Molecular Basis for Ligand Modulation of a Mammalian Voltage-Gated Ca2+ Channel.

The L-type voltage-gated Ca2+ (Cav) channels are modulated by various compounds exemplified by 1,4-dihydropyridines (DHP), benzothiazepines (BTZ), and phenylalkylamines (PAA), many of which have been used for characterizing channel properties and for treatment of hypertension and other disorders. Here, we report the cryoelectron microscopy (cryo-EM) structures of Cav1.1 in complex with archetypal antagonistic drugs, nifedipine, diltiazem, and verapamil, at resolutions of 2.9 Å, 3.0 Å, and 2.7 Å, respectively, and with a DHP agonist Bay K 8644 at 2.8 Å. Diltiazem and verapamil traverse the central cavity of the pore domain, directly blocking ion permeation. Although nifedipine and Bay K 8644 occupy the same fenestration site at the interface of repeats III and IV, the coordination details support previous functional observations that Bay K 8644 is less favored in the inactivated state. These structures elucidate the modes of action of different Cav ligands and establish a framework for structure-guided drug discovery.

The human proton pump inhibitors inhibit Mycobacterium tuberculosis rifampicin efflux and macrophage-induced rifampicin tolerance.

Tuberculosis treatment requires months-long combination chemotherapy with multiple drugs, with shorter treatments leading to relapses. A major impediment to shortening treatment is that Mycobacterium tuberculosis becomes tolerant to the administered drugs, starting early after infection and within days of infecting macrophages. Multiple lines of evidence suggest that macrophage-induced drug tolerance is mediated by mycobacterial drug efflux pumps. Here, using assays to directly measure drug efflux, we find that M. tuberculosis transports the first-line antitubercular drug rifampicin through a proton gradient-dependent mechanism. We show that verapamil, a known efflux pump inhibitor, which inhibits macrophage-induced rifampicin tolerance, also inhibits M.tuberculosis rifampicin efflux. As with macrophage-induced tolerance, the calcium channel-inhibiting property of verapamil is not required for its inhibition of rifampicin efflux. By testing verapamil analogs, we show that verapamil directly inhibits M. tuberculosis drug efflux pumps through its human P-glycoprotein (PGP)-like inhibitory activity. Screening commonly used drugs with incidental PGP inhibitory activity, we find many inhibit rifampicin efflux, including the proton pump inhibitors (PPIs) such as omeprazole. Like verapamil, the PPIs inhibit macrophage-induced rifampicin tolerance as well as intramacrophage growth, which has also been linked to mycobacterial efflux pump activity. Our assays provide a facile screening platform for M. tuberculosis efflux pump inhibitors that inhibit in vivo drug tolerance and growth.

Structural and functional investigation of ABC transporter STE6-2p from Pichia pastoris reveals unexpected interaction with sterol molecules.

Adenosine triphosphate (ATP)-binding cassette (ABC) transporters are multidomain transmembrane proteins, which facilitate the transport of various substances across cell membranes using energy derived from ATP hydrolysis. They are important drug targets since they mediate decreased drug susceptibility during pharmacological treatments. For the methylotrophic yeast Pichia pastoris, a model organism that is a widely used host for protein expression, the role and function of its ABC transporters is unexplored. In this work, we investigated the Pichia ABC-B transporter STE6-2p. Functional investigations revealed that STE6-2p is capable of transporting rhodamines in vivo and is active in the presence of verapamil and triazoles in vitro. A phylogenetic analysis displays homology among multidrug resistance (MDR) transporters from pathogenic fungi to human ABC-B transporters. Further, we present high-resolution single-particle electron cryomicroscopy structures of an ABC transporter from P. pastoris in the apo conformation (3.1 Å) and in complex with verapamil and adenylyl imidodiphosphate (AMP-PNP) (3.2 Å). An unknown density between transmembrane helices 4, 5, and 6 in both structures suggests the presence of a sterol-binding site of unknown function.

Calcium channel inhibitor and extracellular calcium improve aminoglycoside-induced hair cell loss in zebrafish.

