Preparation of nanoparticle and nanoemulsion formulations containing repaglinide and determination of pharmacokinetic parameters in rats.

Repaglinide (RPG) belongs to the class of drugs known as meglitinides and is used for improving and maintaining glycemic control in the treatment of patients with Type 2 diabetes. RPG is a Class II drug (BCS) because of its high permeability and low water solubility. It also undergoes hepatic first-pass metabolism. The oral bioavailability of RPG is low (about 56 %) due to these drawbacks. Our aim in this study is to prepare two different nano-sized drug carrier systems containing RPG (nanoparticle: RPG-PLGA-Zein-NPs or nanoemulsion: RPG-NE) and to carry out a pharmacokinetic study for these formulations. We prepared NPs using PLGA and Zein. In addition, a single NE formulation was developed using Tween 80 and Pluronic F68 as surfactants and Labrasol as co-surfactant. The droplet size values of the blank-NE and RPG-NE formulations were found to be less than 120 nm. The mean particle sizes of blank-Zein-PLGA-NPs and RPG-Zein-PLGA-NPs were less than 260 nm. The Cmax and tmax values of RPG-Zein-PLGA-NPs and RPG-NE (523 ± 65 ng/mL and 770 ± 91 ng/mL; 1.41 ± 0.46 h and 1.61 ± 0.37 h, respectively) were meaningfully higher than those of free RPG (280 ± 33 ng/mL; 0.72 ± 0.28 h) (p < 0.05). The AUC0-∞ values calculated for RPG-Zein-PLGA-NPs and RPG-NE were approximately 4.04 and 5.05 times higher than that calculated for free RPG. These nanosized drug delivery systems were useful in increasing the oral bioavailability of RPG. Moreover, the NE formulation was more effective than the NP formulation in improving the oral bioavailability of RPG (p < 0.05).

Safety Assessment of PEGylated Alkyl Glycerides as Used in Cosmetics.

The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of 60 PEGylated alkyl glycerides. PEGylated alkyl glycerides are mono-, di-, and/or triglycerides that have been modified with ethylene glycol repeat units (in the starting material form as epoxide). Most of the PEGylated alkyl glycerides are reported to function as skin-conditioning agents or surfactants. The Panel reviewed the available animal and clinical data as well as data from the 1999 report for the 5 polyethylene glycol (PEG) glyceryl cocoates and the 2012 report of PEGylated oils, to determine the safety of these ingredients. The Panel concluded these ingredients are safe in the current practices of use and concentration when formulated to be nonirritating; this conclusion supersedes the 1999 conclusion issued on 5 PEG glyceryl cocoate ingredients.

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.

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.

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.

Ellagic Acid Containing Nanostructured Lipid Carriers for Topical Application: A Preliminary Study.

Ellagic acid (EA) is a potent antioxidant substance of natural origin characterized by poor biopharmaceutical properties and low solubility in water that limit its use. The aim of the present study was to develop lipid-based nanoparticle formulations able to encapsulate EA for dermal delivery. The EA-loaded nanoparticles were prepared using two different lipid compositions, namely tristearin/tricaprylin (NLC-EA1) and tristearin/labrasol (NLC-EA2). The influence of formulations on size, entrapment efficiency, and stability of EA-loaded nanoparticles was investigated. Cryo-TEM and small-angle X-ray scattering (SAXS) analyses showed that no morphological differences are evident among all the types of loaded and unloaded nanostructured lipid carriers (NLCs). The macroscopic aspect of both NLC-EA1 and NLC-EA2 did not change with time. No difference in size was appreciable between empty and drug-containing NLC, thus the nanoparticle diameter was not affected by the presence of EA and in general no variations of the diameters occurred during this time. The entrapment efficiency of both EA-loaded nanoparticles was almost quantitative. In addition, NLC-EA1 maintained EA stability for almost two months, while NLC-EA2 up to 40 days. FRAP (Ferric reducing ability of plasma) assay showed an antioxidant activity around 60% for both the loaded NLC, as compared to the solution. Although both types of NLC are characterized by some toxicity on HaCaT cells, NLC-EA1 are less cytotoxic than NLC-EA2. Taken together these results demonstrated that the inclusion of EA within NLC could improve the water solubility, allowing for a reduction of the dosage. Moreover, both types of NLC-EA maintained a high antioxidant effect and low toxicity.

