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Bioactive Constituents, Metabolites, and Functions
Supersaturable self-emulsifying drug delivery system of krill oil with improved oral absorption and hypotriglyceridemic function Yoshiki Seto, Chikara Morizane, Kodai Ueno, Hideyuki Sato, and Satomi Onoue J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.8b00693 • Publication Date (Web): 14 May 2018 Downloaded from http://pubs.acs.org on May 14, 2018
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Journal of Agricultural and Food Chemistry
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Supersaturable self-emulsifying drug delivery system of krill oil with improved
2
oral absorption and hypotriglyceridemic function
3 4
Yoshiki Seto, Chikara Morizane, Kodai Ueno, Hideyuki Sato, and Satomi Onoue*
5 6
Department of Pharmacokinetics and Pharmacodynamics, School of Pharmaceutical
7
Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
8 9 10 11 12 13 14 15 16 17 18 19
*Corresponding author, Department of Pharmacokinetics and Pharmacodynamics,
20
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku,
21
Shizuoka 422-8526, Japan.
22
[email protected] Tel.: +81-54-264-5630; Fax: +81-54-264-5636, E-mail:
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Page 2 of 32
ABSTRACT
25
This study aimed to develop a supersaturable self-emulsifying drug delivery
26
system (S-SEDDS) of krill oil (KO), a rich source of docosahexaenoic acid and
27
eicosapentaenoic acid (EPA), to improve its hypotriglyceridemic function.
28
of KO (KO/S-SEDDS) was prepared by the addition of lysolecithin, glycerin, and
29
hydroxypropyl methylcellulose (HPMC).
30
HPMC
31
physicochemical and pharmacokinetic properties of KO samples were characterized,
32
and the hypotriglyceridemic function of KO/S-SEDDS was evaluated.
33
droplets in KO/SEDDS and KO/S-SEDDS with a mean diameter of ca. 270 nm could be
34
observed compared with KO and KO/HPMC.
35
tended to enhance the dissolution behavior of KO, and the S-SEDDS formulation
36
improved the dissolution behavior of KO due to micronized droplets and the addition of
37
HPMC.
38
basis of the pharmacokinetic profiling of EPA, and repeated oral administration of
39
KO/S-SEDDS (250 mg-KO/kg/day) for 7 days had a potent hypotriglyceridemic effect
40
on rats with corn oil-induced hypertriglyceridemia compared with orally administered
41
KO.
42
option to enhance the nutraceutical properties of KO.
(KO/HPMC)
were
also
S-SEDDS
SEDDS of KO (KO/SEDDS) and KO with
prepared
for
comparison
purposes.
The
Micronized
Both KO/HPMC and KO/S-SEDDS
KO/S-SEDDS (60 mg-EPA/kg) improved the oral absorption of KO on the
Based on these findings, the S-SEDDS approach might be an efficacious dosage
43 44
KEYWORDS: krill oil, oral absorption, supersaturable self-emulsifying drug delivery
45
system, hypotriglyceridemic function
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ABBREVIATIONS: AUC0–8h, area under the concentration versus time curve from 0
48
to 8 h; AUC0–24h, area under the concentration versus time curve from 0 to 24 h; Cmax,
49
maximum concentration; DHA, docosahexaenoic acid; DLS, dynamic light scattering;
50
EPA,
51
methylcellulose, KO, krill oil; PK, pharmacokinetic; SEDDS, self-emulsifying drug
52
delivery system; SIR, selected ion recording; S-SEDDS, supersaturable self-emulsifying
53
drug delivery system; TEM, transmission electron microscopy; TG, triglyceride; Tmax,
54
time to reach the maximum concentration; UPLC/ESI-MS, ultra-performance liquid
55
chromatography equipped with electrospray ionization mass spectrometry; VLDL, very
56
low-density lipoprotein
eicosapentaenoic
acid;
GI,
gastrointestinal;
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HPMC,
hydroxypropyl
Journal of Agricultural and Food Chemistry
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Page 4 of 32
1. Introduction
58
Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), essential
59
omega-3 polyunsaturated fatty acids, have various biological effects, including
60
hypolipidemic and antithrombolic effects 1, 2, and the main sources of DHA and EPA are
61
marine oils 3.
