Investigation on fabrication process of dissolving microneedle arrays to improve effective needle drug distribution

The dissolving microneedle array (DMNA) offers a novel potential approach for transdermal delivery of biological macromolecular drugs and vaccines, because it can be as efficient as hypodermic injection and as safe and patient compliant as conventional transdermal delivery. However, effective needle drug distribution is the main challenge for clinical application of DMNA. This study focused on the mechanism and control of drug diffusion inside DMNA during the fabrication process in order to improve the drug delivery efficiency. The needle drug loading proportion (NDP) in DMNAs was measured to determine the influences of drug concentration gradient, needle drying step, excipients, and solvent of the base solution on drug diffusion and distribution. The results showed that the evaporation of base solvent was the key factor determining NDP. Slow evaporation of water from the base led to gradual increase of viscosity, and an approximate drug concentration equilibrium was built between the needle and base portions, resulting in NDP as low as about 6%. When highly volatile ethanol was used as the base solvent, the viscosity in the base rose quickly, resulting in NDP more than 90%. Ethanol as base solvent did not impact the insertion capability of DMNAs, but greatly increased the in vitro drug release and transdermal delivery from DMNAs. Furthermore, the drug diffusion process during DMNA fabrication was thoroughly investigated for the first time, and the outcomes can be applied to most two-step molding processes and optimization of the DMNA fabrication.

An impact of the ring substitution in nicorandil on its adsorption on silver nanoparticles. Surface-enhanced Raman spectroscopy studies

The substituent effect on structure and surface activity of biologically active nicorandil was investigated by means of surface-enhanced Raman spectroscopy (SERS). Vibrational characterization was a basis for investigation of the adsorption profile of nicorandil and 1-methylnicorandil on silver nanoparticles. An assignment of SERS bands was performed by the comparison of the Raman spectra of both compounds in the solid state and in solutions, complemented by DFT calculations. Even though the nitro group was found to be the most attractive to the silver surface, the strong impact of the methyl substituent changed this preferable adsorption mechanism in 1-methylnicorandil. Protonation of the nitrogen atom in the pyridinium ring was also found to have an impact on absorption mechanism.

Antiarthritic activity of Cynodon dactylon (L.) Pers

Cynodon dactylon (L.) (Poaceae) is traditionally used herb to treat fevers, skin diseases and rheumatic affections. The ethanolic extract of C. dactylon was found to be safe at all the dose levels (100, 200 and 400 mg/kg, orally) and there was no mortality up to the dose of 5000 mg/kg of extract when administered orally. C. dactylon showed significant antiarthritic activity against Freund's complete adjuvant induced arthritis in rats. Treatment with C. dactylon significantly reduced the mean percentage change in injected and non injected paw, ankle diameter, clinical severity and significantly increased body weight. Results were confirmed using biochemical parameters; there was a significant improvement in the levels of Hb and RBC in C. dactylon treated rats. The increased levels of WBC, ESR, C- reactive protein (CRP) and TNFalpha were significantly suppressed in C. dactylon treated rats. C. dactylon showed protective effect in arthritic joints but it has been supported by an improvement in bone lesions rather than in cartilage lesions. It can be concluded that ethanolic extract of C. dactylon at a dose of 400 mg/kg is effective in improving haematological level, CRP and reducing TNFalpha level. Phytochemical screening showed the presence of alkaloids, flavonoids and glycosides in ethanolic extract. All the above results support the traditional uses of the plant in the treatment of rheumatoid arthritis.

Compatibility of amiodarone hydrochloride with vasopressin during simulated Y-site administration

The objective of this study was to determine the compatibility of amiodarone hydrochloride with vasopressin during simulated Y-site administration. Amiodarone hydrochloride is compatible with vasopressin under simulated-use conditions when administered according to the Advanced Cardiac Life Support Guidelines. A simulated-use approach is a more appropriate way to evaluate compatibility of drug solutions and to assure safe and adequate drug delivery to the patient, particularly when the drug being evaluated is well-documented to have physical or chemical incompatibility concerns with various drugs. When amiodarone hydrochloride (50 mg/mL) was diluted to 6 mg/mL with 5% dextrose injection, then mixed with an equal volume of vasopressin (0.2 units/mL in normal saline) in a glass test tube, no visual incompatibility was observed for up to 24 hours. The purpose of our study was to assess compatibility of the two drugs under simulated-use conditions and to measure the recovery of amiodarone by high-performance liquid chromatography after sequential administration of vasopressin and amiodarone hydrochloride according to the Advanced Cardiac Life Support Guidelines.

