Free Simvastatin Research Articles

Chitosan-enclosed SLN improved SV-induced hepatocellular cell carcinoma death by modulation of IQGAP gene expression, JNK, and HDAC activities.

Hepatocellular carcinoma (HCC) is a global life-threatening problem and therapeutic interventions are still encountered. IQGAP genes are involved in HCC oncogenesis. The modulatory effect of statins on the expression of IQGAP genes is still unclear. This study aims to study the effect of free SV and chitosan (CS) decorated simvastatin (SV) loaded solid lipid nanoparticles (C-SV-SLNs) on HCC mortality. Plain, SV-SLN, and C-SV- SLN were prepared and characterized in terms of particle size (PS), zeta potential (ZP), and polydispersity index (PDI). The biosafety of different SLN was investigated using fresh erythrocytes, moreover, cytotoxicity was investigated using HepG2 cell lines. The effect of SLNs on IQGAPs gene expression as well as JNK, HDAC6, and HDAC8 activity was investigated using PCR and MOE-docking. The current results displayed that SV-SLNs have nanosized, negative ZP and are homogenous, CS decoration shifts the ZP of SLN into cationic ZP. Furthermore, all SLNs exhibited desirable biosafety in terms of no deleterious effect on erythrocyte integrity. SV solution and SV-SLN significantly increase the mortality of HepG2 compared to undertreated cells, however, the effect of SV-SLN is more pronounced compared to free SV. Remarkably, C-SV-SLN elicits high HepG2 cell mortality compared to free SV and SV-SLN. The treatment of HepG2 cells with SV solution, SV-SLN, or C-SV-SLN significantly upregulates the IQGAP2 gene with repression of IQGAP1 and IQGAP3 genes. MOE-docking studies revealed both SV and tenivastatin exhibit interactions with the active sites of JNK, HDAC6, and HDAC8. Moreover, tenivastatin exhibited greater interactions with magnesium and zinc compared to SV. This research provides novel insights into the therapeutic potential of SV, SV-SLN and C-SV-SLNs in HCC treatment, modulating critical signaling cascades involving IQGAPs, JNK, and HDAC. The development of C-SV-SLNs presents a promising strategy for effective HCC therapy.

In Vitro Targeted Delivery of Simvastatin and Niacin to Macrophages Using Mannan-Grafted Magnetite Nanoparticles.

Atherosclerosis, a leading cause of mortality worldwide, involves various subsets of macrophages that contribute to its initiation and progression. Current treatment approaches focus on systemic, long-term administration of cholesterol-lowering antioxidants such as statins and certain vitamins, which unfortunately come with prolonged side effects. To overcome these drawbacks, a mannose-containing magnetic nanoparticle (NP) is introduced as a drug delivery system to specifically target macrophages in vitro using simvastatin or niacin and a combinational therapy approach that reduces local inflammation while avoiding unwanted side effects. The synthesized NPs exhibited superparamagnetic behavior, neutrally charged thin coating with a hydrodynamic size of 77.23 ± 13.90 nm, and a metallic core ranging from 15 to 25 nm. Efficient loading of niacin (87.21%) and simvastatin (75.36%) on the NPs was achieved at respective weights of 20.13 and 5.03 (w/w). In the presence of a mannan hydrolyzing enzyme, 79.51% of simvastatin and 67.23% of niacin were released from the NPs within 90 min, with a leakage rate below 19.22%. Additionally, the coated NPs showed no destructive effect on J774A macrophages up to a concentration of 200 μg/mL. Simvastatin-loaded NPs exhibited a minimal increase in IL-6 expression. The low dosage of simvastatin decreased both IL-6 and ARG1 expressions, while niacin and combined simvastatin/niacin increased the level of ARG1 expression significantly. Toxicity evaluations on human umbilical vein endothelial cells and murine liver cells revealed that free simvastatin administration caused significant toxicity, whereas the encapsulated forms of simvastatin, niacin, and a combination of simvastatin/niacin at equivalent concentrations exhibited no significant toxicity. Hence, the controlled release of the encapsulated form of simvastatin and niacin resulted in the effective modulation of macrophage polarization. The delivery system showed suitability for targeting macrophages to atherosclerotic plaque.