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.

Labrasol® is an efficacious intestinal permeation enhancer across rat intestine: Ex vivo and in vivo rat studies.

Labrasol® ALF (Labrasol®), is a non-ionic surfactant excipient primarily used as a solubilising agent. It was investigated here as an intestinal permeation enhancer in isolated rat colonic mucosae in Ussing chamber and in rat in situ intestinal instillations. Labrasol® comprises mono-, di- and triglycerides and mono- and di- fatty acid esters of polyethylene glycol (PEG)-8 and free PEG-8, with caprylic (C8)- and capric acid (C10) as the main fatty acids. Source components of Labrasol® as well as Labrasol® modified with either C8 or C10 as the sole fatty acid components were also tested to determine which element of Labrasol® was responsible for its permeability-enhancing properties. Labrasol® (4, 8 mg/mL) enhanced the transport of the paracellular markers, [14C] mannitol, FITC-dextran 4000, and FITC-insulin across colonic mucosae. The enhancement was non-damaging, transient, and molecular weight-dependent. The PEG ester fraction of Labrasol® also had enhancing properties. When insulin was administered with Labrasol® in instillations, it had a relative bioavailability of 7% in jejunum and 12% in colon. C8- and C10 versions of Labrasol® and the PEG ester fraction also induced similar bioavailability values in jejunal instillations: 6, 5 and 7% respectively. Inhibition of lipases in instillations did not reduce the efficacy of Labrasol®, suggesting that its mechanism as a PE is not simply due to liberated medium chain fatty acids. Labrasol® acts as an efficacious intestinal permeation enhancer and has potential for use in oral formulations of macromolecules and BCS Class III molecules.

Drug-Lipid-Surfactant Miscibility for the Development of Solid Lipid Nanoparticles.

This research aimed to study the correlation between miscibility of flutamide (FLT), lipids and surfactant on the particle size of solid lipid nanoparticles (SLNs). Physical mixtures (PMs) of lipids-glyceryl monooleate (GMO), Precirol® (glyceryl palmitostearate, PRE), glyceryl monostearate (GMS), and Compritol® (glyceryl dibehenate, COM) were prepared with surfactant-Gelucire® (stearoyl polyoxyl-32 glycerides, GEL) 50/13 and 44/14. PMs were prepared in 5:2 w/w ratio (lipid:surfactant) and 2:1 w/w (Flutamide (FLT):lipids/GEL 50/13) by co-melting. Miscibility of PMs was investigated using modulated differential scanning calorimetry (MDSC). SLNs with and without drug were prepared using GEL 50/13 by the ultra-sonication method and particle size analysis was conducted. PMs of GMO, GMS, and PRE with both surfactants showed a decrease in the melting temperature, no change in melting and crystallization peak was observed with COM-GELs, indicating immiscibility. Similarly, MDSC data suggests good miscibility of FLT in GMO, GMS, and GEL 50/13 but not in PRE and COM. The particle size of drug-loaded SLNs prepared from GMO and GMS with GEL 50/13 was found to be 70.2 ± 5.4 and 92.6 ± 8.5 compared to > 200-nm particles obtained from PRE and COM. On lyophilization, an increase in particles size was observed with COM only. The particle size of SLNs with PRE and COM was prominently increased during stability studies indicating SLNs prepared with GMO and GMS are more stable due to miscibility and ability to reduce the crystallinity of FLT. The results established a good correlation between drug, lipids, and surfactants miscibility to the obtained particle size of SLNs before and after lyophilization. Graphical Abstract ᅟ.

Lyotropic Liquid Crystalline Nanoparticles of Amphotericin B: Implication of Phytantriol and Glyceryl Monooleate on Bioavailability Enhancement.