Aminoglycosides are commonly used antibiotics for treatment of gram-negative bacterial infections, however, they might act on inner ear, leading to hair-cell death and hearing loss. Currently, there is no targeted therapy for aminoglycoside ototoxicity, since the underlying mechanisms of aminoglycoside-induced hearing impairments are not fully defined. This study aimed to investigate whether the calcium channel blocker verapamil and changes in intracellular & extracellular calcium could ameliorate aminoglycoside-induced ototoxicity in zebrafish. The present findings showed that a significant decreased number of neuromasts in the lateral lines of zebrafish larvae at 5 days' post fertilization after neomycin (20 µM) and gentamicin (20 mg/mL) exposure, which was prevented by verapamil. Moreover, verapamil (10-100 µM) attenuated aminoglycoside-induced toxic response in different external calcium concentrations (33-3300 µM). The increasing extracellular calcium reduced hair cell loss from aminoglycoside exposure, while lower calcium facilitated hair cell death. In contrast, calcium channel activator Bay K8644 (20 µM) enhanced aminoglycoside-induced ototoxicity and reversed the protective action of higher external calcium on hair cell loss. However, neomycin-elicited hair cell death was not altered by caffeine, ryanodine receptor (RyR) agonist, and RyR antagonists, including thapsigargin, ryanodine, and ruthenium red. The uptake of neomycin into hair cells was attenuated by verapamil and under high external calcium concentration. Consistently, the production of reactive oxygen species (ROS) in neuromasts exposed to neomycin was also reduced by verapamil and high external calcium. Significantly, zebrafish larvae when exposed to neomycin exhibited decreased swimming distances in reaction to droplet stimulus when compared to the control group. Verapamil and elevated external calcium effectively protected the impaired swimming ability of zebrafish larvae induced by neomycin. These data imply that prevention of hair cell damage correlated with swimming behavior against aminoglycoside ototoxicity by verapamil and higher external calcium might be associated with inhibition of excessive ROS production and aminoglycoside uptake through cation channels. These findings indicate that calcium channel blocker and higher external calcium could be applied to protect aminoglycoside-induced listening impairments.

Fluid-solid coupling numerical simulation of the effects of different doses of verapamil on cancellous bone in type 2 diabetic rats.

BACKGROUND: The purpose of this study was to investigate the effects of four different doses of verapamil on the mechanical behaviors of solid and the characteristics of fluid flow in cancellous bone of distal femur of type 2 diabetes rats under dynamic external load. METHODS: Based on the micro-CT images, the finite element models of cancellous bones and fluids at distal femurs of rats in control group, diabetes group, treatment groups VER 4, VER 12, VER 24, and VER 48 (verapamil doses of 4, 12, 24, and 48 mg/kg/day, respectively) were constructed. A sinusoidal time-varying displacement load with an amplitude of 0.8 µm and a period of 1s was applied to the upper surface of the solid region. Then, fluid-solid coupling numerical simulation method was used to analyze the magnitudes and distributions of von Mises stress, flow velocity, and fluid shear stress of cancellous bone models in each group. RESULTS: The results for mean values of von Mises stress, flow velocity and FSS (t = 0.25s) were as follows: their values in control group were lower than those in diabetes group; the three parameters varied with the dose of verapamil; in the four treatment groups, the values of VER 48 group were the lowest, they were the closest to control group, and they were smaller than diabetes group. Among the four treatment groups, VER 48 group had the highest proportion of the nodes with FSS = 1-3 Pa on the surface of cancellous bone, and more areas in VER 48 group were subjected to fluid shear stress of 1-3 Pa for more than half of the time. CONCLUSION: It could be seen that among the four treatment groups, osteoblasts on the cancellous bone surface in the highest dose group (VER 48 group) were more easily activated by mechanical loading, and the treatment effect was the best. This study might help in understanding the mechanism of verapamil's effect on the bone of type 2 diabetes mellitus, and provide theoretical guidance for the selection of verapamil dose in the clinical treatment of type 2 diabetes mellitus.

Molecular, immunological, and physiological evidences of a sphingosine-activated plasma membrane Ca2+-channel in Trypanosoma equiperdum.

