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Zn/Al layered double hydroxides (LDHs) were intercalated with the anionic antihypertensive drugs Enalpril, Lisinopril, Captopril and Ramipril by using coprecipitation or ion-exchange technique. TG-MS analyses suggested that the thermal stability of Ena{sup -}, Lis{sup -} (arranged with monolayer, resulted from X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) analysis was enhanced much more than Cap{sup -} and Ram{sup -} (arranged with bilayer). The release studies show that the release rate of all samples markedly decreased in both pH 4.25 and 7.45. However, the release time of Ena{sup -}, Lis{sup -} were much longer compared with Cap{sup -}, Ram{sup -} in both pH 4.25 and 7.45, it is possible that the intercalated guests, arranged with monolayer in the interlayer, show lesser repulsive force and strong affinity with the LDH layers. And the release data followed both the Higuchi-square-root law and the first-order equation well. Based on the analysis of batch release, intercalated structural models as well as the TG-DTA results, we conclude that for drug-LDH, stronger the affinity between intercalated anions and the layers is, better the thermal property and the stability to the acid attack of drug-LDH, and the intercalated anions are easier apt to monolayer arrangement within themore » interlayer, were presented. - Graphical abstract: A series of antihypertensive drugs including Enalpril, Lisinopril, Captopril and Ramipril were intercalated into Zn/Al-NO{sub 3}-LDHs successfully by coprecipitation or ion-exchange technique. We focus on the structure, thermal property and low/controlled release property of as-synthesized drug-LDH composite intended for the possibility of applying these LDH-antihypertensive nanohybrids in drug delivery and controlled release systems.« less

An optical fiber transformer as an optical shutter and a light source divider both, a shadowgraphic set as an image system and a polygonal cone as an image divider are employed to form a camera for high speed photography. One end of the fiber transformer is arranged in a row and other end is in a circle, and by means of a small high sensitive optical scanner, a laser beam is swept from one end to the other end of this row and flashed on the circle. A high speed shadowgraphic camera with multi-point light source rounded within 1 0mm in dia. is obtained. The framing rate will be 1 o6 pp or more and the exposure time of each frame will be O.8jts or less if an 1 KHz scanner is used. Sixteen shadowgrams can be obtained at a time. The distance between any two fibers can be adjusted individually to get the records with nonequal time interval to match the event under study. The high speed interferography will be made if the single mode fibers are used. The framing rate can also be increased by use of a faster scanner and a more power laser.