Tomonobu Uchino

Transdermal delivery of flurbiprofen from surfactant-based vesicles: Particle characterization and the effect of water on in vitro transport

Flurbiprofen loaded rigid and elastic vesicles comprising the bilayer-forming surfactant sucrose-ester laurate were prepared by the film rehydration and extrusion method. The charge-inducing agent sodium dodecyl sulfate, and the micelle-forming surfactants, sorbitan monolaurate, polyethylene glycol monolaurate, and polysorbate 20, were used to enhance elasticity. Vesicle formulations were evaluated for size, zeta potential, (1)H and (19)F nuclear magnetic resonance (NMR) spectra, and in vitro skin permeation across Yucatan micropig (YMP) skin. Vesicle formulations were stable for 2 weeks and their mean sizes were 95-135 nm. NMR spectroscopy showed that flurbiprofen molecular mobility was restricted by interaction with vesicle components because of entrapment in vesicle bilayers. Moreover, sorbitan monolaurate-containing vesicles strongly retained flurbiprofen molecules. After non-occlusive application to YMP skin, flurbiprofen transport from all vesicle formulations was superior to that of flurbiprofen alone and remarkably decreased after water vaporization. Polarization microscopy and small-angle X-ray diffraction analysis showed that the vesicle formulation was transferred to liquid crystalline state. Suppression of vesicle transition to the liquid crystalline state was observed with applications of both large quantities and diluted samples. The presence of water in the formulations was associated with maintenance of the vesicle structure and greater flurbiprofen transport across YMP skin.

Glyceryl Monooleyl Ether-Based Liquid Crystalline Nanoparticles as a Transdermal Delivery System of Flurbiprofen: Characterization and in Vitro Transport

Liquid crystalline nanoparticles (LCNs) were prepared using glyceryl monooleyl ether (GME) by the modified film rehydration method. Hydrogenated lecithin (HL), 1,3-butylene glycol (1,3-BG), and Poloxamer 407 were used as additives. The prepared LCN formulations were evaluated based on particle size, small-angle X-ray diffraction (SAXS) analysis, (1)H- and (19)F-NMR spectra, and in vitro skin permeation across Yucatan micropig skin. The composition (weight percent) of the LCN formulations were GME-HL-1,3-BG (4 : 1 : 15), 4% GME-based LCN and GME-HL-1,3-BG (8 : 1 : 15), 8% GME-based LCN and their mean particle sizes were 130-175 nm. Flurbiprofen 5 and 10 mg was loaded into 4% GME-based LCN and 8% GME-based LCN systems, respectively. The results of SAXS and NMR suggested that both flurbiprofen-loaded formulations consist of particles with reverse type hexagonal phase (formation of hexosome) and flurbiprofen molecules were localized in the lipid domain through interaction of flurbiprofen with the lipid components. Flurbiprofen transport from the LCN systems across the Yucatan micropig skin was increased compared to flurbiprofen in citric buffer (pH=3.0). The 8% GME-based LCN systems was superior to the 4% GME-based LCN for flurbiprofen transport. Since the internal hexagonal phase in the 8% GME-based LCN systems had a higher degree of order compared to the 4% GME-based LCN in SAXS patterns, the 8% GME-based LCN system had a larger surface area, which might influence flurbiprofen permeation. These results indicated that the GME-based LCN system is effective in improving the skin permeation of flurbiprofen across the skin.

Modulation mechanism of the stratum corneum structure during permeation of surfactant-based rigid and elastic vesicles

We evaluated the interaction between human stratum corneum (SC) and surfactant-based rigid or elastic vesicles during permeation using synchrotron X-ray diffraction to obtain the mechanism action of surfactant-based vesicles for enhanced skin permeation. The effects of vesicle elasticity on the interaction with SC were also investigated. Changes in the small-angle X-ray diffraction peaks of the human SC after buffer control and vesicle application were monitored. In the small-angle region, the control as the citrate buffer induced no significant changes of diffraction peaks for the lamellar structure of short periodicity phase (SPP), which is observed as a main peak in the human SC. Application of rigid vesicles resulted in small changes in the diffraction peaks attributed to lamellar phase of SPP. After application of elastic vesicles, however, a large shift to smaller angles due to swelling of the lamellar phase of SPP was clearly observed from the intensity difference profiles. All peaks due to the vesicles were still observed after 2h of application for all formulations, indicating that both vesicles interacted with the SC while maintaining their structures. These results strongly suggest that vesicles affect the lamellar phase of SPP of the intercellular lipids in the SC during permeation.

