Acetonitrile

Ciprofloxacin powder (CIP; Mw = 331.35; purity > 98%) was donated by Teva Pharmaceutical Works Ltd. (Debrecen, Hungary) for research work. Polyvinylpyrrolidone (PVP; Mw = 1,300,000) was purchased from Alfa Aesar (Heysham, UK). The solvents for the ES solutions, the ethanol (99.99% purity), and the glacial acetic acid were obtained from Fisher Scientific (Loughborough, UK) and Sigma-Aldrich (Hamburg, Germany), respectively. As a reference for the in vitro dissolution studies, commercially available CIP-containing filmcoated per os tablets (Ciprinol^® 250 mg, KRKA, d. d., Novo mesto, Slovenia) were used. Acetonitrile was purchased from Molar Chemicals (Halasztelek, Hungary). The thiazolyl blue tetrazolium bromide (MTT) reagent and sodium dodecyl sulfate were obtained from Sigma-Aldrich (Hamburg, Germany). Phosphate buffer solutions (PBS; pH 2.8 and pH 7.4) were prepared in-house. All other chemicals were analytical grade, and purified water was used.

Chloroform, ethyl acetate and methanol of reagent grade as well as HPLC-grade methanol and acetonitrile were purchased from Molar Chemicals Kft. (Halásztelek, Hungary). Dimethyl sulfoxide (DMSO), n-dodecane, sodium chloride (NaCl), hydrochloric acid (HCl), disodium hydrogen phosphate heptahydrate (Na₂HPO₄∙7H₂O) and sodium dihydrogen phosphate monohydrate (NaH₂PO₄∙H₂O) were obtained from Reanal-Ker (Budapest, Hungary), while phosphatidylcholine, cholesterol and the porcine polar brain lipid extract were purchased from Merck (Darmstadt, Germany). Acetic acid 100% for HPLC LiChropur™, pyruvate and PBS tablet (Phosphate Buffered Saline, pH 7.4) were acquired from Sigma-Aldrich (Steinheim, Germany). Roswell Park Memorial Institute 1640 medium (RPMI-1640) and Dulbecco’s Modified Eagle’s Medium (DMEM) were supplied by Lonza (Basel, Switzerland). Fetal bovine serum (FBS) was purchased from Biosera (Nuaille, France). Non-essential amino acids, penicillin/streptomycin (10,000 units penicillin and 10 mg streptomycin/mL) and trypsin were obtained from Gibco (Thermo Fisher Scientific, Waltham, MA, USA). High-purity water was gained by a Millipore Direct Q5 Water Purification System (Billerica, MA, USA).