The hemoparasite Trypanosoma equiperdum belongs to the Trypanozoon subgenus and includes several species that are pathogenic to animals and humans in tropical and subtropical areas across the world. As with all eukaryotic organisms, Ca2+ is essential for these parasites to perform cellular processes thus ensuring their survival across their life cycle. Despite the established paradigm to study proteins related to Ca2+ homeostasis as potential drug targets, so far little is known about Ca2+ entry into trypanosomes. Therefore, in the present study, the presence of a plasma membrane Ca2+-channel in T. equiperdum (TeCC), activated by sphingosine and inhibited by verapamil, is described. The TeCC was cloned and analyzed using bioinformatic resources, which confirmed the presence of several domains, motifs, and a topology similar to the Ca2+ channels found in higher eukaryotes. Biochemical and confocal microscopy assays using antibodies raised against an internal region of human L-type Ca2+ channels indicate the presence of a protein with similar predicted molar mass to the sequence analyzed, located at the plasma membrane of T. equiperdum. Physiological assays based on Fura-2 signals and Mn2+ quenching performed on whole parasites showed a unidirectional Ca2+ entry, which is activated by sphingosine and blocked by verapamil, with the distinctive feature of insensitivity to nifedipine and Bay K 8644. This suggests a second Ca2+ entry for T. equiperdum, different from the store-operated Ca2+ entry (SOCE) previously described. Moreover, the evidence presented here for the TeCC indicates molecular and pharmacological differences with their mammal counterparts, which deserve further studies to evaluate the potential of this channel as a drug target.

Efficacy of High-Density Three-Dimensional Mapping for Verapamil-Sensitive Left Posterior Fascicular Ventricular Tachycardia in Pediatric Patients.

In verapamil-sensitive left posterior fascicular ventricular tachycardia (LPF-VT), radiofrequency catheter ablation (RFA) is performed targeting mid-to-late diastolic potential (P1) and presystolic potential (P2) during tachycardia. This study included four patients who had undergone electrophysiological study (EPS) and pediatric patients with verapamil-sensitive LPF-VT who had undergone RFA using high-density three-dimensional (3D) mapping. The included patients were 11-14 years old. During EPS, right bundle branch block and superior configuration VT were induced in all patients. VT mapping was performed via the transseptal approach. P1 and P2 during VT were recorded in three of the four patients. All patients initially underwent RFA via the transseptal approach. In three patients, P1 during VT was targeted, and VT was terminated. The lesion size indices in which VT was terminated were 4.6, 4.6, and 4.7. For one patient whose P1 could not be recorded, linear ablation was performed perpendicularly in the area where P2 was recorded during VT. Among the three patients in whom VT was terminated, linear ablation was performed in two to eliminate the ventricular echo beats. In all patients, VT became uninducible in the acute phase and had not recurred 8-24 months after RFA. High-density 3D mapping with an HD Grid Mapping Catheter allows recording of P1 and P2 during VT and may improve the success rate of RFA in pediatric patients with verapamil-sensitive LPF-VT.

In situ evaluation of the impact of metformin or verapamil coadministration with vildagliptin on its regional absorption from the rabbit's intestine.

This research aims to identify regional differences in vildagliptin absorption across the intestinal membrane. Furthermore, it was to investigate the effect of verapamil or metformin on vildagliptin absorptive clearance. The study utilized an in situ rabbit intestinal perfusion technique to determine vildagliptin oral absorption from duodenum, jejunum, ileum, and ascending colon. This was conducted both with and without perfusion of metformin or verapamil. The findings revealed that the vildagliptin absorptive clearance per unit length varied by site and was in the order as follows: ileum < jejunum < duodenum < ascending colon, implying that P-gp is significant in the reduction of vildagliptin absorption. Also, the arrangement cannot reverse intestinal P-gp, but the observations suggest that P-gp is significant in reducing vildagliptin absorption. Verapamil co-perfusion significantly increased the vildagliptin absorptive clearance by 2.4 and 3.2 fold through the jejunum and ileum, respectively. Metformin co-administration showed a non-significant decrease in vildagliptin absorptive clearance through all tested segments. Vildagliptin absorption was site-dependent and may be related to the intestinal P-glycoprotein content. This may aid in understanding the important elements that influence vildagliptin absorption, besides drug-drug interactions that can occur in type 2 diabetic patients taking vildagliptin in conjunction with other drugs that can modify the P-glycoprotein level.

Verapamil modulates NFAT2 to inhibit tumor growth and potentiates PD1ab immune checkpoint inhibitor therapy in cervical cancer treatment.