Customizing biomimetic surface attributes of dendritic lipopeptide nanoplatforms for extended circulation

The pressing demand for innovative approaches to create delivery systems with heightened drug loading and prolonged circulation has spurred numerous efforts, yielding some successes but accompanied by constraints. Our study proposes employing dendritic lipopeptide with precisely balanced opposing charges to extend blood residency for biomimetic nanoplatforms. Neutrally mixed-charged zwitterionic nanoparticles (NNPs) achieved a notable 19 % simvastatin loading content and kept stable even after one-month storage at 4 °C. These nanoplatforms demonstrated low cytotoxicity in NIH-3T3 and L02 cells and negligible hemolysis (<5 %). NNPs inhibited protein adhesion (>95 %) from positively and negatively charged sources through surface hydration. In comparison to positively charged CNPs, NNPs demonstrated an 86 % decrease in phagocytic rate by BMDMs, highlighting their efficacy. Importantly, NNPs showed prolonged circulation compared to CNPs and free simvastatin. These findings highlight the potential of this biomimetic nanoplatform for future therapeutic applications with enhanced drug loading and circulation traits.

Formulation and evaluation of simvastatin cubosomal nanoparticles for assessing its wound healing effect

Wound healing is one of the most challenging medical circumstances for patients. Pathogens can infect wounds, resulting in tissue damage, inflammation, and disruption of the healing process. Simvastatin was investigated recently, as a wound healing agent that may supersede the present therapies for wounds. Our goal in this paper is to focus on formulation of simvastatin cubosomes for topical delivery, as a potential approach to improve simvastatin skin permeation. By this technique its wound healing effect could be improved. Cubosomes were prepared using the top-down method and the prepared cubosomes were characterized by several techniques. The most optimal simvastatin cubosomal formulation was then included in a cubogel dosage form using different gelling agents. The results showed that the average particle size of the prepared cubosomes was 113.90 ± 0.58 nm, the entrapment efficiency was 93.95 ± 0.49% and a sustained simvastatin release was achieved. The optimized formula of simvastatin cubogel displayed pseudoplastic rheological behavior. This same formula achieved enhancement in drug permeation through excised rat skin compared to free simvastatin hydrogel with flux values of 46.18 ± 2.12 mcg cm−2 h−1 and 25.92 ± 3.45 mcg cm−2 h−1 respectively. Based on the in-vivo rat studies results, this study proved a promising potential of simvastatin cubosomes as wound healing remedy.

Optimization of Statin-Loaded Delivery Nanoparticles for Treating Chronic Liver Diseases by Targeting Liver Sinusoidal Endothelial Cells.

In this study, we developed functionalized polymeric micelles (FPMs) loaded with simvastatin (FPM-Sim) as a drug delivery system to target liver sinusoidal endothelial cells (LSECs) for preserving liver function in chronic liver disease (CLD). Polymeric micelles (PMs) were functionalized by coupling peptide ligands of LSEC membrane receptors CD32b, CD36 and ITGB3. Functionalization was confirmed via spectroscopy and electron microscopy. In vitro and in vivo FPM-Sim internalization was assessed by means of flow cytometry in LSECs, hepatocytes, Kupffer and hepatic stellate cells from healthy rats. Maximum tolerated dose assays were performed in healthy mice and efficacy studies of FPM-Sim were carried out in bile duct ligation (BDL) and thioacetamide (TAA) induction rat models of cirrhosis. Functionalization with the three peptide ligands resulted in stable formulations with a greater degree of in vivo internalization in LSECs than non-functionalized PMs. Administration of FPM-Sim in BDL rats reduced toxicity relative to free simvastatin, albeit with a moderate portal-pressure-lowering effect. In a less severe model of TAA-induced cirrhosis, treatment with FPM-CD32b-Sim nanoparticles for two weeks significantly decreased portal pressure, which was associated with a reduction in liver fibrosis, lower collagen expression as well as the stimulation of nitric oxide synthesis. In conclusion, CD32b-FPM stands out as a good nanotransporter for drug delivery, targeting LSECs, key inducers of liver injury.

