STATIONARY PHASE AND COLUMN USING CUCURBITURIL BONDED SILICA GEL , AND SEPARATION METHOD OF TAXOL USING THE COLUMN
TECHNICAL FIELD
The present invention relates to a stationary phase and a column using a cucurbi turil-bound silica gel, and a method of separating taxane using the column. More parti cularly, the present invention relates to a stationary phase and a column that achieve hi ghly purified taxane at low costs, and a method of separating taxane using the column.
BACKGROUND ART
Paclitaxel has been approved as one of the most important anticancer drugs ov er the last 15 years. Natural products (e.g., paclitaxel), called "taxanes", are known as therapeutic drugs for cancer-associated diseases, and their applications have been exp anded to many other drugs. Paclitaxel is a natural taxane extracted from the bark of th e Pacific yew tree (Taxus BrevifoHa). In addition, taxanes are derived from Taxus bacc ata, Taxus canadensis, Taxus wallichiana, Taxus yunnanensis, Taxus densiformis, Tax us hicksii, Taxus wardii, Taxus cuspidata, Taxus capitata, Taxus brownie, etc. [Miller et al. J. Org. Chem., 46: 1469 (1981 ); McLaughlin et al. J. Nat. Prod., 44: 321 (1981 ); King ston et al. J. Nat. Prod., 45: 466 (1982)].
Taxanes are also derived from in-vitro cultured plant cells (U.S. Pat. Nos. 5,019, 504; 5,637,484; 5,665,576; 5,871 ,979), fungi (U.S. Pat. No. 5,322,779), bacteria (U.S. Pat. No. 5,561 ,055), etc.
Taxanes, i.e., crude taxane extracts were tested for drug screening in 1960. A n effective ingredient (paclitaxel) of a crude taxane extract was separated by Wani et al. in 1971 , and the chemical structure of paclitaxel was identified by the same group. P aclitaxel has a potent, broad-spectrum anticancer activity in animal models of solid turn ors, melanoma, leukemia, various cancers, sarcomas, and non-Hodgkin lymphomas. Clinical trials using paclitaxel have demonstrated that paclitaxel-containing drugs have potent cancer-combating properties. Thus, paclitaxel (Taxol™) and its semisynthetic an alogue, docetaxel (Taxotere™) have been used alone or in combination with other drug (s), such as cisplatin, for the treatment of ovarian cancer, breast cancer, and non-small- cell lung cancer.
The analysis of paclitaxel and other taxanes is performed mainly by reverse-pha se High-Performance Liquid Chromatography (reverse-phase HPLC), although other m ethods such as multimodal thin layer chromatography, micellar electrokinetic chromatog raphy, tandem mass spectrometry, and gas chromatography have been reported. Rev erse-phase HPLC is more effective in yielding taxane crystals, and the HPLC-based se paration of taxanes from both plant materials and biological fluids was recently reported by Theodoridis, et al. [Phytochem. Anal. 7: 169-184, 1996]. In order to effectively sep arate taxane from a taxane mixture, there has been used an HPLC column packed with silica, alumina, an alkyl (e.g., C18 and C8)-functionalized silica resin, or a polystyrene divinylbenzene resin. For the purpose of appropriate separation of taxanes, researche rs have developed silica gels modified with a diversely functional ized alkyl chain, such a s a phenyl-, biphenyl-, pentafluorophenyl-, or cyano-modified silica gel. Ketchum, et al
. [J. Liq. Chromatogr. 16: 2519-2530, 1993] investigated a separation efficiency of taxan es according to the type of a stationary phase column. Furthermore, a polyfluorinated reverse-phase column for taxane separation was recently reported [Anal. Chim. Acta., 3
19: 187-190, 1996]. As a result of intensive research on a column material, some com panies have developed various silica-based columns, such as Phenomenex, Curosil, W hatman TAC1 , Metachem Taxil, and Zorbax SW-Taxane. However, some of these col umns are more suitable for bark extracts, and some other columns are more suitable fo r needle extracts. More recently, a polymer-coated silica material for taxane separatio n was developed (PCT International Publication No. WO 2004/083176).
However, the above-described techniques have some limitations in terms of purif ication costs and product purity. Therefore, a taxane purification technique capable o f reducing purification costs and increasing taxane purity is needed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an HPLC pattern of paclitaxel separated from a crude extract (paclitaxe I purity: 62.9 wt%) derived from a yew tree according to Example 4;
FIG. 2 is an HPLC pattern of paclitaxel separated from a crude extract (paclitaxe I purity: 26.6 wt%) derived from a yew tree according to Example 5;
FIG. 3 is an HPLC pattern of paclitaxel separated from a crude extract (paclitaxe I purity: 7.1 wt%) derived from a yew tree according to Example 6;
FIG. 4 is an HPLC pattern of paclitaxel separated from a crude extract (paclitaxe
I purity: 51.6 wt%) derived from a cell culture according to Example 7;
FIG. 5 is an HPLC pattern of paclitaxel separated from a crude extract (paclitaxe I purity: 19.3 wt%) derived from a cell culture according to Example 8;
FIG. 6 is an HPLC pattern of pure paclitaxel (99.9 wt%) according to Comaparat ive Example 1 ;
FIG. 7 is an HPLC pattern of paclitaxel separated from a crude extract (paclitaxe I purity: 19.3 wt%) derived from a cell culture according to Example 10; and
FIG. 8 is a 1H-NMR spectrum of paclitaxel that forms a paclitaxel-cucurbit[7]uril c omplex in deuterated water (D2O) according to Example 11.
DETAILED DESCRIPTION OF THE INVENTION Technical Goal of the Invention
The present invention provides a stationary phase for taxane separation using a cucurbituril-bound silica gel to achieve highly purified taxane at low costs. The present invention also provides a column for taxane separation including th e stationary phase to achieve highly purified taxane at low costs.
The present invention also provides a method of separating taxane using the col umn to achieve highly purified taxane at low costs.
