**3. Results**

### **3.1 Characterization of crystalline forms of paclitaxel**

Crystalline forms of paclitaxel obtained from different sources were determined by DSC, xray diffraction and scanning electron microscopy. Paclitaxel can exist as different polymorphs having distinct physical properties, which could influence the manufacturing process of the formulations (Liggins et al., 1997; Lee et al., 2001). Paclitaxel obtained from Samyang Genex (Genexol, Korea) had the glass transition temperature at 150 C and an exothermic transition at 220 C whereas paclitaxel obtained from Indena had the melting transition at 210 C as shown in Figure 2, corresponding to amorphous and anhydrous crystalline forms, respectively, as shown in the literature (Liggins et al., 1997). X-ray diffraction data revealed the differences in the crystallinity of paclitaxel. Diffraction pattern of Genexol showed two broad scattering peaks centered at *ca*. 10 and 20 characteristic of the amorphous form. Paclitaxel from Indena, on the other hand, revealed a pattern with strong and sharp diffraction peaks at 5.7 and 12.6 indicating a highly ordered structure. Surface morphology was also visualized by SEM. Genexol was observed to be in the powder form with highly contoured surfaces. We note that the grain size or the surface area of the powder varied depending on the lot numbers of Genexol (data not shown). For instance, Genexol 131 was composed of powders with wrinkled surfaces whereas Genexol 183 contained smooth and round particles as well when observed by SEM. Needle-like crystals were observed for paclitaxel from Indena. Based on DSC, XRD and SEM experiments,

concentrations in blood were calculated based on a standard curve of paclitaxel in blank

Suspension of NCI-H358 human non-small cell lung cancer cells (1.2×107 cells/mouse), purchased from American Type Culture Collection (ATCC, Manassas, VA), was injected subcutaneously to the dorsal flank of male Balb/c athymic mice (8 weeks). When the tumor volume (length × width × height × 0.5236) reached *ca*. 100 mm3 in 10 days after the injection (day 0), the experimental groups were divided at random into three groups (n=8). On days 1, 2, 3, 4 and 5, G2 formulation (DHP107) was administered orally at a dose of 50 mg/kg (G2). For controls, mice injected intravenously with diluted Taxol® (Taxol, 10 mg/kg) and

X-Ray diffraction (XRD) measurements were made by using an x-ray diffractometer (D8 Discover, Bruker, Karlsruhe, Germany) with the general area detector diffraction system (GADDS, Bruker, Karlsruhe, Germany). The Cu Kα radiation of wavelength 1.542 Å was provided by the x-ray generator (FL CU 4 KE, Bruker, Karlsruhe, Germany) operating at 40 kV and 45 mA. Sample-to-detector distance was 300 mm. Exposure time was 1 ~ 5 h. To avoid air scattering, the beam path was filled with helium. The surface morphology of paclitaxel was observed by scanning electron microscopy (SEM; Hitachi S-2460N, Japan) at an accelerating voltage of 15 kV after Pt/Au sputter coating (Hitachi E1010 Ion sputter,

Crystalline forms of paclitaxel obtained from different sources were determined by DSC, xray diffraction and scanning electron microscopy. Paclitaxel can exist as different polymorphs having distinct physical properties, which could influence the manufacturing process of the formulations (Liggins et al., 1997; Lee et al., 2001). Paclitaxel obtained from Samyang Genex (Genexol, Korea) had the glass transition temperature at 150 C and an exothermic transition at 220 C whereas paclitaxel obtained from Indena had the melting transition at 210 C as shown in Figure 2, corresponding to amorphous and anhydrous crystalline forms, respectively, as shown in the literature (Liggins et al., 1997). X-ray diffraction data revealed the differences in the crystallinity of paclitaxel. Diffraction pattern of Genexol showed two broad scattering peaks centered at *ca*. 10 and 20 characteristic of the amorphous form. Paclitaxel from Indena, on the other hand, revealed a pattern with strong and sharp diffraction peaks at 5.7 and 12.6 indicating a highly ordered structure. Surface morphology was also visualized by SEM. Genexol was observed to be in the powder form with highly contoured surfaces. We note that the grain size or the surface area of the powder varied depending on the lot numbers of Genexol (data not shown). For instance, Genexol 131 was composed of powders with wrinkled surfaces whereas Genexol 183 contained smooth and round particles as well when observed by SEM. Needle-like crystals were observed for paclitaxel from Indena. Based on DSC, XRD and SEM experiments,