PURPOSE: Current evidence suggests a high co-prevalence of hypertension and cervical cancer. Accordingly, blood pressure control is indicated during anti-tumor drug therapy in this patient population. Over the past few years, immunotherapy has made great strides in treating different cancers. However, the role and clinical significance of verapamil as a first-line anti-hypertensive drug during immunotherapy remain poorly understood, emphasizing the need for further studies. METHODS: Murine cervical cancer models were employed to assess the effect of verapamil monotherapy and combination with PD1ab. Immunohistochemistry was conducted to quantify the abundance of CD8+ T cell and Ki67+ cells. Several in-vitro and in-vivo assays were used to study the effects of verapamil and explore the preliminary mechanism. RESULTS: Monotherapy with verapamil or PD1ab immune checkpoint inhibitor significantly suppressed the growth of subcutaneously grafted U14 cells in WT BABL/c mice, respectively, with increased survival time of mice. Consistent results were observed in the melanoma model. Furthermore, we substantiated that verapamil significantly impaired tumor proliferation and migration of SiHa human cervical cancer cells in vitro and in vivo. In silico analysis using TCGA data revealed that NFAT2 expression negatively correlated with patient survival. The CCK8 assay revealed that verapamil abrogated the stimulatory effect of NFAT2 after knockdown of NFAT2. CONCLUSIONS: Our results suggest that verapamil inhibits tumor growth by modulating NFAT2 expression and enhancing tumor immune responses to PD1ab, which can be harnessed for cervical cancer therapy, especially for patients with comorbid hypertension. Indeed, further clinical trials are warranted to increase the robustness of our findings.

Topical Administration of Verapamil in Poly(ethylene glycol)-Modified Liposomes for Enhanced Sinonasal Tissue Residence in Chronic Rhinosinusitis: Ex Vivo and In Vivo Evaluations.

Verapamil is a calcium channel blocker that holds promise for the therapy of chronic rhinosinusitis (CRS) with and without nasal polyps. The verapamil-induced side effects limit its tolerated dose via the oral route, underscoring the usefulness of localized intranasal administration. However, the challenge to intranasal administration is mucociliary clearance, which diminishes localized dose availability. To overcome this challenge, verapamil was loaded into a mucoadhesive cationic poly(ethylene glycol)-modified (PEGylated) liposomal carrier. Organotypic nasal explants were exposed to verapamil liposomes under flow conditions to mimic mucociliary clearance. The liposomes resulted in significantly higher tissue residence compared with the free verapamil control. These findings were further confirmed in vivo in C57BL/6 mice following intranasal administration. Liposomes significantly increased the accumulation of verapamil in nasal tissues compared with the control group. The developed tissue-retentive verapamil liposomal formulation is considered a promising intranasal delivery system for CRS therapy.

Treatment pattern and response for cluster headache in Korea: A prospective multicenter observation study.

BACKGROUND: Only limited data are available regarding the treatment status and response to cluster headache in an Asian population. Therefore, this study aimed to provide a real-world treatment pattern of cluster headache and the response rate of each treatment in an Asian population. METHODS: Patients with cluster headache were recruited between September 2016 and January 2019 from 16 hospitals in Korea. At the baseline visit, we surveyed the patients about their previous experience of cluster headache treatment, and acute and/or preventive treatments were prescribed at the physician's discretion. Treatment response was prospectively evaluated using a structured case-report form at 2 ± 2 weeks after baseline visit and reassessed after three months. RESULTS: Among 295 recruited patients, 262 experiencing active bouts were included. Only one-third of patients reported a previous experience of evidence-based treatment. At the baseline visit, oral triptans (73.4%), verapamil (68.3%), and systemic steroids (55.6%) were the three most common treatments prescribed by the investigators. Most treatments were given as combination. For acute treatment, oral triptans and oxygen were effective in 90.1% and 86.8% of the patients, respectively; for preventive treatment, evidence-based treatments, i.e. monotherapy or different combinations of verapamil, lithium, systemic steroids, and suboccipital steroid injection, helped 75.0% to 91.8% of patients. CONCLUSION: Our data provide the first prospective analysis of treatment responses in an Asian population with cluster headache. The patients responded well to treatment despite the limited availability of treatment options, and this might be attributed at least in part by combination of medications. Most patients were previously undertreated, suggesting a need to raise awareness of cluster headache among primary physicians.

Cluster headache polygenetic risk and known functional variants of CYP3A4 are not associated with treatment response.

