Molecules 2012, 17, 13221-13234; doi:10.3390/molecules171113221
molecules
ISSN 1420-3049
www.mdpi.com/jou nal/molecules
A icle
P epa a ion o Candesa an and A o as a in Nanopa icles by
Sol en E apo a ion †
Eliska Vaculiko a 1,2,*, Ve onika G unwaldo a 3,4, Vladimi K al 3, Ji i Dohnal 1,5 and
Jose Jampilek 1,5,*
1 Facul y o Pha macy, Uni e si y o Ve e ina y and Pha maceu ical Sciences, Palackeho 1/3,
612 42 B no, Czech Republic
2 Nano echnology Cen e, VSB—Technical Uni e si y o Os a a, 17. lis opadu 15/2172,
708 33 Os a a, Czech Republic
3 Ins i u e o Chemical Technology, Facul y o Chemical Enginee ing, Technicka 5,
166 28 P ague 6, Czech Republic
4 Ins i u e o Ino ganic Chemis y, Academy o Science, 250 68 Rez, Czech Republic
5 Resea ch Ins i u e o Pha macy and Biochemis y, Lidicka 1879/48, 602 00 B no, Czech Republic
† P elimina y esul s we e p esen ed a The Six een h Elec onic Con e ence on Syn he ic O ganic
Chemis y (ECSOC-16, h p://www.sci o um.ne /p esen a ion/1008), 1–30 No embe , 2012
(pape B1008).
* Au ho s o whom co espondence should be add essed; E-Mails: eliska aculiko [email protected] (E.V.);
jose [email protected] (J.J.); Tel.: +420-541-562-925 (J.J.); Fax: +420-541-240-607 (J.J.).
Recei ed: 8 Oc obe 2012; in e ised o m: 31 Oc obe 2012 / Accep ed: 2 No embe 2012 /
Published: 6 No embe 2012
Abs ac : The solubili y, abso p ion and dis ibu ion o a d ug a e in ol ed in he basic
aspec s o o al bioa ailabili y Solubili y is an essen ial cha ac e is ic and in luences he
e iciency o he d ug. O e he las en yea s, he numbe o poo ly soluble d ugs has
s eadily inc eased. One o he p og essi e ways o inc easing o al bioa aibili y is he
echnique o nanopa icle p epa a ion, which allows many d ugs o hus each he in ended
si e o ac ion. Candesa an cilexe il and a o as a in, belonging o class II o he
biopha maceu ical classi ica ion sys em, we e chosen as model ac i e pha maceu ical
ing edien s in his s udy. Fo y samples we e p epa ed ei he by an isol en
p ecipi a ion/sol en e apo a ion me hod o by he emulsion/sol en e apo a ion echnique
wi h a ious commonly used su ace-ac i e excipien s as nanopa icle s abilize s. All
samples we e analyzed by means o dynamic ligh sca e ing. The pa icle size o he
OPEN ACCESS
Molecules 2012, 17 13222
de e mined 36 nanopa icle samples was o 574 nm, whe eas 32 samples con ained
nanopa icles o less han 200 nm. Rela ionships be ween sol en s and excipien s used and
hei amoun a e discussed. Based on he esul s he in es iga ed sol en e apo a ion
me hods can be used as an e ec i e and an a o dable echnique o he p epa a ion
o nanopa icles.
Keywo ds: candesa an cilexe il; a o as a in; nanopa icles; sol en e apo a ion;
excipien s; dynamic ligh sca e ing
1. In oduc ion
Fo ensu e he pha macological ac i i y o an ac i e pha maceu ical ing edien (API), he solubili y
o he API in physiological liquids is equi ed, so ha he API can be a ailable a he place o
abso p ion. Solubili y in a ious sol en s is a cha ac e is ic p ope y o a pa icula compound. The
solubili y o a compound in wa e co ela es o a g ea ex en wi h he solubili y in physiological
liquids and is he i s limi ing ac o o good abso p ion and biodis ibu ion. Con a y o hese ac s,
o e he las en yea s, he numbe o poo ly soluble d ugs has s eadily inc eased. Es ima es sugges
ha 40% o he d ugs in he pipelines ha e solubili y p oblems. Li e a u e s a es ha abou 60% o all
d ugs coming di ec ly om syn hesis nowadays a e poo ly soluble [1–3].