62
their oral bioavailability is limited 5.
63
(Euphausia superba), is abundant in DHA and EPA 6.
64
phospholipids in KO contain DHA and EPA, and DHA and EPA in KO are mainly
65
present in the form of phospholipids (ca. 70% of total DHA; and ca. 70% of total EPA) 4,
66
6
67
because they are emulsified in water
68
addition, KO was reported to contain the free forms of DHA and EPA (ca. 10% of total
69
DHA; and ca. 10% of total EPA); however, the free and phospholipid forms of DHA
70
and EPA in fish oil had been negligible in the previous report 4.
71
considered as an attractive source of DHA and EPA with enhanced oral absorption.
72
Although KO was reported to have many health-promoting properties, such as
73
anti-inflammatory, hypoglycemic, and hypolipidemic effects
74
DHA and EPA levels after KO intake might be insufficient compared with fish oil 10, 11.
75
The intake of KO at 1–3 g/day has been needed to take full advantage of its biological
76
functions, and the similar or relatively higher daily doses of fish oil also provided its
77
attractive biological functions compared with KO
78
the delivery of KO is required to gain access to its attractive biological benefits at a low
79
intake.
80
.
Fish oil is rich in DHA and EPA as triglyceride (TG) forms 4; however, Krill oil (KO), extracted from Antarctic krill Both triacylglycerols and
The phospholipid forms have advantages for the oral absorption of DHA and EPA 7
and incorporated into cell membranes 5.
6, 10
.
In
Thus, KO is
6, 8-10
, increase in plasma
Thus, further improvement in
To improve oral absorption and biological functions of poorly-water soluble
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chemicals, several pharmaceutical technologies were used including solid dispersion,
82
nanoparticles, solid lipid nanoparticles, emulsion, and self-emulsifying drug delivery
83
system (SEDDS) 12-16.
84
had been applied lipid-based formulations
85
supersaturable SEDDS (S-SEDDS) have been developed as attractive lipid-based
86
formulations to enhance the solubility and oral bioavailability of drugs with a limited
87
aqueous solubility
88
co-surfactants, and substances, and it forms an emulsion in digestive fluid.
89
approach has been used to improve the bioavailability and functionality of hydrophobic
90
bioactive nutrients
91
self-emulsifying potential.
92
co-surfactant to KO led to the formation of a fine oil-in-water emulsion, and favorable
93
in vitro anti-inflammatory effects had been observed using KO-in water emulsion
94
S-SEDDS was developed by a water-soluble polymeric precipitation inhibitor to
95
stabilize substances in a temporary supersaturated state
96
bioavailability of some drugs delivered through S-SEDDS was observed compared with
97
that delivered through SEDDS
98
especially the S-SEDDS approach, may be effective for improving the nutraceutical
99
properties of KO; however, the feasibility of using S-SEDDS to improve the
100
Especially, omega-3 polyunsaturated fatty acids, fish oil or KO,
17
.
12, 14
.
In these technologies, SEDDS and
The SEDDS formulation consists of lipids, surfactants,
15, 18-20
.
21
Phospholipids are surfactants
SEDDS
; therefore, KO has a
In a previous report, the addition of glycerol as a
22-24
.
12
.
22
, and the enhanced oral
In this context, lipid-based formulations,
bioavailability of KO is still unclear.
101
In the present study, KO was incorporated into S-SEDDS by mixing KO,
102
lysolecithin, glycerin, and hydroxypropyl methylcellulose (HPMC) to enhance its oral
103
bioavailability and thus its potential health benefits.
104
of KO/S-SEDDS were characterized with focusing on the particle size and dissolution
The physicochemical properties
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105
behaviors.
An in vivo test was also employed to investigate the plasma EPA level after
106
oral administration of KO/S-SEDDS as an indicator of oral absorbability of KO.