BACKGROUND AND PURPOSE: The response to cluster headache treatments has a high interindividual variation. To date, treatment response has only been assessed by a candidate gene approach and no investigations into metabolic pathways have been performed. Our aim was to investigate the association between the polygenetic risk of cluster headache and treatment response to first-line cluster headache treatments as well as known functional variants of CYP3A4 and the response to verapamil. Further, it was aimed to replicate previous single nucleotide polymorphisms found to be associated with treatment response in cluster headache and/or migraine. METHODS: In, 508 cluster headache patients diagnosed according to the International Classification of Headache Disorders were genotyped and participated in a semi-structured interview to evaluate treatment response. Polygenetic risk scores were calculated by the effect retrieved from a meta-analysis of the latest two genome-wide association studies on cluster headache. RESULTS: Inferior treatment response to oxygen, triptans and verapamil is associated with chronicity of cluster headache were confirmed but no evidence was found that a response could be predicted by a high genetic risk of cluster headache. Likewise, verapamil response was not associated with functional variants of CYP3A4. No support of the genetic variants previously reported to be associated with treatment response to triptans or verapamil was found. CONCLUSION: The clinically relevant variation in treatment response for cluster headache was not influenced by genetic factors in the present study.

The Effects of Verapamil, Hydralazine, and Doxazosin on Renin, Aldosterone, and the Ratio Thereof.

PURPOSE: Hydralazine, doxazosin, and verapamil are currently recommended by the Endocrine Society as acceptable bridging treatment in those in whom full cessation of antihypertensive medication is infeasible during screening for primary aldosteronism (PA). This is under the assumption that they cause minimal to no effect on the aldosterone-to-renin ratio, the most widely used screening test for PA. However, limited evidence is available regarding the effects of these particular drugs on said ratio. METHODS: In the present study, we retrospectively assessed the changes in aldosterone, renin, and aldosterone-to-renin values in essential hypertensive participants before and after treatment with either hydralazine (n = 26) or doxazosin (n = 20) or verapamil (n = 15). All samples were taken under highly standardized conditions. RESULTS: Hydralazine resulted in a borderline significant rise in active plasma renin concentration (19 vs 25 mIU/L, p = 0.067) and a significant fall in the aldosterone-to-renin ratio (38 vs 24, p = 0.017). Doxazosin caused declines in both plasma aldosterone concentration (470 vs 330 pmol/L, p = 0.028) and the aldosterone-to-renin ratio (30 vs 20, p = 0.020). With respect to verapamil, we found no statistically significant effect on any of these outcome variables. CONCLUSION: We conclude that the assumption that these drugs can be used with little consequence to the aldosterone-to-renin cannot be substantiated. While it is possible that they are indeed the best option when full antihypertensive drug cessation is infeasible, the potential effects of these drugs must still be taken into account when interpreting the aldosterone-to-renin ratio.

Efficacy and Safety of Verapamil Versus Triamcinolone Acetonide in Treating Keloids and Hypertrophic Scars: A Systematic Review and Meta-Analysis.

BACKGROUND: Keloids and hypertrophic scars can affect the appearance and normal function of patients, and may severely affect patients' physical and mental health. Many methods have been used for the treatment of keloids and hypertrophic scars, there is no standardized method so far. The aim of this study was to compare the efficacy and safety of verapamil and triamcinolone acetonide (TAC) in treating keloids and hypertrophic scars. METHODS: All studies from their inception date up to August 2022 were searched using four databases (PubMed, Cochrane Library, MEDLINE, and EMBASE). The weighted mean differences and the risk ratio were calculated for comparing continuous variables and dichotomous variables, respectively. RESULTS: A total of nine randomized controlled trials involving 567 patients were identified. This meta-analysis indicated that TAC group showed significantly better effects compared with verapamil group in the reduction of height at 3 and 9 weeks, pliability at 3, 9, and 18 weeks, vascularity at 3, 6, 9, 12, 18, and 24 weeks, whereas verapamil group showed significantly better effects compared with TAC group in the reduction of pliability at 21 and 24 weeks. Verapamil group showed a significantly lower incidence of skin atrophy, telangiectasia, and hypopigmentation compared with TAC group. However, the incidence of burning sensation in verapamil group was higher than that in TAC group. CONCLUSION: Concerning the treatment of keloids and hypertrophic scars, TAC was more effective than verapamil for improving vascularity; TAC was superior to verapamil in improving height within 9 weeks of treatment; TAC produced superior result for improving pliability within 18 weeks of treatment, whereas verapamil produced superior result between 18 and 24 weeks of treatment. Verapamil had fewer adverse events than TAC and can be used as a safer alternative for the treatment of keloids and hypertrophic scars. LEVEL OF EVIDENCE II: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Chronic Administration of Ion Channel Blockers Impact Microglia Morphology and Function in a Murine Model of Alzheimer's Disease.