Implication of different dietary specific lipids such as phytantriol (PT) and glyceryl monooleate (GMO) on enhancing the oral bioavailability of amphotericin B (AmB) was examined. Liquid crystalline nanoparticles (LCNPs) were prepared using hydrotrope method, followed by in vitro characterization, Caco-2 cell monolayer uptake, and in vivo pharmacokinetic and toxicity evaluation. Optimized AmB-LCNPs displayed small particle size (< 210 nm) with a narrow distribution (~ 0.2), sustained drug release and high gastrointestinal stability, and reduced hemolytic toxicity. PLCNPs presented slower release, i.e., ~ 80% as compared to ~ 90% release in case of GLCNPs after 120 h. Significantly higher uptake in Caco-2 monolayer substantiated the role of LCNPs in increasing the intestinal permeability followed by increased drug titer in plasma. Pharmacokinetic studies demonstrated potential of PT in enhancing the bioavailability (approximately sixfold) w.r.t. of its native counterpart with reduced nephrotoxicity as presented by reduced nephrotoxicity biomarkers and histology studies. These studies established usefulness of PLCNPs over GLCNPs and plain drug. It can be concluded that acid-resistant lipid, PT, can be utilized efficiently as an alternate lipid for the preparation of LCNPs to enhance bioavailability and to reduce nephrotoxicity of the drug as compared to other frequently used lipid, i.e., GMO.

Cubic Liquid Crystalline Gels Based on Glycerol Monooleate for Intra-articular Injection.

In situ gels containing sinomenine hydrochloride (SMH) for intra-articular (IA) administration to treat rheumatoid arthritis (RA) were designed and investigated in this study. Glycerol monooleate (GMO) was used due to the potential to generate viscous crystalline phase structures upon water absorption. The gels were evaluated using different parameters: syringeability, gelation, viscosity, and drug release. And, polarized light microscopy (PLM), small-angle X-ray scattering investigation (SAXS), and rheological studies were used to analyze their internal structures. In vitro drug release studies were performed by the dialysis membrane diffusion method. The syringeability, viscosity, gelation time, and water for gelation of the obtained preparation met the requirements of IA injection. PLM, SAXS, and rheological analysis showed that all samples had transformed from flowable isotropic solution phases to the inverse cubic (V2) phases upon excess water. And, the gels were found to be able to maintain the drug release for more than 1 week. Results showed that in situ gels based on GMO liquid crystalline could provide a sustained system for SMH. Due to its sustained release, the in situ cubic gels were suitable for IA injection to treat RA.

Influence of Cubosome Surface Architecture on Its Cellular Uptake Mechanism.

Interaction of nanoparticles with biological systems is a key factor influencing their efficacy as a drug delivery vehicle. The inconsistency in defining the optimal design parameters across different nanoparticle types suggests that information gained from one model system need not apply to other systems. Therefore, selection of a versatile model system is critical for such studies. Cubosomes are one of the potential drug delivery vehicles due to their biocompatibility, stability, ability to carry hydrophobic, hydrophilic, and amphiphilic drugs, and ease of surface modification. Here we report the importance of surface architecture of cubosomes by comparing their cellular uptake mechanism with poly-ε-lysine (PεL)-coated cubosomes. Uncoated cubosomes entered cells by an energy-independent, cholesterol-dependent mechanism, whereas PεL-coated cubosomes relied on energy-dependent mechanisms to enter the endosomes. As endosomal entrapment was evaded by uncoated cubosomes, they can be preferably used for cytosolic delivery of therapeutic agents.

Absorption mechanism of DHP107, an oral paclitaxel formulation that forms a hydrated lipidic sponge phase.

