Preparation and Application of Decanoic Acid/Arginine Hydrogels to a Transdermal Formulation.

We prepared a supramolecular hydrogel composed of decanoic acid and arginine (C10/Arg gel) and evaluated its application to a transdermal formulation. C10/Arg gel adjusted to pH 7 with 1 M NaOH aq or 1 M HCl aq provided a translucent hydrogel with a lamellar liquid crystal structure in the concentration region of decanoic acid ≥12% and arginine ≤9%. Rheological measurements showed that C10/Arg gel is a viscoelastic material with both solid and liquid properties, with elasticity being dominant over viscosity in the low shear stress region.

Influence of Surfactant on the Skin Permeation of Methylisothiazolinone and Methylchloroisothiazolinone.

Patch tests are often used in safety evaluations to identify the substance causing skin irritation, but the same substance can sometimes give positive or negative results depending on the test conditions. Here, we investigated differences in the skin penetration of two test compounds under different application conditions. We studied the effects of the anionic surfactant sodium dodecyl sulfate (SDS) and the nonionic surfactant polysorbate 80 (PS) on skin penetration of the preservatives methylisothiazolinone (MT) and methylchloroisothiazolinone (MCT), which are used in cosmetics such as shampoos.

Rheological Properties and Composition Affecting the Skin Permeation of a Model of a Hydrophilic Drug in Lecithin Reverse Wormlike Micelles.

We investigated the effect of the rheological properties and composition of lecithin reverse wormlike micelles (LRWs) on the skin permeation of a model of a hydrophilic drug to determine whether LRWs support uniform hydrophilic drug/oil-based formulations and good drug penetrate into skin. Here, we prepared LRWs with D (-)-ribose (RI) or glycerol (GL) as polar compounds, liquid paraffin (LP) or isopropyl myristate (IPM) as oils, and 6-carboxyfluorescein (CF) as a model for a hydrophilic drug, and evaluated the rheological properties and skin penetration characteristics of the preparations. The LRWs showed moderate viscosity at 25 °C, a typical storage temperature, but decreasing viscosity at 32 °C, the surface temperature of human skin, suggesting that the LRWs would penetrate the microstructure of skin (e.

Effect of the Physicochemical Properties of Liquid Paraffin on the Phase State and Rheological Properties of Lecithin Reverse Wormlike Micelles.

Lecithin reverse wormlike micelles (LRWs) have been studied recently for dermal application dosage use but the effects of the physicochemical properties of oils on the formation and rheological properties of LRWs have not been investigated. We studied the effect of oil on the formation of LRWs using 5 types of liquid paraffin (LP) with kinematic viscosities ranging from 4.00 to 88.

A Method for Measuring the Surface Free Energy of Topical Semi-solid Dosage Forms.

Our aim was to determine the surface free energy (SFE) of semi-solid dosage forms (SSDFs) by establishing a reproducible method for measuring the contact angle of liquids to SSDFs. Four SSDFs were used: petrolatum, an oil/water (O/W) and a water/oil (W/O) cream, and an alcohol-based gel. The SSDFs were evenly spread on a glass slide, and the change in contact angle over time was measured by dropping water, glycerol, diiodomethane and n-hexadecane as the test liquids.

Characteristics of an Emulsion Obtained Using Hydrophobic Hydroxypropyl Methylcellulose as an Emulsifier and a High-Pressure Homogenizer.

Hydrophobically modified hydroxypropyl methylcellulose (HM-HPMC), a polymer in which a small amount of HPMC is stearoxyl substituted, was used as an emulsifier of emulsion-type lotion. A high-pressure homogenizer (microfluidizer) was used. The viscosity of the 1% HM-HPMC aqueous gel decreased after passing through the microfluidizer from 5.

The Molecular Mechanisms Underlying Prostaglandin D-Induced Neuritogenesis in Motor Neuron-Like NSC-34 Cells.

Prostaglandins are a group of physiologically active lipid compounds derived from arachidonic acid. Our previous study has found that prostaglandin E promotes neurite outgrowth in NSC-34 cells, which are a model for motor neuron development. However, the effects of other prostaglandins on neuronal differentiation are poorly understood.

[Preparation and Rheological Properties of Cross-linked Liposomes Using Hydroxypropylmethylcellulose Bearing a Hydrophobic Anchor].

Hydrophobically-modified hydroxypropylmethylcellulose (HM-HPMC) is a thickener with a long hydrophobic alkyl side chain. In this study, we investigated the gelation ability and rheological properties of a liposome/HM-HPMC mixed solution. The liposome suspension and the HM-HPMC aqueous solution each had low viscosities, but the viscosity increased rapidly when they were mixed.

[Prediction of Wettability and Adhesion of Lotion to Skin Based on the OWRK Method].

