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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 tramadol hydrochloride (30% w/w) in SGF from chitosan hydrochloride (5 mg/mL) microspheres without genipin (0 mM) and crosslinked with 2 mM and 5 mM genipin at 50 ºC for 5 h.
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f8-marinedrugs-08-01750: Release profiles of tramadol hydrochloride (30% w/w) in SGF from chitosan hydrochloride (5 mg/mL) microspheres without genipin (0 mM) and crosslinked with 2 mM and 5 mM genipin at 50 ºC for 5 h.

Mentions: The effect of genipin concentration (0 mM, 2 mM and 5 mM) on the release of tramadol hydrochloride from chitosan microspheres is shown in Figure 8. As can be seen, drug release was slower in the case of microspheres crosslinked with genipin in comparison with the non crosslinked ones (0 mM). What is more, the tramadol release rate slowed down with increasing genipin concentration (5 mM genipin microspheres released the drug slower than 2 mM genipin microspheres). In the case of non crosslinked microspheres, a burst effect was observed during the initial hour (>80% of drug) and the total amount of drug encapsulated was released after 2 h. In contrast, the release of drug during the first hour from crosslinked microspheres was significantly lower. The amount of drug released after 2 h from microspheres crosslinked with genipin of different concentrations, 2 and 5 mM, was 97 and 88%, respectively, and it was completely released after 3 h. Therefore, as shown in preliminary studies, crosslinking with genipin controls the release of tramadol hydrochloride [17].


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 tramadol hydrochloride (30% w/w) in SGF from chitosan hydrochloride (5 mg/mL) microspheres without genipin (0 mM) and crosslinked with 2 mM and 5 mM genipin at 50 ºC for 5 h.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f8-marinedrugs-08-01750: Release profiles of tramadol hydrochloride (30% w/w) in SGF from chitosan hydrochloride (5 mg/mL) microspheres without genipin (0 mM) and crosslinked with 2 mM and 5 mM genipin at 50 ºC for 5 h.
Mentions: The effect of genipin concentration (0 mM, 2 mM and 5 mM) on the release of tramadol hydrochloride from chitosan microspheres is shown in Figure 8. As can be seen, drug release was slower in the case of microspheres crosslinked with genipin in comparison with the non crosslinked ones (0 mM). What is more, the tramadol release rate slowed down with increasing genipin concentration (5 mM genipin microspheres released the drug slower than 2 mM genipin microspheres). In the case of non crosslinked microspheres, a burst effect was observed during the initial hour (>80% of drug) and the total amount of drug encapsulated was released after 2 h. In contrast, the release of drug during the first hour from crosslinked microspheres was significantly lower. The amount of drug released after 2 h from microspheres crosslinked with genipin of different concentrations, 2 and 5 mM, was 97 and 88%, respectively, and it was completely released after 3 h. Therefore, as shown in preliminary studies, crosslinking with genipin controls the release of tramadol hydrochloride [17].

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