Drug release insulin

A pH-sensitive gel, poly(AAc), was used as a coating on capsules containing insulin and surfactant. The capsules protected against insulin release in the upper gastrointestinal tract. As the pH increased to 7.5, drug release increased... 

Trenktrog, T., et al. 1996. Enteric coated insulin pellets-development, drug release and in vivo evaluation. Eur J Pharm Sci 4 323. 

In an effort to develop an effective bioadhesive system for buccal administration, insulin was encapsulated into polyacrylamide nanoparticles by the emulsion solvent evaporation method [98]. Though nanoparticle formation ensures even distribution of the drug, pelleting of the nanoparticles was performed to obtain three-dimensional structural conformity. In addition, it was hypothetized that the pelletized particles will remain adhered to the mucosa, leading to good absorption. While studying bioadhesion and drug release profiles, it was found that the... 

A sustained drug release is favourable for drugs with short elimination half-life. It can be controlled by hydration and diffusion mechanisms or ionic interactions between the drug and the polymeric carrier. In the case of diffusion control the stability of the carrier system is essential, as its disintegration leads to a burst release. Therefore, the cohesiveness of the polymer network plays a crucial role in order to control the release over several hours. Due to the formation of disulphide bonds within the network thiomers offer adequate cohesive stability. Almost zero-order release kinetics could be shown for insulin embedded in thiolated polycarbophil matrices (Clausen and Bernkop-Schnurch 2001). In the case of peptide and protein drugs release can be controlled via ionic interactions. An anionic or cationic polymer has to be chosen depending... 

Bio-responsive release the system modulates drug release in response to a biological stimulus (e.g. blood glucose levels triggering the release of insulin from a dmg delivery device). 

Miyazaki S, Yokouchi C, and Takada M. External control of drug release Controlled release of insulin from a hydrophilic pol3nner implant by ultrasound irradiation in diabetic rats. J. Pharm. Pharmacol. 1988 40 716-717. 

The release of a number of drugs from polyanhydride matrices has been studied including ciprofloxacin, p-nitroaniline, cortisone acetate, insulin, and a variety of proteins. ° In many instances, drug release was reported to coincide with polymer degradation. The biocompatibility of polyanhydrides has... 

Various lipids including triglycerides (e.g., trilaurin, trimyristin, tripalmitin and tristearin) and fatty acids were evaluated as carrier materials in sustained-release insulin implants. The drug/wax powder blend was compressed into a disc and implanted subcutaneously into Wistar rats. Monoglycerides tested eroded too fast and were not suitable. The triglycerides only sustained-the insulin release briefly. The best sustained-release properties were obtained with palmitic and stearic acids as the carrier materials. 

Fig. 15. Hypothetical model of how initiators and modulators that affect insulin release may reach A-, B- and D-cells. The first target of arterial blood containing nutrients, hormones, peptides and drugs is the B-cell. From there, via an intraislet portal vein system, blood which now also contains released insulin flows to the mantle where A- and D-cells are localized and from there enters the circulation. Nerves derived from the autonomous nervous system which contain neurotransmitters (acetylcholine, noradrenaline) and neuropeptides (including vasoactive intestinal peptide (VIP), gastrin-releasing peptide (GRP), galanin) are connected to islet cells. Glucagon (A-cells) and somatostatin (D-cells) reach other endocrine cells in the islet in a paracrine manner. The B-cell may also be the target of previously released insulin via a short loop.

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