As the population ages, a high prevalence of multimorbidity will affect the way physicians need to think about drug interactions. With microglia's important involvement in the pathology and progression of Alzheimer's disease (AD), understanding whether systemically administered drugs intended for other affections could impact microglia function, already impacted by the presence of beta-amyloid, is important. The aim of this study was to evaluate morphological changes of microglia, using in vivo 2-photon laser scanning microscopy, in a murine model of AD under systemic administration of sodium or calcium ion channel blockers in order to establish potential effects that these drugs might have on microglia under neuro-inflammatory conditions. A total of 30 mice (age 14-16 weeks, weight 20-25 g) were used, with 25 APP randomly divided into three groups. The remaining animals were CX3CR1GFP/GFP male mice (n = 5) used as WT controls. After baseline behavior testing, all animals received daily intraperitoneal injections for 30 days according to the assigned group [WT (n = 5), Control (n = 5), Carbamazepine (n = 10), and Verapamil (n = 10)]. The results showed that the Verapamil treatment improved short-term memory and enhanced exploratory behavior in APP mice. The Carbamazepine treatment also improved short-term memory but did not elicit significant changes in anxiety-related behavior. Both Verapamil and Carbamazepine reduced the surveillance speed of microglia processes and changed microglia morphology in the cortex compared to the Control group. Due to their complex molecular machinery, microglia are potentially affected by drugs that do not target them specifically, and, as such, investigating these interactions could prove beneficial in our management of neurodegenerative pathologies.

The Combined Treatment of Curcumin with Verapamil Ameliorates the Cardiovascular Pathology in a Williams-Beuren Syndrome Mouse Model.

Williams-Beuren syndrome (WBS) is a rare disorder caused by a recurrent microdeletion with hallmarks of cardiovascular manifestations, mainly supra-valvular aortic stenosis (SVAS). Unfortunately, there is currently no efficient treatment. We investigated the effect of chronic oral treatment with curcumin and verapamil on the cardiovascular phenotype of a murine model of WBS harbouring a similar deletion, CD (complete deletion) mice. We analysed systolic blood pressure in vivo and the histopathology of the ascending aorta and the left ventricular myocardium to determine the effects of treatments and their underlying mechanism. Molecular analysis showed significantly upregulated xanthine oxidoreductase (XOR) expression in the aorta and left ventricular myocardium of CD mice. This overexpression is concomitant with increased levels of nitrated proteins as a result of byproduct-mediated oxidative stress damage, indicating that XOR-generated oxidative stress impacts the pathophysiology of cardiovascular manifestations in WBS. Only the combined therapy of curcumin and verapamil resulted in a significant improvement of cardiovascular parameters via activation of the nuclear factor erythroid 2 (NRF2) and reduction of XOR and nitrated protein levels. Our data suggested that the inhibition of XOR and oxidative stress damage could help prevent the severe cardiovascular injuries of this disorder.

Preparation of Sustained Release Formulation of Verapamil Hydrochloride Using Ion Exchange Resins.

The purpose of this investigation was to formulate and evaluate the interaction between cation exchange resins and verapamil hydrochloride. The uptake studies were conducted using the rotating bottle apparatus. The Langmuir-like equation was applied to the experimental data and the maximum drug loading was determined from the Langmuir-like parameters. The drug-resin complexes were evaluated using XRD, SEM, and particle size analysis. Release studies were performed using USP dissolution apparatus 2. The resin with the lowest percentage of cross-linking had the highest uptake capacity. The percent increase in particle size due to complexation was found to be associated with drug loading; the highest drug loading had the highest increase in particle size. The X-ray diffraction patterns of the resins and the drug-resin complexes showed that they were both amorphous. The maximum drug release was approximately 40% when conventional dissolution testing was used. Results showed that sink conditions could not be maintained using conventional dissolution methods. Maximum drug release increased dramatically by increasing the volume of samples withdrawn and fresh dissolution medium added. Excellent correlation was obtained between sample volume and drug release rate with an R-value of 0.988. Particle diffusion-controlled model and film diffusion-controlled model were both applied to the experimental data. The results indicated that the rate-limiting step is the diffusion of the exchanging cations through the liquid film. The modified release formulation was prepared successfully and correlated very well with the USP monograph for verapamil hydrochloride extended release capsules.

Current treatment options for cluster headache: limitations and the unmet need for better and specific treatments-a consensus article.

