Absorbed Bioactive Compounds Replicate Guanxin II-Induced Endothelium-Associated in/ex vivo Vasodilation.

OBJECTIVE: To develop an interference-free and rapid method to elucidate Guanxin II (GX II)'s representative vasodilator absorbed bioactive compounds (ABCs) among enormous phytochemicals. METHODS: The contents of ferulic acid, tanshinol, and hydroxysafflor yellow A (FTA) in GX II/rat serum after the oral administration of GX II (30 g/kg) were detected using ultra-performance liquid chromatography-mass spectrometry. Totally 18 rats were randomly assigned to the control group (0.9% normal saline), GX II (30 g/kg) and FTA (5, 28 and 77 mg/kg) by random number table method. Diastolic coronary flow velocity-time integral (VTI), i.e., coronary flow or coronary flow-mediated dilation (CFMD), and endothelium-intact vascular tension of isolated aortic rings were measured. After 12 h of exposure to blank medium or 0.5 mmol/L H2O2, endothelial cells (ECs) were treated with post-dose GX II of supernatant from deproteinized serum (PGSDS, 300 µL PGSDS per 1 mL of culture medium) or FTA (237, 1539, and 1510 mg/mL) for 10 min as control, H2O2, PGSDS and FTA groups. Nitric oxide (NO), vascular endothelial growth factor (VEGF), endothelin-1 (ET-1), superoxide dismutase (SOD), malondialdehyde (MDA) and phosphorylated phosphoinositide 3 kinase (p-PI3K), phosphorylated protein kinase B (p-AKT), phosphorylated endothelial nitric oxide synthase (p-eNOS) were analyzed. PGSDS was developed as a GX II proxy of ex vivo herbal crude extracts. RESULTS: PGSDS effectively eliminates false responses caused by crude GX II preparations. When doses equaled the contents in GX II/its post-dose serum, FTA accounted for 98.17% of GX II -added CFMD and 92.99% of PGSDS-reduced vascular tension. In ECs, FTA/PGSDS was found to have significant antioxidant (lower MDA and higher SOD, P<0.01) and endothelial function-protective (lower VEGF, ET-1, P<0.01) effects. The increases in aortic relaxation, endothelial NO levels and phosphorylated PI3K/Akt/eNOS protein induced by FTA/PGSDS were markedly abolished by NG-nitro-L-arginine methyl ester (L-NA, eNOS inhibitor) and wortmannin (PI3K/AKT inhibitor), respectively, indicating an endothelium-dependent vasodilation via the PI3K/AKT-eNOS pathway (P<0.01). CONCLUSION: This study provides a strategy for rapidly and precisely elucidating GX II's representative in/ex vivo cardioprotective absorbed bioactive compounds (ABCs)-FTA, suggesting its potential in advancing precision ethnomedicine.

Treprostinil palmitil inhibits the hemodynamic and histopathological changes in the pulmonary vasculature and heart in an animal model of pulmonary arterial hypertension.

Treprostinil palmitil (TP) is a long-acting inhaled pulmonary vasodilator prodrug of treprostinil (TRE). In this study, TP was delivered by inhalation (treprostinil palmitil inhalation suspension, TPIS) in a rat Sugen 5416 (Su)/hypoxia (Hx) model of pulmonary arterial hypertension (PAH) to evaluate its effects on hemodynamics, pulmonary vascular remodeling, and cardiac performance and histopathology. Male Sprague-Dawley rats received Su (20 mg/kg, s.c), three weeks of Hx (10% O2) and 5 or 10 weeks of normoxia (Nx). TPIS was given during the 5-10 week Nx period after the Su/Hx challenge. Su/Hx increased the mean pulmonary arterial blood pressure (mPAP) and right heart size (Fulton index), reduced cardiac output (CO), stroke volume (SV) and heart rate (HR), and increased the thickness and muscularization of the pulmonary arteries along with obliteration of small pulmonary vessels. In both the 8- and 13-week experiments, TPIS at inhaled doses ranging from 39.6 to 134.1 µg/kg, QD, dose-dependently improved pulmonary vascular hemodynamics, reduced the increase in right heart size, enhanced cardiac performance, and attenuated most of the histological changes induced by the Su/Hx challenge. The PDE5 inhibitor sildenafil, administered at an oral dose of 50 mg/kg, BID for 10 weeks, was not as effective as TPIS. These results in Su/Hx challenged rats demonstrate that inhaled TPIS may have superior effects to oral sildenafil. We speculate that the improvement of the pathobiology in this PAH model induced by TPIS involves effects on pulmonary vascular remodeling due to the local effects of TRE in the lungs.

