the gastrointestinal tract and reaches the peak in plasma 6 h after administration. Afterwards the radioactivity is eliminated from plasma according to a bi-exponential equation, with an initial elimination rate having a t1/2 of 4.5 h and a terminal elimination rate having a t1/2 of 16 h. The elimination rate is probably dependent on the slow absorption rate (flip-flop system) and on an entero-hepatic recirculation of the radioactivity. The radioactivity is excreted with the feces (60.8%) and with the urines (33.5%). No radioactivity is eliminated with the expired air. About 13% of the fecal radioactivity is represented by proglumetacin. This fraction or radioactivity (ca. 8% of the administered) represents probably the non-absorbed amount of substance. The parent proglumetacin is not found in blood, urine and organs. Conversely several indolic metabolites are found, with a predomination of indometacin. Proglumetacin is therefore a pro-drug of indometacin and of other indolic metabolites, which are responsible for the antiinflammatory activity of proglumetacin. The radioactivity is distributed in all tissues. The maximum radioactivity is found in liver and kidneys, however, always in a smaller concentration than in plasma. No "deep compartment" was found.

Pharmacological characterisation of a new potent and specific nonpolypeptidic cholecystokinin antagonist.

D,L-4-(3,4-Dichloro-benzoylamino)-5-(N-3-methoxypropyl- pentylamino)-5-oxo-pentanoic acid (CR 1505) belongs to a newly discovered class of agents with cholecystokinin (CCK) antagonistic activity. CR 1505 displaces CCK-8 from the central CCK receptors at concentrations of 9.1 mumol/l, and from the peripheral CCK receptors at concentrations of 0.33 mumol/l. CR 1505 antagonizes in vitro the contractant effects of CCK-8 on gall bladder strips of the guinea pig at 0.79 mumol/l and those on the small intestine at 1.6 mumol/l. These antagonistic effects are dose dependent and of competitive type. The antagonistic activities of CR 1505 against contractions of smooth muscles elicited by CCK-8 are at least 1000 times more potent than those against the contractions elicited by acetylcholine, BaCl2, histamine, serotonin, Substance P, bradykinin or dimethylphenylpiperazine. CR 1505 is also practically ineffective against the contractions of the small intestine of the guinea pig elicited by electrical field stimulations either as "cholinergic twich" (0.05 Hz), or as "cholinergic contractions" (trains of 10 min at 1 Hz), or as "non-cholinergic contractions" (200 impulses at 5 Hz in presence of atropine). CR 1505 is therefore a potent, specific, competitive and reversible CCK antagonist.

Plasma levels of proglumetacin and its metabolites after intravenous or oral administration in the dog.

The absolute bioavailability of 1H-indole-3-acetic acid, 1-(4-chlorobenzoyl)-5-methoxy-2-methyl 2-[4-[4-[[4-(benzoylamino)-1,5-dioxopentyl]oxy]propyl]-1- piperazinyl]-ethyl ester (+/-) (proglumetacin, CR 604) was studied in 12 dogs, in a triple cross-over experiment with single doses of i.v. proglumetacin diphosphate, oral proglumetacin diphosphate or oral proglumetacin dimaleate. Determined were proglumetacin, 2'-[4-(3-hydroxypropyl)-piperazin-1-yl]-ethyl-(1-p- chlorobenzoyl-5-methoxy-2-methylindol-3-yl)-acetic acid (CR 1015), indometacin and proglumide in plasma. Proglumetacin and CR 1015 were found in plasma only after the i.v. administration. Conversely indometacin and proglumide were found after all administration routes. The areas under the curve of indometacin and of proglumide did not differ significantly after the three treatments, as shown by the analysis of variance.

Antispasmodic activity on the gallbladder of the mouse of CR 1409 (lorglumide) a potent antagonist of peripheral CCK.

Cholecystokinin (CCK) is a hormonal regulator of the motility of the gallbladder. CCK-8, i.e. the biologically active C-terminal octapeptide of the hormone, elicits contraction and emptying of the gallbladder. Endogenous CCK released by egg yolk or fatty acids in the duodenum gives the same results. CR 1409 (lorglumide), a glutaramic acid derivative with peripheric competitive CCK-antagonistic activity, was evaluated in comparison with proglumide (the model CCK-receptor antagonist) and other conventional antispasmodic drugs, for their ability to inhibit the emptying of the gallbladder induced in mice by CCK-8 or by lyophylized egg yolk. CR 1409 (1-10 mg/kg) prevented dose-dependently the emptying of the gallbladder in both experimental models; proglumide exhibited a comparable activity at much higher doses (200-800 mg/kg). On the contrary the anticholinergic drug atropine, the calcium-antagonist nifedipine, and the phosphodiesterase inhibitor papaverine were almost ineffective. The present data support the hypothesis that the effects of CCK on gallbladder motility are mediated by a CCK-dependent specific mechanism.

