Slow-release drug products

The main clinical use of COMT inhibitors is as adjunct (or additional adjunct) in the therapy of Parkinson s disease. The standard therapy of Parkinson s disease is oral L-dopa (as a drug levodopa) given with a dopa decarboxylase (DDC) inhibitor (e.g. carbidopa and benserazide), which does not reach the brain. When the peripheral DDC is inhibited, the concentration of 3-O-methyldopa (3-OMD), a product of COMT, in plasma is many times that of L-dopa. Since the half-life of 3-OMD is about 15 h, compared to about 1 h for L-dopa, the concentration of 3-OMD remains particularly high during chronic therapy, especially if new slow release L-dopa preparations are used. A triple therapy (L-dopa plus DDC inhibitor plus COMT-inhibitor) will... 

In recent years, interest in multiple-layered tablets as an oral controlled release system has increased. Multiple-layered tablets have some obvious advantages compared with conventional tablets. In addition to avoiding chemical incompatibibties of formulation components by physical separation, release profiles may be modified by combining layers with different release patterns or by combining slow release with immediate release layers. If the core layer of multilayered tablet is completely covered by a surrounding layer, the product is commonly referred to as a dry-coated tablet. An example is the Smartrix tablet, in which the release profile of a drug is determined by the increase in release surface caused by erosion (dissolution) of the cover layers.39... 

Fig. 1 Inhaled drug in a carrier can exist in the slow clearing pulmonary compartment (Pi) without mucociliary clearance or in the faster clearing pulmonary compartment with mucociliary clearance (P2), tracheobronchial compartment (TB) or gastrointestinal tract (GI). When the drug is released into these compartment (the released drug is represented by italicized letters Pi, P2, TB, GI), it can be absorbed into the bloodstream, or it can be removed by non-productive pathways such as mucociliary clearance represented by the vertical arrows, or chemical and enzymatic decomposition. Large molecules may also enter lymphatics before they appear in the blood stream. (The detailed model was described while the simplified three-compartment model represented by the ellipses is from Refl l)...

In medicine, also, considerable use is being made of ion exchangers, particularly in the production of water to meet the stringent quality specification required for pharmaceutical and cosmetic formulations. The controlled, slow release of drugs and other chemicals into the body has also been made possible by means of these versatile components. 

Slow-release versions of aspirin for long-term use as an anti-inflammatory drug are described in U.S. 5,855,915. Estimate the cost of production of each of the slow-release formulations given. 

This paper has reported only products of the reaction which were Isolated and characterized. However, the potential for further chelation and therefore doubling or trebling the molecular weight to polymer proportions exists. This suggests the possibility of a polymeric drug moiety which would be Inherently slow releasing In vivo. It Is planned to continue this line of research In the future. 

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