107
hypotriglyceridemic effect after repeated oral administration of KO and KO/S-SEDDS
108
was evaluated by measuring the TG level in rat plasma after oral administration of corn
109
oil.
110
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2. Materials and Methods
112
2.1. Materials
113
KO was kindly supplied by ACRESS (Osaka, Japan).
The content rate of
114
phospholipids was 40% in KO, and the content rates of DHA and EPA as phospholipid
115
forms in KO were 6% and 13%, respectively.
116
mPa・s (2% solution at 20°C)] was kindly supplied by Shin-Etsu Chemical (Tokyo,
117
Japan).
118
non-hydrogenation] was obtained from Tsuji Seiyu (Mie, Japan).
119
tamoxifen were bought from Wako Pure Chemical industries (Osaka, Japan).
120
chemicals were purchased from commercial sources.
HPMC [TC-5○R , Grade: R, viscosity: 6
Lysolecithin [SLP-paste lyso, the content rate of phospholipids: 95–98%, Glycerin and All other
121 122 123
2.2. Preparation of KO formulations The selection of surfactant, co-surfactant, and polymer was with reference to 17, 22, 24, 25
124
the previous reports
125
KO to prepare KO/HPMC, and KO/HPMC was agitated with vortex mixer (VORTEX
126
Genius 3; IKA, Staufen, Germany) and mixed by inverting under room temperature.
127
To obtain KO/SEDDS, KO, lysolecithin, and glycerin were simultaneously mixed by
128
inverting, and the oily liquid state of KO/SEDDS was agitated using vortex mixer
129
under room temperature.
130
powder to prepared KO/SEDDS, and the oily liquid was agitated with a spatula and
131
mixed by inverting under room temperature.
132
are described in Table 1.
.
HPMC powder, a hydrophilic polymer, was added to
KO/S-SEDDS was prepared by the addition of HPMC
The compositions of KO formulations
133 134
2.3. Transmission electron microscopy (TEM)
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An aliquot of KO samples suspended in distilled water (40 mg-KO/mL) using
136
vortex mixer was placed on a Formvar 200 mesh Cu (Nisshin EM, Tokyo, Japan).
137
sample was allowed to stand for 1 min, and then any excess solution was removed by
138
blotting.
139
heptamolybdate tetrahydrate and allowed to dry.
140
HT7700 TEM System (Hitachi High-Technologies, Tokyo, Japan).
The
The samples were negatively stained with 1% (w/v) hexaammonium They were then visualized under an
141 142
2.4. Dynamic light scattering (DLS)
143
The particle size distributions of KO and its formulations after dispersion in
144
distilled water were measured by the DLS method using a Zetasizer Nano ZS
145
(MALVERN, Worcestershire, UK).
146
distilled water (ca. 0.13 mg-KO/mL), and the samples were mixed with vortex mixer
147
before measurement.
The KO and its formulations were suspended in
148 149
2.5. Dissolution tests
150
To evaluate initial self-emulsifying potentials of KO samples, dissolution
151
tests of KO samples (1 g-KO) were carried out in pH1.2 solution (100 mL) at 37°C
152
with constant stirring at 50 rpm using a magnetic stirrer (SST-66, Shimadzu, Kyoto,
153
Japan).
154
120 min) and centrifuged at 6,000×g for 5 min.
155
with the same volume of acetonitrile, and the absorbance at 241 nm, the maximum
156
absorption wavelength of diluted KO samples within 230–700 nm, was measured by
157
SAFIRE (TECAN, Männedolf, Switzerland) to determine the KO concentration.
Samples were collected at the indicated periods (0, 5, 15, 30, 45, 60, 90, and Obtained supernatants were diluted
158
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2.6. In vivo preparation
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Male Sprague-Dawley rats at 6–10 weeks of age (ca. 286±110 g body weight)
161
were purchased from SLC Inc. (Hamamatsu, Japan), housed in the laboratory with
162
free access to food and water, and maintained on a 12-h dark/light cycle in a room
163
with controlled temperature (24±1°C) and humidity (55±5%).
