Polysorbate 20 and 80

The (-)-PTZ was gifted by Global Pharmaceutical Industry, Islamabad, Pakistan. The polysorbate 20 and 80 were obtained from Sigma-Aldrich (Burlington, MA, USA). Soya lecithin was purchased from Lipoid GmbH (Ludwigshaften, Germany). Sucrose, cetyl palmitate, and stearic acid were purchased from Cognis GmbH (Mannheim, Germany). Glycerol monostearate (GMS) and cetyl-alcohol were obtained from Acros Organics (Fair Lawn, New Jersey, USA). Dichloromethane (DCM), acetone, and acetonitrile (ACN), of analytical grade, were purchased from Merck (Darmstadt, Germany). Distilled water (dH₂O) was obtained from the Pharmacy Department, COMSATS University Islamabad, Abbottabad campus, Pakistan.

All chemicals and reagents were used as received without further purification. Polysorbate 20 and 80, sodium phosphate monobasic, sodium phosphate dibasic, sodium chloride, sodium citrate, and mannitol were obtained from Sigma-Aldrich (St. Louis, MO, USA). Acetonitrile and methanol (HPLC grade) were from J.T. Baker (Phillipsburg, NJ, USA). Formic acid (LC–MS grade) was from Thermo Fisher Scientific (Waltham, MA, USA). Three different hydroxypropyl substituted HPβCD products, namely, KLEPTOSE^® HP (biopharma grade), KLEPTOSE^® HPB (biopharma grade), and KLEPTOSE^® HPB-LB (parenteral grade), were used without purification (chemical information summarized in Table 1). The monoclonal antibody adalimumab was produced in Chinese hamster ovary (CHO) cells (SD-16) and purified in-house.