Disclosure of the Invention
According to an aspect of the present invention, there is provided a stationary ph ase for taxane separation, including a cucurbituril-bound silica gel in which a cucurbituril represented by Formula 1 or 2 below is covalently bound to a modified silica gel repres ented by Formula 3 below: <Formula 1 >
wherein at least one of R-i's is selected from the group consisting of hydrogen, a hydroxy group, a substituted or unsubstituted alkyloxy group of C1-C30, a substituted or unsubstituted alkenyloxy group of C1-C30, a substituted or unsubstituted alkynyloxy
group of C1 -C30, a substituted or unsubstituted carbonylalkyloxy group of C2-C30, a su bstituted or unsubstituted thioalkyloxy group of C1-C30, a substituted or unsubstituted a Ikylthioloxy group of C1-C30, a substituted or unsubstituted hydroxyalkyloxy group of C 1-C30, a substituted or unsubstituted alkylsiloxy group of C1-C30, a substituted or unsu bstituted aminoalkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylthiol alkyloxy group of C1-C30, a substituted or unsubstituted cycloalkyloxy group of C5-C30, a substituted or unsubstituted heterocycloalkyloxy group of C2-C30, a substituted or u nsubstituted aryloxy group of C6-C30, a substituted or unsubstituted arylalkyloxy group of C6-C20, a substituted or unsubstituted heteroaryloxy group of C4-C30, a substituted or unsubstituted heteroarylalkyloxy group of C4-C30, a substituted or unsubstituted alky lthio group of C1-C30, a substituted or unsubstituted alkenylthio group of C1-C30, a sub stituted or unsubstituted alkynylthio group of C1-C30, a substituted or unsubstituted car bonylalkylthio group of C2-C30, a substituted or unsubstituted thioalkylthio group of C1- C30, a substituted or unsubstituted hydroxyalkylthio group of C1-C30, a substituted or u nsubstituted alkylsilylthio group of C1-C30, a substituted or unsubstituted aminoalkylthio group of C1-C30, a substituted or unsubstituted aminoalkylthiolalkyithio group of C1-C
30, a substituted or unsubstituted cycloalkylthio group of C5-C30, a substituted or unsu bstituted heterocycloalkylthio group of C2-C30, a substituted or unsubstituted arylthio gr oup of C6-C30, a substituted or unsubstituted arylalkylthio group of C6-C20, a substitut ed or unsubstituted heteroarylthio group of C4-C30, a substituted or unsubstituted heter oarylalkylthio group of C4-C30, a substituted or unsubstituted alkylamine group of C1-C 30, a substituted or unsubstituted alkenylamine group of C1-C30, a substituted or unsu bstituted alkynylamine group of C1-C30, a substituted or unsubstituted carbonylalkylami ne group of C2-C30, a substituted or unsubstituted thioalkylamine group of C1-C30, a s ubstituted or unsubstituted hydroxyalkylamine group of C1-C30, a substituted or unsubs tituted alkylsilylamine group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alk yl-carbamate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-thioca rbamate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyloxy group o f C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-carbonyloxy group of C1-C 30, a substituted or unsubstituted trialkyloxysilyl heteroalkyl-alkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylamine group of C1-C30, a substituted or unsub stituted aminoalkylthiolalkylamine group of C1-C30, a substituted or unsubstituted cyclo alkylamine group of C5-C30, a substituted or unsubstituted heterocycloalkylamine grou
p of C2-C30, a substituted or unsubstituted arylamine group of C6-C30, a substituted or unsubstituted arylalkylamine group of C6-C20, a substituted or unsubstituted heteroar ylamine group of C4-C30, a substituted or unsubstituted heteroarylalkylamine group of C4-C30, a substituted or unsubstituted alkylazide group of C1-C30, a substituted or uns ubstituted arylazide group of C1-C30, a substituted or unsubstituted alkylcarboxylazide group of C1-C30, and a substituted or unsubstituted arylcarboxylazide group of C1-C30
X is O. S, or NH; and n is an integer of 4 to 20, <Formula 2>
wherein at least one of R's is selected from the group consisting of hydrogen, a hydroxy group, a substituted or unsubstituted alkyloxy group of C1-C30, a substituted or unsubstituted alkenyloxy group of C1-C30, a substituted or unsubstituted alkynyloxy gr oup of C1-C30, a substituted or unsubstituted carbonylalkyloxy group of C2-C30, a sub stituted or unsubstituted thioalkyloxy group of C1-C30, a substituted or unsubstituted al kylthioloxy group of C1-C30, a substituted or unsubstituted hydroxyalkyloxy group of C1 -C30, a substituted or unsubstituted alkylsiloxy group of C1-C30, a substituted or unsub stituted aminoalkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylthiolal kyloxy group of C1-C30, a substituted or unsubstituted cycloalkyloxy group of C5-C30, a substituted or unsubstituted heterocycloal kyloxy group of C2-C30, a substituted or un substituted aryloxy group of C6-C30, a substituted or unsubstituted arylalkyloxy group o f C6-C20, a substituted or unsubstituted heteroaryloxy group of C4-C30, a substituted o r unsubstituted heteroarylalkyloxy group of C4-C30, a substituted or unsubstituted alkylt hio group of C1-C30, a substituted or unsubstituted alkenylthio group of C1-C30, a subs tituted or unsubstituted alkynylthio group of C1-C30, a substituted or unsubstituted carb onylalkylthio group of C2-C30, a substituted or unsubstituted thioalkylthio group of C1-C 30, a substituted or unsubstituted hydroxyalkylthio group of C1-C30, a substituted or un
substituted alkylsilylthio group of C1-C30, a substituted or unsubstituted aminoalkylthio group of C1-C30, a substituted or unsubstituted aminoalkylthiolalkylthio group of C1-C3 0, a substituted or unsubstituted cycloalkylthio group of C5-C30, a substituted or unsub stituted heterocycloalkylthio group of C2-C30, a substituted or unsubstituted arylthio gro up of C6-C30, a substituted or unsubstituted arylalkylthio group of C6-C20, a substitute d or unsubstituted heteroarylthio group of C4-C30, a substituted or unsubstituted hetero arylalkylthio group of C4-C30, a substituted or unsubstituted alkylamine group of C1-C3 0, a substituted or unsubstituted alkenylamine group of C1-C30, a substituted or unsub stituted alkynylamine group of C1-C30, a substituted or unsubstituted carbonylalkylamin e group of C2-C30, a substituted or unsubstituted thioalkylamine group of C1-C30, a su bstituted or unsubstituted hydroxyalkylamine group of C1-C30, a substituted or unsubsti tuted alkylsilylamine group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl -carbamate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-thiocarb amate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyloxy group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-carbonyloxy group of C1-C3 0, a substituted or unsubstituted trialkyloxysilyl heteroalkyl-alkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylamine group of C1-C30, a substituted or unsubst ituted aminoalkylthiolalkylamine group of C1-C30, a substituted or unsubstituted cycloal kylamine group of C5-C30, a substituted or unsubstituted heterocycloalkylamine group of C2-C30, a substituted or unsubstituted arylamine group of C6-C30, a substituted or u nsubstituted arylalkylamine group of C6-C20, a substituted or unsubstituted heteroaryla mine group of C4-C30, a substituted or unsubstituted heteroarylalkylamine group of C4- C30, a substituted or unsubstituted alkylazide group of C1-C30, a substituted or unsubs tituted arylazide group of C1-C30, a substituted or unsubstituted alkylcarboxylazide gro up of C1-C30, and a substituted or unsubstituted arylcarboxylazide group of C1-C30; X is O, S, or NH; and n is an integer of 3 to 19, and <Formula 3>
OH i I
O OH
—Si —
I I wherein R2 is an alkylthiol group with an alkyl moiety of C2-C10, an alkylamine g roup with an alkyl moiety of C2-C10, an epoxyalkyloxyalkyl group with an alkyl moiety of C2-C10, an isocyanatoalkyl group with an alkyl moiety of C2-C10, a halogenated alkyl group with an alkyl moiety of C2-C10, or a hydroxy group.
The cucurbituril of Formula 1 or 2 above may be covalently bound to the modifie d silica gel of Formula 3 above via a silane linker represented by Formula 4 below: <Formula 4>
wherien Y is selected from the group consisting of a thiol group, an amino group
, an epoxy group, an isocyanate group, an isothiocyanate group, a hydroxy group, a car boxylated halogen, an azide group, an alkenyloxy group, a carbonylalkyloxy group, a thi oalkyloxy group, an alkylthioloxy group, a hydroxyalkyloxy group, an alkylsilyloxy group, an aminoalkyloxy group, an aminoalkylthiolalkyloxy group, a cycloalkyloxy group, a hete rocycloalkyloxy group, an aryloxy group, an arylalkyloxy group, a heteroaryloxy group, a heteroarylalkyloxy group, an alkylthio group, an alkenylthio group, an alkynylthio group
, a carbonylalkylthio group, a thioalkylthio group, a hydroxyalkylthio group, an alkylsilylth io group, an aminoalkylthio group, an aminoalkylthiolalkylthio group, a cycloalkylthio gro up, a heterocycloalkylthio group, an arylthio group, an arylalkylthio group, a heteroarylth io group, a heteroarylalkylthio group, an alkylamine group, an alkenylamine group, an al kynylamine group, a carbonylalkylamine group, a thioalkylamine group, a hydroxyalkyla mine group, an alkylsilylamine group, an aminoalkylamine group, an aminoalkylthiolalky lamine group, a cycloalkylamine group, a heterocycloalkylamine group, an arylamine gr oup, an arylalkylamine group, a heteroarylamine group, and a heteroarylalkylamine gro up; a is an integer of 1 to 10; and
R3 is selected from the group consisting of hydrogen, a halogen atom, an allyl gr
oup, an alkyl group of C1-C20, a halogenated alkyl group of C1-C20, and an alkyloxy gr oup of C1-C20.