Impact of Cilostazol Pharmacokinetics on the Development of Cardiovascular Side Effects in Patients with Cerebral Infarction.

This study investigated the impact of polymorphisms of metabolic enzymes on plasma concentrations of cilostazol and its metabolites, and the influence of the plasma concentrations and polymorphisms on the cardiovascular side effects in 30 patients with cerebral infarction. Plasma concentrations of cilostazol and its active metabolites, and CYP3A5*3 and CYP2C19*2 and *3 genotypes were determined. The median plasma concentration/dose ratio of OPC-13213, an active metabolite by CYP3A5 and CYP2C19, was slightly higher and the median plasma concentration rate of cilostazol to OPC-13015, another active metabolite by CYP3A4, was significantly lower in CYP3A5*1 carriers than in *1 non-carriers (p = 0.082 and p = 0.002, respectively). The CYP2C19 genotype did not affect the pharmacokinetics of cilostazol. A correlation was observed between changes in pulse rate from the baseline and plasma concentrations of cilostazol (R = 0.539, p = 0.002), OPC-13015 (R = 0.396, p = 0.030) and OPC-13213 (R = 0.383, p = 0.037). A multiple regression model, consisting of factors of the plasma concentration of OPC-13015, levels of blood urea nitrogen, and pulse rate at the start of the therapy explained 55.5% of the interindividual variability of the changes in pulse rate. These results suggest that plasma concentrations of cilostazol and its metabolites are affected by CYP3A5 genotypes, and plasma concentration of OPC-13015, blood urea nitrogen, and pulse rate at the start of therapy may be predictive markers of cardiovascular side effects of cilostazol in patients with cerebral infarction.

Pharmacokinetics and pharmacodynamics of sildenafil in fetal lambs on extracorporeal support.

BACKGROUND: Maternal transplacental administration of sildenafil is being considered for a variety of fetal conditions. Clinical translation also requires evaluation of fetal safety in a higher species, such as the fetal lamb. Experiments with the pregnant ewe are curtailed by minimal transplacental transfer as well as limited access to the fetus. The EXTra-uterine Environment for Neonatal Development (EXTEND) model renders the isolated fetal lamb readily accessible and allows for direct fetal administration of sildenafil. METHODS: Five fetal lambs were placed on extracorporeal support in the EXTEND device and received continuous intravenous (IV) sildenafil (0.3-0.5-0.7 mg/kg/24hr) for a duration of one to seven days. Plasma sildenafil concentrations were sampled at regular intervals to establish the pharmacokinetic profile using population pharmacokinetic modeling. Serial Doppler ultrasound examination, continuous non-invasive hemodynamic monitoring and blood gas analysis were done to evaluate the pharmacodynamic effects and fetal response. FINDINGS: The target concentration range (47-500 ng/mL) was attained with all doses. Sildenafil induced an immediate and temporary reduction of pulmonary vascular resistance, mean arterial pressure and circuit flow, without change in fetal lactate levels and acid-base status. The duration of the systemic effects increased with the dose. INTERPRETATION: Immediate temporary pulmonary vascular and systemic hemodynamic changes induced by sildenafil were biochemically well tolerated by fetal lambs on extracorporeal support, with the 0.5 mg/kg/24 h dose balancing rapid attainment of target concentrations with short-lived systemic effects. RESEARCH IN CONTEXT: None. SEARCH STRATEGY BEFORE UNDERTAKING THE STUDY: A literature review was conducted searching online databases (Medline, Embase and Cochrane), using search terms: fetal OR prenatal OR antenatal AND sildenafil, without time-limit and excluding human studies. Where relevant, investigators were contacted in order to avoid duplication of work. EVIDENCE BEFORE THIS STUDY: Prenatal therapy with sildenafil, a phosphodiesterase-5 inhibitor with vasodilatory and anti-remodeling effects on vascular smooth muscle cells, has been considered for a variety of fetal conditions. One multicenter clinical trial investigating the benefit of sildenafil in severe intrauterine growth restriction (the STRIDER-trial) was halted early due to excess mortality in the sildenafil-exposed arm at one treatment site. Such findings demonstrate the importance of extensive preclinical safety assessment in relevant animal models. Transplacentally administered sildenafil leads to decreased pulmonary arterial muscularization, preventing or reducing the occurrence of pulmonary hypertension in rat and rabbit fetuses with diaphragmatic hernia (DH). Validation of these results in a higher and relevant animal model, e.g. fetal lambs, is the next step to advance clinical translation. We recently demonstrated that, in contrast to humans, transplacental transfer of sildenafil in sheep is minimal, precluding the in vivo study of fetal effects at target concentrations using the conventional pregnant ewe model. ADDED VALUE OF THIS STUDY: We therefore used the extracorporeal support model for fetal lambs, referred to as the EXTra-uterine Environment for Neonatal Development (EXTEND) system, bypassing placental and maternal metabolism, to investigate at what dose the target concentrations are reached, and what the fetal hemodynamic impact and response are. Fetal hemodynamic and metabolic tolerance to sildenafil are a crucial missing element on the road to clinical translation. This is therefore the first study investigating the pharmacokinetics, hemodynamic and biochemical effects of clinical-range concentrations of sildenafil in fetal lambs, free from placental and maternal interference. IMPLICATIONS OF ALL THE AVAILABLE EVIDENCE: We demonstrated self-limiting pulmonary vasodilation, a decrease of both systemic arterial pressures and circuit flows, induced by clinical range concentrations of sildenafil, without the development of fetal acidosis. This paves the way for further investigation of prenatal sildenafil in fetal lambs on extracorporeal support. A dose of 0.5 mg/kg/24 h offered the best trade-off between rapid achievement of target concentrations and shortest duration of systemic effects. This is also the first study using the EXTEND as a model for pharmacotherapy during pregnancy.