fed orally with the vehicle only (eG2) on days 1, 2, 3, 4 and 5 were also observed.

pooled animal blood with the internal standard.

**2.9 Characterization of crystalline forms of paclitaxel** 

**3.1 Characterization of crystalline forms of paclitaxel** 

**2.8 Tumor experiment** 

Japan).

**3. Results** 

Fig. 2. Differential Scanning calorimetry, x-ray diffraction and scanning electron microscopy of paclitaxel obtained from of Genexol (upper panels) and Indena (lower panels).

we confirmed that Paclitaxel from Samyang Genex and Indena were in amorphous and anhydrous crystalline forms, respectively.

Due to the differences in the grain size and crystalline forms, we used two different procedures in preparing the oral formulations. Genexol 131 was readily soluble in all of the lipid mixtures in Table 2 when sonicated for *ca*. 30 s. Genexol 183, which had larger grains than Genexol 131, and paclitaxel from Indena did not dissolve in the lipid mixture. In these cases, paclitaxel was solubilized completely in the mixture of methylene chloride and triglyceride. Methylene chloride was evaporated completely from the mixture before other ingredients were added to prepare the formulations in Table 3.

#### **3.2 Physical properties of oral paclitaxel formulations**

Oral paclitaxel formulations existed as oil/wax mixtures at ambient temperatures, but formed clear liquid at 37 C except for the Formulation T12 (Table 2). The T12 formulation existed as solid wax at ambient temperatures. Thermal behavior of the formulations containing different triglycerides was investigated by performing DSC (Figure 3A).

The thermograms were identical with or without paclitaxel in the formulations, and those with paclitaxel are shown in the Figure. Tween 80, liquid at room temperature, did not show any phase transition in the temperature range from 0 to 60 C. Lamellar crystalline-to-fluid isotropic, or the chain melting, phase transition of monoolein was observed at 32 C, which is similar to the values reported for pure monoolein (Briggs et al., 1996; Qiu & Caffrey, 2000) or Myverol 18-99K (Clogston, 2000) in the literature. The chain melting transition of monoolein for the monoolein/Tween 80 (55.0:16.5 by weight) mixture was observed at 26 C, since Tween 80 lowered the transition temperature of monoolein. In the formulations T2, T4 and T6, only the chain melting transition of monoolein was observed because triacetin,

Development, Optimization and Absorption Mechanism of

triglycerides (Figure 3B).

**injection** 

DHP107, Oral Paclitaxel Formulation for Single-Agent Anticancer Therapy 365

the undercooled liquid for the measurement. Solubility of paclitaxel was *ca*. 250 ± 30 mg/ml for the formulation containing triacetin, but was *ca*. 120 ± 40 mg/ml for those with other