Paclitaxel is a most widely used anticancer drug with low oral bioavailability, thus it is currently administered via intravenous infusion. DHP107 is a lipid-based paclitaxel formulation that can be administered as an oral solution. In this study, we investigated the mechanism of paclitaxel absorption after oral administration of DHP107 in mice and rats by changing the dosing interval, and evaluated the influence of bile excretion. DHP107 was orally administered to mice at various dosing intervals (2, 4, 8, 12, 24 h) to examine how residual DHP107 affected paclitaxel absorption during subsequent administration. Studies with small-angle X-ray diffraction (SAXS) and cryo-transmission electron microscopy (cryo-TEM) showed that DHP107 formed a lipidic sponge phase after hydration. The AUC values after the second dose were smaller than those after the first dose, which was correlated to the induction of expression of P-gp and CYP in the livers and small intestines from 2 h to 7 d after the first dose. The smaller AUC value observed after the second dose was also attributed to the intestinal adhesion of residual formulation. The adhered DHP107 may have been removed by ingested food, thus resulting in a higher AUC. In ex vivo and in vivo mucoadhesion studies, the formulation adhered to the villi for up to 24 h, and the amount of DHP107 that adhered was approximately half that of monoolein. The paclitaxel absorption after administration of DHP107 was not affected by bile in the cholecystectomy mice. The dosing interval and food intake affect the oral absorption of paclitaxel from DHP107, which forms a mucoadhesive sponge phase after hydration. Bile excretion does not affect the absorption of paclitaxel from DHP107 in vivo.

Formulation and Optimization of Candesartan Cilexetil Nano Lipid Carrier: In Vitro and In Vivo Evaluation.

PURPOSE: The objective of this study was to formulate and optimize Candesartan Cilexetil (CC) loaded nanostructured lipid carriers (NLCs) for enhanced oral bioavailability. METHOD: Glycerol monostearate (GMS), Oleic acid, Tween 80 and Span 40 were selected as a solid lipid, liquid lipid, surfactant and co- surfactant, respectively. The CC-NLCs were prepared by hot emulsion probe sonication technique and optimized using experimental design approach. The formulated CC-NLCs were evaluated for various physicochemical parameters and further optimized formulation (CC-NLC-Opt) was assessed for in vivo pharmacokinetic and pharmacodynamic activity. RESULTS: The optimized formulation (CC-NLC-Opt) showed particle size (183.5±5.89nm), PDI (0.228±0.13), zeta potential (-28.2±0.99mV), and entrapment efficiency (88.9±3.69%). The comparative in vitro release study revealed that CC-NLC-Opt showed significantly better (p<0.05) release and enhanced permeation as compared to CC-suspension. The in vivo pharmacokinetic study gave many folds increase in oral bioavailability than CC suspension, which was further confirmed by antihypertensive activity in a murine model. CONCLUSION: Thus, the results of ex vivo permeation, pharmacokinetic study and pharmacodynamics study suggest the potential of CC-NLCs for improved oral delivery.

Evaluation of the versatile character of a nanoemulsion formulation.

The formulate-ability of six model active pharmaceutical ingredients (API), with different physico-chemical profiles, in a nanoemulsion designed to be intraveinously administrable was explored. Nanoemulsions were spontaneously generated at room temperature by pouring a phosphate buffer in an anhydrous mixture containing pharmaceutically acceptable triglycerides and non-ionic surfactants. After determination of the apparent solubility of each API in excipients and characterization of mixtures by DSC, API-loaded nanoemulsions were formulated and characterized in terms of granulometric properties, surface potential, drug recovery efficiency, pH, osmolarity, in vitro drug release, and stability. Except ciprofloxacin, a BCS class IV drug, all studied APIs were soluble in at least one excipient used, i.e. Labrasol. At 2 wt% API, all drug-loaded nanoemulsions present properties compatible with i.v. administration. The formulation should permit to increase apparent solubility of poorly water-soluble APIs, and also to prolong delivery of hydrophobic as well of more hydrophilic compounds. Herein, the relative affinity of the API for nanodroplets and the release medium would directly influence drug release profiles. Nanoemulsions were stable for 7 days. They could also been extemporaneously reconstituted before use. Such a versatile nanoemulsion would provide a valuable option as formulation strategy for improvement of drug properties.

Examining the gastrointestinal transit of lipid-based liquid crystalline systems using whole-animal imaging.

