The endocannabinoid 2-arachidonoylglycerol and dual ABHD6/MAGL enzyme inhibitors display neuroprotective and anti-inflammatory actions in the in vivo retinal model of AMPA excitotoxicity.

The endocannabinoid system has been shown to be a putative therapeutic target for retinal disease. Here, we aimed to investigate the ability of the endocannabinoid 2-arachidonoylglycerol (2-AG) and novel inhibitors of its metabolic enzymes, α/ß-hydrolase domain-containing 6 (ABHD6) and monoacylglycerol lipase (MAGL), a) to protect the retina against excitotoxicity and b) the mechanisms involved in the neuroprotection. Sprague-Dawley rats, wild type and Akt2-/- C57BL/6 mice were intravitreally administered with phosphate-buffered saline or (RS)-α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid hydrobromide (AMPA). 2-AG was intravitreally co-administered with AMPA in the absence and presence of AM251 or AM630 (cannabinoid 1 and 2 receptor antagonists, respectively) or Wortmannin [Phosphoinositide 3-Kinase (PI3K)/Akt inhibitor]. Inhibitors of ABHD6 and dual ABHD6/MAGL (AM12100 and AM11920, respectively) were co-administered with AMPA intravitreally in rats. Immunohistochemistry was performed using antibodies raised against retinal neuronal markers (bNOS), microglia (Iba1) and macroglia (GFAP). TUNEL assay and real-time PCR were also employed. The CB2 receptor was expressed in rat retina (approx. 62% of CB1 expression). 2-AG attenuated the AMPA-induced increase in TUNEL+ cells. 2-AG activation of both CB1 and CB2 receptors and the PI3K/Akt downstream signaling pathway, as substantiated by the use of Akt2-/- mice, afforded neuroprotection against AMPA excitotoxicity. AM12100 and AM11920 attenuated the AMPA-induced glia activation and produced a dose-dependent partial neuroprotection, with the dual inhibitor AM11920 being more efficacious. These results show that 2-AG has the pharmacological profile of a putative therapeutic for retinal diseases characterized by neurodegeneration and neuroinflammation, when administered exogenously or by the inhibition of its metabolic enzymes.

Microemulsion systems to enhance the transdermal permeation of ivermectin in dogs: A preliminary in vitro study.

This study aims to evaluate the influence of the phase behavior of microemulsions in the transdermal administration ("spot-on") of ivermectin, an antiparasitic drug widely used in the treatment of endoparasites and ectoparasites in dogs. In this regard, pseudoternary phase diagrams composed of water (aqueous phase), isopropyl myristate (oil phase), tween 80 (surfactant) and labrasol (cosurfactant) were obtained in a different surfactant: cosurfactant (S:CS) ratios. S:CS in 1:3 ratio presented a larger region of microemulsion formation and three microemulsions were selected from it and characterized. Subsequently, in vitro permeation and retention studies were conducted using canine skin as membrane. SAXS, rheology and conductivity data were employed to confirm the phase behavior of the microemulsions (w/o, bicontinuous or o/w). The cutaneous permeation and retention tests showed that the w/o microemulsion, followed by bicontinuous microemulsion, resulted in a higher amount of drug permeated through canine skin, suggesting better transdermal permeation. On the other hand, o/w microemulsion resulted in a higher amount of drug accumulated into the skin, suggesting better topical activity. Thus, it can be concluded that phase behavior of microemulsions influenced the drug permeation in the canine skin differently from other animal models. Microemulsions, especially w/o and bicontinuous, can be promising vehicles regarding the transdermal delivery of ivermectin.

Peripheral deficiency and antiallodynic effects of 2-arachidonoyl glycerol in a mouse model of paclitaxel-induced neuropathic pain.