Impact of porous microsponges in minimizing myotoxic side effects of simvastatin

Simvastatin (SV) is a poorly soluble drug; its oral administration is associated with a significant problem: Myopathy. The present study aims to formulate SV microsponges that have the potential to minimize the myotoxicity accompanying the oral administration of the drug. SV microsponges were prepared by exploiting the emulsion solvent evaporation technique. The % entrapment efficiency (%EE) of the drug approached 82.54 ± 1.27%, the mean particle size of SV microsponges ranged from 53.80 ± 6.35 to 86.03 ± 4.79 µm in diameter, and the % cumulative drug release (%CDR) of SV from microsponges was significantly higher than that from free drug dispersion much more, the specific surface area of the optimized microsponges formulation was found to be 16.6 m2/g revealed the porosity of prepared microsponges. Histological and glycogen histochemical studies in the skeletal muscles of male albino rats revealed that microsponges were safer than free SV in minimizing myotoxicity. These findings were proven by Gene expression of Mitochondrial fusion and fission (Mfn1) & (Fis1) and (Peroxisome proliferator-activated receptor gamma co-activator 1α) PGC-1α. Finally, our study ascertained that SV microsponges significantly decreased the myotoxicity of SV.

A ROS-Responsive Simvastatin Nano-Prodrug and its Fibronectin-Targeted Co-Delivery System for Atherosclerosis Treatment.

Nanoprodrugs with responsive release properties integrate the advantages of stimuli-responsive prodrugs and nanotechnology. They would provide ultimate opportunity in fighting atherosclerosis. In this study, we synthesized a redox-responsive nanoprodrug of simvastatin (TPTS) by conjugating α-tocopherol polyethylene glycol derivative to the pharmacophore of simvastatin with a thioketal linker. TPTS formed nanoparticles and released parent simvastatin in the presence of hydrogen peroxide. Moreover, by taking advantage of the self-assembly behavior of TPTS, we developed a fibronectin-targeted delivery system (TPTS/C/T) to codelivery simvastatin prodrug and ticagrelor. In vitro and in vivo experiments indicated that TPTS and TPTS/C/T had good stability, which could reduce off-target leakage of drugs. They greatly inhibited the M1-type polarization of macrophages; reduced intracellular reactive oxygen species level and inflammatory cytokine; and TNF-α, MCP-1, and IL-1β were secreted by macrophage cells, thus providing enhanced anti-inflammatory and antioxidant effects compared with free simvastatin. TPTS/C/T realized targeted drug release to plaques and synergistic therapeutic effects of simvastatin and ticagrelor on atherosclerosis treatment in an ApoE-/- mouse model, resulting in excellent atherosclerosis therapeutic efficacy and a promising biosafety profile. Therefore, this study provides a new method for manufacturing statin nanodrugs and a new design idea for related responsive drug release nanosystems for atherosclerosis.

Evaluation of the efficiency of simvastatin loaded PLGA nanoparticles against acute paraquat-intoxicated rats

Here, we reported a novel nanotherapeutic platform for paraquat (PQ)-induced acute lung injury in animal models using simvastatin (SV) loaded into Poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs). In this way, Male Wistar rats orally received PQ (120 mg / kg) plus saline, SV (20 mg / kg) or PLGA–SV NPs containing 5, 10 and 20 mg SV/ kg. The levels of TNFα, IL-1β, IL-6 and glutathione content were evaluated. In addition, the pathological changes in the lung were monitored. Our results indicated that PQ (120 mg/kg) significantly reduced the body weight of rats compared to the control group. The most decrease in the level of inflammatory cytokines, bleeding, alveolar destruction as well as lymphocytic infiltration in the lung was observed at group treated with PLGA-SV NPs (10 mg). Free SV (20 mg) as well as PLGA-SV NPs (5 mg) modulated the inflammatory factors and glutathione content, however, they could not prevent tissue damage of PQ. Interestingly, PLGA-SV NPs (20 mg) could not improve the PQ- induced pulmonary damage. In conclusion, PLGA-SV NPs (10 mg) attenuated PQ-induced lung injury. The underlying mechanism may be relevant to increasing glutathione levels and inhibition of the production of inflammatory factors.

