The improvement of bioavailability of poorly water-soluble drugs is important for oral administration. Amorphization is one of the techniques that has been commonly used for solubility enhancement.1,2) Amorphous material of drug can be obtained by several methods, e.g., spray-drying, 3) solid dispersion, 4) co-grinding with cyclodextrins 5) or crystalline cellulose, 6) and mixing with porous materials. 7,8) Porous materials have a unique capacity to adsorb organic compounds due to their large specific surface area and porous structure. Activated carbon, porous crystalline cellulose, and zeolites are examples of porous materials that have been used widely for pharmaceuticals. [9][10][11] Folded sheets mesoporous material (FSM-16) has been synthesized by an intercalation of quaternary ammonium surfactant as a template in a layered polysilicate kanemite, followed by calcination.12-16) FSM-16 is composed of hexagonal channels and has extremely large specific surface area and large pore volume. Due to its highly uniform porous structure with hexagonal arrays, FSM-16 is widely used as a reactor for catalytic reaction, as an adsorbent and as a host for the inclusion of large molecules. 17,18) Itoh et al. 19) studied the photostability of chlorophyll a after adsorption into FSM-16. The enhancement of the photostability was attributable to the interactions between chlorophyll and FSM-16 to form chlorophyll-FSM conjugate, and also between two chlorophyll molecules to form a chlorophyll dimer within the pores of FSM-16.In the previous paper, we investigated the use of FSM-16 for pharmaceutical applications. We reported the change in molecular state of salicylamide from crystal to amorphous by adsorption into the FSM-16 channels during sealed-heating process. The amorphization of the drug accordingly resulted in enhanced dissolution of sealed-heated sample. 20) In the present study, three kinds of FSM-16 with different pore diameters [FSM-16(Oc), FSM-16(Do) and FSM-16(Doc)] were employed to investigate the molecular state of the drug and its interaction with FSM-16. Flurbiprofen (FBP), a poorly water-soluble non-steroidal anti-inflammatory drug, was used as a model compound. Changes in the molecular state of FBP were investigated using powder X-ray diffractometry, thermal analysis and FT-IR spectroscopy. The changes in pore diameter and specific surface area of samples prepared by various methods were investigated using small angle X-ray scattering and nitrogen gas adsorption BET method for understanding the effect of adsorption of FBP molecules on pore structure of FSM-16. ExperimentalMaterials Flurbiporfen (FBP) of reagent grade was kindly supplied by Kaken Pharmaceutical, Co. Ltd., Japan, and was used without further purification. Three kinds of mesoporous silica FSM-16, i.e., FSM-16(Oc), FSM-16(Do) and FSM-16(Doc), were kindly supplied by Toyota Central R&D Labs., Inc., Japan. Mean pore width and specific surface area of FSM-16(Oc), FSM-16(Do), FSM-16(Doc) were 16.0, 21.6, 45.0 Å and 700, 1250, 1040 m 2 /g, respectively...
Though advanced composites with embedded actuator materials such as shape memory alloys and piezo ceramics have been developed as active materials, another one by making use of thermal deformation of composites was proposed and an active laminate was prepared as an example by hot-pressing of aluminum plate as material of high coef®cient of thermal expansion (CTE), uni-directional carbon ®ber reinforced plastics (CFRP) prepreg as low CTE material and electric resistance heater, polymer adhesive ®lm as insulator between them, and copper foils as electrodes. Actuation of this laminate is different from that of bimetal because CTE of the CFRP layer is strongly anisotropic due to directionality of its reinforcement ®ber. As CTEs of the CFRP layer and the aluminum plate in the ®ber direction are quite different from each other though they are close to each other in the transverse direction, smooth and uni-directional actuation becomes possible. In this study, its fundamental performances such as shape change and output force were observed and evaluated, and after establishment of its fabrication, an optical loss type sensor was formed in the active composite, by embedding multiply pre-notched optical ®ber in the CFRP layer and breaking it at the pre-notches under bending, followed by lamination on aluminum plate with adhesive. As the sensing part can be formed inside the matrix without any complicated processes, a robust and low cost sensor is obtained. From the results, it becomes clear that: (1) curvature of the active composite linearly changes as a function of temperature between room temperature and its hot pressing temperature by electric resistance heating of the CFRP layer and cooling, (2) its output force against a ®xed punch during heating from room temperature up to around glass transition temperature of the resin phase almost linearly increases with increasing temperature, (3) the multiply pre-notched, embedded and fractured optical ®ber works as a sensitive sensor for monitoring the curvature of the active composite.
This article describes the formation of strain sensors embedded in a matrix material by breaking a notched optical fiber in the matrix. When a specimen with an embedded optical fiber with a notch is tensile tested, fracture of the fiber at the notch occurs, producing an optical interference type strain sensor. During the formation process optical transmission loss is recorded. The case of multiply notched optical fibers is also considered and it is shown that the optical loss of the embedded optical fiber during tensile test increases with the number of breaks. Using bending, instead of tension, to form the sensor, allows a reduction of break pitch and consequently improves the local nature of the sensor. The multiple fractured type optical fiber sensor has also been used on an active laminate to monitor its curvature change during actuation.KEY WORDS: smart material, optical fiber, composite, strain sensor, active material.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.