## 2 Methods for Determination of Lipophilicity
### Indirect Experimental Determination of Lipophilicity
#### 2.3.2 Reversed-Phase High-Performance Liquid Chromatography
** \\ \hline \multirow{6}{*}{\(\beta\)-Blockers and anti-arrhythm drugs} & Determine the effects of stationary phase on the retention in terms of hydrophobicity & \multirow{2}{*}{RP-HPLC/DAD (220, 230, 254 and 280 nm)} & Columns: SG-CHOL (250 \(\times\) 4.6 mm) cholesterol; SG-AP (250 \(\times\) 4.6 mm); End-capped Supelcosil & \multirow{2}{*}{[74]} \\  & & RP-HPLC/DAD & C18-DB (250 \(\times\) 4.6 mm, 5.0 \(\mu\)m); Merck Chromolith & \\  & stationary phase & (220, 230, 254 and 280 nm) & Performance RP-18e (100 \(\times\) 4.6 mm, 5.0 \(\mu\)m); MP: & \\  & & 280 nm) & mixtures of ACN or MeOH (20–100\%) (gradient & \\  & hydrophobicity & & mode); & \\  & & & FR: 1.0 mL/min & \\ \hline \multirow{6}{*}{\(\beta\)-Blockers and anti-arrhythm drugs} & \multirow{2}{*}{Estimate lipophilicity} & \multirow{2}{*}{RP-HPLC/DAD (230 nm)} & Column: LiChrospher 100 R C18 (100 \(\times\) 4.6 mm, 5.0 \(\mu\)m); MP: mixtures of ACN (35–65\%) and water with 0.01\% TFA; FR: 1.0 mL/min & \\  & & & with 0.01\% TFA; FR: 1.0 mL/min & \\  & moiety & & & \\ \hline \multirow{6}{*}{\(meta\) and _para_ Substituted benzenesulfonamides} & \multirow{2}{*}{Estimate lipophilicity} & RP-HPLC/ UV-Vis (254 nm) & Column: \(\mu\)-bondapak C18 (150 \(\times\) 3.9 mm,10 \(\mu\)m); MP: mixtures of MeOH or ACN and water; FR: 1.0 mL/min & \\  & & & & \\ \hline \multirow{6}{*}{\(T\)repenoids} & Determine lipophilicity by RP-HPLC and compare with & \multirow{2}{*}{RP-HPLC/DAD (215 nm); MP: mixtures of MeOH (30–75\%) and 0.02 M MOPS buffer at pH 7.2; FR: 1.0 mL/min} & \\  & & RP-HPLC/RI & & \\ \hline \multirow{6}{*}{\(\beta\)-Entiodes of pyrazine-2-carboxylic acid and 4-benzylsulfonylpyridine derivatives} & Determine lipophilicity by RP-HPLC/ & Column: Chromolith RP18e; (100 \(\times\) 4.6 mm); MP: mixture of MeOH (37–42\%) and 0.05 M phosphate buffer at pH 7.4; FR: 4.0 mL/min & \\  & & RP-HPLC and (254 nm) & & \\ \hline \multirow{6}{*}{\(\beta\)-Entiodes of substituted 6-aminohexanoic acid} & Determine lipophilicity by RP-HPLC and & \multirow{2}{*}{RP-HPLC/ DAD (204 nm)} & Column: Zorbax Eclipse XDB C18 (150 mm \(\times\) 4.6 mm, 5 \(\mu\)m); MP: mixture of MeOH (85\%) and water; FR: 0.4 mL/min & \\  & & RP-HPLC and (204 nm) & & \\ \hline \multirow{6}{*}{\(\beta\)-Entiodes of compounds representing various functional groups such as ketones, acids, or alcohols & Determine lipophilicity by RP-HPLC and (220 and 254 nm) & Columns: Discovery RP Amide C16 (150 \(\times\) 4.0 mm, 5.0 \(\mu\)m) and Discovery RP Amide C16 (20 \(\times\) 4.0 mm, 5.0 \(\mu\)m); MP: mixtures of MeOH and phosphate buffer at pH 3 with octanol (0.25%); FR: 1.0 or 2.0 mL/min & \\  & & RP-HPLC/ & \\ \hline \multirow{6}{*}{\(N\)-(Bemothiazol-2-yl)-\(\alpha\)-amino alkyl phosphonic diesters} & Compare lipophilicity & \multirow{2}{*}{RP-HPLC/ UV-Vis (230 nm)} & Column: ODS (250 \(\times\) 4.6 mm, 5 \(\mu\)m); MP: mixtures of MeOH (70–90\%) and water, FR: 1.0 mL/min & \\  & & RP-HPLC and & \\ \cline{1-1}  & & RP-HPLC/ & \\ \cline{1-1}  & & RP-HPLC and & \\ \cline{1-1}  & & RP-HPLC/ & \\ \cline{1-1}  & & RP-HPLC and & \\ \cline{1-1}  & & RP-HPLC and & \\ \cline{1-1}  & & RP-HPLC/ & \\ \cline{1-1}  &  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Analytes** & **Aim** & \multicolumn{2}{c}{**Chromotographic**} & \multicolumn{1}{c}{**Chromotographic Conditions**} & **Ref.