Egg lecithin epcs

Sodium chloride, pepsin from porcine gastric mucosa (Ph. Eur., lot BCBL9753V) and nifedipine powder (≥ 98% HPLC) were purchased from Sigma-Aldrich Chemie GmbH (Steinheim, Germany). Egg-lecithin (Lipoid E PCS, Phosphatidylcholine from egg) was from Lipoid GmbH (Ludwigshafen, Germany). Sodium taurocholate was purchased or kindly donated by Prodotti Chimici e Alimentari S.p.A (Basaluzzo, AL, Italy). Ethanol 96% Ph.Eur. was from VWR BDH Prolabo Chemicals (Leuven, Belgium). Immediate release (IR) soft gelatine capsules of nifedipine (Adalat ® 10 mg, 90 soft capsules, batch n°: ITA26UU, from Bayer Pharma AG, Leverkusen, Germany) were used in the studies. Water was of Milli-Q grade. Cellulose nitrate (CN) membrane syringe filters with a pore size of 0.45 µm were from Whatman ® (GE Healthcare Life Sciences, UK), while regenerated cellulose (RC) membrane syringe filters with a pore size of 0.45 µm were from (Cronus, LabHut Ltd, UK). All other reagents and chemicals were of analytical grade and were used as received, without further purification.

Azithromycin analytical standard (90%), dichloromethane, acetonitrile [High-performance liquid chromatography (HPLC) grade], and methanol (HPLC grade) were obtained from Fisher Scientific (UK). Sodium hydroxide, 37% hydrochloric acid, sodium chloride, potassium dihydrogen phosphate, sodium acetate trihydrate were purchased from Fisher Scientific (UK). Water was ultra-pure (Milli-Q) laboratory grade. Ultrafree filter units were obtained from Merck Millipore, USA, and azithromycin dihydrate (98%) was purchased from VWR Chemicals, UK. Zithromax Ò powder for the suspension (azithromycin dihydrate 209.64 mg/5 ml containing the equivalent of 200 mg azithromycin base per 5 ml , Pfizer Ltd., UK) was obtained from UK pharmacies and Belgium pharmacies. Glass microfiber GF/F and GF/D filters (0.7 and 2.7 mm, respectively) (Whatman Ò , UK), pepsin (from porcine), were purchased from Sigma Sigma-Aldrich Company Ltd. (UK). Sodium taurocholate (Prodotti Chimici Alimentari S.P. A., Italy), egg lecithin -Lipoid EPCS (Lipoid GmbH, Germany), and Glyceryl monooleate (Biosynth Carbosynth Ò , UK) were obtained from the specified sources. Ultra-high-temperature treated whole cow's milk standardised to less than 4% fat was acquired from Sainsbury's, UK. Polytetrafluoroethylene (PTFE) filters (13 mm, 0.45 mm) were used in the solubility experiments and were purchased from Fisher Scientific (UK).