Gastrointestinal therapeutic systems

Grundy, J. S., Foster, R. T., The nifedipine gastrointestinal therapeutic system (GITS) - Evaluation of pharmaceutical, pharmacokinetic and... 

FitzpatrickJM, Desgrandchamps F. The clinical efficacy and tolerability of doxazosin standard and gastrointestinal therapeutic system for benign prostatic hyperplasia. BJUbit. 2005 95 575-579. 

Sastry, S. V., Reddy, I. K., and Khan, M. A. Atenolol gastrointestinal therapeutic system optimization of formulation variables using response surface methodology. J. Contr. Rel. 45(2) 121-130, 1997. 

Anegon M, Esteban J, Jimenez-Garcia R, Sanz de Burgoa V, Martinez J, Gil de Miguel A. A postmarketing, open-label study to evaluate the tolerability and effectiveness of replacing standard-formulation doxazosin with doxazosin in the gastrointestinal therapeutic system formulation in adult patients with hypertension. Clin Ther 2002 24(5) 786-97. 

Kirby RS, Andersen M, Gratzke P, Dahlstrand C, Hoye K. A combined analysis of double-blind trials of the efficacy and tolerability of doxazosin-gastrointestinal therapeutic system, doxazosin standard and placebo in patients with benign prostatic hyperplasia. BJU Int 2001 87 192-200. 

Shapiro M, Jarema MA, Gravina S. Magnetic resonance imaging of an oral gastrointestinal-therapeutic-system (GITS) tablet. J Control Release 1996 38(2-3) 123-127. 

Polonia J, Boaventura I, Gama G, Camoes I, Bernardo F, Andrade P, Nunes JP, Brand o F, Cerqueira-Gomes M. Influence of non-steroidal anti-inflammatory drugs on renal function and 24 h ambulatory blood pressure-reducii effects of enalapril and nifedipine gastrointestinal therapeutic system in hypertensive patients. JHypertens (1995) 13, 925-31. 

Grundy, J., Anderson, K., Rogers, J. and Fosters, R. Studies on dissolution testing of the niefedipine gastrointestinal therapeutic system. 1. Description of a two-phase in vitro dissolution test. /. Control. Release 48 1-8, 1997. 

Asmussen, B., Cremer, K., Hoffman, H., et al. Expandable gastroretentive therapeutic system with controlled active substance release in the gastrointestinal tract, U.S. Patent 6,290,989, 2001. 

There are a number of side-effects of opiates that are due to their actions on opiate receptors outside the central nervous system. Opiates constrict the pupils by acting on the oculomotor nucleus and cause constipation by activating a maintained contraction of the smooth muscle of the gut which reduces motility. This diminished propulsion coupled with opiates reducing secretion in the gut underlie the anti-diarrhoeal effect. Opiates contract sphincters throughout the gastrointestinal tract. Although these effects are predominantly peripheral in origin there are central contributions as well. Morphine can also release histamine from mast cells and this can produce irritation and broncho-spasm in extreme cases. Opiates have minimal cardiovascular effects at therapeutic doses. 

Table 4.2 shows the number of groups within which pharmaceutical presentations are classified at different levels of therapeutic differentiation. The classifications are made up of 15 and 14 main therapeutic chapters in England and Spain respectively. At this level, products are grouped according to their therapeutic effect in terms of the main anatomical systems gastrointestinal system, cardiovascular system, respiratory system and so on. 

Cartwright [124] reported that miconazole was slightly absorbed from epithelial and mucosal surface. The drug is well absorbed from the gastrointestinal tract, but caused nausea and vomiting in some patients. The drug may be given intravenously but was associated phlebitis. Up to 90% of the active compound was bound to plasma protein. Distribution into other body compartments was poor. Metabolism was primarily in the liver, and only metabolites were excreted in the urine. At therapeutic levels, they were relatively nontoxic both locally and systematically, but occasionally produced disturbances on the central nervous system. 

Noninvasive drug delivery may require the administration of the drug delivery system (DDS) at an epithelium as a suitable site of absorption of the active compormd. Such regions are usually called mucosae. In the human body several mucosal sites can be identified, the one mostly used for administration and absorption of therapeutics being the gastrointestinal route. In order to increase the residence time at these absorption sites, a so-called mucoadhesive delivery system has to be used. Generally, these systems consist of one or more types of hydrogels. 

---