One o he p og essi e ways how o inc ease he solubili y o an APIs is he p epa a ion o d ug
nanopa icles. The echnique o nanopa icle d ug deli e y allows many pha macological agen s o
each he desi ed si e o ac ion. APIs a e ei he adjus ed alone ill nano size and adminis e ed in
nanopa icle o al dosage o ms o a ached/inco po a ed in o nanopa icles p epa ed om ine
ma e ials which se e as a uni e sal d ug deli e y sys em. The ad an ages o nano echnology a e as
ollows: (i) inc eased bioa ailabili y (quick dissolu ion; imp o ed pene a ion h ough memb anes);
(ii) lowe doses; (iii) lowe oxici y; (i ) a ge ed biodis ibu ion; ( ) educ ion o in luence o ood on
a iabili y; ( i) quicke de elopmen o o mula ions [2,4–7]. Nanopa icles o less han 200 nm a e o
p ac ical impo ance [8–13]. A g ea p oblem is he insu icien ly in es iga ed possible oxici y o
nanopa icles. The oxici y is dependen on he shape and su ace p ope ies o nanopa icles, because
bo h can in luence nanopa icle-cell in e ac ions as well as he a e o pene a ion o cells. Among he
a ious nanopa icle o ms nano ubes we e ound o be one o he mos oxic nanopa icle shapes [14–17].
A wide ange o echniques ha e been de eloped o he p epa a ion o nanoma e ials. These
me hods a e ypically g ouped in o wo ca ego ies: op-down (gene ally dispe ga ion p ocesses)
[11–13,18–21] and bo om-up (gene ally p ecipi a ion p ocesses) [11–13,18,22–24], whe eas he la e
is by a he mos popula in he p epa a ion o nanopa icles. In bo om-up me hods, nanopa icles can
be p oduced by c ys alliza ion/p ecipi a ion and sol en e apo a ion. Sp ay d ying, e apo a i e
p ecipi a ion in o aqueous solu ion, mic oemulsions o supe c i ical luid echnology belong o he
sol en e apo a ion me hods. The liquid an isol en (LAS) p ecipi a ion p ocess is a no ewo hy
me hod ha has been ex ensi ely s udied. An excellen e iew dealing wi h his echnique was
published by Tho a e al. [25]. The cu en pape is aimed a e i ica ion o condi ions o an e ec i e
Molecules 2012, 17 13223
and an a o dable echnique o he p epa a ion o nanopa icles by sol en e apo a ion as was
discussed ecen ly [26].
A pola and nonpola sol en we e used in ou esea ch, he e o e he exac p inciple o he applied
sol en e apo a ion me hod is dependen on he wa e -based sys em, including o no an aqueous
miscible o ganic sol en . The pola ace one (AC) and nonpola dichlo ome hane (DCM) we e chosen
as he mos sui able sol en s o easy dissolu ion o he APIs, so wo di e en possible mechanisms
can be supposed o he nanopa icle syn hesis. When API is dissol ed in AC and hen mixed wi h
wa e con aining a s abilize , nanopa icles a e o med spon aneously and immedia ely upon mixing.
This me hod can be called an isol en p ecipi a ion/sol en e apo a ion, and he p ocedu e is in
p inciple simila o he e apo a i e p ecipi a ion in o aqueous solu ion [27,28] o he liquid an isol en
p ecipi a ion [25]. When he API is dissol ed in DCM and hen mixed wi h wa e con aining
s abilize s, an emulsion (o/w ype) is o med; API is clus e ed by he excipien , which esul s in he
encapsula ion o he API in o nano- esicula. This combina ion o emulsi ica ion and sol en
e apo a ion nanopa icle syn hesis can be called emulsion/sol en e apo a ion [19,29].
