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Chitosan-genipin microspheres for the controlled release of drugs: clarithromycin, tramadol and heparin.

Harris R, Lecumberri E, Heras A - Mar Drugs (2010)

Bottom Line: Once the crosslinking process was characterized as a function of the factors mentioned above, drug loaded hydrochloride chitosan microspheres with different degrees of crosslinking were obtained.In conclusion, genipin showed to be eligible as a chemical-crosslinking agent delaying the outflow of drugs from the microspheres.However, more studies in vitro and in vivo must be carried out to determine adequate crosslinking conditions for different drugs.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Estudios Biofuncionales, Departamento Química-Física II, Universidad Complutense Paseo Juan XXIII, Madrid, Spain. ruthharris@ieb.ucm.es

ABSTRACT
The aim of this study was to first evaluate whether the chitosan hydrochloride-genipin crosslinking reaction is influenced by factors such as time, and polymer/genipin concentration, and second, to develop crosslinked drug loaded microspheres to improve the control over drug release. Once the crosslinking process was characterized as a function of the factors mentioned above, drug loaded hydrochloride chitosan microspheres with different degrees of crosslinking were obtained. Microspheres were characterized in terms of size, morphology, drug content, surface charge and capacity to control in vitro drug release. Clarithromycin, tramadol hydrochloride, and low molecular weight heparin (LMWH) were used as model drugs. The obtained particles were spherical, positively charged, with a diameter of 1-10 microm. X-Ray diffraction showed that there was an interaction of genipin and each drug with chitosan in the microspheres. In relation to the release profiles, a higher degree of crosslinking led to more control of drug release in the case of clarithromycin and tramadol. For these drugs, optimal release profiles were obtained for microspheres crosslinked with 1 mM genipin at 50 °C for 5 h and with 5 mM genipin at 50 °C for 5 h, respectively. In LMWH microspheres, the best release profile corresponded to 0.5 mM genipin, 50 °C, 5 h. In conclusion, genipin showed to be eligible as a chemical-crosslinking agent delaying the outflow of drugs from the microspheres. However, more studies in vitro and in vivo must be carried out to determine adequate crosslinking conditions for different drugs.

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Release profiles of low molecular weight heparin, LMWH, in PBS pH 7.4 from non crosslinked chitosan microspheres and genipin crosslinked microspheres HGBd (0.5 mM genipin, 5 h, 50 ºC).
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f10-marinedrugs-08-01750: Release profiles of low molecular weight heparin, LMWH, in PBS pH 7.4 from non crosslinked chitosan microspheres and genipin crosslinked microspheres HGBd (0.5 mM genipin, 5 h, 50 ºC).

Mentions: In contrast, medium crosslinking conditions, corresponding to 0.5 mM genipin incubated during 5 h at 50 ºC (named HGBd), led to a more controlled release compared with HB. These were the only crosslinking conditions that led to LMWH controlled release within those assayed in this study, summarized in Table 3. As shown in Figure 10, following a burst effect, LMWH release increased from 40% to 60% after 3 h in a similar way to that described for HB. Nevertheless, the drug release to the medium was slower throughout the period 4–8 hours. After 4 h, less than 70% of the LMWH had been released from medium crosslinked microspheres, which is significantly lower than 90% released from HB. Finally, 90% LMWH was released from HGBd after 8 hours, reaching 100% within the period 8–24 hours.


Chitosan-genipin microspheres for the controlled release of drugs: clarithromycin, tramadol and heparin.

Harris R, Lecumberri E, Heras A - Mar Drugs (2010)

Release profiles of low molecular weight heparin, LMWH, in PBS pH 7.4 from non crosslinked chitosan microspheres and genipin crosslinked microspheres HGBd (0.5 mM genipin, 5 h, 50 ºC).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2901822&req=5

f10-marinedrugs-08-01750: Release profiles of low molecular weight heparin, LMWH, in PBS pH 7.4 from non crosslinked chitosan microspheres and genipin crosslinked microspheres HGBd (0.5 mM genipin, 5 h, 50 ºC).
Mentions: In contrast, medium crosslinking conditions, corresponding to 0.5 mM genipin incubated during 5 h at 50 ºC (named HGBd), led to a more controlled release compared with HB. These were the only crosslinking conditions that led to LMWH controlled release within those assayed in this study, summarized in Table 3. As shown in Figure 10, following a burst effect, LMWH release increased from 40% to 60% after 3 h in a similar way to that described for HB. Nevertheless, the drug release to the medium was slower throughout the period 4–8 hours. After 4 h, less than 70% of the LMWH had been released from medium crosslinked microspheres, which is significantly lower than 90% released from HB. Finally, 90% LMWH was released from HGBd after 8 hours, reaching 100% within the period 8–24 hours.

Bottom Line: Once the crosslinking process was characterized as a function of the factors mentioned above, drug loaded hydrochloride chitosan microspheres with different degrees of crosslinking were obtained.In conclusion, genipin showed to be eligible as a chemical-crosslinking agent delaying the outflow of drugs from the microspheres.However, more studies in vitro and in vivo must be carried out to determine adequate crosslinking conditions for different drugs.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Estudios Biofuncionales, Departamento Química-Física II, Universidad Complutense Paseo Juan XXIII, Madrid, Spain. ruthharris@ieb.ucm.es

ABSTRACT
The aim of this study was to first evaluate whether the chitosan hydrochloride-genipin crosslinking reaction is influenced by factors such as time, and polymer/genipin concentration, and second, to develop crosslinked drug loaded microspheres to improve the control over drug release. Once the crosslinking process was characterized as a function of the factors mentioned above, drug loaded hydrochloride chitosan microspheres with different degrees of crosslinking were obtained. Microspheres were characterized in terms of size, morphology, drug content, surface charge and capacity to control in vitro drug release. Clarithromycin, tramadol hydrochloride, and low molecular weight heparin (LMWH) were used as model drugs. The obtained particles were spherical, positively charged, with a diameter of 1-10 microm. X-Ray diffraction showed that there was an interaction of genipin and each drug with chitosan in the microspheres. In relation to the release profiles, a higher degree of crosslinking led to more control of drug release in the case of clarithromycin and tramadol. For these drugs, optimal release profiles were obtained for microspheres crosslinked with 1 mM genipin at 50 °C for 5 h and with 5 mM genipin at 50 °C for 5 h, respectively. In LMWH microspheres, the best release profile corresponded to 0.5 mM genipin, 50 °C, 5 h. In conclusion, genipin showed to be eligible as a chemical-crosslinking agent delaying the outflow of drugs from the microspheres. However, more studies in vitro and in vivo must be carried out to determine adequate crosslinking conditions for different drugs.

Show MeSH