A Lipid-Based Depot Formulation with a Novel Non-lamellar Liquid Crystal Forming Lipid.

PURPOSE: Non-lamellar liquid crystal (NLLC)-forming lipids have gained attention as a novel component because of their ability to self-assemble upon contact with body fluids. In this study, a novel NLLC-forming lipid, mono-O-(5, 9, 13-trimethyl-4-tetradecenyl) glycerol ester (C17MGE), and a model drug with a middle molecule weight, leuprolide acetate (LA), were used to confirm the usefulness of C17MGE as an excipient for depot formulations with sustained release properties. METHODS: A self-constructed depot formulation was prepared by mixing C17MGE and different types of phospholipids. The constructed NLLC structure was evaluated using small angle X-ray analysis and cryo-transmission electron microscopy. In vitro release and blood concentration profiles of LA were investigated. RESULTS: The NLLC structure was confirmed by small angle X-ray analysis. LA release was able to be modified by adding different ratios of various phospholipids to C17MGE. Formulations containing 1, 2-dioleoyl-sn-glycero-3-phosphoglycerol sodium salt with a mixing ratio of 12% or 24% (MDOPG12 or MDOPG24, respectively) exhibited sustained release profiles of LA. In addition, the blood concentration of LA was detected over 21 days or more after administration of MDOPG12, and the absolute bioavailability was calculated to be about 100%. CONCLUSIONS: A depot formulation using C17MGE was useful to achieve sustained release of LA.

Enhancement of Skin Permeation of a Hydrophilic Drug from Acryl-Based Pressure-Sensitive Adhesive Tape.

PURPOSE: Penetration enhancers are necessary to overcome a formidable barrier function of the stratum corneum in the development of topical formulations. Recently, non-lamella liquid crystal (NLLC)-forming lipids such as glycerol monooleate and phytantriol (PHY) are gaining increasing attention as a novel skin permeation enhancer. In the present study, fluorescein sodium (FL-Na) was used as a model hydrophilic drug, and acryl-base pressure-sensitive adhesive (PSA) tape containing NLLC forming lipids, mono-O-(5,9,13-trimethyl-4-tetradecenyl) glycerol ester (MGE) or PHY, was prepared to enhance drug permeation through the skin. METHODS: A PSA patch containing FL-Na was prepared by mixing FL-Na entrapped in NLLC and acrylic polymer. FL permeation through excised hairless rat skin, and also human skin, was investigated. Changes in lipid structure, folding/unfolding state of keratin in the stratum corneum, and penetration of MGE into the stratum corneum were investigated using confocal Raman microscopy. RESULTS: Enhanced FL permeation was observed by the application of a PSA patch containing MGE and PHY. Especially, dramatically enhancement effect was confirmed by 15% of MGE contained formulation. Penetration of MGE provided diminished orthorhombic crystal structure and a peak shift of the aliphatic CH3 vibration of keratin chains toward lower wavenumbers. CONCLUSION: The present results suggested that the formulation development by adding MGE may be useful for improving the skin permeation of mal-permeable drugs such as hydrophilic drugs.

Development of Spray Formulations Applied to the Oral Mucosa Using Non-lamellar Liquid Crystal-Forming Lipids.

We examined the physicochemical and biochemical properties of mono-O-(5,9,13-trimethyl-4-tetradecenyl)glycerol ester (MGE), including ease of handling, high bioadhesiveness, quick and stable in vivo self-organization (forming a non-lamellar lyotropic liquid crystal [NLLC]), and high biomembrane permeation enhancement. We prepared MGE oral mucosa-applied spray preparations containing triamcinolone acetonide (TA), which is widely used in the treatment of stomatitis, and we examined the usefulness of the MGE preparations compared with commercially available oral mucosal application preparations containing 2,3-dihydroxypropyl oleate (1-mono(cis-9-octadecenoyl)glycerol (GMO) (previously studied as an NLLC-forming lipid) preparation. As a result, the MGE preparation applied to the oral mucosa can rapidly formed an NLLC with reverse hexagonal or cubic structures, or a mixture, on contact with water. In addition, by adding hydroxypropyl cellulose to the MGE preparation, similar retention properties on the oral mucous membrane were obtained to that using marketed drug preparations. Furthermore, the MGE spray formulation on the oral mucosa showed an equivalent or higher TA release as well as oral mucous membrane permeability compared with commercial formulations. Because MGE forms a stable NLLC and is easy to handle compared with GMO, MGE was considered to be a useful pharmaceutical additive for a spray preparation applied to the oral mucosa in combination.