Anti-Inflammatory Effect of Very High Dose Local Vessel Wall Statin Administration: Poly(L,L-Lactide) Biodegradable Microspheres with Simvastatin for Drug Delivery System (DDS).

Atherosclerosis involves an ongoing inflammatory response of the vascular endothelium and vessel wall of the aorta and vein. The pleiotropic effects of statins have been well described in many in vitro and in vivo studies, but these effects are difficult to achieve in clinical practice due to the low bioavailability of statins and their first-pass metabolism in the liver. The aim of this study was to test a vessel wall local drug delivery system (DDS) using PLA microstructures loaded with simvastatin. Wistar rats were fed high cholesterol chow as a model. The rat vessels were chemically injured by repeated injections of perivascular paclitaxel and 5-fluorouracil. The vessels were then cultured and treated by the injection of several concentrations of poly(L,L-lactide) microparticles loaded with the high local HMG-CoA inhibitor simvastatin (0.58 mg/kg) concentration (SVPLA). Histopathological examinations of the harvested vessels and vital organs after 24 h, 7 days and 4 weeks were performed. Microcirculation in mice as an additional test was performed to demonstrate the safety of this approach. A single dose of SVPLA microspheres with an average diameter of 6.4 μm and a drug concentration equal to 8.1% of particles limited the inflammatory reaction of the endothelium and vessel wall and had no influence on microcirculation in vivo or in vitro. A potent pleiotropic (anti-inflammatory) effect of simvastatin after local SVPLA administration was observed. Moreover, significant concentrations of free simvastatin were observed in the vessel wall (compared to the maximum serum level). In addition, it appeared that simvastatin, once locally administered as SVPLA particles, exerted potent pleiotropic effects on chemically injured vessels and presented anti-inflammatory action. Presumably, this effect was due to the high local concentrations of simvastatin. No local or systemic side effects were observed. This approach could be useful for local simvastatin DDSs when high, local drug concentrations are difficult to obtain, or systemic side effects are present.

Performance of simvastatin microsponges as a local treatment for chronic periodontitis – Randomized clinical trial

Simvastatin (SV) is a lipid lowering drug exhibits anti-inflammatory and anabolic effects on the bone, so it could be utilized for the local treatment of periodontitis. However, the poor solubility of SV limits its penetration through the gingival sulcus. Encapsulating SV into microsponges may have the potential to enhance the dissolution and subsequently its local penetration. In this study, SV microsponges had been prepared using the emulsion-solvent evaporation technique where, Eudragit RS-100 was employed as the polymer. The % encapsulation efficiency(%EE) of drug approached 77.32 ± 2.03. The prepared microsponges were free flowing, spherical in shape having narrow size distribution range. The particle size of the prepared microsponges was 93.79 ± 7.21 μm in diameter with a small polydispersity index (PDI) of 0.0059 ± 0.0008. In-vitro dissolution studies of SV microsponges showed that the solubility of SV had significantly enhanced upon inclusion inside the microsponges. Fourier transform infrared (FT-IR) spectroscopy indicated hydrogen bond formation between SV and Eudragit RS-100. The prepared microsponges were incorporated in chitosan 2% gels. A clinical study was conducted on 24 selected patients having bony periodontal defects to compare the efficacy of chitosan 2% gel containing free (SV) with that containing SV microsponge in treatment of chronic periodontitis. Results showed that the chitosan gels containing SV microsponges exhibited significant reduction in both pocket depth and clinical attachment loss compared to those prepared with free SV. This might be attributed to hydrogen bond formation between microsponges entrapped SV and chitosan, thus microsponges are auspicious as a carrier for SV for local treatment of periodontitis.

