Development and characterization of biodegradable nanospheres as delivery systems of anti-ischemic adenosine derivatives.
We report a preliminary study concerning the encapsulation modalities in nanoparticles of the anti-ischemic drug N6-cyclopentyladenosine (CPA) and its pro-drug 5'-octanoyl-CPA (Oct-CPA). The release of these compounds and the related pro-drug stability effects in human whole blood have been tested. Moreover, the influence of the delivery systems on CPA interaction toward human adenosine A1 receptor has been analysed. The nanospheres were prepared by nanoprecipitation or double emulsion solvent evaporation method using poly(lactic acid) and recovered by gel filtration or ultracentrifugation or dialysis. Free and encapsulated Oct-CPA was incubated in fresh blood and its stability was analysed with HPLC. Quite spherical nanoparticles with mean diameters ranging between 210+/-50 and 390+/-90 nm were obtained. No encapsulation occurred when CPA was used. Satisfactory results concerning drug content (0.1-1.1% w/w) and encapsulation efficiency (6-56%) were achieved when Oct-CPA was employed. The controlled release of the pro-drug was achieved, being released within a range of 1-4 h, or very slowly, depending on nanoparticle preparations. The hydrolysis rate of Oct-CPA in human whole blood appeared stabilized in human whole blood with modalities related to the release patterns. The presence of all nanoparticle preparations did not interfere with CPA interaction at its action site.
Department of Pharmaceutical Chemistry, Ferrara University, Via Fossato di Mortara 19, I-44100 Ferrara, Italy. dla@dns.unife.it
Alessandro
A
Dalpiaz
Eliana
E
Leo
Federica
F
Vitali
Barbara
B
Pavan
Angelo
A
Scatturin
Fabrizio
F
Bortolotti
Stefano
S
Manfredini
Elisa
E
Durini
Flavio
F
Forni
Barbara
B
Brina
Maria Angela
MA
Vandelli
D020341:Absorbable Implants; D000241:Adenosine / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood / Q000493:pharmacokinetics*; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D003692:Delayed-Action Preparations / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics*; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry*; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry; D008657:Metabolic Clearance Rate; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D011091:Polyesters; D011108:Polymers / Q000737:chemistry; D043682:Receptor, Adenosine A1 / Q000378:metabolism*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics
D003692:Delayed-Action Preparations; D004337:Drug Carriers; D011091:Polyesters; D011108:Polymers; D043682:Receptor, Adenosine A1; D014665:Vasodilator Agents; D019344:Lactic Acid; C033616:poly(lactide); D000241:Adenosine