AIM: Treatment for cluster headache is currently based on a trial-and-error approach. The available preventive treatment is unspecific and based on few and small studies not adhering to modern standards. Therefore, the authors collaborated to discuss acute and preventive treatment in cluster headache, addressing the unmet need of safe and tolerable preventive medication from the perspectives of people with cluster headache and society, headache specialist and cardiologist. FINDINGS: The impact of cluster headache on personal life is substantial. Mean annual direct and indirect costs of cluster headache are more than 11,000 Euros per patient. For acute treatment, the main problems are treatment response, availability, costs and, for triptans, contraindications and the maximum use allowed. Intermediate treatment with steroids and greater occipital nerve blocks are effective but cannot be used continuously. Preventive treatment is sparsely studied and overall limited by relatively low efficacy and side effects. Neurostimulation is a relevant option for treatment-refractory chronic patients. From a cardiologist's perspective use of verapamil and triptans may be worrisome and regular follow-up is essential when using verapamil and lithium. CONCLUSION: We find that there is a great and unmet need to pursue novel and targeted preventive modalities to suppress the horrific pain attacks for people with cluster headache.

Comparing intralesional triamcinolone and verapamil-triamcinolone injections in keloids: A single-blinded randomised clinical trial.

INTRODUCTION: In this clinical trial, we investigated the efficacy of two treatment methods for keloids resulting from surgical incisions: intralesional triamcinolone injections alone versus in combination with verapamil. MATERIAL AND METHODS: Patients were divided into two groups: one received triamcinolone alone (Group T) and the other received a triamcinolone-verapamil blend (Group VT). Regular treatments were conducted until the keloids were nearly flat or for a maximum of eight sessions. RESULTS: Both groups showed significant improvements, but Group VT saw quicker resolution of skin redness and needed fewer sessions. Though the Vancouver Scar Scale (VSS) scores were generally similar across both groups, Group VT exhibited greater improvements, leading to lower final scores. The VT group also attained normal scar flexibility faster than the T group. CONCLUSION: These findings suggest that the combination of verapamil and triamcinolone provides a more effective treatment for keloids, thereby highlighting the potential of verapamil in scar reduction.

Atorvastatin and Fluvastatin Potentiate Blood Pressure Lowering Effect of Amlodipine through Vasorelaxant Phenomenon.

Background and Objectives: We have recently reported that stains have calcium channel blocking activity in isolated jejunal preparations. In this study, we examined the effects of atorvastatin and fluvastatin on blood vessels for a possible vasorelaxant effect. We also studied the possible additional vasorelaxant effect of atorvastatin and fluvastatin, in the presence of amlodipine, to quantify its effects on the systolic blood pressure of experimental animals. Materials and Methods: Atorvastatin and fluvastatin were tested in isolated rabbits' aortic strip preparations using 80mM Potassium Chloride (KCl) induced contractions and 1 micro molar Norepinephrine (NE) induced contractions. A positive relaxing effect on 80 mM KCl induced contractions were further confirmed in the absence and presence of atorvastatin and fluvastatin by constructing calcium concentration response curves (CCRCs) while using verapamil as a standard calcium channel blocker. In another series of experiments, hypertension was induced in Wistar rats and different test concentrations of atorvastatin and fluvastatin were administered in their respective EC50 values to the test animals. A fall in their systolic blood pressure was noted using amlodipine as a standard vasorelaxant drug. Results: The results show that fluvastatin is more potent than amlodipine as it relaxed NE induced contractions where the amplitude reached 10% of its control in denuded aortae. Atorvastatin relaxed KCL induced contractions with an amplitude reaching 34.4% of control response as compared to the amlodipine response, i.e., 39.1%. A right shift in the EC50 (Log Ca++ M) of Calcium Concentration Response Curves (CCRCs) implies that statins have calcium channel blocking activity. A right shift in the EC50 of fluvastatin with relatively less EC50 value (-2.8 Log Ca++ M) in the presence of test concentration (1.2 × 10-7 M) of fluvastatin implies that fluvastatin is more potent than atorvastatin. The shift in EC50 resembles the shift of Verapamil, a standard calcium channel blocker (-1.41 Log Ca++ M). Conclusions: Atorvastatin and fluvastatin relax the aortic strip preparations predominantly through the inhibition of voltage gated calcium channels in high molar KCL induced contractions. These statins also inhibit the effects of NE induced contractions. The study also confirms that atorvastatin and fluvastatin potentiate blood pressure lowering effects in hypertensive rats.