164
used in the present study were conducted according to the guidelines approved by the
165
Institutional Animal Care and Ethical Committee of the University of Shizuoka.
All of the procedures
166 167
2.7. Pharmacokinetic study after oral administration of KO samples
168
As an indicator of the oral absorption of KO, plasma EPA levels in rats were
169
measured after oral administration of KO samples.
Each KO sample was dispersed
170
in distilled water and orally administered to rats (60 mg-EPA/kg; the dose represents
171
the amount of phospholipid forms of EPA).
172
mL/kg) was orally administered.
173
tail vein of unanesthetized rats at the indicated times (0, 0.5, 1, 2, 3, 6, 12, and 24 h)
174
after oral administration of KO samples.
175
centrifugation (4°C, 10,000×g, 10 min) and stored at -20°C until they were analyzed.
176
The plasma samples (50 µL) were deproteinized by the addition of acetonitrile (150 µL)
177
containing an internal standard (tamoxifen) and centrifuged at 10,000×g for 10 min at
178
4°C.
179
USA), the plasma concentration of EPA was analyzed by ultra-performance liquid
180
chromatography with an electron spray ionization mass spectrometry (UPLC-ESI/MS)
181
system.
182
the concentration versus time curve from 0 to 24 h (AUC0–24h) was calculated using
As a control group, distilled water (10
Blood samples (300 µL) were collected from the
Plasma samples were obtained by
After filtration (0.20-µm membrane filter, Millex-LG; Millipore, Billerica, MA,
On the basis of the obtained EPA concentration in the plasma, the area under
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GraphPad Prism 5 for Windows (version 5.04, GraphPad Software, La Jolla, CA, USA).
184 185
2.8. UPLC analysis
186
The plasma concentration of EPA was determined by UPLC-ESI/MS analysis.
187
The UPLC-ESI/MS system consisted of a Waters Acquity UPLC system (Waters,
188
Milford, MA, USA), which included a binary solvent manager, a sample manager, a
189
column compartment, and a micromass SQ detector connected with Waters Masslynx
190
v. 4.1.
191
Φ2.1×50 mm; Waters) was used, and the column temperature was maintained at 40°C.
192
The standards and samples were separated using a gradient mobile phase consisting of
193
Milli-Q containing 5 mM ammonium acetate (A) and acetonitrile (B).
194
conditions of the mobile phase were 0–0.5 min, 70% B; 0.5–3.5 min, 70–95% B (linear
195
gradient curve), and the flow rate was set at 0.25 mL/min.
196
using selected ion recording (SIR) for specific m/z 302.5 for EPA [M–H]- and 372 for
197
tamoxifen [M+H]+.
A Waters Acuity UPLC BEH C18 (particle size: 1.7 µm and column size:
The gradient
Analysis was carried out
198 199
2.9. Functionality test of KO samples
200
Corn oil was used as a TG supplier, and 50% (w/w) corn oil emulsion was
201
prepared by adding the same weight of distilled water with lysolecithin to a final
202
concentration of 1% (w/w) in corn oil emulsion.
203
mg-KO/kg/day, once a day) were orally administered to rats for 7 days, and corn oil
204
emulsion (10 mL/kg) was orally administered at 24 h after final administration of KO
205
samples.
206
for 7 days, and distilled water (10 mL/kg) or corn oil emulsion (10 mL/kg) was orally
KO and KO/S-SEDDS (250
Distilled water (10 mL/kg/day, once a day) was orally administered to rats
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administered at 24 h after final administration of distilled water as a control or vehicle
208
group, respectively.
209
unanesthetized rats at the indicated times (0, 2, 4, 6, and 8 h) after oral administration
210
of corn oil emulsion, and then plasma samples were obtained by centrifugation
211
(3,200×g, 10 min).
212
Briefly, plasma samples (2 µL) and coloring substance (300 µL) were mixed in the
213
wells of 96-well microplate (Asahi Glass, Tokyo, Japan), and the absorbance at 600 nm
214
was measured by SAFIRE after incubation (5 min, 37°C).
