Aaps J
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Comparative Study
Microencapsulation of hemoglobin in chitosan-coated alginate microspheres prepared by emulsification/internal gelation.
Chitosan-coated alginate microspheres prepared by emulsification/internal gelation were chosen as carriers for a model protein, hemoglobin (Hb), owing to nontoxicity of the polymers and mild conditions of the method. The influence of process variables related to the emulsification step and microsphere recovering and formulation variables, such as alginate gelation and chitosan coating, on the size distribution and encapsulation efficiency was studied. The effect of microsphere coating as well its drying procedure on the Hb release profile was also evaluated. ⋯ At pH 6.8, uncoated microspheres dissolved in less than 1 hour; however, Hb release from air-dried microspheres was incomplete. Chitosan coating decreased the release rate of Hb, but an incomplete release was obtained. The 2-stage coated microspheres showed no burst effect, whereas the 1-stage coated microspheres permitted a higher protein release.
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Comparative Study
Pharmacokinetic and pharmacodynamic effects of high-dose monoclonal antibody therapy in a rat model of immune thrombocytopenia.
Intravenous administration of pooled, polyvalent human immunoglobulin (IVIG) has been used for over 20 years as a therapy for immune thrombocytopenia (ITP). IVIG is available in limited quantities, and clinical preparations have been associated with the transfer of human pathogens. We have proposed that high-dose monoclonal antibody may be used in lieu of IVIG to achieve beneficial effects in the treatment of ITP. ⋯ AMI pretreatment dramatically affected 7E3-induced thrombocytopenia, significantly altering the time course of thrombocytopenia (P < .05) and significantly decreasing the severity of 7E3-induced thrombocytopenia (ie, following AMI pretreatment, nadir platelet count was greater than 8-fold that of the control group, P < .05). In addition, AMI pretreatment induced a 57% increase in 7E3 clearance (1.13 +/- 0.13 mL h(-1) kg(-1) vs 0.72 +/- 0.08 mL h(-1) kg(-1), P < .05). Consequently, high-dose monoclonal antibody therapy attenuated thrombocytopenia and produced a moderate increase in the clearance of antiplatelet antibodies in a rat model of ITP.