The aim of this work was to clarify the mechanisms by which the co-encapsulation of cyclodextrins into insulin-loaded PLGA microspheres influences protein release rate. On the basis of our previous results, microspheres were prepared by spray-drying either a W/O emulsion or an acetic acid solution with or without HPbetaCD. In order to achieve a more complete characterization of the system, a spectrophotometric method, based on HPbetaCD complexation with phenolphthalein, was used to measure its loading in and release from the microspheres. Furthermore, in order to get an insight into insulin/HPbetaCD interactions within PLGA microspheres after production and during the release phase, the influence of HPbetaCD addition on the secondary structure of bovine insulin within dried and rehydrated microspheres was assessed. To this end, the most valuable and non-invasive method was considered Fourier transform infrared (FTIR) spectroscopy, which can provide, without altering the controlled release system, detailed information regarding protein conformation.
Effect of cyclodextrin incorporation into protein-loaded PLGA-based microspheres: the case of insulin/hydroxypropyl-beta-cyclodextrin complex / Ungaro, Francesca; D., Larobina; P., Musto; DE ROSA, Giuseppe; Quaglia, Fabiana; LA ROTONDA, MARIA IMMACOLATA. - (2004), pp. 441-442. (Intervento presentato al convegno International Meeting on Pharmaceutics, Biopharmaceutics and Pharmaceutical Technology tenutosi a Nuremberg, Germany nel March 15-18, 2004).
Effect of cyclodextrin incorporation into protein-loaded PLGA-based microspheres: the case of insulin/hydroxypropyl-beta-cyclodextrin complex.
UNGARO, FRANCESCA;DE ROSA, GIUSEPPE;QUAGLIA, FABIANA;LA ROTONDA, MARIA IMMACOLATA
2004
Abstract
The aim of this work was to clarify the mechanisms by which the co-encapsulation of cyclodextrins into insulin-loaded PLGA microspheres influences protein release rate. On the basis of our previous results, microspheres were prepared by spray-drying either a W/O emulsion or an acetic acid solution with or without HPbetaCD. In order to achieve a more complete characterization of the system, a spectrophotometric method, based on HPbetaCD complexation with phenolphthalein, was used to measure its loading in and release from the microspheres. Furthermore, in order to get an insight into insulin/HPbetaCD interactions within PLGA microspheres after production and during the release phase, the influence of HPbetaCD addition on the secondary structure of bovine insulin within dried and rehydrated microspheres was assessed. To this end, the most valuable and non-invasive method was considered Fourier transform infrared (FTIR) spectroscopy, which can provide, without altering the controlled release system, detailed information regarding protein conformation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