Oral paclitaxel formulations were warmed to body temperature and administered to male ICR mice. We note that not the dispersions but the oily formulations were administered, and no other active pharmaceutical ingredients were given to the animals. Diluted Taxol® was given intravenously as a control. Paclitaxel concentration in blood after oral administration of formulation G2 (DHP107, paclitaxel dose of 50 mg/kg) and intravenous injection of Taxol® (10 mg/kg) was plotted as a function of time in Figure 4A (normal scale) and Figure 4B (logarithmic scale). Paclitaxel concentration in blood was 60.2 μg/ml in 1 min after intravenous injection, and dropped to *ca*. 6.2 and 0.8 μg/ml and in 0.5 and 3 h, respectively. Paclitaxel concentration in blood increased and became 1.2 and 2.1 μg/ml at 1 and 3 h, respectively, after oral administration of DHP107. Pharmacokinetic parameters are listed in Table 2. The bioavailability [(BA) (%) = (AUCoral / AUCiv) · (Doseiv/ Doseoral) ×100] of DHP107 in mice was *ca*. 14 %. Since the plasma concentration of paclitaxel above a threshold value of 85.3 ng/ml (dashed line in Figure 4B) was proven to be pharmacologically active,

Treatment group Triglyceride type Tmax (h) Cmax (μg/ml) AUC0-9

T2 Triacetin 3 0.4 1.6 T4 Tributyrin 3 1.5 5.4 T6 Tricaproin 3 3.1 12.0 T8 Tricaprylin 1 2.7 8.9 T10 Tricaprin 1 2.2 8.4 T12 Trilaurin 1 1.5 4.9 Table 2. Pharmacokinetic parameters of paclitaxel after oral administration (50 mg/kg dose) of the formulations containing different triglycerides to Balb/c mice. The composition of the formulations was paclitaxel:monoolein:triglyceride:Tween 80 = 1.0:55.0:27.5:16.5 by weight.

Paclitaxel formulations prepared with various triglycerides (paclitaxel: monoolein: triglyceride:Tween 80 = 1.0:55.0:27.5:16.5 by weight) were administered orally at 50 mg/kg dose to male ICR mice (Table 2, Figure 4C). AUC values were 12.1 ± 2.6, 8.9 ± 1.8 and 8.4 ± 2.7 μg·h/ml for T6, T8 and T10 groups, respectively, with no statistical differences (p<0.15 by Student *t*-test). In case of T2, T4 and T12 groups, AUC of paclitaxel was 1.6 ± 0.5 (p<0.003 compared the AUC with T6 formulation), 5.4 ± 0.7 (p<0.01) and 4.9 ±1.6 μg·h/ml (p<0.01), respectively. Maximum concentration of paclitaxel in blood (Cmax) was also the highest for the formulation with tricaproin (T6) and was 3.2 ± 0.7 μg·h/ml. Interestingly, the time to reach Cmax (Tmax) was 3 h for the formulations with shorter chain triglycerides (T2, T4 and

(μgh /ml)

**3.4 Pharmacokinetics of oral paclitaxel administration and intravenous Taxol** 

DHP107 could be effective for more than 8 h (Huizing et al., 1997).

**3.5 Oral administration of formulations with different triglycerides** 

T6) and 1 h for T8, T10 and T12 groups.

Fig. 3. A) Heating thermograms obtained from the formulations prepared with different triglycerides (T2 ~ T12, in Table 2), Tween 80, monoolein and monoolein/Tween 80 mixture (55.0:16.5 by weight). The concentration of paclitaxel was 1 %(w/w) in all formulations. B) Solubility of paclitaxel in the formulations containing monoolein, triglyceride and Tween 80 at 55.0:27.5:16.5 by weight at 37 C.

tributyrin and tricaprin were immiscible with solid monoolein. We could identify visually the phase separation of these triglycerides below *ca.* 26 C. In T8 formulation, chain melting transitions of tricaprylin and monoolein were observed at 8 and 23 C, respectively. In case of T10 formulation, single transition peak from the melting transition of the eutectic mixture of monoolein and tricaprin (2:1 by weight) was observed at 26 C (Roh et al., 2004). The chain melting transitions of monoolein and trilaurin were observed at 32 and 41 C, respectively, for T12 formulation. Results show that all the formulations existed as solid/liquid or solid/solid mixtures at room temperature, but transforms into the singlephase liquid when heated to the body temperature for T2 ~ T10 formulations or above 45 C for T12 formulation. Paclitaxel was solubilized well inside all of the formulations in the temperature range studied when observed by polarized light microscopy (data not shown).

