Improving solubility and cellular absorption of Paclitaxel with solid lipid nanoparticles and
cyclodextrinJong-Suep Baek, Jae-Woo So, Ji-Sook Hwang, Cheong-Weon Cho
College of Pharmacy, Chungnam National University, Daejeon 305-764, South Korea.
INTRODUCTION
AIMS
Paclitaxel (PTX), the first of a new class of microtubule stabilizing agents, is recognized as an effective chemotherapeutic agent for a wide variety of solid tumors. Clinical application of this highly effective drug in the treatment of cancer is limited because of its poor aqueous solubility and poor oral bioavailability. Therefore, PTX-incorporated SLN, PTX-HPCD and surface-modified PTX-incorporated SLN were prepared and evaluated by the physicochemical and biopharmaceutical characterization in this study. The major peaks of PTX were disappeared in the FT-IR spectra for surface-modified PTX-incorporated SLN. The BET surface area of PTX –incorporated SLN (PS3), and surface-modified PTX-incorporated SLN (FM4) was 4.09 m2/g and 4.79 m2/g, respectively. Based on the increase of BET surface area of FM4 compared to that of PS3, FM4 showed a 20% of dissolution and the cellular uptake of 29-fold increase compared to that of PS3. Taxol formulation showed 78% of cell viability and FM4 showed 72% of cell viability with 10uM of PTX, indicating FM4 did not show the higher toxicity compared to Taxol formulation. Therefore, FM4 could be good carrier for improving solubility and cellular absorption of water insoluble drug.
EXPERIMENTAL METHOD
RESULTS AND DISCUSSION
CONCLUSIONS
1. Preparation of SLN and SLN+HPCD
1. Solubility and in vitro release
2. SEM and particle characteristics
• For improving solubility and increasing cellular uptake of PTX into Caco-2 cells, PTX-incorporated SLN, PTX-HPCD and surface-modified PTX-incorporated SLN were prepared and evaluated by the physicochemical and biopharmaceutical characterization. The major peaks of PTX were disappeared in the FT-IR spectra for surface-modified PTX-incorporated SLN. Surface-modified PTX-incorporated SLN with HPCD showed a 20% of dissolution and the cellular uptake of 29-fold increase compared to that of PTX-incorporated SLN.
Stearic acid (Lipid)
10mg PTX in EtOH
70℃ water bath
Sonification 15 min in 70 water bath ℃
Freeze-drying
4℃ 10% mannitol
Fig 1. low permeability and low solubility of paclitaxel in BCS class
Permeability
Solubility
I
II
PTX : low solubility
low permeability
III
IV
Sonification 15 min in 4 water bath ℃
Surfactant (Poloxamer 188
and lecithin)
10% HPCD
Emulsifying step
Cooling step
Freeze-drying step
PTX
HPCD
PTX incorporated into HPCD
Physical mixture
PTX
Lipid
SLN
SLN+HPCD
SLN+HPCD (physical mixture)
•SLN•HPCD•SLN+HPCD
Table 1. Solubility of each formulation
Fig 2. Dissolution profile of PTX
Fig 3. SEM images
of PTX (A), SLN (B), SLN+HPCD (C)
• Particles revealed spherical shape and SLN+HPCD has smaller particle size than SLN.
• Zeta value was enough to keep in stable status of particles.
Table 2. Physical characteristic
Fig 6. FT-IR spectra of HPCD (A) and SLN+HPCD (B)
(A) (B)
(A) Intensity of the PTX major peak (1730cm-1, 1250cm-1) was reduced in the case of HPCD incorporation. It was evidence of an interaction at the solid state between PTX and HPCD.
(B) Intensity of the lipid major peak (2850cm-1 , 1670cm-1) was reduced in the case of SLN+HPCD. It was evidence that lipid’s surface was surrounded by HPCD.
Fig 7. Caco-2 cellular uptake of each formula
1. Taxol and HPCD was below the LOQ (<0.015%)
2. In case of SLN, Uptake % of PTX was 0.129 (±0.046)%
3. In case of SLN+HPCD, Uptake % was 29 times higher than that of SLN
•Considering the low solubility of PTX, these formulations significantly increased the PTX solubility.
•During 36 hours, SLN-HPCD has the highest dissolution profile.
•After making the SLN formulation, the lipid’s crystallinity was decreased.
0 20 40 60
0
20000
40000
60000
Inte
nsity (
co
un
ts)
Theta
Lipid SLN Physicalmixture
50 100 150
-40
-20
0
He
at flo
w (
mW
)
Temperature
Lipid Physical mixture SLN
Fig 5. DSC (A) and XRD (B)
(A) (B)
a) b) c)
1. 5uM as a loading concentration of cellular uptake study was optimal. (72 % viability in SLN+HPCD)
2. IC50 of each formulation is approximately 10~100uM.
3. Because of high permeability of PTX+HPCD, it has more toxicity than Taxol at Caco-2 cell line.
Fig 8. Caco-2 cell cytotoxicity study of SLN+HPCD and Taxol
0
20
40
60
80
100
120
140
0 0.001 0.01 0.1 1 5 10 100
Concentration (uM)
Cell v
iab
ilit
y (
%)
SLN+HPCD
Taxol
Injection speed - 1.5mL/min
4. DSC and XRD
5. FT-IR
6. Cellular uptake study
7. Cytotoxicity study
3. Surface tension
0
10
20
30
40
50
60
70
50 75 100
Weight (mg)
Tens
ion
(mN/
m)
LecithinPoloxamer 188
Fig 4. Surface tension values of SLN with different surfactant amount
* Both lecithin and poloxamer 188 samples, tension was lowest at 75mg
(A) (B) (C)
0
20
40
60
80
100
120
cont
rol
1pM
10pM
100p
M1n
M10
nM
100n
M1u
M10
uM
Concentration (uM)
Cel
l via
bilit
y (%
)
SLNSLN- CD
Fig 9. HeLA cell cytotoxicity study of SLN and SLN+HPCD
1. IC50 of SLN+HPCD is approximately 10M.