Lipid-based liquid crystalline (LC) systems have the potential to sustain the oral absorption of poorly water-soluble drugs in vivo, facilitating slow drug release from their complex internal structure. To further evaluate the dynamic relationship between gastric retention and sustained drug absorption for these systems, this study aimed to explore non-invasive X-ray micro-CT imaging as an approach to assess gastric retention. Pharmacokinetic studies were also conducted with cinnarizine-loaded LC formulations to correlate gastric retention of the formulation to drug absorption. The in vivo studies demonstrated the interplay between gastric retention and drug absorption based on the digestibility of the LC structures. An increase in non-digestible phytantriol (PHY) composition in the formulation relative to digestible glyceryl monooleate (GMO) increased the gastric retention, with 68 ± 4 % of formulation intensity remaining at 8 h for 85 % w/w PHY, and 26 ± 9 % for 60 % w/w PHY. Interestingly, it was found that PHY 30 % w/w in GMO provided the highest bioavailability for cinnarizine (CZ) amongst the other combinations, including GMO alone. The studies demonstrated that combining digestible and non-digestible lipids into LC systems allowed for an optimal balance between sustaining drug absorption whilst increasing plasma concentration (C max) over time, leading to enhanced oral bioavailability. The results demonstrate the potential for utilising non-invasive X-ray micro-CT imaging to dynamically assess the GI transit of orally administered liquid crystal-forming formulations.

Use of re-esterified palm oils, differing in their acylglycerol structure, in fattening pig diets.

Re-esterified oils are new fat sources obtained from the chemical esterification of acid oils with glycerol (both economically interesting by-products from oil refining and biodiesel industries, respectively). The different fatty acid (FA) positional distribution and acylglycerol composition of re-esterified oils may enhance the apparent absorption of saturated fatty acids (SFA) and, therefore, their overall nutritive value, which might lead to an increased deposition of SFA. The aim of the present study was to investigate the potential use of re-esterified palm oils, in comparison with their corresponding acid and native oils in fattening pig diets, studying their effects on fatty acid apparent absorption, acylglycerol and free fatty acid (FFA) composition of feces, growth performance, carcass-fat depots and fatty acid composition of backfat. Seventy-two crossbred boars and gilts (average weight of 24.7 ± 2.55 kg) were blocked by initial BW (nine blocks of BW for each gender), housed in adjacent individual boxes, and fed one of the four dietary treatments, which were the result of a basal diet supplemented with 4% (as-fed basis) of native palm oil (PN), acid palm oil (PA), re-esterified palm oil low in mono- and diacylglycerols (PEL), or re-esterified palm oil high in mono- and diacylglycerols (PEH). Regarding results from the digestibility balance, PA and PN showed similar apparent absorption coefficients (P>0.05), despite the high, FFA content of the former. However, re-esterified palm oils (both PEL and PEH) showed a higher apparent absorption of total FA than did their corresponding native and acid oils (P0.05). We conclude that re-esterified oils are interesting fat sources to be considered in fattening pigs.

4'-O-methylhonokiol increases levels of 2-arachidonoyl glycerol in mouse brain via selective inhibition of its COX-2-mediated oxygenation.

BACKGROUND AND PURPOSE: 4'-O-methylhonokiol (MH) is a natural product showing anti-inflammatory, anti-osteoclastogenic, and neuroprotective effects. MH was reported to modulate cannabinoid CB2 receptors as an inverse agonist for cAMP production and an agonist for intracellular [Ca2+]. It was recently shown that MH inhibits cAMP formation via CB2 receptors. In this study, the exact modulation of MH on CB2 receptor activity was elucidated and its endocannabinoid substrate-specific inhibition (SSI) of cyclooxygenase-2 (COX-2) and CNS bioavailability are described for the first time. METHODS: CB2 receptor modulation ([35S]GTPγS, cAMP, and ß-arrestin) by MH was measured in hCB2-transfected CHO-K1 cells and native conditions (HL60 cells and mouse spleen). The COX-2 SSI was investigated in RAW264.7 cells and in Swiss albino mice by targeted metabolomics using LC-MS/MS. RESULTS: MH is a CB2 receptor agonist and a potent COX-2 SSI. It induced partial agonism in both the [35S]GTPγS binding and ß-arrestin recruitment assays while being a full agonist in the cAMP pathway. MH selectively inhibited PGE2 glycerol ester formation (over PGE2) in RAW264.7 cells and significantly increased the levels of 2-AG in mouse brain in a dose-dependent manner (3 to 20 mg kg(-1)) without affecting other metabolites. After 7 h from intraperitoneal (i.p.) injection, MH was quantified in significant amounts in the brain (corresponding to 200 to 300 nM). CONCLUSIONS: LC-MS/MS quantification shows that MH is bioavailable to the brain and under condition of inflammation exerts significant indirect effects on 2-AG levels. The biphenyl scaffold might serve as valuable source of dual CB2 receptor modulators and COX-2 SSIs as demonstrated by additional MH analogs that show similar effects. The combination of CB2 agonism and COX-2 SSI offers a yet unexplored polypharmacology with expected synergistic effects in neuroinflammatory diseases, thus providing a rationale for the diverse neuroprotective effects reported for MH in animal models.