Vasorelaxing cell permeant phosphopeptide mimetics for subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) due to rupture of an intracranial aneurysm leads to vasospasm resulting in delayed cerebral ischemia. Therapeutic options are currently limited to hemodynamic optimization and nimodipine, which have marginal clinical efficacy. Nitric oxide (NO) modulates cerebral blood flow through activation of the cGMP-Protein Kinase G (PKG) pathway. Our hypothesis is that SAH results in downregulation of signaling components in the NO-PKG pathway which could explain why treatments for vasospasm targeting this pathway lack efficacy and that treatment with a cell permeant phosphopeptide mimetic of downstream effector prevents delayed vasospasm after SAH. Using a rat endovascular perforation model, reduced levels of NO-PKG pathway molecules were confirmed. Additionally, it was determined that expression and phosphorylation of a PKG substrate: Vasodilator-stimulated phosphoprotein (VASP) was downregulated. A family of cell permeant phosphomimetic of VASP (VP) was wasdesigned and shown to have vasorelaxing property that is synergistic with nimodipine in intact vascular tissuesex vivo. Hence, treatment targeting the downstream effector of the NO signaling pathway, VASP, may bypass receptors and signaling elements leading to vasorelaxation and that treatment with VP can be explored as a therapeutic strategy for SAH induced vasospasm and ameliorate neurological deficits.

Discovery of CYR715: A novel carboxylic acid-containing soluble guanylate cyclase stimulator.

Soluble guanylate cyclase (sGC) is a clinically validated therapeutic target in the treatment of pulmonary hypertension. Modulators of sGC have the potential to treat diseases that are affected by dysregulation of the NO-sGC-cGMP signal transduction pathway. This letter describes the SAR efforts that led to the discovery of CYR715, a novel carboxylic acid-containing sGC stimulator, with an improved metabolic profile relative to our previously described stimulator, IWP-051. CYR715 addressed potential idiosyncratic drug toxicity (IDT) liabilities associated with the formation of reactive, migrating acyl glucuronides (AG) found in related carboxylic acid-containing analogs and demonstrated high oral bioavailability in rat and dose-dependent hemodynamic pharmacology in normotensive Sprague-Dawley rats.

