Trimebutine [3,4,5-trimethoxybenzoic acid 2-(dimethylamino)-2-phenylbutylester] is a noncompetitive spasmolytic agent. The actions of trimebutine on the gastrointestinal tract are mediated via (i) an agonist effect on peripheral mu, kappa and delta opiate receptors and (ii) release of gastrointestinal peptides such as motilin and modulation of the release of other peptides, including vasoactive intestinal peptide, gastrin and glucagon. Trimebutine attenuated colonic motility mainly through the inhibition of L-type Ca(2+) channels at higher concentrations, whereas, at lower concentrations, it depolarized membrane potentials by reducing BK(ca) currents, resulting in the enhancement of the muscle contractions.Trimebutine accelerates gastric emptying, induces premature phase III of the migrating motor complex in the intestine and modulates the contractile activity of the colon. It is indicated for the treatment and relief of symptoms associated with the irritable bowel syndrome (spastic colon); and in postoperative paralytic ileus in order to accelerate the resumption of the intestinal transit following abdominal surgery.

Trimebutine [3,4,5-trimethoxybenzoic acid 2-(dimethylamino)-2-phenylbutylester] is a noncompetitive spasmolytic agent. The actions of trimebutine on the gastrointestinal tract are mediated via (i) an agonist effect on peripheral mu, kappa and delta opiate receptors and (ii) release of gastrointestinal peptides such as motilin and modulation of the release of other peptides, including vasoactive intestinal peptide, gastrin and glucagon. Trimebutine attenuated colonic motility mainly through the inhibition of L-type Ca(2+) channels at higher concentrations, whereas, at lower concentrations, it depolarized membrane potentials by reducing BK(ca) currents, resulting in the enhancement of the muscle contractions.Trimebutine accelerates gastric emptying, induces premature phase III of the migrating motor complex in the intestine and modulates the contractile activity of the colon. It is indicated for the treatment and relief of symptoms associated with the irritable bowel syndrome (spastic colon); and in postoperative paralytic ileus in order to accelerate the resumption of the intestinal transit following abdominal surgery.

Trimebutine [3,4,5-trimethoxybenzoic acid 2-(dimethylamino)-2-phenylbutylester] is a noncompetitive spasmolytic agent. The actions of trimebutine on the gastrointestinal tract are mediated via (i) an agonist effect on peripheral mu, kappa and delta opiate receptors and (ii) release of gastrointestinal peptides such as motilin and modulation of the release of other peptides, including vasoactive intestinal peptide, gastrin and glucagon. Trimebutine attenuated colonic motility mainly through the inhibition of L-type Ca(2+) channels at higher concentrations, whereas, at lower concentrations, it depolarized membrane potentials by reducing BK(ca) currents, resulting in the enhancement of the muscle contractions.Trimebutine accelerates gastric emptying, induces premature phase III of the migrating motor complex in the intestine and modulates the contractile activity of the colon. It is indicated for the treatment and relief of symptoms associated with the irritable bowel syndrome (spastic colon); and in postoperative paralytic ileus in order to accelerate the resumption of the intestinal transit following abdominal surgery.

Trimebutine [3,4,5-trimethoxybenzoic acid 2-(dimethylamino)-2-phenylbutylester] is a noncompetitive spasmolytic agent. The actions of trimebutine on the gastrointestinal tract are mediated via (i) an agonist effect on peripheral mu, kappa and delta opiate receptors and (ii) release of gastrointestinal peptides such as motilin and modulation of the release of other peptides, including vasoactive intestinal peptide, gastrin and glucagon. Trimebutine attenuated colonic motility mainly through the inhibition of L-type Ca(2+) channels at higher concentrations, whereas, at lower concentrations, it depolarized membrane potentials by reducing BK(ca) currents, resulting in the enhancement of the muscle contractions.Trimebutine accelerates gastric emptying, induces premature phase III of the migrating motor complex in the intestine and modulates the contractile activity of the colon. It is indicated for the treatment and relief of symptoms associated with the irritable bowel syndrome (spastic colon); and in postoperative paralytic ileus in order to accelerate the resumption of the intestinal transit following abdominal surgery.