BACKGROUND: Modulation of the endocannabinoid system has been shown to alleviate neuropathic pain. The aim of this study was to evaluate if treatment with paclitaxel, a chemotherapeutic agent that induces neuropathic pain, affects endocannabinoid levels at a time when mice develop paclitaxel-induced mechanical allodynia. We also evaluated the peripheral antiallodynic activity of the endocannabinoid 2-arachidonoyl glycerol (2-AG) and an inhibitor of monoacylglycerol lipase (MAGL), an enzyme responsible for 2-AG hydrolysis. METHODS: Female BALB/c mice were treated intraperitoneally with paclitaxel to induce mechanical allodynia. Levels of the endocannabinoids, N-arachidonoylethanolamine (anandamide, AEA), 2-AG, and the N-acylethanolamines (NAEs), N-palmitoylethanolamide (PEA) and N-oleoylethanolamide (OEA), which are structurally-related to AEA, in the brain, spinal cord and paw skin were measured using LC-MS/MS. Protein expression of MAGL in the paw skin was measured using Wes™. The effects of subcutaneous (s.c.) injection of 2-AG and JZL184 (a MAGL inhibitor) into the right hind paw of mice with paclitaxel-induced mechanical allodynia were assessed using the dynamic plantar aesthesiometer. The effects of pretreatment, s.c., into the right hind paw, with cannabinoid type 1 (CB1) receptor antagonist AM251 and CB2 receptor antagonist AM630 on the antiallodynic effects of 2-AG were also evaluated. RESULTS: The levels of 2-AG were reduced only in the paw skin of paclitaxel-treated mice, whilst the levels of AEA, PEA and OEA were not significantly altered. There was no change in the expression of MAGL in the paw skin. Administration of 2-AG and JZL184 produced antiallodynic effects against paclitaxel-induced mechanical allodynia in the injected right paw, but did not affect the uninjected left paw. The antiallodynic activity of 2-AG was antagonized by both AM251 and AM630. CONCLUSION: These results indicate that during paclitaxel-induced mechanical allodynia there is a deficiency of 2-AG in the periphery, but not in the CNS. Increasing 2-AG in the paw by local administration of 2-AG or a MAGL inhibitor, alleviates mechanical allodynia in a CB1 and CB2 receptor-dependent manner.

Development and skin penetration pathway evaluation of microemulsions for enhancing the dermal delivery of celecoxib.

This study aimed to develop a microemulsion using PEG-6 Caprylic/Capric Glycerides as a surfactant to enhance the dermal delivery of celecoxib. Confocal laser scanning microscopy (CLSM) using the colocalization technique was also used to investigate the skin penetration pathway of the microemulsion. The prepared microemulsion formulations were characterized in terms of size, surface charge, size distribution and type. The celecoxib-loaded microemulsion had particle sizes ranging from 48 to 214 nm with neutral charge and significantly increased the skin penetration of celecoxib. According to the CLSM study, the microemulsion might attach to any part of the skin before releasing the entrapped drug to penetrate the tissue. The transfollicular pathway might be the major skin penetration pathway for the microemulsion, whereas the intercellular and transcellular pathways are minor ones.

Enhancing the oral bioavailability of simvastatin with silica-lipid hybrid particles: The effect of supersaturation and silica geometry.

Silica-lipid hybrid (SLH) microparticles are a solidified lipid-based drug delivery system under investigation for their aptitude to enhance the oral bioavailability of poorly water-soluble drugs. The cholesterol-lowering agent, simvastatin (SIM), is poorly water-soluble and undergoes extensive first pass metabolism, resulting in a low oral bioavailability of approximately 5%. Hence, the current pre-clinical studies investigated the application of SLH technology to SIM with a supersaturation approach, aiming to enhance bioavailability and drug loading capacity. Additionally, the effect of silica was explored by evaluating the performance of SLH fabricated with silica of different particle geometries. SLH microparticles with supersaturated SIM loading levels ranging from 100% to 400% above the equilibrium solubility were successfully fabricated using either Aerosil® 300 or Syloid® 244 silica. All SLH formulations existed as white free-flowing powders, consisting of spherical porous microparticles for Aerosil® 300, and aggregated irregular microparticles for Syloid® 244. During in vitro dissolution in pH 7.0 media, the SLH formulations performed up to 4.4-fold greater than pure SIM powder. Furthermore, in vivo oral pharmacokinetics in male Sprague-Dawley rats revealed that the SLH formulations enhanced the oral bioavailability of SIM up to 6.1-fold and 2.9-fold, in comparison to pure SIM powder and a commercially available formulation (Simvastatin Sandoz®), respectively. The greatest in vivo performance enhancement was observed for the SLH formulation manufactured with Syloid® 244 silica with a supersaturation level of 200%. SLH technology demonstrated to be a successful formulation strategy to significantly improve the oral bioavailability of SIM in rodents and therefore, has a strong potential to also improve the oral bioavailability of SIM in humans.