Studies on metal-organic framework (MOF) nanomedicine preparations of sildenafil for the future treatment of pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is an incurable disease, although symptoms are treated with a range of dilator drugs. Despite their clinical benefits, these drugs are limited by systemic side-effects. It is, therefore, increasingly recognised that using controlled drug-release nanoformulation, with future modifications for targeted drug delivery, may overcome these limitations. This study presents the first evaluation of a promising nanoformulation (highly porous iron-based metal-organic framework (MOF); nanoMIL-89) as a carrier for the PAH-drug sildenafil, which we have previously shown to be relatively non-toxic in vitro and well-tolerated in vivo. In this study, nanoMIL-89 was prepared and charged with a payload of sildenafil (generating Sil@nanoMIL-89). Sildenafil release was measured by Enzyme-Linked Immunosorbent Assay (ELISA), and its effect on cell viability and dilator function in mouse aorta were assessed. Results showed that Sil@nanoMIL-89 released sildenafil over 6 h, followed by a more sustained release over 72 h. Sil@nanoMIL-89 showed no significant toxicity in human blood outgrowth endothelial cells for concentrations up to100µg/ml; however, it reduced the viability of the human pulmonary artery smooth muscle cells (HPASMCs) at concentrations > 3 µg/ml without inducing cellular cytotoxicity. Finally, Sil@nanoMIL-89 induced vasodilation of mouse aorta after a lag phase of 2-4 h. To our knowledge, this study represents the first demonstration of a novel nanoformulation displaying delayed drug release corresponding to vasodilator activity. Further pharmacological assessment of our nanoformulation, including in PAH models, is required and constitutes the subject of ongoing investigations.

TAT-modified serum albumin nanoparticles for sustained-release of tetramethylpyrazine and improved targeting to spinal cord injury.

BACKGROUND: Spinal Cord injury (SCI) is a kind of severe traumatic disease. The inflammatory response is a significant feature after SCI. Tetramethylpyrazine (TMP), a perennial herb of umbelliferae, is an alkaloid extracted from ligustici. TMP can inhibit the production of nitric oxide and reduce the inflammatory response in peripheral tissues. It can be seen that the therapeutic effect of TMP on SCI is worthy of affirmation. TMP has defects such as short half-life and poor water-solubility. In addition, the commonly used dosage forms of TMP include tablets, dropping pills, injections, etc., and its tissue and organ targeting is still a difficult problem to solve. To improve the solubility and targeting of TMP, here, we developed a nanotechnology-based drug delivery system, TMP-loaded nanoparticles modified with HIV trans-activator of transcription (TAT-TMP-NPs). RESULTS: The nanoparticles prepared in this study has integrated structure. The hemolysis rate of each group is less than 5%, indicating that the target drug delivery system has good safety. The results of in vivo pharmacokinetic studies show that TAT-TMP-NPs improves the bioavailability of TMP. The quantitative results of drug distribution in vivo show that TAT-TMP-NPs is more distributed in spinal cord tissue and had higher tissue targeting ability compared with other treatment groups. CONCLUSIONS: The target drug delivery system can overcome the defect of low solubility of TMP, achieve the targeting ability, and show the further clinical application prospect.

Vascular effects of serelaxin in patients with stable coronary artery disease: a randomized placebo-controlled trial.

AIMS: The effects of serelaxin, a recombinant form of human relaxin-2 peptide, on vascular function in the coronary microvascular and systemic macrovascular circulation remain largely unknown. This mechanistic, clinical study assessed the effects of serelaxin on myocardial perfusion, aortic stiffness, and safety in patients with stable coronary artery disease (CAD). METHODS AND RESULTS: In this multicentre, double-blind, parallel-group, placebo-controlled study, 58 patients were randomized 1:1 to 48 h intravenous infusion of serelaxin (30 µg/kg/day) or matching placebo. The primary endpoints were change from baseline to 47 h post-initiation of the infusion in global myocardial perfusion reserve (MPR) assessed using adenosine stress perfusion cardiac magnetic resonance imaging, and applanation tonometry-derived augmentation index (AIx). Secondary endpoints were: change from baseline in AIx and pulse wave velocity, assessed at 47 h, Day 30, and Day 180; aortic distensibility at 47 h; pharmacokinetics and safety. Exploratory endpoints were the effect on cardiorenal biomarkers [N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitivity troponin T (hsTnT), endothelin-1, and cystatin C]. Of 58 patients, 51 were included in the primary analysis (serelaxin, n = 25; placebo, n = 26). After 2 and 6 h of serelaxin infusion, mean placebo-corrected blood pressure reductions of -9.6 mmHg (P = 0.01) and -13.5 mmHg (P = 0.0003) for systolic blood pressure and -5.2 mmHg (P = 0.02) and -8.4 mmHg (P = 0.001) for diastolic blood pressure occurred. There were no between-group differences from baseline to 47 h in global MPR (-0.24 vs. -0.13, P = 0.44) or AIx (3.49% vs. 0.04%, P = 0.21) with serelaxin compared with placebo. Endothelin-1 and cystatin C levels decreased from baseline in the serelaxin group, and there were no clinically relevant changes observed with serelaxin for NT-proBNP or hsTnT. Similar numbers of serious adverse events were observed in both groups (serelaxin, n = 5; placebo, n = 7) to 180-day follow-up. CONCLUSION: In patients with stable CAD, 48 h intravenous serelaxin reduced blood pressure but did not alter myocardial perfusion.