#### **3.3 Solubility of paclitaxel in oral formulations**

The solubility of paclitaxel in the oral formulations with different triglycerides was determined at 37 C. Mixtures of monoolein/triglyceride/Tween 80 were prepared at 55.0:27.5:16.5 by weight and warmed to melt. Paclitaxel in powder form (Genexol, Samyang Genex, lot G131) was added stepwise to these mixtures until undissolved aggregates were observed. The mixtures were vortexed for 10 s and sonicated for 3 min after each addition at 37 C. The formulation containing trilaurin was heated to 60 C and cooled to 37 C to obtain

Fig. 3. A) Heating thermograms obtained from the formulations prepared with different triglycerides (T2 ~ T12, in Table 2), Tween 80, monoolein and monoolein/Tween 80 mixture (55.0:16.5 by weight). The concentration of paclitaxel was 1 %(w/w) in all formulations. B) Solubility of paclitaxel in the formulations containing monoolein, triglyceride and Tween 80

tributyrin and tricaprin were immiscible with solid monoolein. We could identify visually the phase separation of these triglycerides below *ca.* 26 C. In T8 formulation, chain melting transitions of tricaprylin and monoolein were observed at 8 and 23 C, respectively. In case of T10 formulation, single transition peak from the melting transition of the eutectic mixture of monoolein and tricaprin (2:1 by weight) was observed at 26 C (Roh et al., 2004). The chain melting transitions of monoolein and trilaurin were observed at 32 and 41 C, respectively, for T12 formulation. Results show that all the formulations existed as solid/liquid or solid/solid mixtures at room temperature, but transforms into the singlephase liquid when heated to the body temperature for T2 ~ T10 formulations or above 45 C for T12 formulation. Paclitaxel was solubilized well inside all of the formulations in the temperature range studied when observed by polarized light microscopy (data not shown).

The solubility of paclitaxel in the oral formulations with different triglycerides was determined at 37 C. Mixtures of monoolein/triglyceride/Tween 80 were prepared at 55.0:27.5:16.5 by weight and warmed to melt. Paclitaxel in powder form (Genexol, Samyang Genex, lot G131) was added stepwise to these mixtures until undissolved aggregates were observed. The mixtures were vortexed for 10 s and sonicated for 3 min after each addition at 37 C. The formulation containing trilaurin was heated to 60 C and cooled to 37 C to obtain

at 55.0:27.5:16.5 by weight at 37 C.

**3.3 Solubility of paclitaxel in oral formulations** 

the undercooled liquid for the measurement. Solubility of paclitaxel was *ca*. 250 ± 30 mg/ml for the formulation containing triacetin, but was *ca*. 120 ± 40 mg/ml for those with other triglycerides (Figure 3B).

#### **3.4 Pharmacokinetics of oral paclitaxel administration and intravenous Taxol injection**

Oral paclitaxel formulations were warmed to body temperature and administered to male ICR mice. We note that not the dispersions but the oily formulations were administered, and no other active pharmaceutical ingredients were given to the animals. Diluted Taxol® was given intravenously as a control. Paclitaxel concentration in blood after oral administration of formulation G2 (DHP107, paclitaxel dose of 50 mg/kg) and intravenous injection of Taxol® (10 mg/kg) was plotted as a function of time in Figure 4A (normal scale) and Figure 4B (logarithmic scale). Paclitaxel concentration in blood was 60.2 μg/ml in 1 min after intravenous injection, and dropped to *ca*. 6.2 and 0.8 μg/ml and in 0.5 and 3 h, respectively. Paclitaxel concentration in blood increased and became 1.2 and 2.1 μg/ml at 1 and 3 h, respectively, after oral administration of DHP107. Pharmacokinetic parameters are listed in Table 2. The bioavailability [(BA) (%) = (AUCoral / AUCiv) · (Doseiv/ Doseoral) ×100] of DHP107 in mice was *ca*. 14 %. Since the plasma concentration of paclitaxel above a threshold value of 85.3 ng/ml (dashed line in Figure 4B) was proven to be pharmacologically active, DHP107 could be effective for more than 8 h (Huizing et al., 1997).