Development of tamoxifen-loaded surface-modified nanostructured lipid carrier using experimental design: in vitro and ex vivo characterisation.

The present study aimed to develop a surface-modified biocompatible nanostructured lipid carrier (NLCs) system using polyoxyethylene (40) stearate (POE-40-S) to improve the oral bioavailability of poorly water-soluble Biopharmaceutics Classification System class-II drug like tamoxifen (TMX). Also aimed to screen the most influential factors affecting the particle size (PS) using Taguchi (L12 (211)) orthogonal array design (TgL12OA). Then, to optimize the TMX loaded POE-40-S (P) surface-modified NLCs (TMX-loaded-PEG-40-S coated NLC (PNLCs) or PNLCs) by central composite design (CCD) using a four-factor, five-level model. The most influential factors affecting the PS was screened and optimized. The in-vitro study showed that increased drug-loading (DL) and encapsulation efficiency (EE), decreased PS and charge, sustained drug release for the prolonged period of the time with good stability and suppressed protein adsorption. The Ex-vivo study showed that decreased mucous binding with five-fold enhanced permeability of PNLC formulation after surface modification with POE-40-S. The in-vitro cytotoxicity study showed that the blank carrier is biocompatible and cytotoxicity of the formulation was dependent on the concentration of the drug. Finally, it can be concluded that the surface-modified PNLCs formulation was an effective, biocompatible, stable formulation in the enhancement of dissolution rate, solubility, stability with reduced mucus adhesion and increased permeability thereby which indicates its enhanced oral bioavailability.

Improved Oral Pharmacokinetics of Pentoxifylline with Palm Oil and Capmul® MCM Containing Self-Nano-Emulsifying Drug Delivery System.

Pentoxifylline (PTX), an anti-hemorrhage drug used in the treatment of intermittent claudication, is extensively metabolized by the liver resulting in a reduction of the therapeutic levels within a short duration of time. Self-nano-emulsifying drug delivery system (SNEDDS) is well reported to enhance the bio-absorption of drugs by forming nano-sized globules upon contact with the biological fluids after oral administration. The present study aimed to formulate, characterize, and improve the oral bioavailability of PTX using SNEDDS. The formulated SNEDDS consisted of palm oil, Capmul® MCM, and Tween® 80 as oil, surfactant, and co-surfactant, respectively. The mixture design module under the umbrella of the design of experiments was used for the optimization of SNEDDS. The dynamic light-scattering technique was used to confirm the formation of nanoemulsion based on the globule size, in addition to the turbidity measurements. In vivo bioavailability studies were carried out on male Wistar rats. The pharmacokinetic parameters upon oral administration were calculated using the GastroPlus software. The optimized SNEDDS had a mean globule size of 165 nm with minimal turbidity in an aqueous medium. Bioavailability of PTX increased 1.5-folds (AUC = 1013.30 ng h/mL) as SNEDDS than the pure drug with an AUC of 673.10 ng h/mL. In conclusion, SNEDDS was seen to enhance the bioavailability of PTX and can be explored to effectively control the incidents of intermittent claudication.

Preparation, Physicochemical Characterisation and DoE Optimisation of a Spray-Dried Dry Emulsion Platform for Delivery of a Poorly Soluble Drug, Simvastatin.