Simvastatin-loaded polymeric micelles are more effective and less toxic than conventional statins in a pre-clinical model of advanced chronic liver disease

Chronic liver disease (CLD) has no effective treatments apart from reducing its complications. Simvastatin has been tested as vasoprotective drug in experimental models of CLD showing promising results, but also limiting adverse effects. Two types of Pluronic® carriers loading simvastatin (PM108-simv and PM127-simv) as a drug delivery system were developed to avoid these toxicities while increasing the therapeutic window of simvastatin. PM127-simv showed the highest rates of cell internalization in rat liver sinusoidal endothelial cells (LSECs) and significantly lower toxicity than free simvastatin, improving cell phenotype. The in vivo biodistribution was mainly hepatic with 50% of the injected PM found in the liver. Remarkably, after one week of administration in a model of CLD, PM127-simv demonstrated superior effect than free simvastatin in reducing portal hypertension. Moreover, no signs of toxicity of PM127-simv were detected. Our results indicate that simvastatin targeted delivery to LSEC is a promising therapeutic approach for CLD.

Lipid-core nanocapsules containing simvastatin improve the cognitive impairment induced by obesity and hypercholesterolemia in adult rats

The development of cognitive impairment may be related to high levels of plasma cholesterol and obesity. Simvastatin (SV) and lovastatin (LV) are drugs that can potentially be used for the treatment of cognitive deficit. This study aimed to develop and characterize lipid-core nanocapsules (LNC) containing SV (SV-LNC) or LV (LV-LNC), evaluating the effects of SV-LNC in an animal model of cognitive deficit. The formulations SV-LNC and LV-LNC presented a particle average size around 200 nm, a low-polydispersity index, and negative zeta potential. Analysis of differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy showed that there is no reaction among LNC components: LV was crystallized in the suspensions, and SV was molecularly dispersed. The encapsulation efficiency of the SV was high (98.9 ± 1.4%), while that of the LV was low (21.5 ± 1.5%).Based on these results, SV-LNC was used in the preclinical studies. Animals fed with a hyperlipidic diet (HD) developed obesity, hypercholesterolemia, and cognitive impairment, which was corroborated by the brain lesions indicated by histological analysis of some of the animals that received the high-fat diet. We observed that free simvastatin (CS3) was able to reduce the enzymatic activity of pyruvate kinase, an important enzyme for brain energy homeostasis, without affecting the memory of the animals that received a standard diet. However, it failed to improve the cognitive damage caused by a diet high in cholesterol and saturated fats. On the other hand, when simvastatin is "camouflaged" in the lipid-core nanocapsules (HNS3), this cognitive impairment improves. Thus, SV-LNC is a promising alternative therapy for the treatment of cognitive impairment.

Simvastatin nanoliposome induces myocardial and hepatic toxicities due to its absorption enhancement in mice

Nanoliposome is a useful dosage form to increase solubility and absorption of simvastatin (SMV), and consequently improves its therapeutic effects. However, in vivo toxicity of SMV could also be elevated accompanied by the absorption enhancement, which is a decisive factor for the clinical application of SMV nanoliposome (SMV-Lipo), but has not been studied systematically and reported so far. In this study, organ toxicity of SMV-Lipo was evaluated in mice in the presence and absence of isoproterenol and compared to those of free SMV. Results demonstrated that compared to free SMV, the SMV-Lipo administrated at an equal dose of 25 mg/kg/d led to severe myocardiotoxicity, hepatotoxicity at baseline and more pronounced liver injury with elevation of alanine aminotransferase. In addition, muscular adverse effect was also observed in SMV-Lipo treated group but not in SMV group. Pharmacokinetic studies revealed that compared to free SMV, the SMV-Lipo administration significantly improved the plasma SMV concentration, and the oral bioavailability was 6.5 times of free SMV. Notably, when the dosage of free SMV increased to 50 mg/kg/d, yielding the comparable plasma concentration as SMV-Lipo given at 25 mg/kg/d, the myocardiotoxicity was observed in free SMV treated mice as well, which further confirmed that the enhanced absorption of SMV by the nanoliposomal formulation resulted in more severe myocardiotoxicity than the equal dose of free SMV.

