Hydroxypropyl-jS-cyclodextrin

The separation of oxybut mm enantiomers was achieved using HPLC with hydroxypropyl-jS-cyclodextrin as the chiral mobile phase additive and a C18 reversed phase column as the stationary phase (54). Oxybutynin is shown in Figure 1.23. 

An excellent enantioseparation could be achieved with the mobile phase composed of 30 mmol l KH2P04-acetonitrile 80 20 by volume, mixed with 60 mmol l hydroxypropyl-jS-cyclodextrin at a... 

As shown in Table 3.1.2, some authors have proposed adding different reagents to the mobile phase to reduce the peak tailing of some componnds, like for example acetic acid (AcOH) in the event of BZ3 (DiNunzio and Gadde, 1990), or ethylenediaminetetraacetic acid (EDTA) for BDM determination (Schakel et al, 2004). Salts, snch as citrate, phosphate and ammonium or sodium acetates, have often been nsed for bnffering purposes. On the other hand, different authors have proposed the use of voluminous ions like tetram-ethylammonium chloride (TMAC) and/or sodinm perchlorate (Gagliardi et al, 1986, 1987, 1989 De Orsi et al, 1995), or stearyltrimethylammonium chloride (STAC) (Ohba et al, 1991) to establish an ion-pair partition process. Moreover, the nse of cyclodextrines has helped to solve unresolved peaks, as performed by Chisvert et al (2001d) who employed hydroxypropyl-jS-cyclodextrine (HP-j -CD) as mobile-phase modifier. 

SG Penn, DM Goodall, JS Loran. Differential binding of tioconazole enantiomers to hydroxypropyl-beta-cyclodextrin studied by capillary electrophoresis. J Chromatogr 636 149-152, 1993. 

Many drugs interact most favorably with P-CD. Unfortunately, P-CD has the lowest solubility (1.8% in water at 25 C) among the three non-derivatized CDs, thereby limiting its solubilization capacity. To enhance the solubility of the P-CD and to improve its safety, derivatives of P-CD have been developed. Among them, hydroxypropyl-j8-cyclodextrins (HP-/3-CDs) and sulfobutylether-jS-cyclodex-trins (SBE-/3-CDs, mainly as SBE7-J3-CD,... 

Scheme 3 Cyclodextrin-derived stationary phases. LIpodex-stationary phases. Hexakis 2,3,6-tri-0-/>pentyl)-a-cyclodextrin (13). Hexakis(3-0-acetyl-2,6-di-0-/>pentyl)-a-cyclodextrin (14). Heptakis(2,3,6-tri-0-r>pentyl)- -cyclodextrin (15). Heptakis(3-Oacelyl-2,6-di-0-n-pentyl)-jS-cyclodextrin (16). Octakis(2,3,6-tri-0-/>pentyl)-v-cyclodextrin (17). Octakis(3-0-butanoyl-2,6-di-0-n-pentyl)-rcyclo-dextrin (18). Polar cyclodextrin stationary phases. (0-(S)-2-hydroxypropyl)-per-0-methyl)-a-cyclodextrin (PMHP-a-CD) (19). (0- S)-2-hydroxypropyl)-per-0-methyl)-jS-cyclodextrin (PMHP-j5-CD) (20). Hexakis(2,6,-di-0-/>pentyl)-a-cyclodextrin (dipenlyl-a-CD) (21). Heptakis 2,6-di-0-n-pentyl)-jS-cyclodextrin (dipentyl- 8-CD) (22). Heptakis(3-0-trifluoroacetyl-2,6-di-0-n-pentyl)-/ -cyclodextrin (DPTFA-j5-CD) (23). 6-TBDMS-modified cyclodextrin stationary phases. Heptakis(2,3-di-0-acetyl-6-0-fert-butyldimethylsilyl)-j9-cyclodextrin (24). Heptakis 2,3-di-0-methyl-6-0-fert-butyldimethylsilyl)- 8-cyclodextrin (25).

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