Enantioselective assay of nimodipine in human plasma using liquid chromatography-tandem mass spectrometry.

Nimodipine is a dihydropyridine calcium channel blocker that exhibits higher selectivity toward cerebral blood vessels compared with other members of the same class. It has been shown to improve outcomes and prevent delayed cerebral ischemia in the setting of aneurysmal subarachnoid hemorrhage, a life-threatening brain bleed. Nimodipine is a chiral compound and it is marketed as a racemic mixture of (+)-R and (-)-S enantiomers. (-)-S-Nimodipine is approximately twice as potent a vasorelaxant as the racemic mixture and is more rapidly eliminated than the (+)-R counterpart following oral dosing. Few analytical procedures have been reported to determine nimodipine enantiomers in biological samples; however, the reported methods were time-consuming, involved multistep extraction procedures and required large sample volumes. Herein, we present an LC-MS/MS method for quantifying nimodipine enantiomers in human plasma using a small sample volume (0.3 ml) and a single liquid-liquid extraction step. The peak area ratios were linear over the tested concentration ranges (1.5-75 ng/ml) with r2 > 0.99. The intraday CV and percentage error were within ±14% while the interday values were within ±13%, making this analytical method feasible for research purposes and pharmacokinetic studies.

[Pharmacokinetic features of sildenafil spray in healthy men depending on food intake].

AIM: In order to evaluate the bioequivalence and benefits of a new dosage form of the type 5 phosphodiesterase inhibitor, sildenafil, two open-label studies in healthy male volunteers were carried out. MATERIALS AND METHODS: An open, randomized, crossover study to compare the pharmacokinetics after a single dose of sildenafil at a dosage of 50 mg on an empty stomach in a new spray form (test drug) and in a traditional tablet form (comparison drug) on 44 volunteers (18 to 43 years old) was done. To assess the effect of food intake on pharmacokinetics, an open, non-randomized study was conducted on 6 healthy male volunteers (from 23 to 35 years old) who received sildenafil (50 mg) after a meal in timely fashion: 1) spray, under the tongue, without drinking, 2) spray , in the mouth, drinking water and 3) the tablet form, drinking water. For pharmacokinetic analysis, blood was analyzed for 24 hours. Plasma concentration of sildenafil was determined by high performance liquid chromatography with tandem mass spectrometric detection (HPLC/TM/SD). The main parameters were the rate (maximum concentration; Cmax) and the degree of absorption (area under the pharmacokinetic curve "concentration-time" during the observation period; AUC0-t) after a single dose of drugs. In addition, the pharmacokinetic profiles of the bioavailability of sildenafil and its active metabolite, N-desmethyl sildenafil, as well as the safety of the different dosage forms, were evaluated. RESULTS: When comparing taking drugs on an empty stomach, the 90% confidence intervals (CI) of the ratios of the mean Cmax and AUC0-t values of sildenafil were 82-106% and 82-101%, respectively. An earlier achievement of the maximum concentration of sildenafil was detected when taking the test drug compared with the standard form (51 and 62 minutes, respectively, Z-value=-2.25, p-value=0.0244). In addition, it was shown that when taking Viagra after a meal, the determination of sildenafil in plasma was delayed (after 30 minutes) compared to the tested drugs (after 10 minutes), however, significant differences in Tmax between the dosage forms were not seen. In two studies, most adverse events were mild to moderate and resolved uneventfully. DISCUSSION: The bioavailability of the new dosage form, the sildenafil spray, is equivalent to the traditional form, however, it has an advantage in terms of onset of action. For example, when taking a spray, an earlier achievement of the maximum concentration of sildenafil and an earlier detection of sildenafil in plasma are shown compared to the traditional tablet form. CONCLUSIONS: Our results suggest that the new dosage form of sildenafil is a reliable alternative therapeutic option for the treatment of erectile dysfunction.