In the presented study, insight into the development and optimisation of the dry emulsion formulation and spray drying process is provided. The aim was to facilitate the dissolution of the poorly soluble, highly lipophilic drug, simvastatin, by forming spray-dried dry emulsion particles having adequate powder flow properties, while assuring sufficient drug content. Simvastatin and a mixture of caprylic, capric triglyceride and 1-oleoyl-rac-glycerol were employed as a model drug and solubilising oils, respectively. A matrix of the dry emulsions was composed at a fixed ratio mixture of mannitol and HPMC. Tween 20 was used in low amounts as the primary emulsion stabiliser. To facilitate process optimisation, a DoE surface response design was used to study the influence of formulation and process parameters on the particle size distribution, powder bulk properties, emulsion reconstitution ability, drug stability and process yield of spray-dried products. Two-fluid nozzle geometry was identified, studied and confirmed to be important for most product critical quality attributes. Models obtained after the study showed acceptable coefficients of determination and provided good insight in the relationship governing the process and product characteristics. Five model optimised products showed adequate process yield, suitable particle size distribution, good reconstitution ability and improved dissolution profile, when compared to a non-lipid-based tablet and the pure drug. However, the obtained dry emulsion powders exhibited poor flow character according to the Carr index. The optimised product was further analysed with NMR during lipolysis to gain insight into the species formed during digestion and the kinetics of their formation.

Trilactic glyceride regulates lipid metabolism and improves gut function in piglets.

Glycerol-lactate esters are energy supplements for exercise, but effects of trilactic glyceride (TLG) on intestinal function and hepatic metabolism are unknown. We found that dietary supplementation with 0.5% TLG to weanling piglets decreased plasma concentrations of low-density lipoprotein and gamma-glutamyl transferase but increased those of D-xylose and high-density lipoprotein. TLG supplementation enhanced mRNA levels for fatty acid synthase (FASN) and SLC27A2 in white adipose tissue; insulin receptor in duodenum; aquaporin-8 in ileum, jejunum and colon; aquaporin-10 in duodenum and ileum; nuclear factor like-2 in jejunum and colon; glutathione S-transferase and phosphoenolpyruvate carboxykinase-1 in intestines; and abundances of claudin-1 and occludin proteins. TLG supplementation decreased mRNA levels for: hepatic hormone-sensitive lipase E, lipoprotein lipase, FASN, insulin-like growth factor-binding protein-3, and SLC27A2; and intestinal lipoprotein lipase, FASN and NADPH oxidase. Furthermore, TLG supplementation enhanced abundances of genus Bifidobacterium, while reducing abundances of family Enterobacteriaceae in ileum, colon and cecum; jejunal caspase-3 protein and diarrhea rate. In conclusion, dietary supplementation with TLG modulated lipid metabolism and alleviated diarrhea by improving intestinal function and regulating intestinal microflora in piglets.

Novel Phospholipid-Based Labrasol Nanomicelles Loaded Flavonoids for Oral Delivery with Enhanced Penetration and Anti-Brain Tumor Efficiency.

BACKGROUND: Owing to the rich anticancer properties of flavonoids, there is a need for their incorporation into drug delivery vehicles like nanomicelles for safe delivery of the drug into the brain tumor microenvironment. OBJECTIVE: This study, therefore, aimed to prepare the phospholipid-based Labrasol/Pluronic F68 modified nano micelles loaded with flavonoids (Nano-flavonoids) for the delivery of the drug to the target brain tumor. METHODS: Myricetin, quercetin and fisetin were selected as the initial drugs to evaluate the biodistribution and acute toxicity of the drug delivery vehicles in rats with implanted C6 glioma tumors after oral administration, while the uptake, retention, release in human intestinal Caco-2 cells and the effect on the brain endothelial barrier were investigated in Human Brain Microvascular Endothelial Cells (HBMECs). RESULTS: The results demonstrated that nano-flavonoids loaded with myricetin showed more evenly distributed targeting tissues and enhanced anti-tumor efficiency in vivo without significant cytotoxicity to Caco-2 cells and alteration in the Trans Epithelial Electric Resistance (TEER). There was no pathological evidence of renal, hepatic or other organs dysfunction after the administration of nanoflavonoids, which showed no significant influence on cytotoxicity to Caco-2 cells. CONCLUSION: In conclusion, Labrasol/F68-NMs loaded with MYR and quercetin could enhance antiglioma effect in vitro and in vivo, which may be better tools for medical therapy, while the pharmacokinetics and pharmacodynamics of nano-flavonoids may ensure optimal therapeutic benefits.

