2 hydroxypropyl β cyclodextrin

(±) Praziquantel (PZQ)
was supplied by Genera d.d. (Croatia). Cyclodextrins used in this
study included β-cyclodextrin (β-CD), 2-hydroxypropyl-β-cyclodextrin
(HPβCD, with an average degree of substitution, DS = 4.5), randomly
methylated β-cyclodextrin (RMβCD, DS = 12), and sulfobutylether
sodium salt β-cyclodextrin (SBEβCD, DS = 6.5), all obtained
from CycloLab (Hungary). 1,2-Deshydro praziquantel (one of the known
PZQ impurities) was obtained from Toronto Research Chemicals. Complexes
in the solid state were prepared by grinding and analyzed as described
previously.^{12 (link)} In addition to PZQ/CD complexes
prepared in a 1:1 molar ratio, the PZQ/β-CD solid mixture was
also prepared in a 1:4 molar ratio for some NMR measurements. Besides
CDs and the drug, the complexes prepared did not contain any other
additives.
Hydrochloric acid, min. 36.5% p.a., and ammonium
bicarbonate, min. 99.5% p.a., were obtained from Sigma-Aldrich (Germany).
Sodium hydroxide, pellets 2–5 mm p.a., ammonia solution, min.
25% p.a., and hydrogen peroxide, min. 30% p.a., were obtained from
Kemika (Croatia). acetonitrile and methanol, LC-MS grade, as well
as acetonitrile, methanol, and isopropanol, LC grade, were obtained
from Merck (Germany). Ultrapure water was obtained from a Milli-Q
Advantage A10 purification system (Merck). All solvents used for NMR
analysis were purchased from Eurisotop.

(2-hydroxypropyl)-β-cyclodextrin (HPBCD) (degree of substitution (DS) ~ 4.5), β-cyclodextrin (BCD), random methyl-β-cyclodextrin (RAMEB) (DS~12), and sulfobutylated β-cyclodextrin sodium salt (SBECD) (DS~4) were the product of Cyclolab Ltd. (Budapest, Hungary), chrysin (5,7-Dihydroxyflavone) was purchased from Alfa Aesar (by ThermoFisher Scientific, Kandel, Germany), and all other reagents are from Sigma.

The p-nitrophenyl palmitate (p-NPP), p-nitrophenol (p-NP), Mowiol^® 18-88 (poly(vinyl alcohol), PVA; M_W ≈ 130 kDa), sodium chloride, tris(hydroxymethyl)aminomethane (Tris), Triton X100, gum arabic, sodium taurocholate, glacial acetic acid, sodium hydroxide pellets, Burkholderia cepacia lipase (PS Lip), and Aspergillus oryzae lipase (AO Lip) were purchased from Sigma-Aldrich (Saint Louis, MO, USA). β-Cyclodextrin (B-CD), 2-hydroxypropyl-β-Cyclodextrin (HPB-CD, DS = 4.7), 2-hydroxypropyl-γ-cyclodextrin (HPG-CD, DS = 6.3), randomly methylated β-Cyclodextrin (RAMEB-CD), and sulfobutylated-β-Cyclodextrin (SBB-CD, DS = 6.8) were a kind gift from Cyclolab Ltd. (Budapest, Hungary). In all cases, the water was purified by a Millipore Milli Q water purification system (Bradford, MA, USA). In addition, 2-propanol (IPA) was purchased from Merck (Darmstadt, Germany); the Kreon^® 25000 (Lipase:Amylase:Protease = 25,000:18,000:1000 Unit) gastric resistance hard capsule was a product of Mylan EPD Ltd. (Budapest, Hungary), and the Pangrol^® 25000 (Lipase:Amylase:Protease = 25,000:22,500:1250 Unit) gastric resistance hard capsule was produced by Berlin-Chemie Menarini (Berlin, Germany).