Effects of benidipine, paracetamol, and their combination on postoperative and normal tissue pain thresholds

Introduction: In clinical practice, inadequate pain inhibition leads to increased morbidity and mortality. Increased intracellular calcium, oxidants, and proinflammatory cytokines are known to play a role in the pathogenesis of postoperative pain. Therefore, we investigated the analgesic effects of benidipine, paracetamol, and benidipine-paracetamol combination (BPC) on postoperative and normal pain thresholds in rats. Material and methods: Sixty-four male albino Wistar rats weighing 285-295 g were used. The without-incision rats were divided into 4 subgroups: healthy control, benidipine alone, paracetamol alone, and BPC. The scalpel-incision rats were divided into 4 subgroups: scalpel incision, scalpel incision + benidipine, scalpel incision + paracetamol, and scalpel incision + BPC. Paw pain thresholds of rats were measured using a Basile algesimeter. Biochemical analyses were performed on the paw tissues of 6 rats randomly taken from the experimental groups, each containing 8 rats. Rats were sacrificed immediately after the measurements. After the pain threshold tests were finished, the paw tissues were removed and malondialdehyde (MDA), total glutathione (tGSH), cyclooxygenase (COX), and interleukin-6 (IL-6) levels were measured. Results: There was no significant difference between the groups in paw pain threshold and measured biochemical parameters in rats without incision. The decrease in the pain threshold of the incised paw was also best prevented by BPC, followed by benidipine and then paracetamol. Furthermore, increases in scalpel-incised paw tissue MDA, COX-2, and IL-6 levels and the decrease in tGSH were significantly suppressed by benidipine and BPC, while paracetamol could only significantly inhibit the increase in IL-6 production. Conclusion: The combination of the L-type Ca2+ channel blocker benidipine and paracetamol (BPC) may provide potent analgesia. Our experimental results support that BPC may be useful in the treatment of severe pain that cannot be adequately inhibited by paracetamol.

Protective effect of adenosine triphosphate and benidipine separately or together against cardiotoxicity caused by bevacizumab

Bevacizumab is a recombinant humanized monoclonal antibody whose adverse effects include cardiotoxicity. We investigated whether using adenosine triphosphate (ATP) or benidipine either separately or together protects against cardiac damage induced by bevacizumab in rats. Forty Wistar albino male rats were allocated to five groups of eight: bevacizumab (Bv), ATP + bevacizumab (ABv), benidipine + bevacizumab (BBv), ATP + benidipine + bevacizumab (ABBv) and untreated controls. Rats in the ABv group were injected intraperitoneally (i.p.) with 2 mg/kg ATP. The BBv group was given 4 mg/kg benidipine by oral gavage. The ABBv group was injected i.p. with 2 mg/kg ATP and simultaneously administered 4 mg/kg benidipine orally. One hour after administration of ATP, benidipine or normal saline, the Bv, ABv, BBv and ABBv groups were injected i.p. with 10 mg/kg bevacizumab. Malondialdehyde (MDA) and total glutathione (tGSH) levels were measured in cardiac tissue, and troponin I (TP I) and creatine kinase MB (CK-MB) levels were measured in blood samples. Tissue samples were examined for histopathology. We found the lowest TP I, CK-MB and MDA levels and the highest tGSH level in the ABBv group; these results were similar to the control group. Nuclei of cardiomyocytes in the BV group were misshapen and shrunken, and myofibers were disrupted; we also observed eosinophilic degeneration and interstitial edema. Blood capillaries were dilated and congested. We observed amelioration of these findings in the ABBv group. We found that ATP and benidipine alone or in combination reduced cardiac damage associated with the use of bevacizumab. ATP + benidipine combined therapy produced the most favorable results.