Enhanced nose-to-brain delivery of tranilast using liquid crystal formulations.

Intranasal administration is poised as a competent method in delivering drugs to the brain, because the nasal route has a direct link with the central nervous system bypassing the formidable blood-brain barrier. C17-monoglycerol ester (MGE) and glyceryl monooleate (GMO) as liquid crystal (LC)-forming lipids possess desirable formulation characteristics as drug carriers for intranasally administered drugs. This study investigated the effect of LC formulations on the pharmacokinetics of tranilast (TL), a lipophilic model drug, and its distribution in the therapeutic target regions of the brain in rats. The anatomical biodistribution of LC formulations was monitored using micro-computed tomography tandem in vivo imaging systems. MGE and GMO effectively formed LC with suitable particle size, zeta potential, and viscosity supporting the delivery of TL to the brain. MGE and GMO LC formulations enhanced brain uptake by 10- to 12-fold and 2- to 2.4- fold, respectively, compared with TL solution. The olfactory bulb had the highest TL concentration and fluorescent signals among all the brain regions, indicating a direct nose-to-brain delivery pathway of LC formulations. LC-forming lipids, MGE and GMO, are potential biomaterials in formulations intended for intranasal administration.

The Anti-atherogenic Activity of Beauveriolide Derivative BVD327, a Sterol O-Acyltransferase 2-Selective Inhibitor, in Apolipoprotein E Knockout Mice.

The fungal 13-membered cyclodepsipeptides, beauveriolides I and III, were previously reported to be atheroprotective activity in mouse models via inhibiting sterol O-acyltransferase (SOAT) activity. A total of 149 beauveriolide derivatives (BVDs) synthesized combinatorially were evaluated in in silico absorption, distribution, metabolism and excretion (ADME) analysis and inhibitory activity toward the two SOAT isozymes, SOAT1 and SOAT2. Hence, only 11 BVDs exhibited SOAT2-selective inhibition. Among these, we chose BVD327, which had the highest ADME score, for further evaluation. BVD327 administration (50 mg/kg/d, per os (p.o.)) significantly decreased atherosclerotic lesions in the aorta and heart (25.4 ± 6.9 and 20.6 ± 2.9%, respectively) in apolipoprotein E knockout (Apoe-/-) mice fed a cholesterol-enriched diet (0.2% cholesterol and 21% fat) for 12 weeks. These findings indicate that beauveriolide derivatives can be used as anti-atherosclerotic agents.

Controlled release of a model hydrophilic high molecular weight compound from injectable non-lamellar liquid crystal formulations containing different types of phospholipids.

Skin offers an easily accessible and convenient site for the administration of drugs. Therefore, the development of injectable formulations with controlled drug release properties are now expected to deliver middle- and large-size biomolecules. In the present study, formulations mainly composed of a novel polyol ester with an isoprenoid side chain; mono-O-(5,9,13-trimethyl-4-tetradecenyl) glycerol ester (MGE), that was capable of forming a non-lamellar liquid crystal (NLLC), were prepared with different types of phospholipid. Then, factors that affected the release of a model entrapped drug, fluorescein-isothiocyanate dextran (FD-4, M.W. 4,000), from the MGE formulations were analyzed with multi-regression analysis. In addition, self-assembly of the NLLC structure was investigated using small-angle X-ray scattering analysis after contacting the MGE formulations with water. NLLC-forming ability of the formulations after s.c. injection into rats was also confirmed using microscopic observations. FD-4 concentrations in blood were determined after s.c. injection of the MGE formulations. The injectable MGE formulations successfully constructed NLLC structures to form a sponge-like gel after contact with water in vitro and in vivo (in rats) as well. In in vitro conditions, the amount of FD-4 released from the formulations was altered by changing the type and concentration of phospholipid in the MGE formulations and can be expressed with parameters such as MGE content and interplanar spacing of the NLLC. A significantly sustained FD-4 level in the blood was observed after s.c. injection of the formulations. These results suggested that injectable MGE formulations may have the potential to achieve controlled release profiles of drugs after s.c. injection.

Antiadhesion effect of the C17 glycerin ester of isoprenoid-type lipid forming a nonlamellar liquid crystal.