In this study, we propose a new technique for evaluating wetting and adhesion of lotions to skin using surface tension measurements, contact angle measurements and calculations based on the Owens-Wendt-Rabel-Kaelble (OWRK) method. Three prescription lotions (Napageln Lotion 3%, Sumilu Lotion 3% and Felbinac Lotion 3% ｢Rakool｣） and two over-the-counter lotions (Feitas Lotion and Salomethyl FB Lotion α) were used. Based on the dispersive and polar components of the surface free energy of Yucatan micro pig (YMP) skin, isograms of contact angle (wetting envelope) and adhesion work of the YMP skin surface were constructed.

[Optimum Volume of Water Needed for the Paste State of Pediatric Powders: Considerations Based on Yield Values and Applications to Generic Medicine].

To clarify the volume of water required to paste pediatric powders, we herein established a standard for the powder paste state by measuring yield values when water was added to powders. The powders used in the present study were selected from 8 types including original and generic drugs. Tipepidine hibenzate is prescribed in the pediatric field in combination with ambroxol hydrochloride and l-carbocysteine.

The Comparison of Surface Free Energy of Human, Yucatan Micropig, and Hairless Mouse Skins and Influence of Surfactant on Surface Free Energy of the Skin.

Surface free energy (SFE) is an important factor for evaluation of wettability or adhesion. Thus, the SFE of a Yucatan micropig (YMP) skin and a hairless mouse (HM) skin, which are commonly used in skin permeation studies instead of human skin, were compared with the human skin. Contact angles of water and 1-bromo naphthalene to skin were measured and the SFE was calculated using the Owens-Wendt equation.

Application of Pickering Emulsion with Cyclodextrin as an Emulsifier to a Transdermal Drug Delivery Vehicle.

The emulsion prepared with β-cyclodextrin as an emulsifier (βCDE) is considered to be a Pickering emulsion. We examined the characteristics of βCDEs using captopril (CP) as a model drug, and studied the in vitro skin permeation of CP from βCDEs through hairless mouse skin. The stability of βCDE was increased with increasing βCD concentration and conversely decreased with increasing CP concentration.

Highly Viscoelastic Reverse Wormlike Micellar Systems from a Mixture of Lecithin, Polyglycerol Fatty Acid Monoesters, and an Oil.

We report new lecithin reverse wormlike micelles with high viscoelasticity formed using lecithin/polyglycerol fatty acid monoester (PGLFA)/oil systems. In this study, the influence of the amphiphilicity (i.e.

Influence of Characteristics of Oily Vehicle on Skin Penetration of Ufenamate.

Skin penetration amounts of a highly lipophilic drug, ufenamate, prepared in four oily vehicles, including white petrolatum (WP), liquid paraffin (LP), isopropyl myristate (IPM), and isocetyl stearate (ICS), were compared. Ufenamate was mixed in each vehicle at 5% and applied at a rate of 2 mg/cm to intact, stripped, and delipidized Yucatan micropig skin. The amounts of ufenamate and IPM in the stratum corneum (SC), epidermis, and dermis were determined.

Skin Permeation of Testosterone from Viscoelastic Lecithin Reverse Wormlike Micellar Solution.

We evaluated testosterone-containing lecithin reverse wormlike micelles (reverse worms) composed of a polar substance/lecithin/isopropyl myristate for transdermal application. Water, D-ribose, or tetraglycerol were used as the polar substance and were key ingredients for forming the reverse worms. Using the reverse worms, 1 wt% of testosterone could be stably solubilized.

Rheological properties of elastomeric impression materials for selective pressure impression technique.

Purpose: The selective impression technique is recommended for removable prosthodontics. However, the viscoelastic rheological properties of impression materials, particularly the time-dependent viscoelastic changes in impression material immediately after tray seating, are unknown. The objective of this study is to clarify the viscoelastic rheological properties of impression materials by focusing on tray seating.

A new reverse worm-like micellar system from a lecithin, multivalent carboxylic acid and oil mixture.

We developed new lecithin organogels composed of reverse worm-like micelles with lecithin/multivalent carboxylic acid/oil systems, and discussed their phase behavior and rheological properties. The most important findings in this study are the following. From a screening test of many carboxylic acids for gelation, it was found that the number and position of the carboxyl groups of the multivalent carboxylic acids are the determinants for the formation of reverse worm-like micelles, and appropriate carboxylic acids such as citric acid and 1,2,3-propanetricarboxylic acid can change the lecithin/oil solution into a gel.

New lecithin organogels from lecithin/polyglycerol/oil systems.

