An ideal colon specific drug delivery system needs to perform multiple functions like higher bio availability, less toxicity and higher therapeutic effectiveness, all of which require high degree of smartness

An ideal colon specific drug delivery system needs to perform multiple functions like higher bio availability, less toxicity and higher therapeutic effectiveness, all of which require high degree of smartness. particular, due to its high level of sensitivity to the stimuli, this system has been identified as a sensible platform for releasing drug at appropriate site and at appropriate time. Clostridia etc are the different microbial human population in the digestive tract. These microflora perform fermentation by creating enzymes like galactosidase, xylosidase, arabinosidase, glucuronidase dehydroxylase, nitroreductase etc.56 Osmotic controlled medication delivery program To be able to attain systemic absorption from the medication for curing illnesses related to digestive tract, osmotic [controlled] launch oral [delivery] program (OROS-CT) proves to be always a viable technique. The OROS-CT program comprises an individual osmotic device or may consist of as much as 5-6 push-pull devices, that are encapsulated within a difficult gelatin capsule.57 The press draw device contain osmotic press medication and coating coating which form a bilayer. Both the levels are enclosed with a semi permeable membrane which consists of an orifice close to the medication coating. The gelatin capsule including the push-pull devices are dissolved following the administration of OROS-CT orally.58 The current presence of drug-impermeable enteric coating in push-pull unit won’t allow water to get absorbed in acidic nature of abdomen and therefore delivery of medication gets prevented. The current presence of an increased pH (higher than 7) in little intestine causes the layer to dissolve and enables the water to find yourself in the machine.59 Admittance of water qualified prospects to the bloating of osmotic press compartment and creates a flow able gel in the compartment. The medication gel can be pushed from the orifice when the osmotic press area swells up.60 It forces out for a price controlled from the price of drinking water via semi permeable membrane accurately. For the treating ulcerative colitis, the machine can be proposed so in order to avoid the medication delivery in little intestine with a couple of hours of post gastric hold off.61 When OROSCT devices reaches the digestive tract, it initiates the medication Tipelukast Tipelukast release and maintains a regular price for medication release for almost one day in the digestive Tipelukast tract Tipelukast or can focus on medication to get a duration of few hours.62 Using the advancement of technology new program is here which promises to be always a better system for medicines delivery towards the colon. Many evaluation Tipelukast strategies are invented to check the efficiency and sensibility of CDDS.63 pH responsive system The pH of our empty stomach is between 1 and 2 but after the ingestion of food pH starts to rise. The pH of proximal small intestine is 6.5 and in the cecum it is about 6.4 while the transverse colon has a pH of 6.6 and descending colon has a pH of about 7.0.64 Table 2 shows the commonly used pH dependent polymers for various drugs in colon drug delivery.65 MYH9 Eudragit L 100 and Eudragit S 100 are solid white powders with faint characteristic odor and they are chemically anionic copolymers based on methacrylic acid and methyl methacrylate while Eudragit RS 100 is a solid colorless, clear to cloudy granules with faint amine like odor and chemically a copolymer of ethyl acrylate, methyl methacrylate and a low content of methacrylic acid ester with quaternary ammonium groups. Eudragit polymer coating finds application in gene and vaccine delivery, ophthalmic, buccal and sublingual, transdermal, vaginal, intestinal, gastrointestinal and colon drug delivery.66 In colon drug delivery, they played a role in treating ulcerative colitis, Crohns disease and IBD and the drug used for IBD was tegaserod maleate. These pH responsive gels depending on the pH change gets protonated or deprotonated. The swelling behavior of the gel is modified by the protonation and deprotonation which alters the attractive forces between each polymeric chain in the gel.67 Poly(acrylic acid), poly(methacrylic acid) and alginate gel swells the maximum in alkaline pH whereas gels of chitosan, poly(L-lysine), poly (vinyl pyridine), poly(2-diisopropylaminoethyl methacrylate) etc swells in the acidic pH. Repulsive forces are experienced in the neighbouring polymer chains when they are in their charged states. In order to equalize the repulsion, the counter ions enter into the gel matrix from the medium along with water.