Development of stability-indicating method for separation and characterization of benidipine forced degradation products using LC-MS/MS

The present study describes forced degradation of benidipine (BEN) as per  Q1A (R2) and Q1B guidelines of the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. BEN degraded under hydrolysis (neutral, acidic, and alkaline), hydrogen peroxide induced oxidation, and UV light mediated photolytic degradation. A total of 14 degradation products (DPs) were found in all degradation studies, comprising 4 hydrolytic DPs, 8 oxidative DPs, and 4 photolytic DPs. A selective stability-indicating method was developed using an XBridge BEH C18 column with gradient elution program consisting of ammonium acetate (10 mM, 4.8 pH, acetic acid) and acetonitrile. The flow rate was maintained at 1 ml min^-1 . All DPs were separated well using the developed HPLC method and were characterized using LC-MS/MS data. As this method is effective in identifying and separating BEN and its DPs with sufficient resolution, it can be used in laboratories for quality control of drugs in daily routine analysis and stability studies.

Sensitivity Enhanced Ecofriendly UV Spectrophotometric Methods for Quality Control of Telmisartan and Benidipine Formulations: Comparison of Whiteness and Greenness with HPLC Methods

The development of an environmentally friendly analytical technique for simultaneous measurement of medicines with large concentration differences is difficult yet critical for environmental protection. Hence, in this work, new manipulated UV-spectroscopic methods with high scaling factors were established for concurrent quantification of telmisartan (TEL) and benidipine (BEN) in fixed-dose combinations. Two different methods were developed and established by calculation of peak height at zero crossing point of second derivative and the ratio of first derivative spectra with a scaling factor of 200 and 100, respectively. The absorption difference between the peaks and troughs of the ratio spectra, as well as continuous subtraction from ratio spectra, were established as additional methods. In addition, new procedures were validated using ICH recommendations. The proposed methods’ linearity curves were constructed in the range of 0.5–10 µg mL⁻¹ and 1–30 µg mL⁻¹ for BEN and TEL, respectively, under optimized conditions. Furthermore, both the detection (0.088–0.139 µg mL⁻¹ for BEN and 0.256–0.288 µg mL⁻¹ for TEL) and quantification limits (0.293–0.465 µg mL⁻¹ for BEN and 0.801–0.962 µg mL⁻¹ for TEL) were adequate for quantifying both analytes in the formulation ratios. The accuracy and precision were confirmed by the good recovery percent (98.37%–100.6%), with low percent relative error (0.67%–1.70%) and less than 2 percent relative standard deviation, respectively. The specificity of the methods was proven by accurate and precise outcomes from the standard addition method and analysis of laboratory mixed solutions with large differences in concentrations of both analytes. Finally, the BEN and TEL content of the formulations was determined simultaneously without prior separation using these first ever reported spectroscopic methods. Furthermore, developed UV derivative spectroscopic methods demonstrated high greenness and whiteness when compared to the reported HPLC methods. These findings show that the projected methods were effective, practical, and environmentally acceptable for quality control of BEN and TEL in multicomponent formulations.

Effect of adenosine triphosphate, benidipine and their combinations on bevacizumab-induced kidney damage in rats

BACKGROUND

Bevacizumab-induced vascular endothelial growth factor (VEGF) inhibition may lead to a decrease in adenosine triphosphate (ATP) levels, an increase in intracellular Na+ and Ca2+ concentrations and an increase in reactive oxygen species (ROS) generation, as well as to cell damage.

OBJECTIVES

To investigate the biochemical and histopathological effects of ATP, benidipine and ATP in combination with benidipine on bevacizumab-induced kidney damage in rats.

MATERIAL AND METHODS

Rats were divided into 5 treatment groups: bevacizumab (BVZ) alone, ATP + bevacizumab (ABVZ), benidipine + bevacizumab (BBVZ), ATP + benidipine + bevacizumab (ABBVZ), and healthy controls (HC). Adenosine triphosphate (25 mg/kg), benidipine (4 mg/kg orally), ATP (25 mg/kg) + benidipine (4 mg/kg), or saline were administered to albino Wistar rats. One hour after treatment, bevacizumab was injected at a dose of 10 mg/kg to induce kidney damage. Two doses of bevacizumab were delivered 15 days apart. Adenosine triphosphate + benidipine were administered once a day for 1 month.