The model APIs candesa an cilexe il (I) and a o as a in calcium (II) we e chosen as
ep esen a i es o poo ly aqueous soluble compounds belonging o class II d ugs o he
biopha maceu ical classi ica ion sys em (BCS). D ugs o he men ioned class a e cha ac e ized by low
aqueous solubili y and high pe meabili y [30]. Candesa an (2-e hoxy-1-({4-[2-(2H-1,2,3,4- e azol-5-
yl)phenyl]phenyl}me hyl)-1H-1,3-benzodiazole-6-ca boxylic acid) is an angio ensin II ecep o
an agonis used mainly o he ea men o hype ension. The p od ug candesa an cilexe il, see Figu e 1,
is ma ke ed by As aZeneca and Takeda Pha maceu icals, commonly unde he ade names Blop ess®,
A acand®, Amias®, and Ra acand®. The use o a p od ug o m inc eases he bioa ailabili y o
candesa an. Despi e his, i s absolu e o al bioa ailabili y is ela i ely poo (app ox. 15%) [31,32].
A o as a in [(3R,5R)-7-[2-(4- luo ophenyl)-3-phenyl-4-(phenylca bamoyl)-5-p opan-2-ylpy ol-1-yl]-
3,5-dihyd oxyhep anoic acid] inhibi s HMG-CoA educ ase and hus causes a dec ease o choles e ol
in he body. A o as a in is used as a calcium sal , see Figu e 1, and is ma ke ed by P ize unde
he ade names Lipi o ® o So is®. The low plasma concen a ion (app ox. 12%) o a o as a in is
especially caused by an ex ensi e i s -pass me abolism in he li e , ne e heless he o e all solubili y
o a o as a in is s ic ly pH-dependen (many a o as a in solid dosage o ms a e bu e ed, e.g., by
ca bona es), and adminis a ion wi h ood p oduces a 25% educ ion o a o as a in abso p ion [33,34].
As men ioned, bo h APIs a e BCS class II d ugs, hence hei o al bioa ailabili y is solubili y a e
limi ed [30–32,35–37]. Fo enhancemen o solubili y o candesa an cilexe il a ious app oaches can
be used, such as pec in complexes [38], sel -emulsi ying d ug deli e y sys ems [39] o de elopmen o
nanopa icle o mula ions [7,40]. The solubili y o a o as a in calcium can be enhanced, o example,
using an amo phous API [41], by applica ion o he liquisolid echnique [42], o mula ion o
sel -mic oemulsi ying d ug deli e y sys ems [43], u iliza ion o d ug-polyme in e ac ions ound due
o physical mixing [44] o p epa a ion o amo phous nanopa icles [45].
Va ious ypes o su ace-ac i e excipien s we e used as nanopa icle s abilize s and ela ionships
be ween a subs ance, a sol en and a used excipien a e discussed. Used excipien s ep esen a ious
classes o pha maceu ical adju an s (emulsi ie s/ iscosi y modi ie s/ hickene s, nonionic o anionic
su ac an s) ha can be u ilized as solubili y modi ying compounds/nanopa icle s abilize s, such as
Tween 80 (TW), sodium dodecyl sul a e (SDS), mac ogol 6000 (PEG), sodium ca boxyme hyl
Molecules 2012, 17 13224
cellulose (SCMC) and sodium sal o ca boxyme hyl dex an (SCMD). The main c i e ia o excipien
selec ion we e i s pha maceu ical sa e y (all excipien s a e GRAS, Gene ally Recognized as Sa e,
subs ances) and hei a o dabili y. Based on a p e ious s udy 5% and 10% concen a ions o each
excipien we e chosen [26]. The op imal concen a ion o su ac an is impo an o op imal pa icles
we ing. I he concen a ion is oo low, pa icles loa on he su ace. I he concen a ion is oo high
bubbles appea [46].
Figu e 1. S uc u es o candesa an cilexe il as p od ug and a o as a in calcium sal .