Blood samples (300 µL) were collected from the tail vein of
Plasma TG levels were determined using LabAssayTM Triglyceride.
215 216
2.10. Data analysis
217
For statistical comparisons, one-way ANOVA with pairwise comparison by
218
Fisher’s least significant difference procedure was used. A p-value of less than 0.05
219
was considered significant for all analyses.
220
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3. Results and Discussion
222
3.1. Physicochemical characterization of KO samples
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The physicochemical characteristics of KO samples after dispersion in distilled
223 224
water were evaluated in terms of droplet sizes and dissolution behaviors.
225
samples could disperse when introduced into distilled water, and the morphology of KO
226
samples after dispersion was observed using TEM (Fig. 1).
227
samples were found to be spherical particles, and KO/SEDDS and KO/S-SEDDS
228
formed fine droplets compared with KO and KO/HPMC.
229
samples after dispersion in distilled water were measured by DLS (Table 2).
230
basis of DLS analysis, the mean diameter of KO was calculated to be 566 nm, and the
231
droplet size of KO/HPMC was not changed, as evidenced by a mean diameter of 565
232
nm.
233
and 266 nm, respectively, and the polydispersity indexes of KO/SEDDS and
234
KO/S-SEDDS were lower than those of KO and KO/HPMC, suggesting micronized
235
droplets with narrow size distributions in KO/SEDDS and KO/S-SEDDS.
236
zeta-potential of KO ranged from ca. –36 to –32 mV owing to the presence of
237
negatively charged phospholipids and free fatty acids in KO.
238
samples in DLS analysis were mostly consistent with the diameters in TEM observation.
239
In a previous investigation, a S-SEDDS formulation of ginger extract was prepared, and
240
the obtained data from particle size analysis were similar between SEDDS and
241
S-SEDDS formulations of ginger extract
242
lysolecithin and glycerin would contribute to the formation of fine and uniform droplets
243
in KO/SEDDS and KO/S-SEDDS, whereas the addition of HPMC would not affect the
244
particle size of KO droplets.
All KO
All droplets in all KO
The droplet sizes of KO On the
The mean diameters of KO/SEDDS and KO/S-SEDDS were calculated to be 269
25
.
The
The droplet sizes of KO
Based on these findings, the addition of
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SEDDS formulations can spontaneously form an emulsion when introduced 17
246
into aqueous media in the gastrointestinal (GI) tract
247
self-emulsifying performances, the dissolution/dispersion profiles of KO samples were
248
monitored in acidic solution (pH1.2) at 37°C up to 120 min (Fig. 2).
249
gradually dispersed with the amount of ca. 2.6% of the total at 120 min under the
250
present conditions.
251
almost the same as that of KO, the initial dissolution/dispersion of KO/HPMC and
252
KO/SEDDS was slightly improved.
253
reached a plateau at 30 min, and the amount of KO dispersed in KO/S-SEDDS at 30
254
min was 5.6-fold higher than that in KO.
255
behaviors of KO in KO/S-SEDDS could be observed, and the S-SEDDS approach may
256
facilitate the rapid and high-level oral absorption of active components in KO.
.
To evaluate the
KO was
Although the amounts of these formulations at 120 min were
In KO/S-SEDDS, the level of KO dispersed
Therefore, rapid dissolution and dispersion
257 258
3.2. Pharmacokinetic behaviors of EPA after oral administration of KO samples
259
In preliminary study, plasma DHA and EPA concentrations were also
260
monitored after oral administration of KO formulations; however, the variation in DHA
261
levels in the plasma were too wide to use as an indicator of oral KO absorption.
262
to clarify the enhancement in the oral absorption of KO by the S-SEDDS approach,
263
plasma EPA levels, employed as an indicator of the oral absorption of KO, were
264
monitored after oral administration of KO samples (60 mg-EPA/kg) (Fig. 3), and
265
AUC0–24h values of EPA were calculated.
266
absolute increases in oral absorption of EPA by KO.
267
could be detected after 24-h fasting, and the concentrations of EPA in the plasma were
268
at comparable levels.
