Studies Of Recombinant Human Epidermal Growth Factor Bioadhesive Enteric Capsules

Since recombinant human epidermal growth factor (rhEGF) released to clinical use as a genetic engineered product, some good effects have been achieved in treatment of burn, trauma and a variety of chronic surfaces of wound. With continuous study on the product, its clinical use has been gradually exended, including preliminary trials on repairing of lesions in the gastrointestinal tract in recent years with limitation only to local EGF injection or spry under the endoscopy for treatment of peptic ulcer. And some reports deal with administration of oral liquid of rhEGF for the same purpose. Lesions in the gastrointestinal tract have most commonly followed burn, trauma and a great deal of severe infections and there aren't satisfied approaches available to these lesions at present. In order to seek out some effective medications for repairing of lesions in the gastrointestinal tract, we conducted studies to develop an intestine-released capsule of biological adhesive rhEGF. The present study deals with in vivo and in vitro animal experimental models of small intestines for measurement of conglutinative force of biological adhesives in the form of granules to screen and assess their adhesive property. The results proved that biological adhesives, such as CP934P, CP940P, SCMC and HPC, showed to some extent adhesion to the tested animal intestines. Of them CP940P as well as CP934P has the most adhesive force, while HPC takes second place. The adhesive property has a positive correlation to their additive proportion. CP940, HPC and lactose in an appropriate blending ratio could offer a biological adhesive granule with an applicable adhesion property. With increased additive proportion of the adhesive materials mentioned above, the adhesive force could rise accordingly. A satisfied mixture could be obtained with proportions of lactose:CP:HPC (78-82:10-15:8-13), having more than 95% retention rate.We have established methods of radioimmunoassay (RIA) and alive-cell identification to measure its content and biological activity of the enteric capsule of biological adhesive rhEGF with reference to Guidance for Biological Products in China. At present both of RIA and alive-cell identification are still the leadingmethods for measurement of rhEGF, both of the approaches having an identified result in terms of measuring the metabolites from the hydroxyl moiety of rhEGF. In addition, RIA has been used to observe the stability of rhEGF under the condition of artificial peptic juices. The content of rhEGF in artificial gastric juice (pH=2) and intestinal juice (pH=6.8) was prone to decrease over the time, lowering 44.44% and 55.75% from their baselines 6 hours later, respectively. But the decrease in the content of rhEGF would reach 95.43% and 97.64% after 6 hours in the presence of peptic enzymes, respectively.rhEGF in the artificial peptic juices was relatively stable and could meet the need for repair of lesions in the alimentary canal, although the process of its breakdown could be greatly expedited in the presence of peptic enzymes. The breakdown process could be attenuated through modified release of the adhesive materials.The key technique in this preparation may be the blending approach in that the prescription design in the present study includes very low amount of main active ingredient, rhEGF. Accounting for major part of excipients in the recipe, a proportion of lactose was first mixed with rhEGF for its dilution. The resultant mixture underwent lyophilized process, which was evaluated for its feasibility by biological assay for rhEGF. It was noted that the lyophilized process could keep a good uniformity in the content of rhEGF in the preparation and make ready for the next step, although the lyophilized process slightly attenuated its bioactivity. The lyophilized mixture of rhEGF and lactose could be taken as an intermediate product in whole the preparation process. The assayed value of rhEGF content was taken as a measure for the next step to decide the additive amount of rhEGF.We screened pre...