Intraluminal Delivery of Simvastatin Attenuates Intimal Hyperplasia After Arterial Injury

Oral statins reduce intimal hyperplasia (IH) after arterial injury by only ∼25%. Alternative drug delivery systems have gained attention as carriers for hydrophobic drugs. We studied the effects of simvastatin (free vs hyaluronic acid-tagged polysialic acid-polycaprolactone micelles) on vascular smooth muscle cell (VSMC) migration, VSMC proliferation and intimal hyperplasia. We hypothesized both free and micelle containing simvastatin would inhibit VSMC chemotaxis and proliferation, and local statin treatment would be more effective than oral in reducing IH in rats following carotid balloon injury. VSMCs pretreated with free simvastatin (20 minutes or 20 hours) or simvastatin-loaded micelles underwent chemotaxis and proliferation to platelet-derived growth factor. Next, rats that underwent balloon injury of the common carotid artery received statin therapy-intraluminal simvastatin-loaded micelles prior to injury, periadventitial pluronic gel following injury, or combinations of gel, micelle, and oral simvastatin. After 14 days, morphometric analysis determined the -intimal to medial ratio. Findings were compared to controls receiving oral simvastatin or no statin therapy. Statistical analysis was by analysis of variance for the in vitro experiments and a factorial general linear model for the in vivo experiments. The simvastatin-loaded micelles and free simvastatin inhibited VSMC chemotaxis (54%-60%). IH was induced in all injured vessels. Simvastatin in pluronic gel or micelles reduced IH compared to untreated controls (0.208 ± 0.04 or 0.160 ± 0.03 vs 0.350 ± 0.03, respectively); however, neither gel nor simvastatin-loaded micelles were superior to oral statins (0.261 ± 0.03). Addition of oral statins or combining both local therapies did not provide additional benefit. Micelles were the single greatest contributing factor in IH attenuation. Intraluminally or topically delivered statins reduced IH. The efficacy of single-dose, locally delivered statin alone may lead to novel treatments to prevent IH. The different routes of administration may allow for treatment during endovascular procedures, without the need for systemic therapy.

Simvastatin nanoparticles attenuated intestinal ischemia/reperfusion injury by downregulating BMP4/COX-2 pathway in rats.

The purpose of the research was to explore the therapeutic action of simvastatin-loaded poly(ethylene glycol)-b-poly(gamma-benzyl l-glutamate) (PEG-b-PBLG50) on intestinal ischemia/reperfusion injury (II/RI) through downregulating bone morphogenetic protein 4 (BMP4)/cyclooxygenase-2 (COX-2) pathway as compared to free simvastatin (Sim). Sprague Dawley rats were preconditioned with 20 mg/kg Sim or simvastatin/PEG-b-PBLG50 (Sim/P) compounds, and then subjected to 45 min of ischemia and 1 h of reperfusion. The blood and small intestines were collected, serum levels of interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-α, and nitric oxide (NO) were checked, and the dry/wet intestine ratios, superoxide dismutase activity, myeloperoxidase content, reactive oxygen species, endothelial nitric oxide synthase, protein 47 kDa phagocyte oxidase (p47phox), BMP4, COX-2, and p38 mitogen-activated protein kinase (p38MAPK) expressions were measured in intestinal tissues. Both Sim and Sim/P pretreatment reduced intestinal oxidative damnification, restricted inflammatory harm, and downregulated the BMP4 and COX-2 expressions as compared to II/RI groups, while Sim/P remarkably improved this effect.