RESULTS

Malondialdehyde (MDA), total oxidant status (TOS), creatinine, and blood urea nitrogen (BUN) levels of the BVZ, BBVZ, ABVZ, ABBVZ, and HC groups were ranked from highest to lowest. Conversely, total glutathione (tGSH) and total antioxidant status (TAS) kidney tissue values were ranked from lowest to highest, respectively. Hemorrhage, tubular necrosis and grade 3 focal tubular atrophy were observed in the BVZ group. Atrophy and grade 2 necrosis were observed in the BBVZ group and atrophy and grade 1 necrosis were observed in the ABVZ group. Only grade 1 atrophy was observed in the ABBVZ group.

CONCLUSIONS

Adenosine triphosphate reduced bevacizumab-induced renal toxicity significantly more effectively than benidipine. However, the combination of ATP + benidipine further reduced bevacizumab-induced renal toxicity relative to benidipine or ATP alone. These data indicate that ATP + benidipine might be a potential therapeutic strategy for the prevention of bevacizumab-induced renal toxicity.

Development and optimization of drug-loaded nanoemulsion system by phase inversion temperature (PIT) method using Box-Behnken design

OBJECTIVE

The objective of the present investigation was to develop a stable and optimized drug-loaded nanoemulsion system using the phase inversion temperature (PIT) method.

SIGNIFICANCE

The PIT method has been widely used for the development of food-grade nanoemulsion systems. For the first time, a simple and cost-effective, PIT method was used for the development of a stable drug-loaded nanoemulsion system.

METHODS

Box-Behnken experimental design was used for the development of an optimized drug-loaded nanoemulsion system by the PIT method. The independent variables were optimized for responses by using the desirability function. The hydrophobic drug, benidipine was used as a modal drug. Optimized oil phase (blend of long-chain triglycerides oil, medium-chain triglycerides oil and essential oil) was used for the development of oil in water (O/W) nanoemulsion system.

RESULTS

Optimum nanoemulsion formulation was stable, transparent and contained 50% of oil to surfactant percentage with a droplet size of 96.57 ± 1.61 nm. The optimum formulation also showed higher in-vitro drug diffusion from dialysis membrane as compared to the marketed formulation. Nanoemulsion droplets were observed as spherical in the transmission electron microscopy (TEM) images. Box-Behnken statistical analysis revealed that all the independent variables had a significant impact on characteristics of nanoemulsion and the predicated value of independent variables was found to be valid.

CONCLUSION

It was concluded that the PIT method produces a stable and efficient drug-loaded nanoemulsion system. Further, the optimized oil phase can be used as an alternative to costly, commercial medium-chain triglycerides (MCT) oils, for the development of a stable nanoemulsion system.

The Effects of Different Calcium Channel Blockers on Aldosterone-Producing Adenoma Cells

Purpose: The aim of this study is to examine the effects of different kinds of calcium channel blockers (CCBs) on primary aldosterone-producing adenoma (APA) mainly with KCNJ5 mutations. Primary cultured APA cells were treated with different calcium channel blockers (L/T type CCB benidipine, T-type CCB mibefradil and L-type CCB nifedipine), and aldosterone secretagogues with or without nifedipine. Aldosterone level, aldosterone synthase (CYP11B2) mRNA expression and cell proliferation were detected. The results showed that all three CCBs significantly inhibit aldosterone secretion and CYP11B2 mRNA expression. Benidipine was relatively more effective than mibefradil or nifedipine. In addition, only mibefradil marginally inhibited cell proliferation. Adrenocorticotropin (ACTH) had a much stronger effect in stimulating aldosterone secretion and promoting cell proliferation from APA's than angiotensin II (ATII). Different from ACTH and ATII, potassium had no effect. Nifedipine inhibited the basal and ACTH-, ATII-elicited aldosterone secretion. Twenty three of 24 APAs had somatic KCNJ5 mutation. In conclusion, benidipine, mibefradil and nifedipine significantly inhibit aldosterone secretion in primary cultured APA cells.