In Formula 4 above, R3 may be -OC2H5, Y may be NCO, and a may be 3.
The cucurbituril-bound silica gel may be represented by Formula 5 or 6 below:
<Formula 5>
wherein n is an integer of 4 to 20, and <Formula 6>
wherein n is an integer of 4 to 20.
In Formula 1 above, at least one of R-i's may be selected from the group consist ing of hydrogen, a hydroxy group, an aminophenyl group, an aryloxy group, a halometh yl group, and an aminoalkyl group of C1-C10, X may be O, and n may be 7. The halo methyl group may be a bromomethyl group, a fluoromethyl group, or an iodomethyl gro Up.
In Formula 1 above, R-Ts may be each a hydroxy group.
In Formula 2 above, at least one of R's may be selected from the group consisti ng of hydrogen, a hydroxy group, an aminophenyl group, an aryloxy group, a halomethy
I group, and an aminoalkyl group of C1-C10, X may be O, and n may be 6. The halom ethyl group may be a bromomethyl group, a fluoromethyl group, or an iodomethyl group
In Formula 2 above, R's may be each C6H5-NH2. In Formula 3 above, R2 may be a hydroxy group. According to another aspect of the present invention, there is provided a column
for taxane separation, being packed with the above-described stationary phase.
According to still another aspect of the present invention, there is provided a me thod of separating taxane, the method including: preparing a column for taxane separati on, the column being packed with a stationary phase including a cucurbituril-bound silic a gel in which a cucurbituril represented by Formula 1 or 2 below is covalently bound to a modified silica gel represented by Formula 3 below; dissolving a taxane powder in a s olvent to prepare a taxane-containing solution; applying the taxane-containing solution t o the column; supplying a mobile-phase solvent to the column to obtain a taxane extrac t from the column; and purifying taxane from the taxane extract: <Formula 1>
wherein at least one of R
1 1S is selected from the group consisting of hydrogen, a hydroxy group, a substituted or unsubstituted alkyloxy group of C1-C30, a substituted or unsubstituted alkenyloxy group of C1-C30, a substituted or unsubstituted alkynyloxy group of C1-C30, a substituted or unsubstituted carbonylalkyloxy group of C2-C30, a su bstituted or unsubstituted thioalkyloxy group of C1-C30, a substituted or unsubstituted a Ikylthioloxy group of C1-C30, a substituted or unsubstituted hydroxyalkyloxy group of C 1-C30, a substituted or unsubstituted alkylsiloxy group of C1-C30, a substituted or unsu bstituted aminoalkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylthiol alkyloxy group of C1-C30, a substituted or unsubstituted cycloalkyloxy group of C5-C30, a substituted or unsubstituted heterocycloalkyloxy group of C2-C30, a substituted or u nsubstituted aryloxy group of C6-C30, a substituted or unsubstituted arylalkyloxy group of C6-C20, a substituted or unsubstituted heteroaryloxy group of C4-C30, a substituted or unsubstituted heteroarylalkyloxy group of C4-C30, a substituted or unsubstituted alky lthio group of C1-C30, a substituted or unsubstituted alkenylthio group of C1-C30, a sub stituted or unsubstituted alkynylthio group of C1-C30, a substituted or unsubstituted car bonylalkylthio group of C2-C30, a substituted or unsubstituted thioalkylthio group of C1- C30, a substituted or unsubstituted hydroxyalkylthio group of C1-C30, a substituted or u nsubstituted alkylsilylthio group of C1-C30, a substituted or unsubstituted aminoalkylthio
group of C1-C30, a substituted or unsubstituted aminoalkylthiolalkylthio group of C1-C
30, a substituted or unsubstituted cycloalkylthio group of C5-C30, a substituted or unsu bstituted heterocycloalkylthio group of C2-C30, a substituted or unsubstituted arylthio gr oup of C6-C30, a substituted or unsubstituted arylalkylthio group of C6-C20, a substitut ed or unsubstituted heteroarylthio group of C4-C30, a substituted or unsubstituted heter oarylalkylthio group of C4-C30, a substituted or unsubstituted alkylamine group of C1-C
30, a substituted or unsubstituted alkenylamine group of C1-C30, a substituted or unsu bstituted alkynylamine group of C1-C30, a substituted or unsubstituted carbonylalkylami ne group of C2-C30, a substituted or unsubstituted thioalkylamine group of C1-C30, a s ubstituted or unsubstituted hydroxyalkylamine group of C1-C30, a substituted or unsubs tituted alkylsilylamine group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alk yl-carbamate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-thioca rbamate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyloxy group o f C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-carbonyloxy group of C1-C 30, a substituted or unsubstituted trialkyloxysilyl heteroalkyl-alkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylamine group of C1-C30, a substituted or unsub stituted aminoalkylthiolalkylamine group of C1-C30, a substituted or unsubstituted cyclo alkylamine group of C5-C30, a substituted or unsubstituted heterocycloalkylamine grou p of C2-C30, a substituted or unsubstituted arylamine group of C6-C30, a substituted or unsubstituted arylalkylamine group of C6-C20, a substituted or unsubstituted heteroar ylamine group of C4-C30, a substituted or unsubstituted heteroarylalkylamine group of
C4-C30, a substituted or unsubstituted alkylazide group of C1-C30, a substituted or uns ubstituted arylazide group of C1-C30, a substituted or unsubstituted alkylcarboxylazide group of C1-C30, and a substituted or unsubstituted arylcarboxylazide group of C1-C30 ;
X is O, S, or NH; and n is an integer of 4 to 20, <Formula 2>
wherein at least one of R's is selected from the group consisting of hydrogen, a hydroxy group, a substituted or unsubstituted alkyloxy group of C1-C30, a substituted or unsubstituted alkenyloxy group of C1-C30, a substituted or unsubstituted alkynyloxy gr oup of C1-C30, a substituted or unsubstituted carbonylalkyloxy group of C2-C30, a sub stituted or unsubstituted thioalkyloxy group of C1-C30, a substituted or unsubstituted al kylthioloxy group of C1-C30, a substituted or unsubstituted hydroxyalkyloxy group of C1
-C30, a substituted or unsubstituted alkylsiloxy group of C1-C30, a substituted or unsub stituted aminoalkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylthiolal kyloxy group of C1-C30, a substituted or unsubstituted cycloalkyloxy group of C5-C30, a substituted or unsubstituted heterocycloalkyloxy group of C2-C30, a substituted or un substituted aryloxy group of C6-C30, a substituted or unsubstituted arylalkyloxy group o f C6-C20, a substituted or unsubstituted heteroaryloxy group of C4-C30, a substituted o r unsubstituted heteroarylalkyloxy group of C4-C30, a substituted or unsubstituted alkylt hio group of C1-C30, a substituted or unsubstituted alkenylthio group of C1-C30, a subs tituted or unsubstituted alkynylthio group of C1-C30, a substituted or unsubstituted carb onylalkylthio group of C2-C30, a substituted or unsubstituted thioalkylthio group of C1-C 30, a substituted or unsubstituted hydroxyalkylthio group of C1-C30, a substituted or un substituted alkylsilylthio group of C1-C30, a substituted or unsubstituted aminoalkylthio group of C1-C30, a substituted or unsubstituted aminoalkylthiolalkylthio group of C1-C3 0, a substituted or unsubstituted cycloalkylthio group of C5-C30, a substituted or unsub stituted heterocycloalkylthio group of C2-C30, a substituted or unsubstituted arylthio gro up of C6-C30, a substituted or unsubstituted arylalkylthio group of C6-C20, a substitute d or unsubstituted heteroarylthio group of C4-C30, a substituted or unsubstituted hetero arylalkylthio group of C4-C30, a substituted or unsubstituted alkylamine group of C1-C3 0, a substituted or unsubstituted alkenylamine group of C1-C30, a substituted or unsub stituted alkynylamine group of C1-C30, a substituted or unsubstituted carbonylalkylamin e group of C2-C30, a substituted or unsubstituted thioalkylamine group of C1-C30, a su
bstituted or unsubstituted hydroxyalkylamine group of C1-C30, a substituted or unsubsti tuted alkylsilylamine group of C1-C30, a substituted or unsubstituted trial kyloxysilyl alkyl -carbamate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-thiocarb amate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyloxy group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-carbonyloxy group of C1-C3 0, a substituted or unsubstituted trialkyloxysilyl heteroalkyl-alkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylamine group of C1-C30, a substituted or unsubst ituted aminoalkylthiolalkylamine group of C1-C30, a substituted or unsubstituted cycloal kylamine group of C5-C30, a substituted or unsubstituted heterocycloalkylamine group of C2-C30, a substituted or unsubstituted arylamine group of C6-C30, a substituted or u nsubstituted arylalkylamine group of C6-C20, a substituted or unsubstituted heteroaryla mine group of C4-C30, a substituted or unsubstituted heteroarylalkylamine group of C4- C30, a substituted or unsubstituted alkylazide group of C1-C30, a substituted or unsubs tituted arylazide group of C1-C30, a substituted or unsubstituted alkylcarboxylazide gro up of C1-C30, and a substituted or unsubstituted arylcarboxylazide group of C1-C30;
X is O, S, or NH; and n is an integer of 3 to 19, and
<Formula 3>
: OH i I
— Si— O — Si — R2
O OH
—Si —
wherein R2 is an alkylthiol group with an alkyl moiety of C2-C10, an alkylamine g roup with an alkyl moiety of C2-C10, an epoxyalkyloxyalkyl group with an alkyl moiety of C2-C10, an isocyanatoalkyl group with an alkyl moiety of C2-C10, a halogenated alkyl group with an alkyl moiety of C2-C10, or a hydroxy group.
