The Blending of Poly(glycolic acid) with Polycaprolactone and Poly(l-lactide): Promising Combinations.

Poly(glycolic acid) (PGA) holds unique properties, including high gas barrier properties, high tensile strength, high resistance to common organic solvents, high heat distortion temperature, high stiffness, as well as fast biodegradability and compostability. Nevertheless, this polymer has not been exploited at a large scale due to its relatively high production cost. As such, the combination of PGA with other bioplastics on one hand could reduce the material final cost and on the other disclose new properties while maintaining its "green" features.

BIMT 17, a 5-HT1A receptor agonist/5-HT2A receptor antagonist, directly activates postsynaptic 5-HT inhibitory responses in the rat cerebral cortex.

BIMT 17 (1-[2-[4-(3-trifluoromethyl phenyl) piperazin-1-yl] ethyl] benzimidazol- [1H]-2-one), a 5-HT1A receptor agonist/5-HT2A receptor antagonist (see Borsini et al., accompanying paper), in a dose range of 1-10 mg/kg i.v.

BIMT 17, a 5-HT2A receptor antagonist and 5-HT1A receptor full agonist in rat cerebral cortex.

In the search for antidepressant agents with a rapid onset of action, we have found that compound BIMT 17 (1-[2-[4-(3-trifluoromethylphenyl)piperazin-1- yl]ethyl]benzimidazol-[1H]-2-one) shows a good affinity for cerebral cortical 5-HT1A (pKi = 7.72) and 5-HT2A (pKi = 6.90) receptors, with no appreciable affinity for the other 5-HT receptor subtypes, including 5-HT2C.

Gastroprokinetic properties of the benzimidazolone derivative BIMU 1, an agonist at 5-hydroxytryptamine4 and antagonist at 5-hydroxytryptamine3 receptors.

We have investigated the in vivo motor stimulating and gastroprokinetic properties of the azabicycloalkyl benzimidazolone derivative BIMU 1 (3-ethyl-2,3-dihydro-N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-2-oxo-1H- benzimidazole-1-carboxamide hydrochloride) and its binding profile at 5-hydroxytryptamine3 and 5-hydroxytryptamine4 receptors, in an attempt to assess the serotonergic mechanism underlying its prokinetic action.

The effect of DAU 6215, a novel 5HT-3 antagonist, in animal models of anxiety.

The aim of the present study was to evaluate the effect of DAU 6215 (N-(endo-8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-2, 3-dihydro-2-oxo-1H-benzimidazol-1-carboxamide, hydrochloride), which is a 5HT-3 receptor antagonist, chemically different from the other 5HT-3 antagonists, on a wide variety of animal models sensitive to anxiolytics.

Pharmacological properties of a novel class of 5-HT3 receptor antagonists.

The pharmacological profile of six representative members of a novel class of 5-HT3 receptor antagonists is described. The compounds are esters and amides of benzimidazolone-1-carboxylic acid with a basic azabicycloalkyl moiety (compounds 1-3) and their respective ethyl derivatives (compounds 4-6). In isolated preparations (rabbit heart and guinea pig ileum) all compounds antagonized the 5-HT3 receptor-mediated effects of serotonin, with potencies comparable with those of the reference compounds, ICS 205.

Malonamic acid derivatives as M1 selective muscarinic receptor antagonists.

A series of malonamic acid esters with suitable amino alcohols, typical of antimuscarinic compounds, was synthesized and the affinities for the three pharmacologically defined muscarinic receptor subtypes, namely M1, M2 and M3, were evaluated by radioligand displacement experiments. It was found that the esters with 3-quinuclidinol 7b, 7f-g, 8 and 9 are ligands with intermediate to high affinity for the M1 receptors, for which they show a preferential binding. Unexpectedly, the ester 7a with tropine bound with negligible affinity to all the receptors investigated.

Substituent effect on the stereochemistry of H2-receptor antagonists of the phenylformamidine series. A conformation-dependent mode of interaction with the H2 receptor.

The influence of alkyl substitution on the stereoisomerism of the formamidine cation (E,E vs E,Z) of several N-substituted (imidazolylphenyl)formamidines (1-10) was investigated. As (imidazolylphenyl)formamidines having alkyl substituents of more than three carbon atoms bind to H2-receptor preparations in a pseudoirreversible mode causing unsurmountable antagonism, the four isomeric butylformamidines (5-7 and 9) having comparable lipophilic character but different E,E/E,Z composition were investigated in H2-receptor assays to determine quantitatively any difference in their pseudoirreversible inhibitory pattern. It was found that the geometry of the formamidine cation is affected by the steric bulk of the substituent on the formamidine nitrogen.

Synthesis and biological evaluation of new muscarinic receptor antagonists bearing cyclic amidines as cationic heads.

