Oral drug delivery dissolution-controlled release

The size of the microparticles that can be controlled by the concentration of the dope solution, flow rate and applied voltage, are in the range of 100-300 ym. The sweUing and dissolution of the sericin microparticles are suppressed at pH 2.2 and increased at pH 7.4, indicating their potential in oral drug delivery applications. Diclofenac was used as a model drug, and its release from the sericin microparticles was suppressed in a stomach-simulated fluid but was increased in a small intestine-simulated fluid (61). 

Another facet of parenteral drug delivery is the implanted device, and this is perhaps the most promising and most readily commercialised area for responsive and/or active polymers. For an implanted vehicle or depot, drag release rate is controlled by dissolution and/or diffusion in the formulation, or for solid polymer implants by diffusion and/or degradation of the polymer. For more complex polymer hydrogels, the release can be controlled by the linking chemistries, and these can be made responsive to a wide variety of stimuli such as enzymatic action, redox potential and so on, as well as those noted above for the oral route. 

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