The cucurbituril of Formula 1 or 2 above may be covalently bound to the modifie d silica gel of Formula 3 above via a silane linker represented by Formula 4 below:
<Formula 4> Y\,rH ^Si(Rs)3
wherien Y is selected from the group consisting of a thiol group, an amino group
, an epoxy group, an isocyanate group, an isothiocyanate group, a hydroxy group, a car boxylated halogen, an azide group, an alkenyloxy group, a carbonylalkyloxy group, a thi oalkyloxy group, an alkylthioloxy group, a hydroxyalkyloxy group, an alkylsilyloxy group, an aminoalkyloxy group, an aminoalkylthiolalkyloxy group, a cycloalkyloxy group, a hete rocycloalkyloxy group, an aryloxy group, an arylalkyloxy group, a heteroaryloxy group, a heteroarylalkyloxy group, an alkylthio group, an alkenylthio group, an alkynylthio group
, a carbonylalkylthio group, a thioalkylthio group, a hydroxyalkylthio group, an alkylsilylth io group, an aminoalkylthio group, an aminoalkylthiolalkylthio group, a cycloalkylthio gro up, a heterocycloalkylthio group, an arylthio group, an arylalkylthio group, a heteroarylth io group, a heteroarylalkylthio group, an alkylamine group, an alkenylamine group, an al kynylamine group, a carbonylalkylamine group, a thioalkylamine group, a hydroxyalkyla mine group, an alkylsilylamine group, an aminoalkylamine group, an aminoalkylthiolalky lamine group, a cycloalkylamine group, a heterocycloalkylamine group, an arylamine gr oup, an arylalkylamine group, a heteroarylamine group, and a heteroarylalkylamine gro up; a is an integer of 1 to 10; and
R3 is selected from the group consisting of hydrogen, a halogen atom, an allyl gr oup, an alkyl group of C1-C20, a halogenated alkyl group of C1-C20, and an alkyloxy gr oup of C1-C20.
In Formula 4 above, R3 may be -OC2H5, Y may be NCO, and a may be 3. The cucurbituril-bound silica gel may be represented by Formula 5 or 6 below: <Formula 5>
wherein n is an integer of 4 to 20, and
<Formula 6>
wherein n is an integer of 4 to 20.
In the method of the present invention, the purification of the taxane from the ta xane extract may include distilling the taxane extract under vacuum to obtain an organic solvent-free taxane concentrate and crystallizing the taxane concentrate.
The purification of the taxane from the taxane extract may further include lyophil izing the taxane concentrate after the crystallization.
Preferable examples of R1 1S of Formula 1 and R's of Formula 2 are as illustrated above.
Effect of the Invention
According to the present invention, a stationary phase for taxane separation usi ng a cucurbituril-bound silica gel can reduce purification costs and increase the purity of taxane. A column for taxane separation including the stationary phase can reduce purifi cation costs and increase the purity of taxane.
A method of separating taxane using the column can achieve highly purified tax ane at low costs.
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will now be described more fully with reference to the ace ompanying drawings, in which exemplary embodiments of the invention are shown.
The present invention provides a stationary phase for taxane separation, includi ng a cucurbituril-bound silica gel in which a cucurbituril represented by Formula 1 or 2 b elow is covalently bound to a modified silica gel represented by Formula 3 below: <Formula 1 >
wherein at least one of R
1 1S is selected from the group consisting of hydrogen, a hydroxy group, a substituted or unsubstituted alkyloxy group of C1-C30, a substituted or unsubstituted alkenyloxy group of C1-C30, a substituted or unsubstituted alkynyloxy group of C1-C30, a substituted or unsubstituted carbonylalkyloxy group of C2-C30, a su bstituted or unsubstituted thioalkyloxy group of C1-C30, a substituted or unsubstituted a
Ikylthioloxy group of C1-C30, a substituted or unsubstituted hydroxyalkyloxy group of C
1-C30, a substituted or unsubstituted alkylsiloxy group of C1-C30, a substituted or unsu bstituted aminoalkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylthiol alkyloxy group of C1-C30, a substituted or unsubstituted cycloalkyloxy group of C5-C30, a substituted or unsubstituted heterocycloalkyloxy group of C2-C30, a substituted or u nsubstituted aryloxy group of C6-C30, a substituted or unsubstituted arylalkyloxy group of C6-C20, a substituted or unsubstituted heteroaryloxy group of C4-C30, a substituted or unsubstituted heteroarylalkyloxy group of C4-C30, a substituted or unsubstituted alky lthio group of C1-C30, a substituted or unsubstituted alkenylthio group of C1-C30, a sub stituted or unsubstituted alkynylthio group of C1-C30, a substituted or unsubstituted car bonylalkylthio group of C2-C30, a substituted or unsubstituted thioalkylthio group of C1- C30, a substituted or unsubstituted hydroxyalkylthio group of C1-C30, a substituted or u nsubstituted alkylsilylthio group of C1-C30, a substituted or unsubstituted aminoalkylthio group of C1-C30, a substituted or unsubstituted aminoalkylthiolalkylthio group of C1-C 30, a substituted or unsubstituted cycloalkylthio group of C5-C30, a substituted or unsu bstituted heterocycloalkylthio group of C2-C30, a substituted or unsubstituted arylthio gr oup of C6-C30, a substituted or unsubstituted arylalkylthio group of C6-C20, a substitut ed or unsubstituted heteroarylthio group of C4-C30, a substituted or unsubstituted heter oarylalkylthio group of C4-C30, a substituted or unsubstituted alkylamine group of C1-C 30, a substituted or unsubstituted alkenylamine group of C1-C30, a substituted or unsu bstituted alkynylamine group of C1-C30, a substituted or unsubstituted carbonylalkylami ne group of C2-C30, a substituted or unsubstituted thioalkylamine group of C1-C30, a s ubstituted or unsubstituted hydroxyalkylamine group of C1 -C30, a substituted or unsubs
tituted alkylsilylamine group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alk yl-carbamate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-thioca rbamate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyloxy group o f C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-carbonyloxy group of C1-C 30, a substituted or unsubstituted trialkyloxysilyl heteroalkyl-alkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylamine group of C1-C30, a substituted or unsub stituted aminoalkylthiolalkylamine group of C1-C30, a substituted or unsubstituted cyclo alkylamine group of C5-C30, a substituted or unsubstituted heterocycloalkylamine grou p of C2-C30, a substituted or unsubstituted arylamine group of C6-C30, a substituted or unsubstituted arylalkylamine group of C6-C20, a substituted or unsubstituted heteroar ylamine group of C4-C30, a substituted or unsubstituted heteroarylalkylamine group of
C4-C30, a substituted or unsubstituted alkylazide group of C1-C30, a substituted or uns ubstituted arylazide group of C1-C30, a substituted or unsubstituted alkylcarboxylazide group of C1-C30, and a substituted or unsubstituted arylcarboxylazide group of C1-C30 ;
X is O, S, or NH; and n is an integer of 4 to 20.