Physico-chemical characterisation, cytotoxic activity, and biocompatibility studies of tamoxifen-loaded solid lipid nanoparticles prepared via a temperature-modulated solidification method.

CONTEXT: Solid lipid nanoparticles (SLNs) can efficiently and efficaciously incorporate anti-cancer agents. OBJECTIVE: To prepare and characterise tamoxifen (TAM)-loaded SLNs. MATERIALS AND METHODS: Glyceryl monostearate, Tween-80, and trehalose were used in SLNs. SLNs were tested via dynamic light scattering (DLS), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). RESULTS: Characterisation studies revealed SLNs of about 540 nm with a negative surface charge and confirmed the entrapment of TAM in the SLNs. The entrapment efficiency was estimated to be 60%. DISCUSSION: The in vitro drug release profile demonstrated a gradual increase followed by a release plateau for several days. A drug concentration-dependent increase in cytotoxic activity was observed when the SLNs were evaluated in cell cultures. CONCLUSION: Biocompatible and stable lyophilised SLNs were successfully prepared and found to possess properties that may be utilised in an anti-cancer drug delivery system.

Biological artificial fluid-induced non-lamellar phases in glyceryl monooleate: the kinetics pathway and its digestive process by bile salts.

BACKGROUND: The cubic (Q(II)) phase is a promising sustained-release system. However, its rigid gel-like propensity is highly viscous, which makes it difficult to handle in pharmaceutical applications. To circumvent this problem, a less viscous lamellar (L(α)) phase that could spontaneously transform to Q(II) phase by the introduction of water or biological artificial fluid can be used. However, the kinetics pathway of phase transition, susceptibility to digestive processes and impact of the transition on drug release are not yet well understood. METHOD: We investigated various biological artificial fluid-induced L(α) to inverse Q(II) phase transition over time in glyceryl monooleate (GMO) by water penetration scan and light polarizing microscopy. To reveal the structure stability, fluorescence spectroscopy studies were conducted using pyrene as a probe. Furthermore, the release mechanism of pyrene as a lipophilic drug model in the spontaneously formed Q(II) was investigated. RESULT: Although hexagonal (H(II)) mesophases occurred when phosphate buffered saline (PBS) 7.4, 0.1 M HCl or sodium taurocholate (NaTC) solutions were introduced to GMO at room temperature, they disappear with the exception of 0.1 M HCl at 37 °C. Compared with 25 °C, L(α) to Q(II) phase transition was in a faster rate as almost completely transforms were observed after 2 h post-immersion. The spontaneously formed mesophases were stable over 24 h immersions in PBS or pancreatic lipase solutions as proven by the extremely low fluorescence signal, however they were digestible by bile salts. This result indicated that digestion by bile salts was the major pathway instead of digestion by lipases. Moreover, pyrene fluorescence spectroscopy confirmed that the digestion by bile salts induced the formation of GMO-bile salt mixed micelles whose performance depended on the bile salt concentrations. This dependence influenced the drug release from the spontaneously formed Q(II) phase. CONCLUSION: All the results concluded that temperature, pH and ionic strength tendencies for the formation of non-lamellar structures greatly influenced the self-assembly process, thereby affecting the final mesophase structure. The results of this study are important to understand the lamellar to non-lamellar lipid-phase transitions and their possible pharmaceutical applications.