Table 2. Pharmacokinetic parameters of paclitaxel after oral administration (50 mg/kg dose) of the formulations containing different triglycerides to Balb/c mice. The composition of the formulations was paclitaxel:monoolein:triglyceride:Tween 80 = 1.0:55.0:27.5:16.5 by weight.

#### **3.5 Oral administration of formulations with different triglycerides**

Paclitaxel formulations prepared with various triglycerides (paclitaxel: monoolein: triglyceride:Tween 80 = 1.0:55.0:27.5:16.5 by weight) were administered orally at 50 mg/kg dose to male ICR mice (Table 2, Figure 4C). AUC values were 12.1 ± 2.6, 8.9 ± 1.8 and 8.4 ± 2.7 μg·h/ml for T6, T8 and T10 groups, respectively, with no statistical differences (p<0.15 by Student *t*-test). In case of T2, T4 and T12 groups, AUC of paclitaxel was 1.6 ± 0.5 (p<0.003 compared the AUC with T6 formulation), 5.4 ± 0.7 (p<0.01) and 4.9 ±1.6 μg·h/ml (p<0.01), respectively. Maximum concentration of paclitaxel in blood (Cmax) was also the highest for the formulation with tricaproin (T6) and was 3.2 ± 0.7 μg·h/ml. Interestingly, the time to reach Cmax (Tmax) was 3 h for the formulations with shorter chain triglycerides (T2, T4 and T6) and 1 h for T8, T10 and T12 groups.

Development, Optimization and Absorption Mechanism of

Treatment group

G2

G5 (DHP107, Nonfasting)

Treatment group

respectively.

**3.7 Fasting vs. non-fasting conditions** 

the absorption of paclitaxel.

Paclitaxel Dose (mg/kg)

Paclitaxel Dose (mg/kg)

DHP107, Oral Paclitaxel Formulation for Single-Agent Anticancer Therapy 367

80

G1 25 (p.o.) 0.5 55.5 27.5 16.5 - - 3 1.3 5.2 Amorphous

(DHP107) 50 (p.o.) 1.0 55.0 27.5 16.5 - - 3 2.0 11.0 Amorphous G3 75 (p.o.) 1.5 54.5 27.5 16.5 - - 1 2.0 4.7 Amorphous G4 100 (p.o.) 2.0 54.0 27.5 16.5 - - 1 1.5 3.1 Amorphous

G6 50 (p.o.) 1.0 55.0 27.5 16.5 - - 3 1.6 8.3 Crystalline G7 50 (p.o.) 1.0 66.0 33.0 - - - 1 2.7 6.3 Amorphous eG2 0 (p.o.) 0.0 56.0 27.5 16.5 - - - - - - Taxol 10 (i.v.) 0.6 - - - 57.0 42.4 0.016 60.2 15.7 Amorphous

Composition [%(w/w)] Tmax

G8 50 (p.o.) 0.3 16.2 8.0 5.5 70 - 3 1.2 4.6 Vortex G9 50 (p.o.) 0.3 16.2 8.0 5.5 - 70 3 1.8 7.5 Vortex G10 50 (p.o.) 0.3 16.2 8.0 5.5 - 70 1 1.6 7.1 Sonication

We prepared the formulations with different Paclitaxel contents while fixing the weight ratio of monoolein:tricaprylin:Tween 80 to 55.0:27.5:16.5 by weight (G1, G2, G3 and G4 in Table 3, Figure 4D). Bioavailability was 13 % and 14 % when the concentration of paclitaxel was 0.5 and 1 %(w/w), respectively, in the formulation. When the concentration was 1.5 and 2.0 %(w/w), bioavailability decreased with increasing paclitaxel dose and was 4 % and 2 %,