Targeting delivery of simvastatin using ICAM-1 antibody-conjugated nanostructured lipid carriers for acute lung injury therapy

Acute lung injury (ALI) is a critical illness without effective therapeutic modalities currently. Recent studies indicated potential efficacy of statins for ALI, while high-dose statins was suggested to be significant for attenuating inflammation in vivo. Therefore, a lung-targeted drug delivery system (DDS) delivering simvastatin (SV) for ALI therapy was developed, attempting to improve the disease with a decreased dose and minimize potential adverse effects. SV-loaded nanostructured lipid carriers (SV/NLCs) with different size were prepared primarily. With particle size increasing from 143.7 nm to 337.8 nm, SV/NLCs showed increasing drug-encapsulated efficiency from 66.70% to 91.04%. Although larger SV/NLCs exhibited slower in vitro cellular uptake by human vascular endothelial cell line EAhy926 at initial stage, while in vivo distribution demonstrated higher pulmonary accumulation of the larger ones. Thus, the largest size SV/NLCs (337.8 nm) were conjugated with intercellular adhesion molecule 1 (ICAM-1) antibody (anti-ICAM/SV/NLCs) for lung-targeted study. The anti-ICAM/SV/NLCs exhibited ideal lung-targeted characteristic in lipopolysaccharide-induced ALI mice. In vivo i.v. administration of anti-ICAM/SV/NLCs attenuated TNF-α, IL-6 and inflammatory cells infiltration more effectively than free SV or non-targeted SV/NLCs after 48-h administration. Significant histological improvements by anti-ICAM/SV/NLCs were further revealed by H&E stain. Therefore, ICAM-1 antibody-conjugated NLCs may represent a potential lung-targeted DDS contributing to ALI therapy by statins.

The Evaluation of Therapeutic Efficacy and Safety Profile of Simvastatin Prodrug Micelles in a Closed Fracture Mouse Model

To evaluate the therapeutic efficiency of a micellar prodrug formulation of simvastatin (SIM/SIM-mPEG) and explore its safety in a closed femoral fracture mouse model. The amphiphilic macromolecular prodrug of simvastatin (SIM-mPEG) was synthesized and formulated together with free simvastatin into micelles. It was also labeled with a near infrared dye for in vivo imaging purpose. A closed femoral fracture mouse model was established using a three-points bending device. The mice with established closed femoral fractures were treated with SIM/SIM-mPEG micelles, using free simvastatin and saline as controls. The therapeutic efficacy of the micelles was evaluated using a high-resolution micro-CT. Serum biochemistry and histology analyses were performed to explore the potential toxicity of the micelle formulation. Near Infrared Fluorescence (NIRF) imaging confirmed the passive targeting of SIM/SIM-mPEG micelles to the bone lesion of the mice with closed femoral fractures. The micelle was found to promote fracture healing with an excellent safety profile. In addition, the accelerated healing of the femoral fracture also helped to prevent disuse-associated ipsilateral tibia bone loss. SIM/SIM-mPEG micelles were found to be an effective and safe treatment for closed femoral fracture repair in mice. The evidence obtained in this study suggests that it may have the potential to be translated into a novel therapy for clinical management of skeletal fractures and non-union.

Abstract 174: Periadventitial or Intraluminal Delivery of Simvastatin Attenuates Intimal Hyperplasia After Arterial Injury