Postoperative adhesion is a relevant clinical problem that causes a variety of clinical complications after abdominal surgery. The objective of this study is to develop a liquid-type antiadhesion agent and evaluate its efficacy in preventing tissue adhesion in a rat peritoneal adhesion model. The liquid-type agent was prepared by submicron-sized emulsification of C17 glycerin ester (C17GE), squalene, pluronic F127, ethanol, and water with a high-pressure homogenizer. The primary component was C17GE, which is an amphiphilic lipid of one isoprenoid-type hydrophobic chain and can form two phases of self-assembly nonlamellar liquid crystals. The C17GE agent consisted of nanoparticles with an internal inverted hexagonal phase when evaluated by small-angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (cryo-TEM). Upon contact with the biological tissue, this agent formed a thin membrane with a bioadhesive property. After this agent was applied to a sidewall injury of rats, it showed a percentage average of adhesion significantly less than that obtained with the Seprafilm® antiadhesion membrane in a rat model. Additionally, the retention of the agent prolonged at the applied site in the peritoneal cavity of rats. In conclusion, the C17GE agent is promising as an antiadhesion material. STATEMENT OF SIGNIFICANCE: Postoperative adhesion remains a common adverse effect. Although various materials have been investigated, there are few products commercially available to prevent adhesion. For the sheet-type agent, it is inconvenient to be applied through small laparotomy, especially in laparoscopic surgery. Additionally, the liquid-type agent currently used requires a complicated procedure to spray at the targeted site. Our liquid-type antiadhesion agent can form liquid crystals and act as a thin membrane-like physical barrier between the peritoneum and tissues to prevent adhesion. Indeed, the antiadhesion agent used in our present study significantly prevents adhesion compared with the antiadhesion membrane most used clinically. Moreover, our agent is highly stable by itself and easy to use in laparoscopic surgery, thus leading to a promising new candidate as an antiadhesion material.

Development and Optimization of Orally and Topically Applied Liquid Crystal Drug Formulations.

Liquid crystal (LC)-forming lipids represent an important class of biocompatible amphiphiles and their application extends to cosmeceutical, dietary, and pharmaceutical technologies. In the present study, we aimed to develop strategies for designing and optimizing oral and topical LC formulations by evaluating their in vitro and in vivo drug absorption performances. C17-Monoglycerol ester (MGE) was used as a LC-forming lipid. p-Amino benzoic acid, methyl PABA, ethyl PABA, and sodium fluorescein were selected as drug models with different physiochemical properties. Various oral and topical LC formulations were designed based on changes in the LC forming lipid contents in the formulations and entrapped with different physiochemical properties of the drugs. The LC phase structures were evaluated using small-angle X-ray scattering (SAXS). The drug-release profiles from LC formulations were determined using a dialysis membrane method. In vivo oral absorption of LC formulations was conducted in Wistar rats. Furthermore, the skin penetration of drugs from LC formulations was investigated by in vitro skin permeation studies. As a result, although the release profile was influenced by changes in MGE concentration, it was more dramatically influenced by changes in the physiochemical properties of the entrapped drugs. Drug absorption after oral and topical administration of LC formulations was dramatically affected by the concentration of MGE. The concentration of LC-forming lipid and the physiochemical properties of entrapped drugs are key issues for good performance of the LC formulations in various pharmaceutical applications. The present results could enable researchers to manipulate LC formulation approaches intended to improve the oral absorption and skin permeation of drugs.

PE859, A Novel Curcumin Derivative, Inhibits Amyloid-ß and Tau Aggregation, and Ameliorates Cognitive Dysfunction in Senescence-Accelerated Mouse Prone 8.

Aggregation of amyloid-ß (Aß) and tau plays a crucial role in the onset and progression of Alzheimer's disease (AD). Therefore, the inhibition of Aß and tau aggregation may represent a potential therapeutic target for AD. Herein, we designed and synthesized both Aß and tau dual aggregation inhibitors based on the structure of curcumin and developed the novel curcumin derivative PE859. In this study, we investigated the inhibitory activity of PE859 on Aß aggregationin vitro and the therapeutic effects of PE859 on cognitive dysfunction via dual inhibition of Aß and tau aggregation in vivo. PE859 inhibited Aß aggregation in vitro and protected cultured cells from Aß-induced cytotoxicity. Furthermore, PE859 ameliorated cognitive dysfunction and reduced the amount of aggregated Aß and tau in brains of senescence-accelerated mouse prone 8 (SAMP8). These results warrant consideration of PE859 as a candidate drug for AD.