When the formulation is given orally, the fullness of stomach can influence the pharmacokinetics of the administered drug. Throughout the experiments, we administered the oral formulations after 8 h of fasting. In G5, however, we fed DHP107 to mice with free access to food and water before and after the drug administration in order to observe the influence of stomach emptiness on the absorption of the drug. Under the non-fasting condition, Cmax increased to 3.4 μg/ml when compared to the fasting condition (2.0 μg/ml) and Tmax was reduced to 1 h (Figure 4E). The AUC values for non-fasting and fasting conditions were 15.3 (20 % BA) and 11.0 μg·h /ml (14 % BA), respectively. We could conclude that the food in the gastrointestinal tract did not interfere with, but rather helped

Table 3. Compositions of paclitaxel formulations and pharmacokinetic parameters of

**3.6 Oral administration of formulations with different paclitaxel contents** 

<sup>80</sup>Syrup Water

Paclitaxel Monoolein Tricaprylin Tween

paclitaxel after intravenous or oral administration in Balb/c mice.

of paclitaxel Paclitaxel Monoolein Tricaprylin Tween

EL Ethanol

Cremophor

50 (p.o.) 1.0 55.0 27.5 16.5 - - 1 3.4 15.3 Amorphous

Tmax (h)

(h)

Cmax (μg/ml) AUC0-9 (μg h

/ml) Dispersing method

Cmax (μg/ml) AUC0-9 (μg h /ml)

Crystallinity

Composition [%(w/w)]

Fig. 4. Mean blood concentration of paclitaxel after intravenous administration of Taxol® and administration of oral formulations. Comparison between intravenous Taxol (⊞, 10 mg/kg) and oral DHP107 (G2, , 50 mg/kg) is shown in normal (A) and logarithmic (B) scales. The dashed line in B) indicates the pharmacologically effective concentration (85.3 ng/ml). Oral administration of paclitaxel formulations C) with different triglycerides (T2: , T4: , T6: , T8: , T10: , T12: ), D) with different paclitaxel contents (G1: , 5 mg paclitaxel/ml formulation, G2, DHP107: , 10 mg/ml, G3: , 15 mg/kg, G4: , 20 mg/ml), E) under the fasting (G2, DHP107: ) and non-fasting (G5: ) conditions, F) prepared with crystalline (G6: ) and amorphous (G2, DHP107: ) paclitaxel, G) with (G2, DHP107: ) or without (G7: ) Tween 80, and H) dispersed in syrup (G8: ) or in water (G9: ) by vortexing and in water by sonication (G10: ) or given per se (G2, DHP107: ). The oral dose of paclitaxel was 50 mg/kg except for G1 (25 mg/kg), G3 (75 mg/kg) and G4 (100 mg/kg).


Development, Optimization and Absorption Mechanism of DHP107, Oral Paclitaxel Formulation for Single-Agent Anticancer Therapy 367

Fig. 4. Mean blood concentration of paclitaxel after intravenous administration of Taxol® and administration of oral formulations. Comparison between intravenous Taxol (⊞, 10 mg/kg) and oral DHP107 (G2, , 50 mg/kg) is shown in normal (A) and logarithmic (B) scales. The dashed line in B) indicates the pharmacologically effective concentration (85.3 ng/ml). Oral administration of paclitaxel formulations C) with different triglycerides (T2: , T4: , T6: , T8: , T10: , T12: ), D) with different paclitaxel contents (G1: , 5 mg paclitaxel/ml formulation, G2, DHP107: , 10 mg/ml, G3: , 15 mg/kg, G4: , 20 mg/ml), E) under the fasting (G2, DHP107: ) and non-fasting (G5: ) conditions, F) prepared with crystalline (G6: ) and amorphous (G2, DHP107: ) paclitaxel, G) with (G2, DHP107: ) or without (G7: ) Tween 80, and H) dispersed in syrup (G8: ) or in water (G9: ) by vortexing and in water by sonication (G10: ) or given per se (G2, DHP107: ). The oral dose of paclitaxel was 50 mg/kg except for G1 (25 mg/kg), G3 (75 mg/kg) and G4 (100

mg/kg).