Nimodipine Pharmacokinetic Variability in Various Patient Populations.

Nimodipine has been shown to improve outcomes following aneurysmal subarachnoid hemorrhage. Guidelines recommend that all patients receive a fixed dose of oral nimodipine for 21 days. However, pharmacokinetic studies have suggested variability of nimodipine pharmacokinetics in subarachnoid hemorrhage and in other patient populations. The clinical relevance of such variability is unknown. Therefore, the objective of the present review is, first, to conduct a literature review and summarize nimodipine pharmacokinetic data and sources of variability in various patient groups. Second, to determine if there is any evidence reporting an association between nimodipine exposure and clinical outcomes in patients with subarachnoid hemorrhage. A systematic literature search was performed in MEDLINE and EMBASE. The following keywords were used: ("nimodipine" OR "nymalize" OR "nimotop") AND ("pharmacokinetic*", OR "PK"). The search results were limited to English language and human studies. A large interpatient variability in nimodipine pharmacokinetics has been reported. Patient-specific factors that had an influence on pharmacokinetic parameters are age, comorbidities, variabilities in metabolism due to genetic polymorphism and co-administered medications, as well as nimodipine administration technique. The association between nimodipine exposure and clinical outcomes remains unclear and data available are too scarce to reach a firm conclusion. Here, we present a narrative review with a systematic literature search discussing nimodipine pharmacokinetic variability in various patient populations. It is not clear if minimal or lack of systemic exposure to nimodipine denies its benefit and contributes to worsening outcomes in patients with subarachnoid hemorrhage. Further studies are needed to determine if such an association exists.

Single Ascending Dose Study to Assess Pharmacokinetic Linearity, Safety, and Tolerability of Trimetazidine - Modified Release in Healthy Human Subjects.

AIM: This study assessed the linearity of pharmacokinetics (PK) of trimetazidine (TMZ) modified-release tablets (indicated in adults as an add-on therapy for stable angina pectoris) and measured its renal elimination, safety, and tolerability in healthy subjects. METHODS: This was a randomized, open-label, single-ascending dose study in healthy subjects. Subjects were administered with a single dose of 35, 70, or 105 mg TMZ-modified release tablets (six subjects each). Pharmacokinetic evaluations and safety analysis were performed before the first dose and till 48 h post-first dose. RESULTS: Following administration of 35, 70, and 105 mg TMZ-modified release; the Cmax (mean±SD) was 79.32 (±23.08), 153.17 (±23.08), and 199.67 (±23.08) ng/mL, the Tmax was 5.42 (±0.49), 4.51 (±1.27), and 4.57 (±0.96) h, t1/2 was 7.75 (±1.62), 6.40 (±1.23), and 6.50 (±1.18) h, AUC(0-inf) was 1116.89 (±378.35), 1838.39 (±284.50), and 2504.84 (±348.35) ng.h/mL, CLR was 13.70 (±2.24), 14.80 (±5.91), and 19.58 (±6.24) L·h-1 and CL/F was 33.69 (±8.51), 38.85 (±6.15), and 42.74 (±7.10) L·h-1, respectively. Slope estimates for AUC(0-inf), AUC(0-t), and Cmax were less than 1. Corresponding 95% CI of the slope for the AUC parameters excluded 1, indicating that the deviation from dose-proportionality was statistically significant. Corresponding 95% CI of the slope for Cmax included 1, indicating that the less than dose-proportional increase in Cmax was not statistically significant. No significant adverse events were observed. CONCLUSION: Substantial deviation from a dose-proportional increase in AUC(0-inf) and AUC(0-t) suggested a non-linear PK for TMZ-modified release. Single dose of TMZ-modified release was well tolerated and safe.

Propylene glycol free 5% minoxidil lotion formulation: cosmetic acceptability, local tolerability, clinical efficacy and in-vitro skin absorption evaluations.

