P. Lecorre et al., IN-VITRO CONTROLLED-RELEASE KINETICS OF LOCAL-ANESTHETICS FROM POLY(D, L-LACTIDE) AND POLY(LACTIDE-CO-GLYCOLIDE) MICROSPHERES, Journal of microencapsulation, 14(2), 1997, pp. 243-255
Citations number
32
Categorie Soggetti
Pharmacology & Pharmacy","Chemistry Applied","Engineering, Chemical
Poly(D, L)lactide and polylactide-co-glycolide drug-loaded microsphere
s were prepared with lipophilic (bupivacaine and etidocaine) and hydro
philic (mepivacaine and lidocaine) local anaesthetics. Formulations of
drug-loaded microspheres were characterized by the drug content, the
in-vitro release kinetics and by the physical state of the drug within
the microspheres. Release rates of the local anaesthetics from the mi
crospheres were different and could not be accounted for by the intrin
sic dissolution rates of the drugs. The encapsulation efficiency was h
ighly dependent on the lipophilicity of the drugs, reaching the maximu
m for the lipophilic drugs and the poly(lactide-co-glycolide) polymers
. The influence of the molecular weight of the poly(lactide-co-glycoli
de) polymers on the release rate and on the release mechanism depended
on the drug studied and its physical state within the polymeric matri
ces. Diffusion-controlled release was evidenced in various formulation
s as a result of the linearity of the release as a function of the squ
are root of time.