Lappaconitine: influence of halogen substituent on the antiarrhythmic activity

The current paper presents research results related to antiarrhythmic activity of halogen-containing derivatives of lappaconitine. Lappaconitine derivatives with iodine, chlorine or bromine substituting the anthranilate moiety at C-5` position were shown in vivo and in vitro to exhibit a more (Br, I) or less (Cl) pronounced antiarrhythmic activity in the models of calcium chloride- and adrenaline-induced arrhythmias as compared with the reference compound lappaconitine. The intensity of antiarrhythmic action depending on halogen substituent was found to be expressed by the following order: Cl < I < Br.

Semisynthesis and myocardial activity of thaliporphine N-homologues

The N-homologues and optical isomers of thaliporphine (5a), a potent antiarrhythmic agent, were prepared starting from laurolitsine (1), an abundant aporphine present in Phoebe formosana. Treating N-propylnorglaucine with 90% H2SO4 yielded one additional product, an 11-sulfonyl-1,11-anhydroaporphine. Reaction of N-formylnorglaucine (3a) with 90% H2SO4, however, yielded the 9-sulfonyl-seco product as a major product. Treatment of 3a with 98% H2SO4 yielded pancordine (10), which, upon catalytic hydrogenation, yielded (±)-wilsonirine. (1)H NMR spectroscopic analysis was applied successfully to monitor the optical purity of the crystalline salt while undertaking optical resolution. Thaliporphine (5a) was demonstrated to possess better positive inotropic and less negative chronotropic effects than the left-hand optical isomer and showed the best activity on rat cardiac tissue among the N-homologues prepared.

Effect of daurisoline on HERG channel electrophysiological function and protein expression

Daurisoline (1) is a bis-benzylisoquinoline alkaloid isolated from the rhizomes of Menispermum dauricum. The antiarrhythmic effect of 1 has been demonstrated in different experimental animals. In previous studies, daurisoline (1) prolonged action potential duration (APD) in a normal use-dependent manner. However, the electrophysiological mechanisms for 1-induced prolongation of APD have not been documented. In the present study, the direct effect of 1 was investigated on the hERG current and the expression of mRNA and protein in human embryonic kidney 293 (HEK293) cells stably expressing the hERG channel. It was shown that 1 inhibits hERG current in a concentration- and voltage-dependent manner. In the presence of 10 μM 1, steady-state inactivation of V(1/2) was shifted negatively by 15.9 mV, and 1 accelerated the onset of inactivation. Blockade of hERG channels was dependent on channel opening. The expression and function of hERG were unchanged by 1 at 1 and 10 μM, while hERG expression and the hERG current were decreased significantly by 1 at 30 μM. These results indicate that 1, at concentrations below 30 μM, exerts a blocking effect on hERG, but does not affect the expression and function of the hERG channel. This may explain the relatively lower risk of long QT syndrome after long-term usage.

l-Tetrahydropalmatine, an active component of Corydalis yanhusuo W.T. Wang, protects against myocardial ischaemia-reperfusion injury in rats

l-Tetrahydropalmatine (l-THP) is an active ingredients of Corydalis yanhusuo W.T. Wang, which protects against acute global cerebral ischaemia-reperfusion injury. In this study, we show that l-THP is cardioprotective in myocardial ischaemia-reperfusion injury and examined the mechanism. Rats were treated with l-THP (0, 10, 20, 40 mg/kg b.w.) for 20 min before occlusion of the left anterior descending coronary artery and subjected to myocardial ischaemia-reperfusion (30 min/6 h). Compared with vehicle-treated animals, the infarct area/risk area (IA/RA) of l-THP (20, 40 mg/kg b.w.) treated rats was reduced, whilst l-THP (10 mg/kg b.w.) had no significant effect. Cardiac function was improved in l-THP-treated rats whilst plasma creatine kinase activity declined. Following treatment with l-THP (20 mg/kg b.w.), subunit of phosphatidylinositol 3-kinase p85, serine⁴⁷³ phosphorylation of Akt and serine¹¹⁷⁷ phosphorylation of endothelial NO synthase (eNOS) increased in myocardium, whilst expression of inducible NO synthase (iNOS) decreased. However, the expression of HIF-1α and VEGF were increased in I_{30 min}R_{6 h}, but decreased to normal level in I_{30 min}R_{24 h}, while treatment with l-THP (20 mg/kg b.w.) enhanced the levels of these two genes in I_{30 min}R_{24 h}. Production of NO in myocardium and plasma, activity of myeloperoxidase (MPO) in plasma and the expression of tumour necrosis factor-α (TNF-α) in myocardium were decreased by l-THP. TUNEL assay revealed that l-THP (20 mg/kg b.w.) reduced apoptosis in myocardium. Thus, we show that l-THP activates the PI3K/Akt/eNOS/NO pathway and increases expression of HIF-1α and VEGF, whilst depressing iNOS-derived NO production in myocardium. This effect may decrease the accumulation of inflammatory factors, including TNF-α and MPO, and lessen the extent of apoptosis, therefore contributing to the cardioprotective effects of l-THP in myocardial ischaemia-reperfusion injury.