A Novel Chemical Enhancer Approach for Transdermal Drug Delivery with C17-Monoglycerol Ester Liquid Crystal-forming Lipid.

Transdermal administration of drugs represents an excellent alternative to conventional pharmaceutical dosage forms. However, insufficient penetration of the active pharmaceutical substance through the skin is a common problem. Thus, in the present study we evaluated the skin permeation enhancing ability of liquid crystal (LC) topical formulations. A recently developed LC-forming lipid, C17- monoglycerol ester (MGE), was evaluated and compared with glycerol monoolate (GMO), which is considered as the gold standard for LC formulations. We initially prepared LC formulations containing drugs with different physiochemical properties (tranexamic acid [TXA], 4-methoxy-salicylic acid [4-MS], catechin [CC], and calcein [Cal]), and confirmed the LC phase structures in the prepared formulations using a polarizing light microscope and a small-angle X-ray scattering (SAXS). The physicochemical properties of these formulations were also assessed using a viscometer and a zetasizer. The release rate of the drugs from the LC formulations was determined using a dialysis release method. The skin penetration-enhancing ability of LC formulations was also investigated in an in vitro skin permeation study. The results showed that both MGE- and GMO-LC-forming lipids shared the same behavior in terms of their birefringence indexes, LC phase structures, particle sizes, and zeta potentials. Both the MGE- and GMO-LC formulations managed to improve the skin permeation for various drugs with a range of physiochemical properties. However, MGE formulations showed lower viscosity, faster drug release rate, and better skin penetration-enhancing ability than GMO formulations, strongly suggesting that the low viscosity of MGELC-forming lipids might influence drug diffusivity and permeability through the skin. The present MGELC formulation might be utilized as a promising new topical formulation for therapeutic drugs and cosmetic ingredients.

Design and synthesis of curcumin derivatives as tau and amyloid ß dual aggregation inhibitors.

Alzheimer's disease (AD) is the most common form of dementia. In an AD patient's brain, senile plaques and neurofibrillary tangles, the abnormal aggregates of amyloid ß (Aß) peptide and tau protein, are observed as the two major hallmarks of this disease. To develop a new drug for treatment of AD, we have designed and synthesized a series of curcumin derivatives and evaluated their inhibitory activities against both tau and Aß aggregation. In this study, we describe the development of the more potent aggregation inhibitor 3-[(1E)-2-(1H-indol-6-yl)ethenyl]-5-[(1E)-2-[2-methoxy-4-(2-pyridylmethoxy) phenyl] ethenyl]-1H-pyrazole (compound 4, PE859). This compound has a better pharmacokinetic profile and pharmacological efficacy in vivo than curcumin, making it suitable as a drug for AD.

PE859, a novel tau aggregation inhibitor, reduces aggregated tau and prevents onset and progression of neural dysfunction in vivo.

In tauopathies, a neural microtubule-associated protein tau (MAPT) is abnormally aggregated and forms neurofibrillary tangle. Therefore, inhibition of the tau aggregation is one of the key approaches for the treatment of these diseases. Here, we have identified a novel tau aggregation inhibitor, PE859. An oral administration of PE859 resulted in the significant reduction of sarkosyl-insoluble aggregated tau along with the prevention of onset and progression of the motor dysfunction in JNPL3 P301L-mutated human tau transgenic mice. These results suggest that PE859 is useful for the treatment of tauopathies.

Design, synthesis, evaluation and QSAR analysis of N(1)-substituted norcymserine derivatives as selective butyrylcholinesterase inhibitors.

We synthesized a series of N(1)-substituted norcymserine derivatives 7a-p and evaluated their anti-cholinesterase activities. In vitro evaluation showed that the pyridinylethyl derivatives 7m-o and the piperidinylethyl derivative 7p improved the anti-butyrylcholinesterase activity by approximately threefold compared to N(1)-phenethylnorcymserine (PEC, 2). A quantitative structure-activity relationship (QSAR) study indicated that logS might be a key feature of the improved compounds.

Design, synthesis and evaluation of carbamate-modified (-)-N(1)-phenethylnorphysostigmine derivatives as selective butyrylcholinesterase inhibitors.

We synthesized carbamate-modified (-)-N(1)-phenethylnorphysostigmine derivatives 3a-u and evaluated their anti-cholinesterase activities. In vitro evaluation showed that cyclohexylmethylcarbamate derivative 3u potently and selectively inhibits butyrylcholinesterase.