Dry Powder Coating using Planetary Centrifugal Mixer

PURPOSE Extemporaneous compounding is an important part of pharmacy practice, and should be standardized and sophisticated to ensure the quality of the compounded preparations. Recently, we applied a planetary centrifugal mixer (PCM) to powder blending, which has attracted interest for its small scale and lack of contamination. In this study, we aimed to reveal the feasibility of dry powder coating through ordered mixing of fine particles using PCM. METHODS Cohesive lactose powders (Pharmatose450M) were dry coated with magnesium stearate (MgSt) using from 0.1 to 5%(w/w) content. The operational variables tested were operation time (1-30 min), operation speed (400-1000 rpm), vessel size (24-100 mL), and charging rate in the vessel (20-40%). The processed powders were evaluated for their surface morphology, flowability, and wettability. Furthermore, fine ibuprofen particles were coated with various lubricants, and then the dissolution profiles were examined. The crystallinity of ibuprofen was assessed using FT-IR and PXRD. RESULTS Lactose powders were successfully coated with MgSt using PCM. When the level of MgSt was over 1%, the surface of the lactose powders was thoroughly covered. Angles of repose were 51° and 41° for unprocessed and processed powders with 1% MgSt, respectively. The contact angle of the water drop on the 1% MgSt sample leached to be 132°, changing to a hydrophobic surface. Investigations under various operational conditions revealed that higher improvement was observed upon higher speed and longer time, and a smaller charging rate in the vessel. Vessel size had no impact. Moreover, improved dissolution of ibuprofen coated with both hydrophilic and hydrophobic lubricants was observed owing to good dispersing behavior. Besides, no alteration of crystallinity was detected. CONCLUSIONS PCM is an effective tool for dry powder coating with low impact stress. The presented method will contribute a great deal to making crushed tablets a functional powder.

Reconstitution of L-Asparaginase in Siliconized Syringes with Shaking and Headspace Air Induces Protein Aggregation.

The aim of this study was to characterize protein aggregation during reconstitution of a highly concentrated solution of lyophilized L-asparaginase (L-ASP). The effect of the preparation method on L-ASP aggregation using siliconized or non-siliconized syringes and the effect of storage after preparation were evaluated by far-UV circular dichroism spectroscopy, Raman microscopy, flow cytometry, and flow particle image analysis. To investigate the effect of syringe type in combination with shaking and headspace air on L-ASP aggregation, four kinds of L-ASP in 5% glucose solutions were prepared (in the presence or absence of silicon oil and headspace air). Slight differences in L-ASP secondary structure were observed between the siliconized and non-siliconized syringe systems before shaking. Large numbers of sub-visible (0.1-100 µm) and submicron (0.1-1 µm) particles were formed by preparation with siliconized syringes and the combination of shaking and headspace air. The number of aggregated particles was not decreased with increased storage time. The Raman microscopy, flow cytometry and flow particle image results suggested that L-ASP interacted with silicone oil, which induced aggregation. Nevertheless, sub-visible and submicron particles were also formed with non-siliconized syringes. However, using non-siliconized syringes, the number of aggregated particles decreased with storage. No changes in particle character were observed before or after shaking with headspace air in non-siliconized syringes, indicating that soluble aggregates formed and dissolved with storage. Silicone oil in syringes, in combination with shaking and headspace air, strongly affected the aggregation of lyophilized L-ASP formulations during preparation.

