PACLITAXEL DERIVATIVE FOR ALBUMIN-ASSISTED DRUG DELIVERY
3
(
2
(
d, 1H, HC = CHVCH2), 4.18 (m, 2H, O CH2CH3),
MHz, CDCl3) *167.1, 36.3, 34.7, 32.1, 29.8, 28.9, 26.5,
+
.19 (q, 2H, (CH2), 1.54 (s, 1H, CH2CHCH2), 1.45
22.9, 14.3. ESI–MS (pos, MeCN) m/z 325.4 [M + H] ,
+
t, 2H, *CH2), 1.30 to 1.26 (m, 29H, CH2CH2,
347.6 [M + Na] .
OCH2CH3), 0.88 (t, 3H, CH3). ESI–mass spectrom-
ꢀ
Paclitaxel-2 -O-3-Pentadecylhemiglutarate (5; PP)
+
etry (MS) (pos, MeOH): 333.5 [M + Na] .
3
Intermediate 4 (21 mg, 64.5 :mol), PTX (50 mg, 58.6
-Pentadecyldiethylglutarate (2)
:
mol), and N,N-dimethylaminopyridine (DMAP) (0.7
To a 10 mL solution of anhydrous EtOH containing
sodium metal (111 mg, 4.83 mmol) was added di-
mg, 5.86 :mol) were dissolved in 0.8 mL dry pyridine
and the reaction mixture stirred overnight at room
temperature. After evaporation, the solid was taken
up in dichloromethane (DCM) and washed with 0.1 N
HCl. The DCM was dried, filtered, and concentrated.
The solid was adsorbed onto silica and eluted with
(1:1) EtOAc in petroleum ether supplemented with
1% AcOH. The product was recovered as a white solid
ethylmalonate (386 mg/367 :L, 2.42 mmol) and (1)
◦
(
500 mg, 1.61 mmol) in 5 mL dry EtOH at 0 C. The
solution was stirred overnight at room temperature.
The solution was concentrated, diluted with water,
and extracted with EtOAc. The EtOAc layer was dried
with magnesium sulfate and evaporated to a colorless
oil. To the oil in DMSO was added 1 eq of H2O and
1
(58.4 mg, 85%). H NMR (400 MHz, CDCl3) * 8.12 (d,
2
eq of NaCl at a concentration of 6 g/mL and the
2H, ArH), 7.75 (d, 2H, ArH), 7.62 to 7.24 (m, 11H,
ArH), 6.29 (s, 1H, C10), 6.24 (t, 1H, C 13), 5.99 (dd,
1H, C 3’), 5.68 (d, 1H, C 2), 5.50 (d, 1H, C 2’), 4.97
(d, 1H, C 5), 4.40 (dd, 1H, C 7), 4.29 (d, 1H, C 20),
4.20 (d, 1H, C 20), 3.80 (d, 1H, C 3), 2.56 2.50 (m,
1H, CH2 CH CH2 ), 2.45 (s, 3H, OAc), 2.40–2.28
(m, 3H, CH2 CH CH2 , C 6"), 2.24–2.13 (m, 7H,
OAc, C 14, CH2 CH CH2 ), 2.00–1.85 (m, 4H,
C 18, C 6$), 1.66 (s, 3H, C 19), 1.26–1.19 (m, 31H,
CH2CH3, C 17), 1.13 (s, 3H, C 16), 0.88 (t, 3H,
solution refluxed for 5 h. Dilution with water and ex-
traction into EtOAc yielded a colorless oil. The prod-
uct was purified on silica gel eluting with 5% EtOAc
in petroleum ether (603 mg, 94% over two steps). H
NMR (400 MHz, CDCl3) * 4.13 (q, 4H, OCH2CH3),
1
2.34 (m, 5H, CH2CHCH2), 1.33 to 1.24 (m, 34H,
CH2CH2, OCH2CH3), 0.88 (t, 3H, CH3). 13C NMR
(
2
100 MHz, CDCl3) * 172.8, 60.4, 38.9, 34.2, 32.4, 32.1,
9.8, 26.8, 22.9, 14.4, 14.3. ESI–MS (pos, MeOH) m/z
+
+
+
13
399.7 [M + H] , 421.8 [M + Na] , 437.8 [M + K] .
