Calcium channel blockers in emergency medicine

Multicomponent synthesis of chromophores – The one-pot approach to functional π-systems

Multicomponent reactions, conducted in a domino, sequential or consecutive fashion, have not only considerably enhanced synthetic efficiency as one-pot methodology, but they have also become an enabling tool for interdisciplinary research. The highly diversity-oriented nature of the synthetic concept allows accessing huge structural and functional space. Already some decades ago this has been recognized for life sciences, in particular, lead finding and exploration in pharma and agricultural chemistry. The quest for novel functional materials has also opened the field for diversity-oriented syntheses of functional π-systems, i.e. dyes for photonic and electronic applications based on their electronic properties. This review summarizes recent developments in MCR syntheses of functional chromophores highlighting syntheses following either the framework forming scaffold approach by establishing connectivity between chromophores or the chromogenic chromophore approach by de novo formation of chromophore of interest. Both approaches warrant rapid access to molecular functional π-systems, i.e. chromophores, fluorophores, and electrophores for various applications.

Evaluation of the chiral recognition properties and the column performances of three chiral stationary phases based on cellulose for the enantioseparation of six dihydropyridines by high-performance liquid chromatography

Separations of six dihydropyridine enantiomers on three commercially available cellulose-based chiral stationary phases (Chiralcel OD-RH, Chiralpak IB, and Chiralpak IC) were evaluated with high-performance liquid chromatography (HPLC). The best enantioseparation of the six chiral drugs was obtained with a Chiralpak IC (250 × 4.6 mm i.d., 5 μm) column. Then the influence of the mobile phase including an alcohol-modifying agent and alkaline additive on the enantioseparation were investigated and optimized. The optimal mobile phase conditions and maximum resolution for every analyte were as follows respectively: n-hexane/isopropanol (85:15, v/v) for nimodipine (R = 5.80) and cinildilpine (R = 5.65); n-hexane/isopropanol (92:8, v/v) for nicardipine (R = 1.76) and nisoldipine (R = 1.92); and n-hexane/isopropanol/ethanol (97:2:1, v/v/v) for felodipine (R = 1.84) and lercanidipine (R = 1.47). Relative separation mechanisms are discussed based on the separation results, and indicate that the achiral parts in the analytes' structure showed an important influence on the separation of the chiral column.

Four-component synthesis of polyhydroquinolines under catalyst- and solvent-free conventional heating conditions: mechanistic studies

A convenient and environmentally friendly procedure for the synthesis of polyhydroquinolines via a one-pot four-component reaction has been developed. A detailed mechanistic study of the reaction is presented.

One-pot pseudo three-component reaction of nitroketene-N,S-acetals and aldehydes for synthesis of highly functionalized hexa-substituted 1,4-dihydropyridines

Pseudo three-component condensation of aliphatic/aromatic/α,β-unsaturated aldehydes and nitroketene-N,S-acetals to afford diversely functionalized hexa-substituted 1,4-dihydropyridines under 2-aminopyridine catalysis was achieved.

A Facile Eco-Friendly One-Pot Five-Component Synthesis of Novel 1,2,3-Triazole-Linked Pentasubstituted 1,4-Dihydropyridines and their Biological and Photophysical Studies

An eco-friendly one-pot five-component synthesis of novel 1,2,3-triazole-linked pentasubstituted 1,4-dihydropyridines under ultrasonic and microwave irradiation in polyethylene glycol (PEG) 400 is described. All newly synthesised compounds were evaluated for antibacterial activity, antifungal activity, antioxidant activity, and photophysical properties. Antimicrobial activity was evaluated against six microbial strains. All compounds exhibited antifungal activity against Aspergillus niger and Aspergillus flavus and moderate antibacterial activity against Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis). Antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. All compounds showed good to moderate antioxidant activity. Furthermore all new compounds showed strong fluorescence in solution.

Dihydropyridines: evaluation of their current and future pharmacological applications

The 1,4-dihydropyridines (DHPs), a class of drugs, possess a wide variety of biological and pharmacological actions, have represented one of the most important groups of calcium-channel-modulating agents and have experienced widespread use in the treatment of cardiovascular disease. Moreover, it has been demonstrated that DHPs could prove to be highly important as multidrug-resistance-reversing agents in cancer chemotherapy. Recent reports suggest that this class also has other notable activities, particularly as antimycobacterial and anticonvulsant agents. Finally, it might be possible for the DHP motif to serve as a scaffold for other pharmacological applications.

Potentiation of cocaine toxicity with calcium channel blockers

Three calcium channel blockers were studied for efficacy in preventing seizures and death from cocaine intoxication. Rats were first pretreated with a test drug then subjected to high dose intraperitoneal cocaine. In this model, control animals developed seizures within six minutes, followed by death within ten minutes. Animals that were pretreated with diltiazem, nifedipine, or verapamil developed seizures significantly faster than controls, and at specific doses the death rate was higher than in controls for all three drugs. The potentiation of seizures and death by 2 mg/kg nifedipine pretreatment was further shown by challenge with three different doses of cocaine. This study fails to demonstrate a protective effect and suggests augmentation of cocaine toxicity by pretreatment with the three currently available calcium channel blockers. Several mechanisms by which calcium channel blockers may augment cocaine-induced toxicity are discussed.

Charcoal hemoperfusion for the treatment of a combined diltiazem and metoprolol overdose

We describe the management of a 49-year-old woman who ingested 1,200 mg diltiazem and 500 mg metoprolol. The patient was bradycardic and hypertensive, requiring large doses of inotropic agents and temporary transvenous pacing. Charcoal hemoperfusion was used as an adjunct technique to hasten drug elimination; it rapidly lowered plasma drug levels, with a parallel improvement in the patient's clinical condition.

A randomized comparison of nifedipine and sodium nitroprusside in severe hypertension

We randomized patients with severe hypertension in the Medical Intensive Care Unit to a treatment regimen of oral nifedipine or intravenous nitroprusside. Patients treated with nifedipine achieved a sustained reduction in diastolic blood pressure to less than or equal to 120 mm Hg in an average of less than five hours. Patients treated with nitroprusside achieved a similar reduction in 14 hours (p less than 0.05). Treatment with nifedipine was less expensive and required less time in the ICU than treatment with nitroprusside and was accompanied by no associated increase in morbidity or mortality. Oral nifedipine can be used as an alternative to intravenous nitroprusside in severe uncomplicated hypertension.

Poisoning by antidysrhythmic drugs

This article discusses the management of antidysrhythmic drug overdoses in children and adolescents.

Syncope and conduction disturbances following sublingual nifedipine for hypertension

We present a case of a 79-year-old woman with periods of syncope, complete heart block (CHB), and ventricular standstill during periods of increased vagal tone following sublingual nifedipine for hypertension. The syncopal episodes were associated with periods of elevated vagal tone (micturition and vomiting) with one monitored episode showing a clear time course of emesis; CHB then ensued, progressing to ventricular standstill with loss of consciousness that resolved over several minutes. Although nifedipine is not thought to affect conduction at current clinical dosages, it seems likely that the additive effects of nifedipine and elevated vagal tone produced the observed conduction abnormalities. This is the first case report of nifedipine administration followed by syncope and conduction disturbances.