Alginates in Oral Delivery Systems of HPMC

Dennis et al. (2002) filled hard gelatin capsules with a mixture of drugs, alginate, and a pH-independent polymer (HPMC). Upon ingestion, the capsules absorbed gastric fluid, initiating surface hydration of the polymer. The formation of a surface gel layer led to air entrapment, and the capsules began to float. Over time, the gel layer eroded, resulting in the movement of the gel–dissolution interface toward the core of the capsules. Eventually, the device lost its floatability and passed into the intestinal tract, where the alginates dissolved (due to the basic environment in the intestine), making the delivery system more porous and leading to drug release. Alginates have good mucoadhesive properties and have been used with chitosan in various biomedical applications because of this property. Miyazaki et al. developed alginate–chitosan tablets for the sublingual delivery of ketoprofen. Tonnesen and Karlsen reported that alginate microparticles showed strong mucoadhesion toward the stomach mucosa. Coating the particles with chitosan did not change their mucoadhesion property. Such examples demonstrate that alginate-based systems can be developed for drug delivery in the stomach. Mandel et al. reported that alginate-based formulations containing antacids and H2-receptor blockers could treat heartburn and esophagitis as a barrier against acid reflux. Katayama et al. developed a liquid preparation of sodium alginate and ampicillin (an antibiotic) to eradicate Helicobacter pylori. Once ingested, this preparation spreads on the stomach wall releasing the incorporated drug into the mucosa. Finally, sodium alginate has been used to mask the bitter taste of drugs such as amiprilose hydrochloride. If you are looking for high quality, high purity, and cost-effective Hydroxypropyl methylcellulose, or if you require the latest price of Hydroxypropyl methylcellulose, please feel free to email contact mis-asia.