cIstituto Cantonale di Microbiologia, 6500 Bellinzona, Switzerland
Corresponding author at: Laboratory of Pharmaceutics and Biopharmaceutics, School of Pharmaceutical Sciences, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland. Tel.: +41 22 379 33 35; fax: +41 22 379 65 67.
1 Current address: Interlifescience, 6900 Massagno, Switzerland.