CH2CH3). C NMR (100 MHz, CDCl3) * 204.0,
76.7, 171.9, 171.5, 170.2, 168.3, 167.7, 167.2, 142.9,
37.1, 133.8, 133.0, 132.2, 130.5, 129.0, 127.1, 84.7,
1
PDG Acid (3)
1
To 15 mL of MeOH containing 2 (1.06 g, 2.66 mmol)
was added 30 mL 3 N KOH. The mixture was heated
to a reflux with stirring for 3 h causing the suspen-
sion to become clear. The solution was cooled to am-
bient temperature, acidified to pH 1 with HCl, and
extracted with methyl t-butyl ether. The organic layer
was dried and concentrated and the product collected
as a white solid (900 mg, 99%). The compound was
81.3, 79.2, 75.8, 75.3, 74.4, 72.2, 58.7, 53.1, 45.8,
43.4, 38.0, 35.7, 34.1, 32.2, 29.9, 29.7, 27.1, 22.9, 22.3,
21.0, 15.0, 14.3, 9.8. ESI–MS (pos, MeOH) m/z 1201.1
[M+Na] .
+
Cytotoxicity of PP
The cytotoxicity of PP and PTX was determined by
the NCI as part of the NCI-60 DTP Human Tumor
1
28
pure by TLC 10% Me2CO in petroleum ether. H NMR
Cell Line Screen. Briefly, various human cancer
(
400 MHz, CD3OD) * 2.33–2.27 (m, 5H, CH2CHCH2),
cell lines are plated at 5000–40,000 cells/well and
treated with five concentrations of PP or PTX from
10 nM to 100 :M. The effect on cell growth is com-
pared with cell lines fixed at time 0 and the untreated
control via the sulforhodamine B test. Dose–response
curves are then generated across 60 cell lines and the
1
.37 to 1.29 (m, 28H, CH2CH2 ), 0.90 (t, 3H, CH3).
C NMR (100 MHz, CD3OD) *176.7, 39.6, 35.2, 33.5,
3.3, 30.9, 27.8, 23.9, 14.6. ESI–MS (neg, MeOH) m/z
1
3
3
3
−
41.7 [M − H] .
PDG Anhydride (4)
50% growth inhibition (GI50), total growth inhibition
Intermediate 3 (900 mg, 2.63 mmol) was suspended in
(TGI), and 50% lethal concentration (LC ) values are
determined for each cell line.
5
0
3
mL EtOAc and heated gently until dissolved. To the
solution was added trifluoroacetic anhydride (773 mg/
Biochemical Stability of PP
0
.513 mL, 3.68 mmol) and the solution was heated to
◦
37 C with shaking for 2 h. After evaporation, the
Murine-derived CT26 cells were grown in a T-75
6
solid was recrystallized from pentane. Filtration of
the solid and drying under vacuum produces the prod-
flask to confluency (∼4 × 10 cells). The cells were
then washed twice with Hank’s balanced salt solu-
tion (HBSS), scraped off the flask with a cell scraper,
and suspended in 5 mL HBSS. The suspension was
uct as a fluffy white powder in quantitative yield
1
(
853 mg, 100%). H NMR (400 MHz, CDCl3) * 2.89
◦
(dd, 2H, CH2CH CH2), 2.43 (dd, 2H, CH2CHVCH2),
centrifuged at 6000g for 5 min at 4 C. The pellet was
2
2
.19 to 2.12 (m, 1H, CH2CHCH2), 1.40 to 1.26 (m,
homogenized in 0.5 mL fresh HBSS on ice using a
Potter–Elvehjem homogenizer attached to a Hitachi
8H, CH2CH2V), 0.88 (t, 3H, CH3). 13C NMR (100
DOI 10.1002/jps
JOURNAL OF PHARMACEUTICAL SCIENCES