Effect of a Single Injection of Benidipine-Impregnated Biodegradable Microcarriers on Bone and Gingival Healing at the Tooth Extraction Socket

Objective: A dihydropyridine-type calcium channel blocker, benidipine (BD), is extensively used in hypertension therapy. In vitro study reported BD promoting bone metabolism. We evaluated the effect of sustained release of BD-loaded poly(lactic-co-glycolic acid) (PLGA) microcarriers on the promotion of bone and gingival healing at an extraction socket in vivo. In addition, the effect of BD on osteoblasts, osteocytes, fibroblasts, and epithelial cells was evaluated in vitro. Approach: The maxillary first molar of rats was extracted. Next, PLGA microcarriers containing BD were directly injected into the gingivobuccal fold as a single dose. After injection, bone and soft-tissue healing was histologically evaluated. Effect of BD on proliferation, migration, and gene expression of gingival and bone cell was also examined in vitro. Results: After tooth extraction, BD significantly augmented bone volume and density, and also epithelial wound healing. During in vitro studies, BD promoted significant proliferation and migration of fibroblasts and epithelial cells. Real-time RT-PCR revealed that BD upregulated messenger RNA expression of Ahsg (alpha 2-HS glycoprotein) and Csf2 (colony-stimulating factor 2) in osteoblasts. Innovation: The prevention of bone and soft-tissue reduction associated with tooth extraction has been eagerly anticipated in the field of dentistry. This study first reported the effect of BD on extraction socket healing. Conclusion: A single dose of topically administered BD-loaded PLGA microcarriers promoted bone and soft-tissue healing at the extraction site of tooth.

Alternating Electric Fields (TTFields) Activate Cav1.2 Channels in Human Glioblastoma Cells

Tumor treating fields (TTFields) represent a novel FDA-approved treatment modality for patients with newly diagnosed or recurrent glioblastoma multiforme. This therapy applies intermediate frequency alternating electric fields with low intensity to the tumor volume by the use of non-invasive transducer electrode arrays. Mechanistically, TTFields have been proposed to impair formation of the mitotic spindle apparatus and cytokinesis. In order to identify further potential molecular targets, here the effects of TTFields on Ca²⁺-signaling, ion channel activity in the plasma membrane, cell cycle, cell death, and clonogenic survival were tested in two human glioblastoma cell lines in vitro by fura-2 Ca²⁺ imaging, patch-clamp cell-attached recordings, flow cytometry and pre-plated colony formation assay. In addition, the expression of voltage-gated Ca²⁺ (Ca_v) channels was determined by real-time RT-PCR and their significance for the cellular TTFields response defined by knock-down and pharmacological blockade. As a result, TTFields stimulated in a cell line-dependent manner a Ca_v1.2-mediated Ca²⁺ entry, G₁ or S phase cell cycle arrest, breakdown of the inner mitochondrial membrane potential and DNA degradation, and/or decline of clonogenic survival suggesting a tumoricidal action of TTFields. Moreover, inhibition of Ca_v1.2 by benidipine aggravated in one glioblastoma line the TTFields effects suggesting that Ca_v1.2-triggered signaling contributes to cellular TTFields stress response. In conclusion, the present study identified Ca_v1.2 channels as TTFields target in the plasma membrane and provides the rationale to combine TTFields therapy with Ca²⁺ antagonists that are already in clinical use.

Effect of rifampin on enantioselective disposition and anti-hypertensive effect of benidipine

AIMS

In vitro study showed that benidipine is exclusively metabolized by cytochrome P450 (CYP) 3A. This study evaluated the effect of rifampin on the enantioselective disposition and anti-hypertensive effect of benidipine.

METHODS

Benidipine (8 mg) was administered to healthy subjects with or without repeated rifampin dosing, in a crossover design. Plasma concentrations of (S)-(S)-(+)-α and (R)-(R)-(-)-α isomers of benidipine and blood pressure were measured for up to 24 h after dosing. In addition, CYP3A metabolic capacity was evaluated in each subject using oral clearance of midazolam.