Thus,
A control group was employed to clarify In all groups, EPA in the plasma
In the control group, a decrease in the plasma concentration of
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EPA was observed within 1 h, and the plasma EPA level was maintained at ca. 3 µg/mL
270
until at least 24 h.
271
maximum concentration (Cmax) (5.4±0.2 µg/mL) at 3 h, and then the concentration
272
decreased to the initial EPA level at 6 h.
273
KO group (95±1.3 µg・h/mL) was found to be 1.5-fold higher than that in the control
274
group (62±7.5 µg・h/mL), and enhancement of the oral absorption of EPA by KO might
275
still be limited.
276
oil was needed to exhibit its functionality 6, 10; therefore, the potential of KO to improve
277
the oral absorption of EPA and DHA might not be high enough to produce their
278
attractive biological effects.
279
be observed at around 2 to 3 h after oral administration of KO/S-SEDDS compared with
280
the other groups.
281
Cmax levels of EPA compared with the KO group, at 8.3±1.3 and 7.5±0.7 µg/mL,
282
respectively, and KO/HPMC shortened the time to reach the plasma Cmax (Tmax)
283
compared with the KO group.
284
(Fig. 3), increases in plasma EPA levels were similar between KO/HPMC and
285
KO/S-SEDDS groups up to 1 h.
286
behaviors and oral absorption of poorly water-soluble chemicals, and HPMC might
287
inhibit the precipitation of free forms of EPA in the GI tract
288
increase in the plasma EPA level after oral administration of KO/S-SEDDS may mainly
289
be attributed to the addition of HPMC.
290
KO/SEDDS groups were calculated to be 130±4.3 and 105±5.2 µg・h/mL, respectively,
291
and the oral absorption of KO in these groups tended to be higher than that in the KO
After oral administration of KO, the plasma EPA level reached its
The calculated AUC0–24h value of EPA in the
In previous reports, the intake of KO at a dose similar to that of fish
The highest Cmax value of EPA at 10.8±1.6 µg/mL could
Oral administration of KO/HPMC and KO/SEDDS led to higher
On the basis of the plasma concentration-time curves
HPMC had been employed to improve the dissolution
23
.
Thus, the rapid
The AUC0–24h values of EPA in KO/HPMC and
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group.
KO/S-SEDDS exhibited significantly higher AUC0–24h value of EPA compared
293
with the KO group, as evidenced by 161±23 µg・h/mL (P<0.05; versus KO group), and
294
improvement of the oral absorption of EPA would be more potent compared with
295
KO/HPMC and KO/SEDDS.
296
about a higher oral absorption of lipophilic active ingredients compared with SEDDS
297
formulations
298
increase the oral absorption of EPA due to its inhibitory effect on precipitation.
299
contains other active ingredients, and, to clarify the actual improvement of oral
300
absorption of KO, monitoring plasma concentrations of these ingredients would be still
301
needed after the oral administration of KO/S-SEDDS.
302
absorption of other active ingredients in KO is still unclear, an S-SEDDS approach
303
would be useful for improving the oral absorption of KO according to the PK profiles of
304
EPA in the KO/S-SEDDS group, possibly leading to enhanced functionalities of KO.
In previous reports, S-SEDDS formulations had brought
22, 23, 26
. Thus, the addition of HPMC might be of marked benefit to KO
Although enhancement in oral
305 306 307
3.3. Hypotriglyceridemic function of KO/S-SEDDS KO has attractive functions for health, and reduction of the blood TG level by 6, 27, 28
308
orally administered KO or EPA had been reported in several clinical trials
309
According to the results of the present pharmacokinetic study, only KO/S-SEDDS
310
indicated a significant improvement of plasma EPA level compared with KO.
311
evaluate the hypotriglyceridemic effect of KO/S-SEDDS, plasma TG levels in rats
312
pretreated with KO and KO/S-SEDDS (250 mg-KO/kg/day, 7 days, p.o.) were
313
monitored after oral administration of corn oil, and the AUC from 0 to 8 h (AUC0–8h) of
314
plasma TG was calculated (Fig. 4).
