Antihypertensive effect of manidipine

Ultrafast C-C and C-N bond formation reactions in water microdroplets facilitated by the spontaneous generation of carbocations

Carbocations are important electrophilic intermediates in organic chemistry, but their formation typically requires harsh conditions such as extremely low pH, elevated temperature, strong oxidants and/or expensive noble-metal catalysts. Herein, we report the spontaneous generation of highly reactive carbocations in water microdroplets by simply spraying a diarylmethanol aqueous solution. The formation of transient carbocations as well as their ultrafast in-droplet transformations through carbocation-involved C-C and C-N bond formation reactions are directly characterized by mass spectrometry. The intriguing formation and stabilization of carbocations are attributed to the super acidity of the positively charged water microdroplets as well as the high electric fields at the water-air interfaces. Without the utilization of external acids as catalysts, we believe that these microdroplet reactions would pose a new and sustainable way for the construction of aryl-substituted compounds.

1,4-Dihydropyridine: A Dependable Heterocyclic Ring with the Promising and the Most Anticipable Therapeutic Effects

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Nowadays, heterocyclic compounds act as a scaffold and are the backbone of medicinal chemistry. Among all of the heterocyclic scaffolds, 1,4-Dihydropyridine (1,4-DHP) is one of the most important heterocyclic rings that possess prominent therapeutic effects in a very versatile manner and plays an important role in synthetic, medicinal, and bioorganic chemistry. The main aim of the study is to review and encompass relevant studies related to 1,4-DHP and excellent therapeutic benefits of its derivatives. An extensive review of Pubmed-Medline, Embase and Lancet’s published articles was done to find all relevant studies on the activity of 1,4-DHP and its derivatives. 1,4-DHP is a potent Voltage-Gated Calcium Channel (VGCC) antagonist derivative which acts as an anti-hypertensive, anti- anginal, anti-tumor, anti-inflammatory, anti-tubercular, anti-cancer, anti-hyperplasia, anti-mutagenic, anti-dyslipidemic, and anti-ulcer agent. From the inferences of the study, it can be concluded that the basic nucleus, 1,4-DHP which is a voltage-gated calcium ion channel blocker, acts as a base for its derivatives that possess different important therapeutic effects. There is a need of further research of this basic nucleus as it is a multifunctional moiety, on which addition of different groups can yield a better drug for its other activities such as anti-convulsant, anti-oxidant, anti-mutagenic, and anti-microbial. This review would be significant for further researches in the development of several kinds of drugs by representing successful matrix for the medicinal agents.

Screening of FDA-Approved Drugs for Inhibitors of Japanese Encephalitis Virus Infection

Japanese encephalitis virus (JEV), an arthropod-borne flavivirus, is a major cause of acute viral encephalitis in humans. No approved drug is available for the specific treatment of JEV infections, and the available vaccines are not effective against all clinical JEV isolates. In the study described here, a high-throughput screening of an FDA-approved drug library for inhibitors of JEV was performed. Five hit drugs that inhibited JEV infection with a selective index of >10 were identified. The antiviral activities of these five hit drugs against other flavivirus, including Zika virus, were also validated. As three of the five hit drugs were calcium inhibitors, additional types of calcium inhibitors that confirmed that calcium is essential for JEV infection, most likely during viral replication, were utilized. Adaptive mutant analysis uncovered that replacement of Q130, located in transmembrane domain 3 of the nonstructural NS4B protein, which is relatively conserved in flaviviruses, with R or K conferred JEV resistance to manidipine, a voltage-gated Ca²⁺ channel (VGCC) inhibitor, without an apparent loss of the viral growth profile. Furthermore, manidipine was indicated to protect mice against JEV-induced lethality by decreasing the viral load in the brain, while it abrogated the histopathological changes associated with JEV infection. This study provides five antiflavivirus candidates and identifies cytoplasmic calcium to be a novel antiviral target for the treatment of JEV infection. The findings reported here provide therapeutic possibilities for combating infections caused by flaviviruses.