As used herein, the Ri's refer to Ri groups of Formula 1. At least one of R-i's may be selected from the group consisting of hydrogen, a h ydroxy group, an aminophenyl group, an allyloxy group, a halomethyl group, and an ami noalkyl group of C1-C10, X may be O, and n may be 7. More preferably, Ri's may be each a hydroxy group.
The halomethyl group may be a bromomethyl group, a fluoromethyl group, or an iodomethyl group, but the present invention is not limited to the illustrated examples. <Formula 2>
wherein at least one of R's is selected from the group consisting of hydrogen, a hydroxy group, a substituted or unsubstituted alkyloxy group of C1-C30, a substituted or
unsubstituted alkenyloxy group of C1-C30, a substituted or unsubstituted alkynyloxy gr oup of C1-C30, a substituted or unsubstituted carbonylalkyloxy group of C2-C30, a sub stituted or unsubstituted thioalkyloxy group of C1-C30, a substituted or unsubstituted al kylthioloxy group of C1-C30, a substituted or unsubstituted hydroxyalkyloxy group of C1 -C30, a substituted or unsubstituted alkylsiloxy group of C1-C30, a substituted or unsub stituted aminoalkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylthiolal kyloxy group of C1-C30, a substituted or unsubstituted cycloalkyloxy group of C5-C30, a substituted or unsubstituted heterocycloalkyloxy group of C2-C30, a substituted or un substituted aryloxy group of C6-C30, a substituted or unsubstituted arylalkyloxy group o f C6-C20, a substituted or unsubstituted heteroaryloxy group of C4-C30, a substituted o r unsubstituted heteroarylalkyloxy group of C4-C30, a substituted or unsubstituted alkylt hio group of C1-C30, a substituted or unsubstituted alkenylthio group of C1-C30, a subs tituted or unsubstituted alkynylthio group of C1-C30, a substituted or unsubstituted carb onylalkylthio group of C2-C30, a substituted or unsubstituted thioalkylthio group of C1-C 30, a substituted or unsubstituted hydroxyalkylthio group of C1-C30, a substituted or un substituted alkylsilylthio group of C1-C30, a substituted or unsubstituted aminoalkylthio group of C1-C30, a substituted or unsubstituted aminoalkylthiolalkylthio group of C1-C3 0, a substituted or unsubstituted cycloalkylthio group of C5-C30, a substituted or unsub stituted heterocycloalkylthio group of C2-C30, a substituted or unsubstituted arylthio gro up of C6-C30, a substituted or unsubstituted arylalkylthio group of C6-C20, a substitute d or unsubstituted heteroarylthio group of C4-C30, a substituted or unsubstituted hetero arylalkylthio group of C4-C30, a substituted or unsubstituted alkylamine group of C1-C3 0, a substituted or unsubstituted alkenylamine group of C1-C30, a substituted or unsub stituted alkynylamine group of C1-C30, a substituted or unsubstituted carbonylalkylamin e group of C2-C30, a substituted or unsubstituted thioalkylamine group of C1-C30, a su bstituted or unsubstituted hydroxyalkylamine group of C1-C30, a substituted or unsubsti tuted alkylsilylamine group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl -carbamate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-thiocarb amate group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyloxy group of C1-C30, a substituted or unsubstituted trialkyloxysilyl alkyl-carbonyloxy group of C1-C3 0, a substituted or unsubstituted trialkyloxysilyl heteroalkyl-alkyloxy group of C1-C30, a substituted or unsubstituted aminoalkylamine group of C1-C30, a substituted or unsubst ituted aminoalkylthiolalkylamine group of C1-C30, a substituted or unsubstituted cycloal
kylamine group of C5-C30, a substituted or unsubstituted heterocycloalkylamine group of C2-C30, a substituted or unsubstituted arylamine group of C6-C30, a substituted or u nsubstituted arylalkylamine group of C6-C20, a substituted or unsubstituted heteroaryla mine group of C4-C30, a substituted or unsubstituted heteroarylalkylamine group of C4- C30, a substituted or unsubstituted alkylazide group of C1-C30, a substituted or unsubs tituted arylazide group of C1-C30, a substituted or unsubstituted alkylcarboxylazide gro up of C1-C30, and a substituted or unsubstituted arylcarboxylazide group of C1-C30; X is O, S, or NH; and n is an integer of 3 to 19. As used herein, the R's refer to R groups of Formula 2.
At least one of R's may be selected from the group consisting of hydrogen, a hy droxy group, an aminophenyl group, an allyloxy group, a halomethyl group, and an ami noalkyl group of C1-C10, X may be O, and n may be 6. More preferably, R's may be e ach C6H5-NH2. The halomethyl group may be a bromomethyl group, a fluoromethyl group, or an iodomethyl group, but the present invention is not limited to the illustrated examples.
Cucurbiturils were first reported by R. Behrend, E. Meyer, and F. Rusche in 190 5. In early 2000, Ki-Moon Kim and coworkers reported the improved preparation and se paration of well-known cucurbit[6]uril and its homologues, cucurbit[n]urils (n = 5, 7, 8) a nd identified their X-ray crystal structures [J. Am. Chem. Soc. 2000, 122, 540].
The above-described cucurbiturils and cucurbituril derivatives are compounds c onsisting of unsubstituted glycoluril monomer units. Cucurbituril derivatives consisting of substituted glycoluril monomer units are also known [Angew, Chem. Int. Ed. Engl. 19 92, 31 , 1475]. Hereinafter, cucurbiturils and cucurbituril derivatives will be commonly r eferred to simply as "cucurbiturils".
Cucurbiturils are macrocyclic compounds and have a lipophilic cavity and two hy drophilic entrances at upper and lower portions. Thus, lipophilic interactions occur in t he cavity of cucurbiturils, and hydrogen bonds, polar-polar interactions, and positive cha rge-polar interactions occur in the two entrances having six carbonyl groups. Therefore, cucurbiturils have retention capacity for various compounds by a very stable non-coval ent linkage with these compounds. Cucurbiturils form a very stable non-covalent linkag e, in particular, with compounds having a functional group such as an alkyl group, an a mino group, or a carboxyl group, alkaline metals, heavy metals, or amine group-containi
ng gaseous compounds. Based on such characteristics, studies about application of c ucurbiturils in various areas have been continuously conducted.
Cucurbiturils are host molecules having cavities therein, and can form a non-cov alent linkage with guest molecules to produce host-guest complexes [Ace. Chem. Res. 2003, 36, 621]. Furthermore, cucurbiturils also have adsorption capability to various m olecules capable of non-covalently binding with the cucurbiturils, and harmful gases, su ch as CO and NOx, [Angew. Chem. Int. Ed. 2002, 41, 3020]. Thus, cucurbiturils can b e used to filter out specific molecules or gas components.
Hydroxycucurbiturils and their mother cucurbiturils are disclosed, together with t heir chemical structures and synthetic methods, in Korean Patent Application Nos. 02-6 8362, 02-318, 01-57573, 01-39756, and 00-33026, filed by the present applicants, the d isclosures of which are incorporated herein by reference in their entireties.