Amiodarone and the thyroid: a 2012 update

Amiodarone-induced thyroid dysfunction occurs in 15-20% of amiodarone-treated patients. Amiodarone-induced hypothyroidism (AIH) does not pose relevant problems, is easily controlled by L-thyroxine replacement, and does not require amiodarone withdrawal. Most frequently AIH develops in patients with chronic autoimmune thyroiditis. Amiodarone- induced thyrotoxicosis (AIT) is most frequently due to destructive thyroiditis (type 2 AIT) causing discharge of thyroid hormones from the damaged, but otherwise substantially normal gland. Less frequently AIT is a form of hyperthyroidism (type 1 AIT) caused by the iodine load in a diseased gland (nodular goiter, Graves' disease). A clearcut differentiation between the two main forms is not always possible, despite recent diagnostic advances. As a matter of fact, mixed or indefinite forms do exist, contributed to by both thyroid damage and increased thyroid hormone synthesis. Treatment of type 1 (and mixed forms) AIT is based on the use of thionamides, a short course of potassium perchlorate and, if treatment is not rapidly effective, oral glucocorticoids. Glucocorticoids are the first-line treatment for type 2 AIT. Amiodarone should be discontinued, if feasible from a cardiac standpoint. Continuation of amiodarone has recently been associated with a delayed restoration of euthyroidism and a higher chance of recurrence after glucocorticoid withdrawal. Whether amiodarone treatment can be safely reinstituted after restoration of euthyroidism is still unknown. In rare cases of AIT resistance to standard treatments, or when a rapid restoration of euthyroidism is advisable, total thyroidectomy represents a valid alternative. Radioiodine treatment is usually not feasible due to the low thyroidal iodine uptake.

[Amiodarone and thyroid dysfunction]

Amiodarone is a structural analogue of thyroid hormone, and some of its anti-arrhythmic actions and toxicity are attributable to its interaction with nuclear receptors of thyroid hormones. Being highly lipophilic, amiodarone is concentrated in many tissues and is eliminated, consequently, very slowly. It is preferably employed to manage life-threatening arrhythmias, including ventricular fibrillation and unstable ventricular tachycardia. Other indications include atrial fibrillation and flutter, severe congestive heart failure, prevention of atrial fibrillation recurrence, and even in emergency medical situations to prevent sudden cardiac death. The aim of this review is to provide an updated approach on amiodarone and its influence on thyroid physiology and to discuss and analyze in depth its potential and not infrequent thyroidal adverse effects such as hypothyroidism and thyrotoxicosis.

Visible spectrophotometric method for amiodarone

Amiodarone is an antiarrhythmic agent used for various types of tachyarrhythmia, both ventricular and supraventricular (atrial) arrhythmia. A spectrophotometric method for the assay of amiodarone was established. Based on the reduction of potassium ferricyanide in hydrochloric acid medium to potassium ferrocyanide forming a blue colored complex ferric ferrocyanide with Fe (III) ions. The compound was most stable in a mixture of ethylic alcohol and water (2:1, v/v) and it had an absorption maximum at 725 nm. The data were according to the Lambert-Beer Law in the concentration range of 0.5-5.0 microg/sample: correlation and coefficient R = 0.99977, R2 = 0.999541, slope of the line 0.12775, intercept 0.042077. The detection limit (DL) was 0.1032 microg/sample and the quantification limit (QL) 0.344 microg/ sample.

[The research practice of anti-arrhythmic agents targeting on potassium ion channel]

Due to the complicated pathogenesis of cardiac arrhythmia, the safe and effective therapeutic strategies for cardiac arrhythmia remain an urgent medical problems in the recent years. In this paper, we introduced the research practice of anti-arrhythmic agents targeting on potassium ion channel. The research progress of anti-arrhythmic agents in up-to-date literatures were also reviewed and prospected.

[Circular dichroism in study of drug chirality]

Verapamyl substance and market verapamyl were investigated with circular dichroism. It was shown that circular dichroism provided rapid and highly efficient determination of the optic isomers and could be recommended as a method for control of drug quality.