Different peripheral and central antagonistic activity of new glutaramic acid derivatives on satiety induced by cholecystokinin in rats.

New glutaramic acid derivatives with cholecystokinin antagonistic activity were evaluated for their capacity to inhibit the satiety effect induced in the rat by intraperitoneal (i.p.) injection of cholecystokinin octapeptide (CCK-8). The most active compound, CR 1409, is about 4000 times more potent than proglumide when injected peripherally (i.p.). This compound competitively inhibits the action of CCK-8 at the receptor responsible for the satiety effect. In contrast, CR 1409, i.p. or intracerebroventricularly (i.c.v.) injected does not exhibit antagonistic effects when CCK-8 is administered i.c.v., confirming the existence of at least two different populations of CCK receptors.

Protective effect of CR 1409 (cholecystokinin antagonist) on experimental pancreatitis in rats and mice.

CR 1409, a glutaramic acid derivative with competitive cholecystokinin-antagonistic activity, was administered IP and evaluated in comparison with proglumide (the model CCK-receptor antagonist), gabexate (protease inhibitor) and PGE2 (cytoprotective) on two different models of experimental pancreatitis. Acute pancreatitis was induced in mice by six IP injections of 50 micrograms/kg caerulein at hourly intervals. The drugs were administered 30 minutes before each caerulein administration. Blood samples and pancreata were collected 3 hours after the last caerulein injection. In the second experiment, pancreatitis was induced in rats by injecting 0.3 ml 6% sodium taurocholate interstitially into the pancreas. The drugs were administered twice, 30 minutes before and 3 hours after taurocholate. The animals were killed 6 hours after laparotomy and blood samples and pancreata were collected. CR 1409 exhibited on both pancreatitis models a protective effect in a dose range of 0.3-10 mg/kg. Proglumide exhibited a protective activity at higher doses (200-400 mg/kg). Gabexate and PGE2 were effective only in pancreatitis induced by taurocholate in a dose range of 30-60 mg/kg and 60-130 micrograms/kg respectively. These results, showing a high protective effect of CR 1409 on different models of acute pancreatitis, suggest an important role of CCK in the pathogenesis of pancreatitis.

Pharmacokinetics of tiropramide after single doses in man.

The plasma levels and urinary excretions of (+/-) alpha-(benzoylamino)-4-[2-(diethylamino)ethoxy]-N, N-dipropyl-benzenepropanamide (tiropramide) and of some of its metabolites were studied in healthy volunteers after the following single-dose administrations of tiropramide hydrochloride: a) i.v. 50 mg, oral 100 mg or rectal 200 mg; b) i.v. 50 mg or i.m. 50 mg; c) oral 100, 200 or 400 mg. After i.v. bolus the plasma levels of tiropramide are consistent with a three-compartment open pharmacokinetic model. The steady-state volume of distribution is 221 l. The terminal elimination constant is 0.279 h-1 (t1/2 = 2.5 h). After i.m. injection the plasma levels increase rapidly (invasion t1/2 = 2 min) and then are similar to those found after i.v. bolus. After oral administration appreciable plasma levels are found after lag times of 18-27 min. They increase with an invasion t1/2 of 14-22 min. The peak is reached 1-1.7 h after administration and the elimination occurs with a constant of 0.20-0.23 h-1. After rectal administration appreciable plasma levels are found after a lag time of 11 min and increase with an invasion t1/2 of 6 min. The peak is reached at 2.2 h. The elimination constant is 0.21 h-1. Tiropramide and some of its metabolites can be determined in the urine by gas-liquid chromatography. The following percentages of the administered dose of tiropramide and tiropramide-related substances can be found in the 24-h urines. After i.v. bolus: 16.2; after i.m. injection: 17.0; after oral administration: 19.6; after rectal administration 13.1.(ABSTRACT TRUNCATED AT 250 WORDS)

Differentiation of central and peripheral cholecystokinin receptors by new glutaramic acid derivatives with cholecystokinin-antagonistic activity.

Three glutaramic acid derivatives provided with a potent antagonistic activity on the contractions elicited by the carboxyl terminal octapeptide CCK-8 in the guinea pig gallbladder have been evaluated for their capacity to inhibit the binding of [125I]-(Bolton-Hunter)-CCK-8 to both central and peripheric cholecystokinin (CCK) receptors. The most active compound inhibits the CCK binding to rat pancreas acini at a concentration 10(-7) mol/l, but only at 10(-4) mol/l on cerebral cortex membranes, confirming the existence of at least two different populations of CCK receptors.

New glutaramic acid derivatives with potent competitive and specific cholecystokinin-antagonistic activity.

New glutaramic acid derivatives were evaluated for anti-cholecystokinin (CCK) activity in vitro on guinea pig gallbladder. The compounds are competitive and specific CCK-antagonists, causing a parallel right shift of the cumulative dose-response curve of the agonist. The affinity for the binding site of the CCK-receptor for some of these compounds was hundreds of times higher than that of pro-glumide, the model compound.