Gel Drug Delivery

Gel Drug delivery soft- and hard-tissue augmentation... 

Photochromism dyes, 226-7 Photocrosslinking, 42-3, 123 Photoelectric conversion efficiency, 310 Photoinduced electricity, 310 Photoresponsive gels, 248 Photosensitive print materials, 386 PHPeEG, 231 Physical stimuli, 369-70 Physical stimuli-responsive gels, drug delivery control, 74-6 Piezochromism, 225 Piezoelectricity, 309-10 Pigment sedimentation, 386 Platinum, 252, 290, 293, 294 PMAA, 242, 243... 

Applications of Small-Molecule Gels - Drug Delivery... 

The potential use of poloxamers in the medical field has been extensively investigated [5,35]. The use of poloxamers in drug delivery, as gels in the controlled release of drugs and in solid form in the targetting of drugs at specific sites in the body, has received significant atten-... 

The performance of this system is shown in Figure 17 for the release of nifedipine from the GITS system [47], The reproducibility of the release rates is remarkable. Also note that the fractions released over time from three separate doses are basically superimposable. It should also be noted that these systems have an inherent delay in the onset of drug delivery which arises from the time required to build up a sufficient hydrostatic pressure to permit release of the gel that is formed within the tablet during delivery. Figure 18 shows the comparison of the in vitro and in vivo cumulative fraction released for the 30 mg system. Clearly, the in vitro performance is mirrored in the in vivo data. 

C-J Kim, PI Lee. Hydrophobic anionic gel beads for swelling-controlled drug delivery. Pharm Res 9 195-201, 1991. 

Semisynthetic gels are also very useful for the creation of drug delivery systems. Cellulose ethers are particularly important in drug delivery. These compounds are made by derivatizing the cellulose hydroxyls with various groups such as hydroxypropyl, methyl, or carboxymethyl. This substitution breaks up the crystallinity of native cellulose and makes it water-soluble [23], The degree... 

DW Woodward, DST Hsieh. Gels for drug delivery. In DST Hsieh, ed. Controlled Release Systems Fabrication Technology, Vol II. Boca Raton, FL CRC Press, 1988, pp 83-110. 

SH Gehrke, JF McBride, SM O Connor, H Zhu, JP Fisher. Gel-coated catheters as drug delivery systems. Polym Mat Sci Eng 76 234-235, 1997. 

RA Siegel. pH sensitive gels—Swelling equilibria, kinetics and applications for drug delivery. In J Kost, ed. Pulsed and Self-Regulated Drug Delivery. Boca Raton, FL CRC Press, 1990, pp 129-157. 

K Sawahata, M Hara, H Yasunaga, Y Osada. Electrically controlled drug delivery system using polyelectrolyte gels. J Controlled Release 14 253-262, 1990. 

Concerning drug delivery, electrically erodible polymer gels for controlled release of drugs have been prepared, and a measured release rate of insulin has been observed under electrical stimulus [69]. A suspension of zinc insulin in a mixed solution of poly(ethyloxazoline) and PMAA was formed into a gel by decreasing the pH of the suspension. The obtained complex gel with 0.5 wt% of insulin was attached to a woven platinum wire cathode which was 1 cm away from the anode and immersed in 0.9% saline solution. When a stepped function of electrical current of 5 mA was applied to the insulin-loaded gel matrix, insulin was released in a stepwise manner up to a release of 70%. The insulin rate measured was 0.10 mg/h. 

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