RESULTS

The exposure of (S)-(S)-(+)-α-benidipine was greater than that of (R)-(R)-(-)-α-benidipine by approximately three-fold following single dose of benidipine. Repeated doses of rifampin significantly decreased the exposure of both isomers. Geometric mean ratios (GMRs) (95% CI) of C_max and AUC_∞ for (S)-(S)-(+)-α-benidipine were 0.14 (0.10-0.18) and 0.12 (0.08-0.18), respectively. GMRs (95% CI) of C_max and AUC_∞ for (R)-(R)-(-)-α-benidipine were 0.10 (0.06-0.17) and 0.10 (0.06-0.17), respectively. Oral clearances of both isomers were increased equally by approximately 10-fold. There were no significant differences in cardiovascular effect following benidipine administration between control and rifampin treatment. CYP3A activity using midazolam did not appear to correlate with oral clearance of benidipine.

CONCLUSIONS

After single administration of racemic benidipine, enantioselective disposition of (S)-(S)-(+)-α- and (R)-(R)-(-)-α-benidipine was observed. Treatments with rifampin significantly decreased the exposure of both isomers but appeared to marginally affect its blood pressure-lowering effect in healthy subjects. Impact of coadministration of rifampin on the treatment effects of benidipine should be assessed in hypertensive patients.

Moderate hypothermia and responses to calcium channel blockers - Role of the nitric oxide

Moderate hypothermia (25-31 °C) may have a significant influence on vascular tone. At present, very little is known about the role of endothelial nitric oxide on the hypothermia-induced responses. In this study, we investigated the effect of hypothermia (to 28 °C) on the vasodilatation induced by verapamil, a phenylalkylamine calcium channel blocker (10^-9-3 × 10^-4 M) and dihydropyridines, amlodipine (10^-9-3 × 10^-4 M), and benidipine (10^-9-10^-3 M) on 5-hydroxytryptamine (5-HT or serotonin) precontracted calf cardiac veins. Furthermore, the role of nitric oxide in the hypothermia-induced responses was analyzed. Ring preparations of veins obtained from calf hearts were suspended in organ baths containing 15 ml of Krebs-Henseleit solution, maintained at 37 °C, and continuously gassed with 95% O₂-5% CO₂. After a resting period, verapamil, amlodipine, and benidipine were applied cumulatively on serotonin (10^-6 M) precontracted calf cardiac vein rings and induced concentration-dependent relaxations. In another part of the study, the medium temperature was decreased to 28 °C after the preparations were contracted with 5-HT, then cumulative concentrations of verapamil, amlodipine, or benidipine were added. During hypothermia, the pIC₅₀ value, but not the maximal response, to all blockers were significantly higher than at 37 °C. Hypothermia in the presence of N^G-nitro-l-arginine methyl ester (L-NAME, 10^-4 M) decreased the pIC₅₀ and E_max values to verapamil, amlodipine, and benidipine. Only one blocker was tested in each preparation. These results suggest that nitric oxide may play a role in the hypothermia-induced changes in vasodilation caused by verapamil, amlodipine, and benidipine in calf cardiac vein, but further research is needed to explain the complete mechanism.

Edaravone, a potent free radical scavenger and a calcium channel blocker attenuate isoproterenol induced myocardial infarction by suppressing oxidative stress, apoptotic signaling and ultrastructural damage

OBJECTIVES

In the present study, we investigated whether combination therapy of low-dose benidipine with the potent free radical scavenger edaravone has a cardioprotective effect against isoproterenol (ISO)-induced myocardial infarction (MI) in Wistar rats.

METHODS

Rats were pretreated with concurrent doses of benidipine and edaravone (1 μg/kg/day + 1 mg/kg/day and 3 μg/kg/day + 3 mg/kg/day) by intravenous (i.v.) and intraperitoneal (i.p.) routes respectively for 28 days, followed by MI induction using ISO (85 mg/kg) by subcutaneous route for two days at 24 h intervals. After the treatment period, blood was withdrawn and the heart was preserved for biochemical estimations.