<Formula 3>
: OH i I
— Si— O — Si — R2 O OH
wherein R2 is an alkylthiol group with an alkyl moiety of C2-C10, an alkylamine g roup with an alkyl moiety of C2-C10, an epoxyalkyloxyalkyl group with an alkyl moiety of C2-C10, an isocyanatoalkyl group with an alkyl moiety of C2-C10, a halogenated alkyl group with an alkyl moiety of C2-C10, or a hydroxy group.
The modified silica gel of Formula 3 above can be prepared by a synthesis meth od known in the art [U.S. Patent No. 4,539,399; J. Chromatogr. 628(1993) 11 ; Tetrahed ron Lett. 26(1985) 3361].
For example, the modified silica gel of Formula 3 above can be synthesized by r eacting a silane having an end functional group, such as a thiol group, an amine group, an isocyanato group, or an epoxy group, with an uncoated silica gel used for column pu rification.
The cucurbituril-bound silica gel of the present invention can be synthesized by covalently binding the cucurbituril derivative of Formula 1 or 2 above with the modified s ilica gel of Formula 3 above. That is, the cucurbituril of Formula 1 or 2 above can be c
ovalently bound to the modified silica gel of Formula 3 above by reacting an end functio nal group of Ri or R of the cucurbituril, such as a carboxy group, an amino group, a hyd roxy group, or an allyl group, with an end functional group of R2 of the modified silica ge I, such as an amino group, an epoxy group, an isocyanato group, or a thiol group [PCT I ntemational Publication Nos. WO 2004/072151 and WO 2005/010058].
The cucurbituril-bound silica gel of the present invention can also be synthesize d by covalently binding the cucurbituril of Formula 1 or 2 above with the modified silica gel of Formula 3 above via a silane linker represented by Formula 4 below [PCT Interna tional Publication Nos. WO 2004/072151 and WO 2005/010058]. That is, the cucurbit uril-bound silica gel of the present invention can be synthesized by binding the cucurbit uril of Formula 1 or 2 above with the silane compound of Formula 4 below and binding t he resultant product with the silica gel of Formula 3 above. In this case, R2 of Formula 3 may be a hydroxy group. <Formula 4>
(^H2)a wherien Y is selected from the group consisting of a thiol group, an amino group , an epoxy group, an isocyanate group, an isothiocyanate group, a hydroxy group, a car boxylated halogen, an azide group, an alkenyloxy group, a carbonylalkyloxy group, a thi oalkyloxy group, an alkylthioloxy group, a hydroxyalkyloxy group, an alkylsilyloxy group, an aminoalkyloxy group, an aminoalkylthiolalkyloxy group, a cycloalkyloxy group, a hete rocycloalkyloxy group, an aryloxy group, an arylalkyloxy group, a heteroaryloxy group, a heteroarylalkyloxy group, an alkylthio group, an alkenylthio group, an alkynylthio group
, a carbonylalkylthio group, a thioalkylthio group, a hydroxyalkylthio group, an alkylsilylth io group, an aminoalkylthio group, an aminoalkylthiolalkylthio group, a cycloalkylthio gro up, a heterocycloalkylthio group, an arylthio group, an arylalkylthio group, a heteroarylth io group, a heteroarylalkylthio group, an alkylamine group, an alkenylamine group, an al kynylamine group, a carbonylalkylamine group, a thioalkylamine group, a hydroxyalkyla mine group, an alkylsilylamine group, an aminoalkylamine group, an aminoalkylthiolalky lamine group, a cycloalkylamine group, a heterocycloalkylamine group, an arylamine gr oup, an arylalkylamine group, a heteroarylamine group, and a heteroarylalkylamine gro up; a is an integer of 1 to 10; and
R3 is selected from the group consisting of hydrogen, a halogen atom, an ally! gr oup, an alkyl group of C1-C20, a halogenated alkyl group of C1-C20, and an alkyloxy gr oup of C1-C20.
In Formula 4 above, R3 may be -OC2H5, Y may be NCO, and a may be 3.
The present invention also provides a column for taxane separation, being pack ed with the above-prepared stationary phase.
In the present invention, a taxane source is selected from plant species, commo nly called "yew tree", and plant cell culture extracts. Here, the plant cell culture extract s may be cell suspensions derived from Taxus chinensis.
As used herein, the term "taxane or taxane molecule" refers to a compound cont aining, but not limited to, a base baccatin III, or its isomer, homologue, or analogue.
The present invention also provides a method of separating paclitaxel and its na tural analogues represented by the following formulae using the column for taxane sepa ration:
paclitaxel: R
1=Ph, R
2=OH, R
3=H, R
4=CH
3CO 10-deacetyltaxol: Ri=Ph, R
2=OH, R
3=H, R
4=H 7-epitaxol: R
1=Ph, R
2=H, R
3=OH, R
4=CH
3CO cephalomanine: R
1=CH
3-CH=C(CH
3), R
2=OH, R
3=H, R
4=CH
3CO taxol C: R
1=C
5H
11, R
2=OH, R
3=H, R
4=CH
3CO 7-epi-10-deacetyltaxol: R
1=Ph, R
2=H, R
3=OH, R
4=H
7-siloxyltaxol: R1=Ph, R2=H1 R3=CH3CO 7-siloxyMO-deacetyltaxol: Ri=Ph, R2=H, R3=H 7-siloxyl-IO-deacetyltaxol C: R1=C5Hn, R2=H, R3= H
7-siloxyl-10-deacetyl cephalomanine: Ri=CH3-CH=C(CH3), R2=H, R3=H
baccatin III: R=CH
3CO 10-deacetylbaccatin III: R=H
That is, the present invention provides a method of separating taxane compoun ds (including paclitaxel). In detail, paclitaxel analogues and homologues are separate d in high purity from Taxus species or other sources by means of a cucurbituril-bound si lica gel column. The cucurbituril-bound silica gel column may be a High Performance Liquid Chromatography (HPLC) column. Therefore, paclitaxel analogues can be separ ated from natural biomass extracts, products made in the semisynthetic or synthetic pro cess for the taxane family, etc.
In order to purify paclitaxel and other taxane compounds from crude extracts, it i s common to use an HPLC column containing silica, alumina, C8, C18, polystyrene divi nylbenzene, or other material. In the present invention, in order to enhance the separa tion efficiency of paclitaxel and other taxane compounds, a column for taxane separatio n is used. As used herein, the term "column for taxane separation" refers to an HPLC column containing a cucurbituril-bound silica gel.
In the present invention, examples of a starting material of a cucurbituril-bound silica gel used in a stationary phase or a column for taxane separation include, but are not limited to, (1 ) a crude extract including paclitaxel or at least one taxane synthesized or semisynthesized from an intermediate such as baccatin III; (2) a crude extract includi ng at least one taxane prepared from a preliminary chromatography column such as sili ca, alumina, C8, C18, or a polymer; (3) a crude extract including at least one taxane pre
pared by another preliminary chromatography; (4) a crude extract including taxane prep ared by solvent partioning, centrifugation, filtration, precipitation, or a combination there of; and (5) a crude extract including at least one taxane derived from a yew tree or othe r source or a crude extract including at least one taxane derived from a plant cell culture extract.
The separation of some taxane compounds is disclosed in U.S. Pat. No. 5,475,1
20, and J. Org. Chem., Miller R. W. et al., 46:1469-1474 (1981 ). The taxane separatio n method disclosed in the documents includes: (1) extracting a dried source (e.g., bark) of paclitaxel with methanol or ethanol and concentrating the resultant extract; (2) extra cting the resultant concentrate with dichloromethane or other solvent, followed by conce ntration, to obtain a powder; (3) dissolving the powder in a solvent and applying the res ultant solution to a chromatography column such as a Curosil Florisil column or a silica column; (4) purifying a paclitaxel fraction eluted from the chromatography column by twi ce crystallization or countercurrent distribution; and (5) applying a pure paclitaxel to a sil ica column or other chromatography column to perform chromatography.