N
N
N
HN
N
N
O
O O OO
O
N
N
HO
F
OOH OH O
candesa an cilexe il (I)
2
Ca
2
a o as a in calcium (II)
2. Resul s and Discussion
Bo h model APIs I and II dissol ed in dichlo ome hane and ace one (2% concen a ion) we e added
o aqueous solu ions (5%, 10% concen a ion) o excipien s, i.e., eigh samples we e p epa ed wi h
each excipien . The inal API:excipien a ios we e 1:2.5 (2%:5%), 1:5 (2%:10%). The sys ems we e
s i ed o 10 min a 35 °C; a e wa ds he mix u es we e ans e ed o an ul asonic ba h, whe e hey
we e mixed again o 40 min, and simul aneously he o ganic sol en was e apo a ed ( o inal 10 mL
sample olume) by sel -wa ming o he ul asonic ba h. Then all he samples we e cha ac e ized by
dynamic ligh sca e ing [46]. All he esul s a e p esen ed in Tables 1–5 and Figu es 2–8.
Table 1. Pa icle size (x10, x90 [nm]) o APIs I, II and concen a ion [%] o Tween 80 in
dichlo ome hane (DCM) o ace one (AC). All he p esen ed esul s a e epo ed as he
medium alue o ou independen measu emen s. The esul s o nano-size samples a e
exp essed as he mean ± SD (n = 4 measu emen s). The SDs o mic o-size samples a e
no indica ed due o he measu abili y ange o Nanophox. Samples ha con ained
nanopa icles <200 nm a e bolded; nanopa icles <10 nm a e indica ed by as e isk.
(S.No. = sample numbe ).
API/Sol en
Tween 80
S.No. 5% S.No. 10%
x10 x90 x10 x90
Pa icle size
[nm]
I/DCM 1 160 ± 4.8 219 ± 5.6 2 14 ± 0.4 16 ± 0.5 *
I/AC 3 3183 6531 4 2 ± 0.1 3 ± 0.1 *
II/DCM 5 97 ± 2.9 142 ± 4.3 6
145 ± 4.4 213 ± 6.4
II/AC 7 101 ± 3.0 111 ± 3.3 8 3 ± 0.1 4 ± 0.1 *
Molecules 2012, 17 13225
Table 2. Pa icle size (x10, x90 [nm]) o APIs I, II and concen a ion [%] o sodium dodecyl
sul a e in dichlo ome hane (DCM) o ace one (AC). All he p esen ed esul s a e epo ed
as he medium alue o ou independen measu emen s. The esul s o nano-size samples
a e exp essed as he mean ± SD (n = 4 measu emen s). The SDs o mic o-size samples
a e no indica ed due o he measu abili y ange o Nanophox. Samples ha con ained
nanopa icles <200 nm a e bolded; nanopa icles <10 nm a e indica ed by as e isk.
(S.No. = sample numbe ).
API/Sol en
Sodium dodecyl sul a e
S.No. 5% S.No. 10%
x10 x90 x10 x90
Pa icle size
[nm]
I/DCM 9 90 ± 2.7 99 ± 3.0 10 2 ± 0.1 3 ± 0.1 *
I/AC 11 4 ± 0.1 5 ± 0.2 * 12 1 ± 0.03 2 ± 0.1 *
II/DCM 13 1 ± 0.03 2 ± 0.1 * 14 90 ± 2.7 99 ± 3.0
II/AC 15 2 ± 0.1 2 ±0.1 * 16 2 ± 0.1 4 ± 0.1 *
Table 3. Pa icle size (x10, x90 [nm]) o APIs I, II and concen a ion [%] o mac ogol 6000
in dichlo ome hane (DCM) o ace one (AC). All he p esen ed esul s a e epo ed as he
medium alue o ou independen measu emen s. The esul s o nano-size samples a e
exp essed as he mean ± SD (n = 4 measu emen s). The SDs o mic o-size samples a e no
indica ed due o he measu abili y ange o Nanophox. Samples ha con ained
nanopa icles <200 nm a e bolded; nanopa icles <10 nm a e indica ed by as e isk.