Introduction: Oral statin administration reduces intimal hyperplasia (IH) after arterial injury by only ~25%. Alternative drug delivery systems have gained attention as carriers for hydrophobic drugs. We studied the effects of simvastatin (free vs hyaluronic acid tagged polysialic acid-polycaprolactone micelles) in vitro on vascular smooth muscle cell (VSMC) migration and in vivo after arterial injury. We hypothesized both free and micelles containing statins would inhibit VSMC chemotaxis and local statin treatment would reduce IH in Sprague-Dawley (SD) rats following carotid balloon injury greater than oral delivery. Methods: VSMCs pretreated with free simvastatin (1 μM, 20 min or 20 hrs) or simvastatin-loaded micelles underwent chemotaxis to thrombospondin-1 (20 μg/mL) or serum-free media using a modified Boyden chamber. Next, SD rats (13-15 wks) who underwent balloon injury of the common carotid artery (5 atm/5 min) received statin therapy – either intraluminal simvastatin loaded micelles (50 μM, pressurized for 5 min) prior to injury or periadventitial pluronic gel (50 μM simvastatin) following injury. Arteries were harvested 14 days postoperatively. Morphometric analysis was performed using the intimal/media area ratio defined as intima/(intima + media). Findings were compared to our historic animals which received oral simvastatin (10 mg/kg/day) or controls without statin therapy. Statistical analysis was by ANOVA and p &lt;0.05 was significant. Results: Simvastatin loaded micelles and free simvastatin inhibited VSMC chemotaxis (54%-60%, p &lt;0.05). IH was induced in all injured vessels. Simvastatin in pluronic gel or micelles reduced IH compared to untreated controls (0.208 ± 0.04 or 0.160 ± 0.03 vs 0.350 ± 0.03, respectively, p &lt;0.05). However, neither gel nor simvastatin-loaded micelles were superior to oral statins (0.261 ± 0.03, p &gt;0.05). Conclusions: Intraluminally and periadventially delivered statins were effective in reducing IH. The efficacy of single dose, locally delivered statins alone may lead to novel treatment modalities for the prevention of IH. The different routes of administration allow for treatment at the time of both open and endovascular procedures, without the need for systemic therapy.

Simvastatin nanolipid carriers decreased hypercholesterolemia induced cholesterol inclusion and phosphatidylserine exposure on human erythrocytes

This study aimed to develop simvastatin (SV) loaded lipid nanocarriers as solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs) and lipid nanoemulsion (LNE) and to estimate their in vitro erythrocyte uptake to reduce the cholesterol level. Therefore, numerous SLNs were prepared using Imwitor 900K, Stearic acid, Softisan 154 and Dynasan 118. For NLC, 30% w/v of Miglyol 812 was added to the previous lipids and LNE consisting 100% w/v of Miglyol 812 was also prepared for comparison. These lipid nanocarriers exhibited spherical-shapes with negative charges and particle size lower than 400nm (PDI<0.3). Moreover, the optimized formulations were LNE (Miglyol 812), NLC (Stearic acid and Miglyol 812) and SLN (Stearic acid), which showed the highest entrapment efficiency and drug release. In addition, the percent of erythrocyte uptake of SV from free SV solution, optimized SLN, NLC and LNE was 28%, 78%, 85% and 72%, respectively. Furthermore, incubation of erythrocytes with cholesterol enriched plasma resulted in a significant increase in the percent of cholesterol inclusion, hemolysis and eryptosis compared to control. In contrast, the incubation of erythrocytes with cholesterol rich plasma in the presence of the optimized nanocarriers resulted in a significant decrease percent of cholesterol inclusion, hemolysis and eryptosis. However, effect of the lipid nanocarriers on the measured parameters was more pronounced than that of the free drug. Thus, these results suggested that the lipid nanocarriers might be a promising nanocarrier for SV to maintain the native erythrocyte function in hypercholesterolemia.

Effects of simvastatin-loaded polymeric micelles on human osteoblast-like MG-63 cells

To develop an optimized simvastatin (SV) delivery device for bone regeneration, SV-loaded poly(ethylene glycol)-poly(ɛ-caprolactone) (PECL) micelles were constructed. The micelles had an average size of 80nm. The in vitro release behavior of SV from the micelles showed prolonged release compared to the free SV. The following four groups were tested in a cytologic experiment: a free SV group, a SV-loaded micelle group with SV concentrations ranging from 2.5×10−6 to 2.5×10−10M, a drug-free micelle group and a blank control group. The effect of SV-loaded micelles on osteoblast-like MG-63 cells was determined via analysis of cell proliferation, alkaline phosphatase activity, and cell calcification. In addition, the mRNA and protein expression of the BMP-2 gene were determined with real-time fluorescence quantitative polymerase chain reaction and western blot techniques, respectively. The results show that SV-loaded PECL micelles cause effective suppression of the osteoblast early proliferation inhibition, stimulation of osteoblast differentiation and mineralization, and stimulation of the BMP-2 expression. Therefore, SV-loaded PECL micelles are predicted to have great potential in bone regeneration applications.