Two classes of compounds, bearing a cyclic amidino moiety instead of the tertiary amino group of the classical antimuscarinic drugs like hexahydrodifenidol 3 were synthesized. Affinities (KD) for the three pharmacologically defined M1, M2 and M3 mAChR subtypes were measured in radioligand binding assays and in functional in vitro studies (KB) in guinea pig ileum and left atrium. The results showed that the replacement of the tertiary amino group in structural analogues of 3 with a cyclic amidino moiety afforded potent antimuscarinic compounds.

New CCK antagonists derived from the amino acid residues of the CCK-8 fragment.

The synthesis of lipophylic derivatives of the amino acid residues of the CCK-8 fragment is described. According to "in vitro" binding studies and functional test, nearly all the compounds behaves as CCK-antagonists; moreover some compounds are able to interact differentially with CCK-A and CCK-B receptor subtype. In particular, compounds 2c, 2g, and 2h possess a high affinity for the CCK-A receptor subtype coupled with a low affinity for the CCK-B subtype.

Antiemetic activity of the new 5-HT3 antagonist DAU 6215 in animal models of cancer chemotherapy and radiation.

The antiemetic activity of DAU 6215, a novel antagonist of 5-HT3 receptors, was investigated in animal models of cytotoxic treatment-evoked emesis and compared with the antiemetic activity of ondansetron and metoclopramide. In dogs, vomiting was induced by i.v.

Synthesis and biological evaluation of new antimuscarinic compounds with amidine basic centers. A useful bioisosteric replacement of classical cationic heads.

Amidines (guanidine, formamidine, and acetamidine) were introduced as substitutes for the cationic heads present in atropine, scopolamine, and corresponding quaternary derivatives. Amidine systems are intermediate in structure between tertiary amines and quaternary compounds, at least as regards ionization and electronic properties, but differ from the latter in shape (planar not tetrahedral). They have additional binding opportunities on account of their hydrogen-bond-forming capacity.

Synthesis of a new class of 2,3-dihydro-2-oxo-1H-benzimidazole-1-carboxylic acid derivatives as highly potent 5-HT3 receptor antagonists.

A series of 2,3-dihydro-2-oxo-1H-benzimidazole-1-carboxylic acid esters and amides containing a basic azacyclo- or azabicycloalkyl moiety has been synthesized and evaluated for 5-HT3 antagonistic activity in a radioligand binding assay ([3H]ICS 205930) and in the 5-HT-induced von Bezold-Jarisch reflex in the rat. It was found that endo-substituted azabicycloalkyl derivatives (e.g.

4-DAMP analogues reveal heterogeneity of M1 muscarinic receptors.

The muscarinic receptors responsible for two effects elicited by McN-A-343, i.e. the relaxation of the rat duodenum and the inhibition of the twitch contraction of rabbit vas deferens, were investigated by use of derivatives of 4-diphenyl acetoxy-N-methyl piperidine methobromide (4-DAMP).

Hexocyclium derivatives with a high selectivity for smooth muscle muscarinic receptors.

1. The affinity of a number of derivatives of the muscarinic antagonist, hexocyclium, containing an amidine cationic head, for guinea-pig cardiac and ileal receptors was investigated. 2.

Irreversible H2-antagonism of the four isomeric butyl analogues of mifentidine.

It has been hypothesized that bidentate hydrogen bonding plays an important role in the interaction of imidazolylphenylformamidines with the H2-receptor. The present study, in which the degree of pseudo-irreversible H2-antagonism of the four isomeric butyl substituted mifentidine analogues was determined on the spontaneously beating right atrium of the male guinea-pig, lends further support to this hypothesis. In solution the EE/EZ ratio is different for the four isomeric butylated mifentidine analogues.

Guanylpirenzepine distinguishes between neuronal ml and m4 muscarinic receptor subtypes.

Guanylpirenzepine, a polar, non-quaternary analog of pirenzepine, exhibited a novel binding behavior in rat brain regions: in competition binding experiments against [3H]pirenzepine labeling the M1 receptor in membranes from cerebral cortex, hippocampus and striatum, the compound, differently from pirenzepine, displayed heterogeneous binding curves. Computer assisted analysis of these curves, evidenced the existence of two populations of binding sites: a large proportion (84-89%) of high affinity receptors (KH = 64-92 nM) and a remainder with very low affinity (KL = 19-28 microM). Like pirenzepine, guanylpirenzepine showed low affinity for the glandular M3 and the cardiac M2 receptors when [3H]N-methylscopolamine was used to label the receptors in membranes from these two tissues; affinity values for guanylpirenzepine were 1336 and 5790 nM respectively, vs 323 and 683 nM for pirenzepine.

Affinity profile of the novel muscarinic antagonist, guanylpirenzepine.

