Drug delivery stomach

Macleod et al. [92] have studied the potential of pectin-chitosan-hydroxypropyl methylcellulose films for colonic drug delivery [92]. The results showed that in all cases the tablets were able to pass through the stomach and small intestine intact. The tablets started to break up once they were in the colon, due to degradation of the coat by colonic bacteria. 

Enteric coating materials not only protect a dosage form from the acidic environment in the stomach and allow drug delivery to the small intestine, they may also pass through the... 

We include certain excipients in a formulation specifically because they interact with the physiological fluids and the bodily functions in a certain way. For example, as discussed above, we include disintegrants in immediate release tablet and capsule formulations, because we know that when they encounter the aqueous environment of the stomach, they will cause the tablet or capsule to disintegrate and thereby aid dissolution of the API. Another example is the general case of hydrophilic colloid matrices used as prolonged release drug delivery systems. We know that when these materials contact the aqueous environment of the GIT they swell and create a diffusion barrier that slows the rate of dissolution of the dissolved drug. 

Numerous cases exist in the pharmaceutical field in which pH control of drug delivery may be beneficial. For example, the ability to store a drug molecule in the dry state in a polymer, to be released when the polymer reaches a region in the gastrointestinal tract that is characterized by a certain pH range (acidic in stomach, alkaline in the small intestine) has prompted a number of researchers to study pH-sensitive polymer gels as potential drug carriers for oral delivery [1-4]. 

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