Transcutaneous Cancer Vaccine Using a Reverse Micellar Antigen Carrier.

Skin dendritic cells (DCs) such as Langerhans cells and dermal dendritic cells have a pivotal role in inducing antigen-specific immunity; therefore, transcutaneous cancer vaccines are a promising strategy to prophylactically prevent the onset of a variety of diseases, including cancers. The largest obstacle to delivering antigen to these skin DC subsets is the barrier function of the stratum corneum. Although reverse micellar carriers are commonly used to enhance skin permeability to hydrophilic drugs, the transcutaneous delivery of antigen, proteins, or peptides has not been achieved to date because of the large molecular weight of drugs. To achieve effective antigen delivery to skin DCs, we developed a novel strategy using a surfactant as a skin permeation enhancer in a reverse micellar carrier. In this study, glyceryl monooleate (MO) was chosen as a skin permeation enhancer, and the MO-based reverse micellar carrier enabled the successful delivery of antigen to Langerhans cells and dermal dendritic cells. Moreover, transcutaneous vaccination with the MO-based reverse micellar carrier significantly inhibited tumor growth, indicating that it is a promising vaccine platform against tumors.

Efficacy of a mixture of neem seed oil (Azadirachta indica) and coconut oil (Cocos nucifera) for topical treatment of tungiasis. A randomized controlled, proof-of-principle study.

BACKGROUND: Tungiasis is a neglected tropical skin disease caused by the female sand flea (Tunga penetrans), which burrows into the skin causing intense pain, itching and debilitation. People in endemic countries do not have access to an effective and safe home treatment. The aim of this study was to determine the efficacy of a traditionally used and readily available mixture of neem and coconut oil for treatment of tungiasis in coastal Kenya. METHODOLOGY: Ninety-six children aged 6-14 years with at least one embedded viable flea were randomized to be treated with either a mixture of 20% neem (Azadirachta indica) seed oil in coconut oil (NC), or with a 0.05% potassium permanganate (KMnO4) foot bath. Up to two viable fleas were selected for each participant and monitored for 6 days after first treatment using a digital microscope for signs of viability and abnormal development. Acute pathology was assessed on all areas of the feet using a previously established score. Children reported pain levels and itching on a visual scale. RESULTS: The NC was not more effective in killing embedded sand fleas within 7 days than the current standard with KMnO4, killing on average 40% of the embedded sand fleas six days after the initial treatment. However, the NC was superior with respect to the secondary outcomes of abnormal development and reduced pathology. There was a higher odds that fleas rapidly aged in response to NC compared to KMnO4 (OR 3.4, 95% CI: 1.22-9.49, p = 0.019). NC also reduced acute pathology (p<0.005), and there was a higher odds of children being pain free (OR 3.5, p = 0.001) when treated with NC. CONCLUSIONS: Whilst NC did not kill more fleas than KMnO4 within 7 days, secondary outcomes were better and suggest that a higher impact might have been observed at a longer observation period. Further trials are warranted to assess optimal mixtures and dosages. TRIAL REGISTRATION: The study was approved by the Kenya Medical Research Institute (KEMRI) Scientific and Ethical Review Unit (SERU), Nairobi (Non-SSC Protocol No. 514, 1st April 2016) and approved by and registered with the Pharmacy and Poisons Board's Expert Committee on Clinical Trials PPB/ECCT/16/05/03/2016(94), the authority mandated, by Cap 244 Laws of Kenya, to regulate clinical trials in the country. The trial was also registered with the Pan African Clinical Trial Registry (PACTR201901905832601).

Beta-carotene-Encapsulated Solid Lipid Nanoparticles (BC-SLNs) as Promising Vehicle for Cancer: an Investigative Assessment.

