Potassium dihydrogen phosphate

Acetone, Azide-fluor 545, collagenase IA, curcumin, dimethylsulfoxide (DMSO), glutaraldehyde, ethanol, lithium bromide, methanol, potassium chloride, potassium dihydrogen phosphate, sodium carbonate, sodium hydroxide, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and Millipore’s Amicon^® Ultra filters were purchased from Sigma-Aldrich (Milan, Italy). Dialysis cellulose tubes were purchased from Visking, Medicell Membranes Ltd. (London, UK). Moreover, 70 μm nylon meshes were purchased from Greiner Bio-One GmbH (Kremsmunster, Austria). Natriumazide and sodium sulphate were from Carlo Erba Reagenti (Milan, Italy). Caucasian colorectal adenocarcinoma cells (Caco-2), human cervix cancer cells (HeLa) and human urinary bladder (ECV) cancer cells were purchased from the European Collection of Authenticated Cell Cultures Cell Bank (ECACC, Salisbury, UK). All reagents used for cell cultures were purchased from Euroclone (Milan, Italy).

Carbamazepin (CBZ), C₁₅H₁₂N₂O, purity 98%, and pluronic F127 (M_w = 12,600 Da) were purchased from Acros Organics, Thermo Fisher Scientific, Geel, Belgium. Sulfobutylether-β-CD, purity 99%, was received from BLDpharm (https://www.bld-pharm.com/ (accessed on 2 April 2019)). Potassium dihydrogen phosphate (purity ≥99%) and sodium hydroxide (purity ≥98%) were supplied by Merk.
The phosphate buffer pH 6.8 was made as follows: 27.22 g of KH₂PO₄ was dissolved in 1 L of water (Solution 1); 2 g of NaOH was added to 250 mL of H₂O (Solution 2). Then, 250 mL of Solution 1 and 112 mL of Solution 2 were mixed together and diluted with bi-distilled water to 1 L.
All the reagents and solvents were used as received. A FG2-Kit pH meter (Mettler Toledo, Switzerland) standardized with pH 4.00 and 7.00 solutions was used to check the pH of the prepared buffers.

Bicalutamide (purity ≥ 98%) was obtained from a commercial source (Merck, KGaA Darmstadt, Germany). Methylated β-CD (Me-β-CD) (M_n = 1345.0 g·mol⁻¹, DS-12, purity > 95%) and acetylated β-CD (Ac-β-CD) (M_n = 1765.0 g·mol⁻¹, DS-7, purity > 95%) were purchased from CycloLab.LTD (Budapest, Hungary). Polyvinylpyrrolidone K29-32 (PVP, M_n = 58,000) and hydroxypropylmethylcellulose (HPMC, M_n ~ 10,000) were obtained from Sigma-Aldrich (St. Louis, MO, USA). Double distilled water with an electrical conductivity of 2.1 μS cm⁻¹ (PWT H198308, HANNA^® instruments) was used for the preparation of the solutions. Potassium dihydrogen phosphate (purity ≥ 99%) and sodium hydroxide (purity ≥ 98%) were obtained from Merk (Darmstadt, Germany). A buffer solution with pH 6.8, was prepared in the following way: 27.22 g of KH₂PO₄ was dissolved in 1 L of H₂O (solution 1), and 2 g of NaOH was dissolved in 250 mL of H₂O (solution 2); 250 mL and 112 mL of solutions 1 and 2, respectively, were combined and reduced to 1 L. The pH value was measured by using a pH meter (Five Go^TM F2, Mettler Toledo, (Greifenzee, Switzerland)) standardized with pH 4 and pH 7 solutions.