315
KO theoretically contains ca. 32.5 mg of EPA.
.
Thus, to
According to the content rate of EPA, 250 mg of Pretreatment with the ethyl ester form
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of EPA (300 mg/kg/day, 7 days, p.o.) had significantly reduced the rise of TG in rat
317
plasma after oral administration of corn oil
318
difference in AUC0–24h values of EPA between the ethyl ester form of EPA (60
319
mg-EPA/kg) and control groups was calculated to be ca. 13 µg・h/mL.
320
hand, difference in AUC0–24h values of EPA between control and KO/S-SEDDS groups
321
was found to be ca. 100 µg・h/mL based on the present pharmacokinetic profiles.
322
potential of enhancement in plasma EPA level by KO/S-SEDDS may be ca. 10-fold
323
higher than that by the ethyl ester form of EPA.
324
samples was set at 250 mg-KO/kg/day in the present functionality investigation.
325
vehicle group, the plasma TG level increased to around 350 mg/dL within 4 h after oral
326
administration of corn oil, and the calculated AUC0–8h value in the vehicle group was
327
significantly higher than that in the control group.
328
TG levels were increased within 3 h after intake of breakfast containing 20 g of corn oil
329
30
330
effects of KO samples.
331
intake of corn oil was suppressed by pretreatment with KO and KO/S-SEDDS
332
compared with the vehicle group, and the Cmax level of TG in the KO/S-SEDDS group
333
was lower than that in the KO group.
334
KO/S-SEDDS groups gradually decreased to become comparable to that in the control
335
group at 8 and 6 h after oral administration of corn oil, respectively.
336
AUC0–8h values in both KO and KO/S-SEDDS groups were significantly lower than that
337
in the vehicle group, and the hypotriglyceridemic potential of KO/S-SEDDS was
338
1.7-fold higher than that of KO on the basis of the AUC0–8h values.
339
EPA are known to have lipid-lowering effects, the mechanisms of which have been
29
.
In preliminary experiments, the
On the other
The
In this context, the dose of KO In the
In the previous clinical trials, blood
; therefore, the present rat model would be acceptable to evaluate hypotriglyceridemic Elevation of plasma TG levels in rats induced by the oral
Then, the plasma TG levels in the KO and
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The calculated
Both DHA and
Page 17 of 32
Journal of Agricultural and Food Chemistry
340
thought to involve the inhibition of TG production and increase of TG clearance 28, 31, 32.
341
Ethyl ester forms of DHA and EPA suppressed the activity of fatty acid and TG
342
synthesizing enzymes in the rat liver 31.
343
(VLDL) production by omega-3 fatty acids was also reported 28, and the intake of fish
344
oil reduced VLDL-TG secretion from the liver
345
trials, blood VLDL levels were significantly increased in patients with metabolic
346
syndrome compared with healthy subjects
347
with omega-3 fatty acids (4 g/day, 6 weeks) was decreased to become comparable level
348
of control subjects
349
weeks) indicated no significant impact on low-density and high-density lipoproteins
350
levels in blood
351
suppression of increases in plasma TG levels in KO and KO/S-SEDDS groups after oral
352
administration of corn oil.
353
in the acceleration of TG-rich lipoprotein clearance 28.
354
sample groups could be reduced to levels comparable with that in the control group.
355
In this experiment, the plasma levels of TG derived from corn oil was monitored;
356
however, the verified functionality of KO/S-SEDDS may be still limited.
357
further investigations for monitoring the changes of TG, cholesterols and lipoproteins
358
using several metabolic syndrome models would be helpful to prove the functionality of
359
KO/S-SEDDS.
360
elimination of plasma TG were observed in the KO/S-SEDDS group compared with the
361
KO group, and the S-SEDDS approach would be efficacious for enhancing the
362
hypotriglyceridemic function of KO.
35, 36
.
36
.
The reduction of very low-density lipoprotein
32
.