RESULTS

The activities of the cardiac biomarkers (lactate dehydrogenase and creatine kinase-MB), and the level of malondialdehyde (MDA) significantly increased, while antioxidant markers (reduced glutathione, catalase, superoxidase dismutase, glutathione peroxidase, glutathione reductase) were significantly decreased in the ISO intoxicated group compared with the control group. Moreover, the level of C-reactive protein (CRP) and Caspase-3 activity significantly increased in ISO-intoxicated group. An ultrastructure study was also carried out. Pretreatment with a combination of benidipine and edaravone significantly attenuated the activities of the cardiac biomarkers and the level of MDA, and significantly increased the antioxidant markers compared with the ISO-intoxicated group. Furthermore, pretreatment with the combination of benidipine and edaravone significantly decreased the level of CRP and Caspase-3 activity as compared to the ISO-treated group. The ultrastructure study of myocardium revealed that pretreated groups preserved the mitochondrial shape, the membrane and its internal structures.

CONCLUSION

Taken together these results suggest that the combination of benidipine and edaravone showed significant protective effect in ISO-induced MI.

Effects of the antihypertensive drug benidipine on osteoblast function in vitro

The dihydropyridine-type calcium channel blocker, benidipine (BD) has been widely used in hypertension therapy. Previous studies have demonstrated that BD has a positive effect on bone metabolism. Inspired by this promoting phenomenon, the present study investigated the effects of BD on osteoblasts in vitro. Experiments were designed and performed, including an MTT assay, reverse transcription-polymerase chain reaction, western blot analysis, alkaline phosphatase activity measurements and alizarin red S staining. The results demonstrated that BD promoted osteoblast proliferation and osteogenic differentiation at concentrations from 1×10⁻⁶ to 1×10⁻⁹ M by upregulating Runx2, BMP2 and OCN gene expression levels. Overall, BD at appropriate concentrations has been demonstrated to have positive effects on osteoblast function in addition to its conventional clinical usage.

T/L-type calcium channel blocker reduces the composite ranking of relative risk according to new KDIGO guidelines in patients with chronic kidney disease

BACKGROUND

Recently, the Kidney Disease: Improving Global Outcomes (KDIGO) group recommended that patients with chronic kidney disease (CKD) be assigned according to stage and composite relative risk on the basis of glomerular filtration rate (GFR) and albuminuria criteria. The aim of this post-hoc analysis was to investigate the effects of add-on therapy with calcium channel blockers (CCBs) on changes in the composite ranking of relative risk according to KDIGO guidelines. Benidipine, an L- and T-type CCB, and amlodipine, an L-type CCB to angiotensin II receptor blocker (ARB), were examined.

METHODS

Patients with blood pressure (BP) > 130/80 mmHg, an estimated GFR (eGFR) of 30-90 mL/min/1.73 m2, and albuminuria > 30 mg/gCr, despite treatment with the maximum recommended dose of ARB, were randomly assigned to two groups. Each group received one of two treatments: 2 mg benidipine daily, increased to 8 mg daily (n = 52), or 2.5 mg amlodipine daily, increased to 10 mg daily (n = 52).

RESULTS

After 6 months of treatment, a significant and comparable reduction in systolic and diastolic BP was observed in both groups. The eGFR was significantly decreased in the amlodipine group, but there was no significant change in the benidipine group. The decrease in albuminuria in the benidipine group was significantly lower than in the amlodipine group. The composite ranking of relative risk according to the new KDIGO guidelines was significantly improved in the benidipine group; however, no significant change was noted in the amlodipine group. Moreover, significantly fewer cases in the benidipine group than the amlodipine group showed a reduced risk category score.

CONCLUSION

The present post-hoc analysis showed that compared to amlodipine benidipine results in a greater reduction in albuminuria accompanied by an improved composite ranking of relative risk according to the KDIGO CKD severity classification.

TRIAL REGISTRATION

TRIAL REGISTRATION NUMBER

UMIN000002644.