title: Improved bioavailability of darunavir by use of kappa-carrageenan versus microcrystalline cellulose as pelletisation aid.
abstract: The aim of this study was to produce pellet formulations containing a high drug load (80%) of the poorly soluble HIV-protease inhibitor darunavir, using wet extrusion/spheronization with kappa-carrageenan or microcrystalline cellulose (MCC) as pelletization aid. Drug release was assessed in vitro by a standardized paddle-dissolution test and in vivo by a single-dose pharmacokinetic study in dogs. Mean dissolution time (MDT) was 78.2+/-3.5 h from MCC pellets (1301+/-301 microm) and 6.1+/-0.7 min from kappa-carrageenan pellets (966+/-136 microm). In contrast to kappa-carrageenan pellets, MCC pellets did not disintegrate and showed a diffusion-controlled drug release. In line with the in vitro findings, the darunavir peak plasma levels and exposure after the administration of a 300 mg dose were more than 60-fold higher when formulated with kappa-carrageenan pellets when compared with MCC pellets, and 10-fold higher after co-administration with 10mg/kg of ritonavir. The relative bioavailability of darunavir versus the reference tablet (F(rel)) was 155% with kappa-carrageenan pellets and 2% with MCC pellets without ritonavir, while 78% and 9%, respectively, in presence of ritonavir. In conclusion, when compared with MCC pellets, the bioavailability of darunavir was substantially improved in kappa-carrageenan pellets, likely due to their better disintegration behavior.
authors.affiliation: Institute of Pharmaceutics and Biopharmaceutics, Heinrich-Heine-University, Duesseldorf, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Thommes
authors.forename: Lieven
authors.initials: L
authors.lastname: Baert
authors.forename: Gerben
authors.initials: G
authors.lastname: van 't Klooster
authors.forename: Marian
authors.initials: M
authors.lastname: Geldof
authors.forename: Laurent
authors.initials: L
authors.lastname: Schueller
authors.forename: Jan
authors.initials: J
authors.lastname: Rosier
authors.forename: Peter
authors.initials: P
authors.lastname: Kleinebudde
mesh_terms: D000818:Animals; D001682:Biological Availability; D002351:Carrageenan / Q000097:blood / Q000493:pharmacokinetics*; D002482:Cellulose / Q000097:blood / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D000069454:Darunavir; D004285:Dogs; D004343:Drug Implants / Q000493:pharmacokinetics*; D008297:Male; D013449:Sulfonamides / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D004343:Drug Implants; D013449:Sulfonamides; D002351:Carrageenan; D002482:Cellulose; C109691:microcrystalline cellulose; D000069454:Darunavir