According to the previous clinical
33, 34
, and blood VLDL level after treatment
On the other hand, intake of omega-3 fatty acids (4 g/day, 6
In this context, these mechanisms would contribute to the
EPA and DHA increase lipoprotein lipase activity, resulting Thus, plasma TG levels in KO
Therefore,
Based on these findings, lower plasma TG levels and faster
363
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364
Page 18 of 32
4. Conclusion
365
In the present study, KO/S-SEDDS was prepared with the use of the SEDDS
366
technique with the addition of HPMC for improving the oral bioavailability and thus the
367
hypotriglyceridemic activity of KO.
368
and improved dissolution behavior of KO.
369
significant enhancement in the oral absorption of KO compared with other KO samples,
370
and the favorable hypotriglyceridemic function of KO could be observed after oral
371
administration of KO/S-SEDDS to rats with hypertriglyceridemia.
372
findings, the S-SEDDS would be an efficacious carrier to enhance the nutraceutical
373
values of KO.
KO/S-SEDDS indicated micronized droplet size Orally administered KO/S-SEDDS led to a
374
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From these
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Journal of Agricultural and Food Chemistry
375 376
Acknowledgement The authors are grateful to ACRESS (Osaka, Japan) for providing KO.
This
377
work was supported in part by a Grant-in-Aid for Young Scientists (B) (No. 17K15516;
378
Y. Seto and 16K18950; H. Sato) from the Ministry of Education, Culture, Sports,
379
Science and Technology of Japan, and a grant from the Takeda Science Foundation.
380 381
Conflicts of interest
382
The authors declare that there are no conflicts of interest.
383 384
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495
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Page 25 of 32
Journal of Agricultural and Food Chemistry
496
Table 1
The composition of KO formulations KO (wt%)
Lysolecithin (wt%)
Glycerin (wt%)
HPMC (wt%)
KO/HPMC
95
–
–
5
KO/SEDDS
60
30
10
–
KO/S-SEDDS
57
29
9
5
497
25 ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
498
Table 2
Page 26 of 32
Mean diameters and polydispersity index of KO samples
KO samples
Mean diameter (nm)
Polydispersity index
Zeta potential (mV)
KO
566
0.56
–36.1
KO/HPMC
565
0.54
–32.6
KO/SEDDS
269
0.35
–31.8
KO/S-SEDDS
266
0.36
–33.8
499
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Journal of Agricultural and Food Chemistry
500
Figure Legends
501
Fig. 1
502
KO/SEDDS, and (D) KO/S-SEDDS dispersed in distilled water.
503
500 nm.
Transmission electron microscopic images of (A) KO, (B) KO/HPMC, (C) Each bar represents
504 505
Fig. 2
506
KO/HPMC; □, KO/SEDDS; and ●, KO/S-SEDDS.
507
experiments.
▽, KO; △,
Dissolution behaviors of KO samples in pH1.2 solution.
Data represent mean±SE of 3
508 509
Fig. 3
Pharmacokinetic behaviors of EPA in rat plasma after oral administration of KO
510
samples (60 mg-EPA/kg).
511
▽, KO; △, KO/HPMC; □, KO/SEDDS; and ●, KO/S-SEDDS.
512
mean±SE of 4–6 rats.
Plasma concentration-time profiles of EPA.
◇, Control;
Data represent
513 514
Fig. 4
Hypotriglyceridemic effects of KO samples.
515
plasma TG after oral administration of corn oil.
516
and ●, KO/S-SEDDS.
517
plasma TG.
518
to vehicle group.
(A) Concentration-time curves of ◇, Control; ◆, Vehicle; ▼, KO;
Data represent mean±SE of 6 rats.
Data represent mean±SE of 6 rats.
(B) AUC0–8h values of
*P<0.05; ***P<0.001 with respect
27 ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Figure 1 229x172mm (300 x 300 DPI)
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Figure 2 166x188mm (300 x 300 DPI)
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Figure 3 160x166mm (300 x 300 DPI)
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Figure 4 152x251mm (300 x 300 DPI)
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TOC graphic 85x43mm (300 x 300 DPI)
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