Beta-carotene (BC), a red-colored pigment found in plants and animals, is one of the most extensively investigated carotenoids due to its provitamin-A, antioxidant, and anticancer properties. The anticancer activity of BC through oral administration is severely affected due to its low bioavailability and oxidative degradation. The present study aimed to formulate and characterize solid lipid nanoparticles (SLNs) of BC for enhanced bioavailability and therapeutic efficacy. Beta-carotene-loaded solid lipid nanoparticles (BC-SLNs) were prepared employing different combinations of glyceryl monostearate and gelucire. The characterization studies were performed for particle size, morphology, release behavior, and stability. BC-SLNs were also studied for in vitro cytotoxicity in human breast cancer cell lines (MCF-7) and pharmacokinetic studies in Wistar rats. The cytotoxicity studies confirmed that encapsulation of BC within the lipid bilayers of nanoparticles did not affect its anticancer efficacy. An improved anticancer activity was observed in BC-SLNs as compared to the free BC. BC-SLNs enhanced the bioavailability of BC on oral administration by sustaining its release from the lipid core and prolongation of circulation time in the body. Similarly, area under the curve (AUCtotal) enhanced 1.92-times more when BC was incorporated into SLNs as compared to free BC. In conclusion, solid lipid nanoparticles could be an effective and promising strategy to improve the biopharmaceutical properties of carotenoids for anticancer effects.

2-Arachidonoylglycerol mobilizes myeloid cells and worsens heart function after acute myocardial infarction.

AIMS: Myocardial infarction (MI) leads to an enhanced release of endocannabinoids and a massive accumulation of neutrophils and monocytes within the ischaemic myocardium. These myeloid cells originate from haematopoietic precursors in the bone marrow and are rapidly mobilized in response to MI. We aimed to determine whether endocannabinoid signalling is involved in myeloid cell mobilization and cardiac recruitment after ischaemia onset. METHODS AND RESULTS: Intravenous administration of endocannabinoid 2-arachidonoylglycerol (2-AG) into wild type (WT) C57BL6 mice induced a rapid increase of blood neutrophil and monocyte counts as measured by flow cytometry. This effect was blunted when using cannabinoid receptor 2 knockout mice. In response to MI induced in WT mice, the lipidomic analysis revealed significantly elevated plasma and cardiac levels of the endocannabinoid 2-AG 24 h after infarction, but no changes in anandamide, palmitoylethanolamide, and oleoylethanolamide. This was a consequence of an increased expression of 2-AG synthesizing enzyme diacylglycerol lipase and a decrease of metabolizing enzyme monoacylglycerol lipase (MAGL) in infarcted hearts, as determined by quantitative RT-PCR analysis. The opposite mRNA expression pattern was observed in bone marrow. Pharmacological blockade of MAGL with JZL184 and thus increased systemic 2-AG levels in WT mice subjected to MI resulted in elevated cardiac CXCL1, CXCL2, and MMP9 protein levels as well as higher cardiac neutrophil and monocyte counts 24 h after infarction compared with vehicle-treated mice. Increased post-MI inflammation in these mice led to an increased infarct size, an impaired ventricular scar formation assessed by histology and a worsened cardiac function in echocardiography evaluations up to 21 days. Likewise, JZL184-administration in a myocardial ischaemia-reperfusion model increased cardiac myeloid cell recruitment and resulted in a larger fibrotic scar size. CONCLUSION: These findings suggest that changes in endocannabinoid gradients due to altered tissue levels contribute to myeloid cell recruitment from the bone marrow to the infarcted heart, with crucial consequences on cardiac healing and function.

Skin Targeting of Oxiconazole Nitrate Loaded Nanostructured Lipid- Carrier Gel for Fungal Infections.