Table 3. Compositions of paclitaxel formulations and pharmacokinetic parameters of paclitaxel after intravenous or oral administration in Balb/c mice.

#### **3.6 Oral administration of formulations with different paclitaxel contents**

We prepared the formulations with different Paclitaxel contents while fixing the weight ratio of monoolein:tricaprylin:Tween 80 to 55.0:27.5:16.5 by weight (G1, G2, G3 and G4 in Table 3, Figure 4D). Bioavailability was 13 % and 14 % when the concentration of paclitaxel was 0.5 and 1 %(w/w), respectively, in the formulation. When the concentration was 1.5 and 2.0 %(w/w), bioavailability decreased with increasing paclitaxel dose and was 4 % and 2 %, respectively.

#### **3.7 Fasting vs. non-fasting conditions**

When the formulation is given orally, the fullness of stomach can influence the pharmacokinetics of the administered drug. Throughout the experiments, we administered the oral formulations after 8 h of fasting. In G5, however, we fed DHP107 to mice with free access to food and water before and after the drug administration in order to observe the influence of stomach emptiness on the absorption of the drug. Under the non-fasting condition, Cmax increased to 3.4 μg/ml when compared to the fasting condition (2.0 μg/ml) and Tmax was reduced to 1 h (Figure 4E). The AUC values for non-fasting and fasting conditions were 15.3 (20 % BA) and 11.0 μg·h /ml (14 % BA), respectively. We could conclude that the food in the gastrointestinal tract did not interfere with, but rather helped the absorption of paclitaxel.

Development, Optimization and Absorption Mechanism of

DHP107, Oral Paclitaxel Formulation for Single-Agent Anticancer Therapy 369

Fig. 5. Antitumor activity of DHP107 in male Balb/c athymic mice, subcutaneously injected with suspension of NCI-H358 cells (1.2×107 cells/mouse). A) The entire tumor tissue

removed surgically after the experiment. B) The volume of tumor for the oral vehicle control

Paclitaxel was commercially available in at least two different polymorphs. Amorphous paclitaxel was readily soluble in our oral formulations at 10 mg/ml when sonicated for 30 s. Crystalline paclitaxel, on the other hand, did not dissolve in the oily formulations directly. We had to dissolve crystalline paclitaxel in the tricaprylin/methylene chloride mixture completely, and to remove the solvent in turn to obtain the oily solution of paclitaxel/tricaprylin before adding monoolein and Tween 80. Even though paclitaxel could also be dissolved in methylene chloride/tricaprylin/monoolein/Tween 80 as well as in methylene chloride/tricaprylin, monoolein and Tween 80 were not added to the mixture until after evaporating the solvent to minimize the oxidation of these materials containing unsaturated hydrocarbons. Pharmacokinetic study showed that AUC values were identical statistically when paclitaxel

DSC study was performed for the formulations with different triglycerides. In the heating thermograms, two endothermic transitions were observed corresponding to the chain melting transitions of monoolein and triglycerides for T8 and T12 formulations. Chain melting transition of triacetin, tributyrin and tricaproin were not observed since the phase transition temperatures of these triglycerides were below 0 C. There was only a single endothermic transition for the tricaprin/monoolein mixture at the weight ratio of 2:1 since

(eG2, ), intravenous Taxol® (, 10mg/kg) and oral DHP107 (G2, , 50 mg/kg).

from different vendors or different preparation processes was used (Figure 4F).