Characterization and Evaluation of Skin Permeation of Tocopheryl Phosphoric Acid-loaded Phospholipid Nanoparticles

Tocopheryl phosphoric acid (TPA, a hydrophilic vitamin E derivative) loaded liposome and glycerin containing phospholipid nanoparticles (GPLNP) were prepared using the film rehydration and extrusion method. Nanoparticle formulations were evaluated for size, zeta potential, and in vitro permeation across hairless mouse skin, and 31P NMR spectral analysis was performed. The prepared formulations were stable for 2 weeks, and their mean nanoparticle size varied between 90 and 140 nm. Although glycerin did not affect the particle size of the empty (no TPA) system, TPA-loading resulted in the reduction of particle size and conferred a negative charge. The 31P NMR spectral analysis showed that the presence of glycerin in the formulation changed the nanoparticle structure from a bilayer to a nonbilayer. Moreover, it was suggested that TPA molecules interacted with phospholipid by entrapping nanoparticles in the formulations. TPA did not permeate across the hairless mouse skin after 48 h. However, the TPA concentration in the hairless mouse skin after permeation study increased in the nanoparticle systems and the 30% GPLNP formulation was the best formulation for the accelerated TPA permeation in the hairless mouse skin. These results demonstrate that 30% GPLNP improved TPA permeation in the hairless mouse skin model. And it was strongly suggested that glycerin has an important role for changing the structure of nanoparticles and enhancing the skin permeation of TPA.

Immunogenicity of protein aggregates of a monoclonal antibody generated by forced shaking stress with siliconized and nonsiliconized syringes in BALB/c mice

In this study, we aimed to investigate the immunogenicity of protein aggregates of monoclonal antibodies (mAbs), generated by forced shaking stress with siliconized and nonsiliconized syringes in a mouse model.

Influence of molecular weight and structure on diffusion rates and mechanisms of dextran polyelectrolyte complexes

The release profiles of fluorescein isothiocyanate-dextran (FD) at various molecular weights (20-500kDa) and the swelling behaviors of polyelectrolyte complex-forming tablets were investigated. Four types of tablets were prepared using different combinations of the following chemicals: carboxymethyl dextran (CMD), dextran sulfate (DS), 2-diethylaminoethyl dextran (EA), and 2-hydroxypropyltrimethylammonium dextran (CDC). Release tests were conducted via the rotating basket method at pH 6.8. Swelling behaviors were analyzed via the front movement method. For all FDs, release rates decreased with decreasing density of charged groups in the matrix, as follows: CMD-EA, CMD-CDC, DS-EA, and DS-CDC. Front movement profiles showed that the dried core disappeared within 3h, leaving the swollen matrix. Results revealed that the tablets rapidly formed hydrated matrices, with release of the incorporated FDs by diffusion and erosion. The tablets successfully released the macromolecules, and we determined that the release rates could be controlled with a combination of dextran derivatives.

Evaluation of the molecular lipid organization in millimeter-sized stratum corneum by synchrotron X-ray diffraction

The aim of this study was to investigate whether the lamellar and lateral structure of intercellular lipid of stratum corneum (SC) can be evaluated from millimeter‐sized SC (MSC) by X‐ray diffraction.

Development of phospholipid nanoparticles encapsulating 3-O-cetyl ascorbic acid and tocopherol acetate (TA-Cassome) for improving their skin accumulation

ABSTRACT Phospholipid nanoparticles (PNs) encapsulating vitamin C and E derivatives, 3‐O‐cetyl ascorbic acid (CA) and tocopherol acetate (TA), respectively, were examined using the film rehydration and extrusion method. PN formulations (TA‐Cassome) were prepared by mixing CA, soya phosphatidylcholine (Soya PC), sodium cholate, and TA at a molar ratio of 20/80/5/6. Glycerol (GL) or diglycerol (DG) were also added to improve the skin accumulation of CA and TA. Three TA‐Cassome formulations were evaluated using a dynamic light scattering (DLS), NMR, TEM, skin accumulation test for CA and TA, and small‐angle X‐ray diffraction (SAXD) analysis. TA‐Cassome formulations (150nm) were stable for two weeks and they encapsulated 1.8mg/mL of TA. TEM and SAXD analysis revealed that the nanoparticles formed a spherical multilayer structure. 1H and 31P NMR indicated that GL and DG enhanced the proton mobility of choline groups of soya PC molecules located on the membrane surface of TA‐Cassome. Accumulation of CA and TA in the dermis was increased by adding GL and DG. SAXD analysis revealed that GL and DG promoted the formation of new lamellar structures on the stratum corneum, which contributed to improving the skin accumulation of CA and TA.