2 hp γ cd

RA (purity > 95%); 2-HP-α-CD (molar substitution 0.6, Mw~1.180); 2-HP-β-CD (molar substitution 0.8, Mw~1.460); and 2-HP-γ-CD (0.5–0.7 molar substitution, Mw~1.580) were purchased from Sigma-Aldrich (Poznan, Poland). Acetonitrile (high-performance liquid chromatography [HPLC] grade) was provided by Merck (Darmstadt, Germany), and other chemical reagents—including hydrochloric acid, dimethyl sulfoxide, sodium chloride, and potassium dihydrogen phosphate—were obtained from Avantor Performance Materials (Gliwice, Poland). Formic acid 98–100% was purchased from POCH (Gliwice, Poland). Prisma HT, GIT lipid solution, and acceptor sink buffer were supplied by Pion Inc (Forest Row, East Sussex, England).

2-HP-α-CD, 2-HP-β-CD, 2-HP-γ-CD, DIMEB and TRIMEB CDs were purchased from Sigma-Aldrich (Milan, Italy) and used without further purification. The same commercial source was adopted for D₂O and LiClO₄ (99.99% trace metals basis). 4-Thio(2’-deoxy)thymidine (S⁴TdR), having 99+% purity was purchased from Carbosynth (Compton, Berkshire, UK). S⁴TdR and CDs stock solutions (at concentrations of 10⁻² M and 5 × 10⁻² M, respectively) were prepared in doubly distilled water or, in D₂O for ¹H NMR analysis and in the presence of LiClO₄ (0.1 M) for CV experiments. The solutions were stored at 4 °C.