In addition to the above-described taxane separation method, there are many p urification methods for purifying taxane from a natural source. These purification meth ods are different mainly in terms of the type of an organic solvent used in liquid-phase e xtraction, a crystallization process, or a pigment removal technique. According to these conventional taxane separation/purification methods, howev er, the purity of taxane (in particular, paclitaxel) after primary purification is low, and thu s, a purification process must be several times repeated to yield highly purified taxane. Therefore, purification costs are increased, and even when a purification process is re peated several times, the purity of taxane is still low. According to an embodiment of the present invention, a taxane purification meth od includes: (1 ) dissolving a partially purified taxane powder in an appropriate mobile-p hase solvent to obtain a taxane-containing solution; (2) applying the taxane-containing s olution to a column packed with a cucurbituril-bound silica gel to perform chromatograp hy using an appropriate solvent; (3) collecting an appropriate taxane fraction from the c olumn; (4) removing an organic solvent from the taxane fraction by evaporation under v acuum; and (5) crystallizing and lyophilizing the resultant taxane concentrate. Here, th e mobile-phase solvent may be a solvent known in the art.
According to the taxane purification method of the present invention, a taxane w
ith a purity of 95 wt% or more can be yielded. The above-described taxane purification method of the present invention is related to HPLC separation, and subsequent extract ion and purification can be performed by methods known in the art. The separation of highly purified taxane from the column can be achieved by good taxane separation cap ability of the cucurbituril-bound silica gel used as a stationary phase. That is, when a c rude taxane extract is allowed to pass through a column packed with a cucurbituril-boun d silica gel, the retention time of taxane is distinctly different from that of other compone nts (impurities) due to column characteristics, thereby enabling the separation of taxane from the other components, resulting in highly purified taxane. The above-described taxane purification method of the present invention can be applied to a taxane mixture with a taxane purity of at least 7 wt% that is partially purifie d from a taxane source. Most preferably, a taxane compound may be paclitaxel (an ef fective ingredient in drug Taxol™).
A crude extract (preferably, containing at least 7wt% of taxane) is dissolved in a mixture of water and methanol or acetonitrile. In order to dissolve the crude extract, ot her appropriate solvent(s) can also be used. The current embodiment of the present i nvention has been illustrated with respect to a crude extract containing at least 7 wt% of taxane, but the content of taxane may also be less than 7 wt%.
An appropriate aliquot of a taxane-containing solution is loaded on a cucurbituril -bound silica gel column connected to an appropriate HPLC system. At this time, a loa ding amount of the taxane-containing solution may vary according to the dimension of t he column. The dimension of the column may be as follows: 10-50 cm in length and 2
.0-25 mm in diameter, but the present invention is not limited thereto. Any column with an appropriate dimension can also be used. An HPLC analysis can be performed using a gradient elution program. The pre sent inventors found that the separation of taxane from contaminants was appropriately achieved in an isocratic mode. The isocratic mode may include an eluent of methano
I/water, acetonitrile/water, or methanol/acetonitrile/water. In the isocratic mode, metha nol may be used in an amount of 45-75wt%, acetonitrile in an amount of 30-45wt%, and water in an amount of 25-70wt%. An eluent is not limited to the above-described mixt ure of water and methanol and/or acetonitrile. A mixture of water and other appropriat e organic solvent(s) can also be effectively used for separation of taxane.
A taxane fraction eluted from a column is subjected to evaporation under vacuu
m to remove an organic solvent, and precipitated in a residual aqueous phase. Altern atively or preferably, the resultant taxane-containing aqueous phase may be lyophilized.
The extraction of the taxane fraction may be performed on a HPLC column adju sted to 300C . However, the temperature of the HPLC column can be appropriately cha nged.
Taxanes interact with cucurbiturils, which enables the separation of taxanes from crude extracts. The present inventors demonstrated a host-guest interaction betwee n cucurbit[7]uril and taxane by 1H-NMR spectroscopy.
EMBODIMENTS
Hereinafter, the present invention will be described more specifically with refere nee to the following working examples. The following working examples are for illustrat ive purposes and are not intended to limit the scope of the present invention.
Example 1 : Synthesis of cucurbituril-bound silica gel represented by Formula 5 ( n=3)
A cucurbituril-bound silica gel represented by Formula 5 (n=3) below was synthe sized by binding a cucurbituril of Formula 1 above wherein X was O, R1 1S were each OH , and n was 7, with a silica gel of Formula 3 above wherein R2 was OH, via a silane link er of Formula 4 above wherein R3 was -OC2H5, Y was NCO, and a was 3: <Formula 5>
In detail, the cucurbituril-bound silica gel of Formula 5 above was synthesized a S follows.
Hydroxycucurbit[7]uril (6.Og, 4.33 mmol) was dissolved in anhydrous DMSO (65 ml, Aldrich) in a 250 ml round-bottom flask, and pyridine (7.0 ml) was then added to the flask. Then, 3-(triethoxysilyl)propyl isocyanate (2.35 ml, 9.56 mmol, Aldrich) was added
to the flask, and the resultant mixture was incubated at 80 °C for 2 days while sirring un der an argon atmosphere. The resultant silylated cucurbit[7]uril intermediate was trans ferred to a HPLC-grade silica gel (Lichrospher Si 100, particle size of 5 μm, pore size of 100 A, 2.Og, dried at 800C under vacuum for 24 hours) in a 250 ml round-bottom flask, and the resultant mixture was incubated at 110°C for 3 days while stirring under an arg on atmosphere. The resultant product was several times washed with DMSO, acetone , water, and methanol, and dried under vacuum at 50 °C overnight, to thereby give the c ucurbituril-bound silica gel of Formula 5 above.
13C-CP MAS: δ(ppm): 162.3, 155.1 , 98.6, 44.4, 28.6, 23.5, 14.8. FT-IR (KBr): 3485, 3150, 2969, 1737, 1467, 1120-1095 cm"1.
Example 2: Synthesis of cucurbituril-bound silica gel represented by Formula 6 ( n=3)
A cucurbituril-bound silica gel represented by Formula 6 (n=3) below was synthe sized by binding a cucurbituril of Formula 2 above wherein X was O and R's were each C6H5-NH2, with a silica gel of Formula 3 above wherein R2 was OH, via a silane linker of Formula 4 above wherein R3 was -OC2H5, Y was NCO, and a was 3: <Formula 6>
In detail, the cucurbituril-bound silica gel of Formula 6 above was synthesized a s follows.
Di-para-aminophenylcucurbit[7]uril (1.2 g, 0.89 mmol) was dissolved in anhydro us DMSO(30 ml, Aldrich) in a 250 ml round-bottom flask, and pyridine (3.0 ml) was then added to the flask. Then, 3-(triethoxysilyl)propyI isocyanate (0.66 ml, 2.67 mmol, Aldr ich) was added to the flask, and the resultant mixture was incubated at 80 °C for 2 days while sirring under an argon atmosphere. The resultant diaminophenylsilylated cucurbi
t[7]uril intermediate was transferred to a HPLC-grade silica gel (Lichrospher Si 100, part icle size of 5 μm, pore size of 100 A, 0.6 g, dried at 80 °C under vacuum for 24 hours) in a 250 ml round-bottom flask, and the resultant mixture was incubated at 110°C for 3 d ays while stirring under an argon atmosphere. The resultant product was several time s washed with DMSO, acetone, water, and methanol, and dried under vacuum at 5O0C overnight to thereby give the cucurbituril-bound silica gel of Formula 6 above.
13C-CP MAS: δ(ppm): 161.8, 152.5, 133.3, 131.6, 128.9, 121.4, 97.3, 49.6, 27.5 , 25.2, 15.3.
FT-IR (KBr): 3450, 3025, 2978, 1737, 1530, 1471, 1100-1090 cm"1.