BACKGROUND: A new propylene glycol (PG)-free 5% minoxidil (Mnx) lotion has been recently commercialized. Aim of this study was to evaluate the acceptability/tolerability and clinical efficacy of 3-month application of this new PG-free Mnx lotion and the penetration of the active compound in a reconstructed human epidermis (RHE/Episkin) model in comparison with a PG Mnx 5% lotion. METHODS: Thirty subjects of both sex with a diagnosis of AGA were enrolled in the trial. Cosmetic acceptability and clinical efficacy were evaluated after 4, 8 and 12 weeks of treatment. Global tolerability was evaluated at week 12. Cosmetic acceptability evaluation was assessed using a 7-item questionnaire using a 10-point scale score. Global Tolerability was evaluated with a 4-grade scale. Clinical efficacy was evaluated with a 5-grade scale. Skin absorption of PG-free Mnx was evaluated and compared with a PG Mnx solution using the Episkin model. RESULTS: All subjects concluded the study. The 7-item questionnaire mean values were always <2 at each time-point evaluation, demonstrating high cosmetic acceptability/tolerability. No subjects reported burning, itching or redness sensations. Global Tolerability score mean±SD value was 1.7±0.4. Clinical efficacy scores were 0.4, 0.6 and 1.2 at week 4, 8 and 12, respectively. PG-free Mnx showed similar amount of absorbed dose in comparison with PG Mnx. CONCLUSIONS: This new PG-free lotion shows a very good cosmetic acceptability/tolerability profile. Clinical efficacy was also documented. The skin penetration of this formulation is comparable to the PG Mnx lotion, supporting the bioequivalence of the two products.

Enhanced nanoparticle accumulation by tumor-acidity-activatable release of sildenafil to induce vasodilation.

Inefficient nanoparticle accumulation in solid tumors hinders the clinical translation of cancer nanomedicines. Herein, we proposed that sildenafil, a vasodilator ampholyte, could be used to promote nanoparticle accumulation by inducing vasodilation after its tumor acidity-triggered release from the nanocarriers. To confirm this, sildenafil was first encapsulated in a cisplatin-incorporated polymeric micelle. The dense PEG shell of the micelle reduced its endocytosis by cancer cells, which in return resulted in accumulative extracellular release of protonated sildenafil in the acidic tumor microenvironment. The released sildenafil was found to be more effective in enlarging the tumor blood vessels than could be achieved without sildenafil. As a result, we demonstrated considerable improvement in the intratumoral accumulation of the sildenafil-cisplatin co-loaded nanoparticle and its enhanced cancer therapeutic efficacy over the control group. Given the generality of a dense PEG shell and a hydrophobic part in most clinically developed nanomedicines, this work implies the great potential of sildenafil as a simple and universal adjuvant to selectively promote the intratumoral accumulation of nanomedicines, thus improving their clinical translation.

Effect of age and renal impairment on the pharmacokinetics and safety of trimetazidine: An open-label multiple-dose study.

This study evaluated the effect of age and renal impairment on pharmacokinetics of trimetazidine (TMZ) in healthy elderly and renally impaired subjects and assess safety and tolerability. In this open-label, multi-dose study, 73 subjects were divided into six treatment groups: (1) 55-65 years; (2) 66-75 years; (3) >75 years (dosing for groups 1-3 [healthy]: B.D. for 4 days), (4) mild renally impaired (dosed B.D. for 8 days); (5) moderate renally impaired (dosed O.D. for 8 days); and (6) severe renally impaired-no dialysis (dosed once every 48 h for 8 days). Blood and urine samples were collected and analyzed. The geometric least squares mean ratios for; Group 2 and 1 of AUC(0-τ)ss was 112.2 (90% CI; 92.0-136.8) and Cmax,ss was 109.9 (89.6-134.8), Group 3 and 1 of AUC(0-τ),ss was 140.5 (115.9-170.3) and Cmax,ss was 137.8 (112.9-168.2), Group 4 and 1 of AUC(0-τ),ss was 114.2 (90.3-144.4) and Cmax,ss was 120.8 (92.5-157.8), Group 5 and 1 of; AUC(0-τ),ss was 213.0 (153.1-296.3) and Cmax,ss was 123.3 (92.2-164.7) and Group 6 and 1 of AUC(0-τ),ss was 247.4 (197.8-309.6) and Cmax,ss was 95.6 (73.0-125.1). Significant increase in systemic exposure of TMZ was observed in subjects; over 75 year's age and renally impaired compared to healthy subjects. TMZ was safe and well-tolerated.