BACKGROUND: The progression of fungal infections can be rapid and serious due to compromising with immune function. They may cause liver damage, affect estrogen levels or may cause allergic reactions. Oxiconazole nitrate (OXZN) is a broad spectrum commonly used antifungal drug. It acts by erogosterol biosynthesis inhibition, which causes lysis of the fungal cell membrane because of changes in both membrane integrity and fluidity and direct membrane damage of fungal cells. However, its poor water solubility and short half-life (3-5 h) limit its applications. OBJECTIVE: This study aimed to develop and evaluate OXZN-loaded nanostructured lipid carrier (NLC) to improve its solubility and prolong its release for the treatment of fungal infection via topical administration. METHOD: OXZN-NLC was prepared by ultrasonication method using 32 full factorial design. Glyceryl monostearate (GMS) (X1) and oleic acid (X2) were used as independent variables and particle size and percentage entrapment efficiency (% EE) as dependent variables. The OXZN-NLCs were characterized for particle size, particle morphology and entrapment efficiency. RESULTS: The mean diameter of optimized OXZN-NLCs was found to be 124 ± 2 nm. Spherical shape and size were confirmed using scanning electron microscopy (SEM). Skin deposition study showed about 82.74% deposition as compared with the marketed formulation that showed 68.42% deposition. The developed NLCs show a sustained release pattern and high drug disposition in the infected area. CONCLUSION: OXZN-NLC could be a potential alternative for the treatment of topical fungal infection after clinical evaluation in near future.

Dermal peptide delivery using enhancer molecules and colloidal carrier systems. Part III: Tetrapeptide GEKG.

Dermal application of peptides as drugs is an interesting and growing field in therapeutics. Besides therapy, they are increasingly used as cosmetic agents. Peptide delivery into the skin is highly challenging since they provide disadvantageous properties like a high molecular weight, hydrophilicity, polarity and susceptibility to enzymatic degradation. The aim of the presented study was to improve the bioavailability of a dermal administered tetrapeptide GEKG (amino acid sequence in one-letter notation). A nano-sized carrier system (microemulsion, ME) of w/o type was therefore developed since ME provide excellent penetration enhancing properties. Furthermore, enhancers were used to increase the penetration capacity of GEKG. The penetration of GEKG from the ME and enhancer-containing emulsions was compared to the penetration from a standard formulation. For this purpose ex vivo penetration studies with human skin were performed, which provide insights into dermal penetration and also localization and distribution of the active substances in each skin layer as well as the influence of vehicle variations. Experiments with three incubation times (30, 100, 300 min) and 5000 ppm GEKG in the formulations clearly show that the nano-sized carrier system is significantly better suited to transport GEKG rapidly into upper and deeper vital skin layers as well as through the skin compared to the standard cream. Studies with o/w emulsions containing 5% glyceryl caprylate/caprate 2.0× or 1.5× as enhancer and 50 ppm peptide revealed only a tendency to increased penetration into the SC and for the formulation with glyceryl caprylate/caprate 1.5× into the vital epidermis compared to the standard cream without additional enhancer. Significant better penetration rates were observed for the ME with 50 ppm GEKG. It can be concluded that liquid nano-sized systems are significantly more effective as carriers for extremely hydrophilic peptides used in cosmetics and also in therapeutics than classic cosmetic emulsions or enhancer-containing emulsions. CHEMICAL COMPOUNDS: Tetrapeptide-21 (CAS: 960608-17-7) glyceryl caprylate/caprate (CAS: 73398-61-5) sorbitan oleate (CAS: 1338-43-8) polyglyceryl-4 laurate (CAS: 75798-42-4) butylene glycol (CAS: 107-88-0) isopropyl palmitate (CAS: 142-91-6).

Labrasol-Enriched Nanoliposomal Formulation: Novel Approach to Improve Oral Absorption of Water-Insoluble Drug, Carvedilol.

The purpose of the current study was to develop a novel liposomal formulation to improve the oral bioavailability of carvedilol, a Biopharmaceutics Classification System class II with poor aqueous solubility and extensive presystemic metabolism. Conventional and various surfactant-enriched carvedilol-loaded liposomes were prepared by thin film hydration technique and physicochemical properties of liposomes (including size, encapsulation efficiency, release behavior, and morphology) were evaluated. To assess the oral bioavailability, in vivo studies were carried out in eight groups of male Wistar rats (n = 6) and the drug plasma concentration was determined. Conventional and surfactant containing liposomes showed average particle size of 76-104 nm with a narrow size distribution, high encapsulation efficiency (80%≤) and a sustained release profile in simulated intestinal fluid. Compared to the suspension, conventional and Labrasol containing liposomes significantly improved the oral bioavailability and peak plasma concentration of carvedilol. Biocompatibility studies (cell cytotoxicity and histopathological analyses) showed that the enhancing effect might be achieved without any apparent toxicity in the intestine. Decreased oral absorption of carvedilol nanovesicles by using a chylomicron flow blocker indicated contribution of lymphatic transport in nanocapsules absorption. The results reported the successful development of biocompatible Labrasol-enriched carvedilol nanoliposomal formulation with a significant oral enhancement capability. Graphical Abstract ᅟ.