IMPORTANCE No approved therapy for the treatment of Japanese encephalitis virus infection is currently available. Repurposing of approved drugs would accelerate the development of a therapeutic stratagem. In this study, we screened a library of FDA-approved drugs and identified five hit drugs, especially calcium inhibitors, exerting antiflavivirus activity that blocked viral replication. The in vivo efficacy and toxicity of manidipine were investigated with a mouse model of JEV infection, and the viral target was identified by generating an adaptive mutant.

Treatment of hypertensive patients with diabetes: beyond blood pressure control and focus on manidipine

Renin-angiotensin system inhibitors should be considered as the first-line therapy in the treatment of patients with hypertension and diabetes. However, most of the diabetic subjects with hypertension require at least two drugs to achieve blood pressure targets. The ACCOMPLISH trial suggested that the best combination in the treatment of high-risk hypertensive patients should include a renin-angiotensin system inhibitor and a dihydropyridine. However, not all dihydropyridines block the same receptors. Those dihydropyridines that block T-type calcium channel blockers may provide additional advantages. A number of studies suggest that compared with amlodipine, manidipine have the same antihypertensive efficacy, but with a lesser risk of ankle edema. In addition, manidipine, but not amlodipine, significantly reduces urinary albumin excretion rates.

Determination and pharmacokinetics of manidipine in human plasma by HPLC/ESIMS

A sensitive HPLC/ESIMS method was established for the determination of manidipine in human plasma and pharmacokinetics study. After basified plasma with ammonia, manidipine and the internal standard (IS) (felodipine) were extracted with n-hexane and separated on a Hypersil ODS2 column with a mobile phase of methanol-5 mm ammonium acetate solution containing 0.1% acetic acid (85:15, v/v). MS determination was performed by electrospray ionization in the selected ion monitoring mode. Manidipine was monitored at m/z 611.4 and IS at m/z 384. The assay had a calibration range from 0.2 to 20 ng/mL and a lower limit of quantification of 0.1 ng/mL. The method has been successfully applied to the pharmacokinetic study in healthy volunteers.

The effect of nimodipine on calcium homeostasis and pain sensitivity in diabetic rats

1. The pathogenesis of diabetic neuropathy is a complex phenomenon, the mechanisms of which are not fully understood. Our previous studies have shown that the intracellular calcium signaling is impaired in primary and secondary nociceptive neurons in rats with streptozotocin (STZ)-induced diabetes. Here, we investigated the effect of prolonged treatment with the L-type calcium channel blocker nimodipine on diabetes-induced changes in neuronal calcium signaling and pain sensitivity. 2. Diabetes was induced in young rats (21 p.d.) by a streptozotocin injection. After 3 weeks of diabetes development, the rats were treated with nimodipine for another 3 weeks. The effect of nimodipine treatment on calcium homeostasis in nociceptive dorsal root ganglion neurons (DRG) and substantia gelatinosa (SG) neurons of the spinal cord slices was examined with fluorescent imaging technique. 3. Nimodipine treatment was not able to normalize elevated resting intracellular calcium ([Ca(2+)]( i )) levels in small DRG neurons. However, it was able to restore impaired Ca(2+) release from the ER, induced by either activation of ryanodine receptors or by receptor-independent mechanism in both DRG and SG neurons. 4. The beneficiary effects of nimodipine treatment on [Ca(2+)]( i ) signaling were paralleled with the reversal of diabetes-induced thermal hypoalgesia and normalization of the acute phase of the response to formalin injection. Nimodipine treatment was also able to shorten the duration of the tonic phase of formalin response to the control values. 5. To separate vasodilating effect of nimodipine Biessels et al., (Brain Res. 1035:86-93) from its effect on neuronal Ca(2+) channels, a group of STZ-diabetic rats was treated with vasodilator - enalapril. Enalapril treatment also have some beneficial effect on normalizing Ca(2+) release from the ER, however, it was far less explicit than the normalizing effect of nimodipine. Effect of enalapril treatment on nociceptive behavioral responses was also much less pronounced. It partially reversed diabetes-induced thermal hypoalgesia, but did not change the characteristics of the response to formalin injection. 6. The results of this study suggest that chronic nimodipine treatment may be effective in restoring diabetes-impaired neuronal calcium homeostasis as well as reduction of diabetes-induced thermal hypoalgesia and noxious stimuli responses. The nimodipine effect is mediated through a direct neuronal action combined with some vascular mechanism.