New liquid substances that induce the formation of lecithin organogels composed of reverse worm-like micelles were studied. The phase behavior and rheological properties of lecithin/polyglycerol (PGL)/oil systems were investigated in detail; the polymerization degrees of the glycerol residues were 3, 4, 6, 10, 20, and 40. From the partial phase diagrams of the lecithin/PGL/n-decane systems, it was apparent that highly viscoelastic reverse worm-like micelles formed upon the addition of small amounts of the PGL, except in the case of the PGL with a polymerization degree of 40.

[Adhesion loss of syrups in a metering glass which consists of a low surface free energy material].

We previously reported a strong positive correlation between syrup viscosity and the rate of syrup loss due to adhesion to a glass metering device. In this study, we examined differences in the surface free energies of metering devices made of different polymeric materials, since reducing adhesion loss to metering devices could improve the efficiency of drug preparation involving highly viscous syrups. Among metering devices made of glass only, glass with a silicone coating (SLC), polypropylene (PP), and polymethylpentene (PMP) the surface free energy of the glass-only metering device was the highest (49.

Effects of temperature on the rheological behavior of worm-like micelles in a mixed nonionic surfactant system.

We examined the effects of temperature on the rheological behavior of worm-like micelles in a nonionic surfactant system consisting of polyoxyethylene (10) phytosterol (PhyEO(10))/glyceryl monocaprylate (GFA-C(8))/Water. First, the phase diagram of a PhyEO(10)/GFA-C(8)/Water system was examined when the weight ratio, R, of GFA-C(8) to the total surfactants was changed keeping the total concentration of the surfactants at 5 wt%. The formation of worm-like micelles was confirmed over a wide temperature range.

Preparation and characterization of n-alkane/water emulsion stabilized by cyclodextrin.

Emulsions consisting of n-alkane/water using alpha, beta, and gamma-cyclodextrin (alpha, beta, and gamma-CD) as an emulsifier were prepared and characterized by means of several physicochemical techniques. A phase diagram of the n-alkane/CD/water system showed that an oil in water (O/W) emulsion can be prepared from a mixture of the appropriate composition. The dissolved n-alkane/CD complexes formed at low CD concentrations showed surface-activity, but emulsions could not be prepared from these complexes.

Rheological behavior of worm-like micelles in a mixed nonionic surfactant system of a polyoxyethylene phytosterol and a glycerin fatty acid monoester.

In the present study, we examine a worm-like micelle consisting of a nonionic surfactant system of polyoxyethylene phytosterol (PhyEO(m))/glycerin fatty acid monoester (GFA-C(n))/Water (m=10, 20, 30; n=8, 10, 12) using rheological measurements looking towards potential application of the system as a gel base. Phase diagrams in the dilute region of the PhyEO(m)/GFA-C(n)/Water systems show the formation of worm-like micelles in some of the surfactant combinations. It is thought that the worm-like micelles form with the GFA-C(n) solubilized in the palisade layer of a spherical or rod-like micelle consisting of PhyEO(m), resulting in a decrease in the interfacial curvature of the molecular assembly.

Emulsion preparation using beta-cyclodextrin and its derivatives acting as an emulsifier.

The preparation and formation mechanism of n-hexadecane/water emulsions using natural beta-cyclodextrin (beta-CD) and chemically modified beta-CDs (triacylated beta-cyclodextrins) as an emulsifier were investigated. The stable water/oil (W/O) emulsion was formed using tripropanoyl-beta-CD (TP-beta-CD). From observation using the contact angle (theta(ow)) of precipitates derived from CD, it was clarified that oil/water (O/W) emulsion at theta(ow)<90 degrees and (W/O) emulsion at theta(ow)>90 degrees are formed when the composition of each oil and water was mixed with natural beta-CD or triacylated beta-CDs.

Formation and characterization of emulsions using beta-cyclodextrin as an emulsifier.

The preparation and characterization of n-alkane/water emulsions using beta-cyclodextrin (beta-CD) were studied. The prepared n-alkane/water emulsions were of the oil-in-water (O/W) type, and the stability of emulsions was in the order of n-hexadecane > n-dodecane > n-octane. From observations using polarized light microscopy and powder X-ray diffraction measurement, it was suggested that the formation of a dense film at the oil-water interface and the three-dimensional structural network created by precipitated complexes in the continuous phase are associated with the stability of emulsion.

Study on preparation and formation mechanism of n-alkanol/water emulsion using alpha-cyclodextrin.

Surfactants are usually used for the preparation of emulsions; however, some have an adverse effect on the human body such as skin irritation, hemolysis, and protein denaturation, etc. In this study, we examined the preparation and formation mechanism of n-alkanol/water emulsions using alpha-cyclodextrin (alpha-CD) as an emulsifier. Emulsions were prepared by mixing oil and water phases for 4 min at 2500 rpm using a vortex mixer.