The study reports the functional affinity of an amidino derivative of pirenzepine, guanylpirenzepine, for muscarinic receptors mediating relaxation of rat duodenum, inhibition of rabbit vas deferens twitch contraction (both receptors previously classified as M1), guinea pig negative inotropism (M2) and ileal contraction (M3). Unlike pirenzepine, guanylpirenzepine discriminated between duodenum and vas deferens receptors, with a 30-fold greater affinity for the former subtype. The unique selectivity pattern of guanylpirenzepine (duodenum greater than vas deferens greater than ileum greater than atrium) renders it a promising tool for the classification of muscarinic receptor subtypes.

N-(fluoroethyl)(imidazolylphenyl)formamidines. The issue of the active species of mifentidine.

Three N-fluoroethyl-substituted (imidazolylphenyl)formamidine derivatives, namely, 2-fluoroethyl (3b), 2,2-difluoroethyl (3c), and 2,2,2-trifluoroethyl (3d), were prepared to test the effect of fluorine substitution on basicity and, then, on H2-antagonist affinity in comparison with the unsubstituted N-ethyl derivative (3a), taken as a model of mifentidine. Imidazolylphenyl isothiocyanate (1), obtained by reaction of 4-(aminophenyl)imidazole with carbon disulfide and ethyl chloroformate, was condensed with the requisite 2-fluoro-substituted ethylamines to give the intermediate thioureas (2b-d). Desulfurization of these thioureas by Raney nickel furnished the desired formamidines (3b-d).

Pharmacological profile of mifentidine: a novel H2-receptor antagonist.

Mifentidine, a representative compound of a novel class of H2-antagonists, has been investigated for its ability to interact with H2-receptors and to inhibit gastric acid secretion. Affinity estimates (KB) of mifentidine obtained from in vitro studies on cardiac and gastric mucosal histamine (H2) receptors were in the 20-50 nM range. Mifentidine appeared to be endowed with strong anti-secretory properties against histamine-stimulated secretion in the anaesthetized rat and in the conscious dog.

Conformational studies of two histamine H2-receptor antagonistic phenylformamidines: mifentidine and its guanidinothiazole analogue DA 4643.

Two histamine H2-receptor antagonists of the phenylformamidine type, mifentidine (N-isopropyl-N'-(4-1H-imidazol-4-yl-phenyl) formamidine dihydrochloride; I) and DA 4643 (N-methyl-N'-(3-(2-guanidinothiazol-4-yl)-phenyl) formamidine dihydrochloride; II), have been investigated by experimental physico-chemical studies and theoretical conformational analysis. PKa determinations on the two molecules I and II show that these substances exist at physiological pH (7.4) predominantly as their monoprotonated forms at the formamidine moiety.

Cimetidine, ranitidine and mifentidine in specific gastric and duodenal ulcer models.

The protective effect of cimetidine, ranitidine and a newer H2-receptor antagonist, mifentidine (proposed INN), on models of gastric and duodenal damage, caused by activation of H2 receptors, was studied. Gastric erosions were induced in rats by intravenous dimaprit (100 mg/kg) while duodenal damage was investigated in guinea pigs following subcutaneous administration of dimaprit (2 mg/kg, 6 doses). All the compounds reduced or abolished gastric and duodenal damage in rats and guinea pigs, mifentidine being more potent than both cimetidine and ranitidine.

(Imidazolylphenyl)formamidines. A structurally novel class of potent histamine H2 receptor antagonists.

Structure-activity considerations of N alpha-guanylhistamine, the first compound found with detectable H2-antagonist activity, led to the synthesis of a series of conformationally rigid guanylhistamine analogues, namely, (imidazolylphenyl)guanidines, imidazolylbenzamidines, and (imidazolylphenyl)formamidines. It was found that in the guanidine and benzamidine classes, the meta-substituted derivatives (3, 4, 7, and 8) possessed H2-antagonist activity, whereas in the class of formamidines, only the para-substituted derivative 10 was found active. A subsequent increase in the size of the substituent at the formamidino group of 10 led to compounds (15-20) of high H2-antagonist affinity, which was related to the gastric antisecretory effect.

Synthesis and analgetic-antiinflammatory activity of 3,5-pyrazolidinediones bearing small-ring cycloalkyl groups.

Six 1,2-diphenyl-3,5-pyrazolidinediones substituted in the 4-position with small-ring cycloalkyl groups were prepared and tested for analgetic-antiinflammatory activity. Three of the synthesized compounds exerted an analgetic-antiinflammatory activity quantitatively superior to that of phenylbutazone used as a reference standard. In particular, one of the compounds (VI) proved twice as potent as phenylbutazone while possessing the same ulcerogenic effect.

Synthesis and analgesic activity of N-substituted 6,7-benzomorphans.

Some new N-substituted 6,7-benzomorphans were prepared and tested for analgetic activity. The compounds (I) and (II), which proved the most active in a preliminary screening, were submitted to a more detailed investigation, and their ED50 was determined in mice by the phenylquinone, hot-plate and tail-pinch tests. Studies of acute toxicity and physical dependence capacity were also performed.