Bepridil (trade name Vascor) is an amine calcium channel blocker used to treat angina. Bepridil is a calcium channel blocker that has well characterized anti-anginal properties and known but poorly characterized type 1 anti-arrhythmic and anti-hypertensive properties. It is not related chemically to other calcium channel blockers such as diltiazem hydrochloride, nifedipine and verapamil hydrochloride. Bepridil has inhibitory effects on both the slow calcium (L-type) and fast sodium inward currents in myocardial and vascular smooth muscle, interferes with calcium binding to calmodulin, and blocks both voltage and receptor operated calcium channels. Bepridil inhibits the transmembrane influx of calcium ions into cardiac and vascular smooth muscle. This has been demonstrated in isolated myocardial and vascular smooth muscle preparations in which both the slope of the calcium dose response curve and the maximum calcium-induced inotropic response were significantly reduced by bepridil. In cardiac myocytes in vitro, bepridil was shown to be tightly bound to actin. Bepridil regularly reduces heart rate and arterial pressure at rest and at a given level of exercise by dilating peripheral arterioles and reducing total peripheral resistance (afterload) against which the heart works. Bepridil is no longer sold in the United States, but it is still marketed in other countries. Bepridil has antihypertensive and selective anti-arrhythmia activities and acts as a calmodulin antagonist. Although, it contains one chiral center, it is generally administered as a racemates. The drug bepridil is a racemic mixture of two enantiomers for the 2R as CID 16048570 and 2S as CID 445143. (R)-isomer of bepridil is more active than (-S)- isomer, in certain cases. In the retrogradely perfused, paced rat heart the higher activity was found for the ( )-enantiomer, which was 4.27 times more potent in increasing coronary flow than the (-)-isomer. The two enantiomers of bepridil showed a lower activity on maximum systolic left ventricular pressure (MSLVP) than on coronary flow, and a similar 3-4 fold stereoselectivity with both parameters.

(S)-Lercanidipine is enantiomer of antihypertensive drugs Lercanidipine, that acts by blocking L-type calcium channels, allowing relaxation and opening of blood vessels. The dihydropyridine calcium antagonists promote systemic vasodilatation by a reversible blockade of voltage-dependent Ca2+ influx through L-type channels in the cell membrane. (S)-Lercanidipine has 100- to 200-fold greater affinity than the (R)-enantiomer for the L-type calcium channel. The pharmacokinetics of (S)- Lercanidipine has been evaluated in healthy volunteers, in elderly and non-elderly patients with hypertension, and in patients with renal or hepatic impairment. Patients from these studies were investigated after receiving a single 10 or 20 mg dose of [14C]-labeled rac-Lercanidipine as a solution. The maximum plasma concentrations of (S)-Lercanidipine were reached within 2–3 h and the area under the plasma concentration-time curves were not linearly related to the dose, indicating a saturable first-pass metabolism. The absorption of (S)-LER increases after the ingestion of a high-fat meal. Lercanidipine is highly bound to plasma protein (>98%) in humans. Its volume of distribution of 2–2.5 L/kg was determined in healthy volunteers after intravenous infusion of 2 mg. Lercanidipine is extensively metabolized by CYP 3A4 to inactive pyridine derivatives. A crossover study involving a single administration of either 10 mg of (R)- or (S)-LER or 20 mg of rac-LER as a solution demonstrated no in vivo enantiomer interconversion

Nebentan (YM598) is an orally active synthetic substituted phenylethenesulfonamide. As a selective endothelin A receptor antagonist, YM598 inhibits endothelin-mediated mechanisms involved in tumor cell growth and progression, angiogenesis, and metastasis. The inhibitory dissociation constant value of YM598 was 0.772 nM for native human ETA receptors, and 143 nM for native human ETB subtypes. The calculated selectivity ratio of YM598 for ETA versus ETB receptors was 222. In pithed rats, YM598 inhibited the big endothelin-1 (1 nmol/kg)-induced pressor response in a dose-dependent manner, after both intravenous and oral administration. YM598 showed not only superior antagonistic activity and higher-selectivity for endothelin ET(A) receptor in vitro, but at least a 30-fold higher potency in vivo than bosentan.