Preparation of emulsifying wax/glyceryl monooleate nanoparticles and evaluation as a delivery system for repurposing simvastatin in bone regeneration.

Simvastatin (Sim) is a widely known drug in the treatment of hyperlipidemia, which has attracted so much attention in bone regeneration due to its potential osteoanabolic effect. However, repurposing of Sim in bone regeneration will require suitable delivery systems that can negate undesirable off-target/side effects. In this study, we have investigated a new lipid nanoparticle (NP) platform that was fabricated using a binary blend of emulsifying wax (Ewax) and glyceryl monooleate (GMO). Using the binary matrix materials, NPs loaded with Sim (0-500 µg/mL) were prepared and showed an average particle size of about 150 nm. NP size stability was dependent on Sim concentration loaded in NPs. The suitability of NPs prepared with the binary matrix materials in Sim delivery for potential application in bone regeneration was supported by biocompatibility in pre-osteoclastic and pre-osteoblastic cells. Additional data demonstrated that biofunctional Sim was released from NPs that facilitated differentiation of osteoblasts (cells that form bones) while inhibiting differentiation of osteoclasts (cells that resorb bones). The overall work demonstrated the preparation of NPs from Ewax/GMO blends and characterization to ascertain potential suitability in Sim delivery for bone regeneration. Additional studies on osteoblast and osteoclast functions are warranted to fully evaluate the efficacy of Sim-loaded Ewax/GMO NPs using in-vitro and in-vivo approaches.

Vitamin E TPGS Emulsified Vinorelbine Bitartrate Loaded Solid Lipid Nanoparticles (SLN): Formulation Development, Optimization and In vitro Characterization.

BACKGROUND: Vinorelbine bitartrate (VRL), a semi synthetic vinca alkaloid approved for breast cancer, has been proven to be beneficial as first line and subsequent therapies. However, its hydrophilic and thermo labile nature provides hindrance to oral clinical translation. OBJECTIVES: The current work focused on the application of DOE a modern statistical optimization tool for the development and optimization of a solid lipid nanoparticle (SLN) formulation that can encapsulate hydrophilic and thermolabile Vinorelbine bitartrate (VRL) to a maximum extent without compromising integrity and anticancer activity of the drug. METHODS: SLNs were prepared by solvent diffusion technique employing Taguchi orthogonal array design with optimized formulation and process variables. The emulsifying nature and low melting point of glyceryl mono-oleate (GMO) were exploited to enhance entrapment and minimizing temperature associated degradation, respectively. Moreover, two types of surfactants, Vitamin E TPGS (TPGS) and Poloxamer-188 were utilized to obtain TPGS-VRL-SLNs and PL-VRL-SLNs, respectively. The SLNs were characterized for various physicochemical properties, in-vitro drug release kinetics and anticancer activity by MTT assay on MCF-7 cancer cell lines. RESULTS: The SLNs were found to be spherical in shape with entrapment efficiency (EE) up to 58 %. Invitro release studies showed biphasic release pattern following Korsemeyer peppas model with fickian release kinetics. Results of MTT assay revealed that TPGS-VRL-SLNs and PL-VRL-SLNs were 39.5 and 18.5 fold more effective, respectively, compared to the pristine VRL. CONCLUSION: DOE approach was successfully applied for the development of VRL-SLNs. Enhanced entrapment and anticancer efficacy of TPGS-VRL-SLN can be attributed to emulsifying nature of GMO and inherent cytotoxic nature of TPGS, respectively, which synergizes with VRL. Therefore, TPGS associated SLNs may be potential carrier in cancer chemotherapeutics.