Spider-venom peptides as therapeutics

Spiders are the most successful venomous animals and the most abundant terrestrial predators. Their remarkable success is due in large part to their ingenious exploitation of silk and the evolution of pharmacologically complex venoms that ensure rapid subjugation of prey. Most spider venoms are dominated by disulfide-rich peptides that typically have high affinity and specificity for particular subtypes of ion channels and receptors. Spider venoms are conservatively predicted to contain more than 10 million bioactive peptides, making them a valuable resource for drug discovery. Here we review the structure and pharmacology of spider-venom peptides that are being used as leads for the development of therapeutics against a wide range of pathophysiological conditions including cardiovascular disorders, chronic pain, inflammation, and erectile dysfunction.

["Structure-anti-arrhythmic activity" relationship of N-phenilacetamide derivatives and amides of aromatic carbonic acids]

Using the computer system SARD-21 (Structure Activity Relationship & Design) structural features of high- and low-effective anti-arrhythmic agents have been recognized and the influence of these features on the anti-arrhythmic properties has been evaluated. This information has been used for generation of the model for prediction of anti-arrhythmic effectiveness of pharmaceutical preparations with the 82%-level of recognition by two methods. The recognized structural parameters may be successfully used for design of new highly effective anti-arrhythmic drugs, and also for modification of structures of known anti-arrhythmic drugs for the increase of effectiveness of their anti-arrhythmic action.

Antiarrhythmic and antioxidant activity of novel pyrrolidin-2-one derivatives with adrenolytic properties

A series of novel pyrrolidin-2-one derivatives (17 compounds) with adrenolytic properties was evaluated for antiarrhythmic, electrocardiographic and antioxidant activity. Some of them displayed antiarrhythmic activity in barium chloride-induced arrhythmia and in the rat coronary artery ligation-reperfusion model, and slightly decreased the heart rate, prolonged P–Q, Q–T intervals and QRS complex. Among them, compound EP-40 (1-[2-hydroxy-3-[4-[(2-hydroxyphenyl)piperazin-1-yl]propyl]pyrrolidin-2-one showed excellent antiarrhythmic activity. This compound had significantly antioxidant effect, too. The present results suggest that the antiarrhythmic effect of compound EP-40 is related to their adrenolytic and antioxidant properties. A biological activity prediction using the PASS software shows that compound EP-35 and EP-40 can be characterized by antiischemic activity; whereas, compound EP-68, EP-70, EP-71 could be good tachycardia agents.

Synthesis and adrenolytic activity of new propanolamines

The synthesis of (2R,S)-1-(6-methoxy-4-(methoxymethyl)-1H-indol-5-yloxy)-3-(2-(2-methoxyphenoxy)ethylamino)propan-2-ol and (2R,S)-1-(4-methoxy-6-(methoxymethyl)-1H-indol-5-yloxy)-3-(2-(2-methoxyphenoxy)ethylamino)propan-2-ol is described. The compounds were tested for electrographic, antiarrhythmic, hypotensive, and spasmolytic activity, as well as for alpha(1)-, alpha(2)- and beta(1)-adrenoceptor binding affinity.

[Antiarrhythmic properties of afobazole and other 2-mercaptobensimidazole derivatives]

Experiments on conscious male rats have shown that, under conditions of the aconitine-induced arrhythmia model, afobazole and other 2-mercaptobensimidazole derivatives exhibit antiarrhythmic effect, i.e. possess properties of rapid Na+ channel antagonists. The effect of afobazole under these conditions was significantly more pronounced than that of the reference drugs lidocaine and procainamide. The antiarrhythmic (antifibrillatory) effect of afobazole was also detected under the conditions of arrhythmia caused by high doses of calcium chloride. This drug was 1.5 times more effective in its antifibrillatory action than lidocaine, but it was less effective than verapamil. It has been also found that afobazole possesses a wider therapeutic spectrum than the well-known antiarrhythmic drugs of class I and IV (lidocaine, procainamide, ethmosine and verapamil).

[HPLC fingerprint of the antiarrhythmic fraction of Valeriana officinalis]

OBJECTIVE

To establish HPLC fingerprints of the Antiarrhythmic fraction of Valeriana officinalis.

METHODS

Agilent C18 (250 mm x 4.6 mm, 5 microm) column was used and the acetonitrile-water was chosen as the mobile phase in a gradient mode. The column temperature was 380 degrees C and the detection wavelength was 218 nm. The detection time was 70 min, and the flow rate was 1.0 mL/ min.

RESULTS

Fifteen characteristic peaks were indicated in HPLC fingerprints. The relative retention time and the ranges of relative areas of the common peaks were also determined.

CONCLUSION

This method is simple and accurate with a good reproducibility and provides a reference standard for the quality control of Valeriana officinalis.