Example 3: Preparation of HPLC column using cucurbituril-bound silica gel Methanol (50 ml) was added to the cucurbituril-bound silica gel (2.5 g) prepared in Example 1 to make a slurry, and the slurry was then tightly packed into a HPLC steel column (15 cm in length and 0.46 cm in inner diameter, SUPELCO, U.S.A.) using a slur ry packing tool. Then, the resultant HPLC steel column was washed with methanol un der a pressure of 800 psi for 3 hours prior to HPLC analysis. The HPLC column thus p repared was used as a stationary phase column for HPLC analysis after being attached to a HPLC system.
Example 4: Separation of paclitaxel from crude extract (paclitaxel purity: 62.9 wt
%) derived from yew tree using cucurbituril-bound silica gel stationary phase
The separation of paclitaxel from a crude extract (paclitaxel purity: 62.9 wt%) de rived from a yew tree was performed using the HPLC column prepared in Example 3. The crude extract was dissolved in a mixture of acetonitrile and water and a 10 μi aliq uot of the resultant solution was loaded on the HPLC column. At this time, an eluent ( a mixture of acetonitirile and water (35:65, v/v)) was allowed to flow down through the H PLC column at a flow rate of 0.4 ml/min, and an eluate was monitored by a UV detector at 227 nm. The chromatographic results are shown in FIG. 1. The chromatographic results of FIG. 1 show that reverse-phase HPLC analysis can distinctly separate a high Iy purified paclitaxel peak from impurity peaks.
Example 5: Separation of paclitaxel from crude extract (paclitaxel purity: 26.6 wt
%) derived from yew tree using cucurbituril-bound silica gel stationary phase
The separation of paclitaxel from a crude extract (paclitaxel purity: 26.6 wt%) de rived from a yew tree was performed using the HPLC column prepared in Example 3. T he crude extract was dissolved in a mixture of acetonitrile and water and a 10 μi aliquo t of the resultant solution was loaded on the HPLC column. HPLC analysis was perfor med under the same conditions as in Example 4, and the chromatographic results are s hown in FIG. 2. The chromatographic results of FIG. 2 show that reverse-phase HPLC analysis can distinctly separate a highly purified paclitaxel peak from impurity peaks.
Example 6: Separation of paclitaxel from crude extract (paclitaxel purity: 7.1 wt
%) derived from yew tree using cucurbituril-bound silica gel stationary phase
The separation of paclitaxel from a crude extract (paclitaxel purity: 7.1 wt%) deri ved from a yew tree was performed using the HPLC column prepared in Example 3. Th e crude extract was dissolved in a mixture of acetonitrile and water and a 10 μi aliquot of the resultant solution was loaded on the HPLC column. HPLC analysis was perform ed under the same conditions as in Example 4, and the chromatographic results are sh own in FIG. 3. The chromatographic results of FIG. 3 show that reverse-phase HPLC analysis can distinctly separate a highly purified paclitaxel peak from impurity peaks.
Example 7: Separation of paclitaxel from crude extract (paclitaxel purity: 51.6 wt
%) derived from cell cuture using cucurbituril-bound silica gel stationary phase
The separation of paclitaxel from a crude extract (paclitaxel purity: 51.6 wt%) de rived from a cell culture was performed using the HPLC column prepared in Example 3. The crude extract was dissolved in a mixture of acetonitrile and water and a 10 μi aliq uot of the resultant solution was loaded on the HPLC column. HPLC analysis was perfo rmed under the same conditions as in Example 4, and the chromatographic results are shown in FIG. 4. The chromatographic results of FIG. 4 show that reverse-phase HPLC analysis can distinctly separate a highly purified paclitaxel peak from impurity peaks.
Example 8: Separation of paclitaxel from crude extract (paclitaxel purity: 19.3 wt
%) derived from cell culture using cucurbituril-bound silica gel stationary phase
The separation of paclitaxcel from a crude extract (paclitaxel purity: 19.3 wt%) d
erived from a cell culture was performed using the HPLC column prepared in Example 3. The crude extract was dissolved in a mixture of acetonitrile and water and a 10 μJt al iquot of the resultant solution was loaded on the HPLC column. HPLC analysis was p erformed under the same conditions as in Example 4, and the chromatographic results are shown in FIG. 5. The chromatographic results of FIG. 5 show that reverse-phase HPLC analysis can distinctly separate a highly purified paclitaxel peak from impurity pe aks.
Comparative Example 1 : Separation of pure paclitaxel (purity: 99.9 wt%) using c ucurbituril-bound silica gel stationary phase
The analysis of pure paclitaxel (purity: 99.9 wt%) was performed using the HPL C column prepared in Example 3. The pure paclitaxel was dissolved in a mixture of ac etonitrile and water and a 10 ≠ aliquot of the resultant solution was loaded on the HPL C column. HPLC analysis was performed under the same conditions as in Example 4, and the chromatographic results are shown in FIG. 6. Based on the position of a pad itaxel peak of Comparative Example 1 as shown in FIG. 6, the positions of paclitaxel pe aks of the other working examples of the present invention can be determined.
Example 9: Preparation of HPLC column using diaminophenylcucurbituril-bound silica gel
Methanol (55 ml) was added to the diaminophenylcucurbituril-bound silica gel (2 .6 g) prepared in Example 2 to make a slurry, and the slurry was then tightly packed int o a HPLC steel column (15 cm in length and 0.46 cm in inner diameter, SUPELCO, U. S .A.) using a slurry packing tool. Then, the resultant HPLC steel column was washed wi th methanol under a pressure of 800 psi for 3 hours prior to HPLC analysis. The HPL C column thus prepared was used as a stationary phase column for HPLC analysis afte r being attached to a HPLC system.
Example 10: Separation of paclitaxel from crude extract (paclitaxel purity: 19.3 wt%) derived from cell culture using diaminophenylcucurbituril-bound silica gel stationar v phase
The separation of paclitaxel from a crude extract (paclitaxel purity: 19.3 wt%) de
rived from a cell culture was performed using the HPLC column prepared in Example 9.
The crude extract was dissolved in a mixture of acetonitrile and water and a 10 μi aliq uot of the resultant solution was loaded on the HPLC column. HPLC analysis was perf ormed under the same conditions as in Example 4, and the chromatographic results are shown in FIG. 7. The chromatographic results of FIG. 7 show that reverse-phase HP
LC analysis can distinctly separate a highly purified paclitaxel peak from impurity peaks.
Example 11 : 1H-NMR analysis of cucurbit[7]uril-bound paclitaxel Pure paclitaxel (4 mg) was dissolved in D2O (1 ml), and cucurbit[7]uril (10 mg) w as then added thereto. 1H-NMR analysis of a cucurbituril-paclitaxel complex wherein p aclitaxel molecules were partially trapped in cucurbit[7]uril molecules was performed at room temperature by 1H-NMR spectroscopy to investigate a host-guest interaction betw een cucurbit[7]uril and paclitaxel, and the results are shown in FIG. 8. In FIG. 8, an up per 1H-NMR spectrum is for a paclitaxel solution, and a lower 1H-NMR spectrum is for a paclitaxel-cucurbit^uril solution. Referring to FIG. 8, aromatic ring proton peaks deri ved from C6H5-CO of paclitaxel in the paclitaxel solution were observed in 7.45-8.15 pp m range. These aromatic ring protons were shifted upfield (6.35-7.05 ppm range) after an interaction between paclitaxel and cucurbit[7]uril occurred. This shows that paclita xel molecules are trapped in cucurbit[7]uril molecules. After forming a cucurbit[7]uril-p aclitaxel complex, aliphatic proton peaks of paclitaxel were observed in 0.4-1.0 ppm ran ge. This shows that the aliphatic groups of paclitaxel interact with cucurbit[7]uril.
While the present invention has been particularly shown and described with refer ence to exemplary embodiments thereof, it will be understood by those of ordinary skill i n the art that various changes in form and details may be made therein without departin g from the spirit and scope of the present invention as defined by the following claims.