A Liposomal Formulation for Improving Solubility and Oral Bioavailability of Nifedipine.

Proliposomes were used to improve the solubility and oral bioavailability of nifedipine. Nifedipine proliposomes were prepared by methanol injection-spray drying method. The response surface method was used to optimize formulation to enhance the encapsulation efficiency (EE%) of nifedipine. The particle size of nifedipine proliposomes after rehydration was 114 nm. Surface morphology of nifedipine proliposomes was observed by a scanning electron microscope (SEM) and interaction of formulation ingredients was assessed by differential scanning calorimetry (DSC). The solubility of nifedipine is improved 24.8 times after forming proliposomes. In vitro release experiment, nifedipine proliposomes had a control release effect, especially in simulated gastric fluid. In vivo, nifedipine proliposomes significantly improved the bioavailability of nifedipine. The area under the concentration-time curve (AUC0-∞) of nifedipine proliposomes was about 10 times than nifedipine after oral administration. The elimination half-life (T1/2ß) of nifedipine was increased from 1.6 h to 6.6 h. In conclusion, proliposomes was a promising system to deliver nifedipine through oral route and warranted further investigation.

Optimized preparation of vinpocetine micelles and in vivo evaluation of its pharmacokinetics in rats.

This study aimed to develop a novel monomethoxy poly(ethylene glycol)-b-poly(D, L-lactide) (mPEG5000-PLA10 000) micelle drug delivery system to improve vinpocetine's (VP) dissolution and sustain VP concentrations in plasma. Three micelle fabrication methods were examined to maximize VP loading, followed by structurally characterization and investigation in vitro release and in vivo pharmacokinetics in Sprague-Dawley rats. The thin-film hydration is the most appropriate method of the three methods because of its high loading content. The loaded micelles exhibited a sustained release behavior up to 48 h. Following intraperitoneal administration (9 mg/kg), VP loaded micelles provided significantly higher (335%) AUC (area under concentration-time) compared to VP injection. And also increased the mean residence time [MRT(0-t)] and elimination half-life (t1/2z). There were obviously two peaks at 2 h and 9 h in VP loaded micelles concentration-time profile. In summary, these data demonstrated that poly mPEG-PLA micelles can efficiently sustain VP concentrations in plasma for 36 h, thus apprehending polymeric micelles suitability as poor aqueous solubility drug carriers.

Moringa oleifera leaf extract induces vasorelaxation via endothelium-dependent hyperpolarization and calcium channel blockade in mesenteric arterial beds isolated from L-NAME hypertensive rats.

BACKGROUND: An aqueous extract of Moringa oleifera leaves (MOE) is known to cause relaxation of mesenteric resistance arteries of rats in which hypertension has been induced by the administration of L-NAME, but the mechanism(s) of action of MOE remains unclear. The purpose of this study was to investigate these mechanisms in mesenteric arterial beds isolated from L-NAME induced hypertensive rats. Methods: An investigation of vascular reactivity was conducted on isolated mesenteric arterial beds by measuring the changes in perfusion pressure using an in vitro system. RESULTS: MOE (0.001-3 mg in 0.1 ml injection volume) caused a dose-dependent relaxation in methoxamine (5 µM) pre-contracted arterial beds, which was partially abolished by endothelium removal. The endothelium-dependent component of vasorelaxation was insensitive to both L-NAME (100 µM) and indomethacin (10 µM), while completely inhibited in high KCl (45 mM)-induced contraction. MOE (1 and 3 mg/ml) showed a dose-dependent inhibitory effect on CaCl2-induced contractions of denuded preparations in Ca2+-free medium containing a high KCl (60 mM) or methoxamine (10 µM). In Ca2+-free medium, MOE (3 mg/ml) also inhibited phenylephrine-induced contractions of denuded preparations. Conclusion: These findings suggest that MOE relaxes mesenteric arterial beds of L-NAME hypertensive rats via both endothelium-dependent and endothelium-independent mechanisms. The endothelium-dependent action occurred via endothelium-derived hyperpolarizing factor-mediated hyperpolarization. The endothelium-independent action was related to blocking the entry of extracellular Ca2+ via voltage-operated and receptor-operated Ca2+ channels, and inhibiting mobilization of sarcolemmal Ca2+ via inositol trisphosphate receptor Ca2+ channels. MOE may be potentially useful as a natural vasodilator against hypertension.