(R)-Lercanidipine is enantiomer of antihypertensive drugs Lercanidipine, that acts by blocking L-type calcium channels, allowing relaxation and opening of blood vessels. The dihydropyridine calcium antagonists promote systemic vasodilatation by a reversible blockade of voltagedependent Ca2+ influx through L-type channels in the cell membrane. (S)-Lercanidipine has 100- to 200-fold greater affinity than the (R)-enantiomer for the L-type calcium channel. The pharmacokinectics of (S)- Lercanidipine has been evaluated in healthy volunteers, in elderly and non-elderly patients with hypertension, and in patients with renal or hepatic impairment. Patients from these studies were investigated after receiving a single 10 or 20 mgdose of [14C]-labeled rac-Lercanidipine as a solution. The maximum plasma concentrations of (S)-Lercanidipine were reached within 2–3 h and the area under the plasma concentration–time curves were not linearly related to the dose, indicating a saturable first-pass metabolism. The absorption of (S)-LER increases after the ingestion of a highfat meal. Lercanidipine is highly bound to plasma protein (>98%) in humans. Its volume of distribution of 2–2.5 L/kg was determined in healthy volunteers after intravenous infusion of 2 mg. Lercanidipine is extensively metabolized by CYP 3A4 to inactive pyridine derivatives. A crossover study involving a single administration of either 10 mg of (R)- or (S)-LER or 20 mg of rac-LER as a solution demonstrated no in vivo enantiomer interconversion

Bepridil (trade name Vascor) is an amine calcium channel blocker used to treat angina. Bepridil is a calcium channel blocker that has well characterized anti-anginal properties and known but poorly characterized type 1 anti-arrhythmic and anti-hypertensive properties. It is not related chemically to other calcium channel blockers such as diltiazem hydrochloride, nifedipine and verapamil hydrochloride. Bepridil has inhibitory effects on both the slow calcium (L-type) and fast sodium inward currents in myocardial and vascular smooth muscle, interferes with calcium binding to calmodulin, and blocks both voltage and receptor operated calcium channels. Bepridil inhibits the transmembrane influx of calcium ions into cardiac and vascular smooth muscle. This has been demonstrated in isolated myocardial and vascular smooth muscle preparations in which both the slope of the calcium dose response curve and the maximum calcium-induced inotropic response were significantly reduced by bepridil. In cardiac myocytes in vitro, bepridil was shown to be tightly bound to actin. Bepridil regularly reduces heart rate and arterial pressure at rest and at a given level of exercise by dilating peripheral arterioles and reducing total peripheral resistance (afterload) against which the heart works. Bepridil is no longer sold in the United States, but it is still marketed in other countries. Bepridil has antihypertensive and selective anti-arrhythmia activities and acts as a calmodulin antagonist. Although, it contains one chiral center, it is generally administered as a racemates. The drug bepridil is a racemic mixture of two enantiomers for the 2R as CID 16048570 and 2S as CID 445143. (R)-isomer of bepridil is more active than (-S)- isomer, in certain cases. In the retrogradely perfused, paced rat heart the higher activity was found for the ( )-enantiomer, which was 4.27 times more potent in increasing coronary flow than the (-)-isomer. The two enantiomers of bepridil showed a lower activity on maximum systolic left ventricular pressure (MSLVP) than on coronary flow, and a similar 3-4 fold stereoselectivity with both parameters.

Manidipine, (R)- is enantiomer of Manidipine a lipophilic, third-generation dihydropyridine calcium channel antagonist with a high degree of selectivity for the vasculature, thereby inducing marked peripheral vasodilation with negligible cardiodepression. Manidipine has different pharmacological effects and (S)-manidipine is shown to be about 30–80 times more potent than (R)-manidipine in its antihypertensive action and in the radioligand binding assay. Patch-clamp experiments revealed that the S-enantiomers of manidipine displayed a faster onset of action and produced a greater blockade than the R-enantiomer. Also, manidipine enantiomers have markedly different pharmacokinetics and the S/R ratio for (S)- and (R)-enantiomer concentrations is 2.0