(S.No. = sample numbe ).
API/Sol en
Mac ogol 6000
S.No. 5% S.No. 10%
x10 x90 x10 x90
Pa icle size
[nm]
I/DCM 17 2 ± 0.1 3 ± 0.1 * 18 2 ± 0.1 3 ± 0.1 *
I/AC 19 2 ± 0.1 3 ± 0.1 * 20 156 ± 4.7 206 ± 6.2
II/DCM 21 1639 1804 22 5231 5755
II/AC 23 6 ± 0.2 8 ± 0.2 * 24 4 ± 0.1 6 ± 0.2 *
Table 4. Pa icle size (x10, x90 [nm]) o APIs I, II and concen a ion [%] o sodium
ca boxyme hyl cellulose in dichlo ome hane (DCM) o ace one (AC). All he p esen ed
esul s a e epo ed as he medium alue o ou independen measu emen s. The esul s o
nano-size samples a e exp essed as he mean ± SD (n = 4 measu emen s). The SDs o
mic o-size samples a e no indica ed due o he measu abili y ange o Nanophox. Samples
ha con ained nanopa icles <200 nm a e bolded; nanopa icles <10 nm a e indica ed by
as e isk. (S.No. = sample numbe ).
API/Sol en
Sodium ca boxyme hyl cellulose
S.No. 5% S.No. 10%
x10 x90 x10 x90
Pa icle size
[nm]
I/DCM 25 11 ± 0.3 13 ± 0.4 26 2 ± 0.1 3 ± 0.1 *
I/AC 27 1 ± 0.03 2 ± 0.1 * 28 32 ± 1.0 35 ± 1.1
II/DCM 29 401 ± 12 574 ± 17 30 1 ± 0.03 2 ± 0.1 *
II/AC 31 6 ± 0.2 7 ± 0.2 * 32 27 ± 0.8 30 ± 0.9

Molecules 2012, 17 13226
Table 5. Pa icle size (x10, x90 [nm]) o APIs I, II and concen a ion [%] o sodium
ca boxyme hyl dex an in dichlo ome hane (DCM) o ace one (AC). All he p esen ed
esul s a e epo ed as he medium alue o ou independen measu emen s. The esul s o
nano-size samples a e exp essed as he mean ± SD (n = 4 measu emen s). The SDs o
mic o-size samples a e no indica ed due o he measu abili y ange o Nanophox. Samples
ha con ained nanopa icles <200 nm a e bolded; nanopa icles <10 nm a e indica ed by
as e isk. (S.No. = sample numbe ).
API/Sol en
Sodium ca boxyme hyl dex an
S.No. 5% S.No. 10%
x10 x90 x10 x90
Pa icle size
[nm]
I/DCM 33 2 ± 0.1 2 ± 0.1 * 34 1 ± 0.03 1 ± 0.03 *
I/AC 35 3 ± 0.1 4 ± 0.1 * 36 39 ± 1.2 43 ± 1.3
II/DCM 37 2 ± 0.1 2 ± 0.1 * 38 9345 10281
II/AC 39 2 ± 0.1 3 ± 0.1 * 40 70 ± 2.1 77 ± 2.3
Figu e 2. Dependence o pa icle size (x90 [nm]) o model APIs I, II on concen a ion [%]
o Tween 80 in dichlo ome hane (DCM) o ace one (AC). (A) Samples a e g ouped
acco ding o APIs; (B) samples a e g ouped acco ding o excipien pe cen age. Fo cla i y
sake, he alues on y-axis a e only o 300 nm.
Figu e 3. Dependence o pa icle size (x90 [nm]) o model APIs I, II on concen a ion [%]
o sodium dodecyl sul a e in dichlo ome hane (DCM) o ace one (AC). (A) Samples a e
g ouped acco ding o APIs; (B) samples a e g ouped acco ding o excipien pe cen age.
Fo cla i y sake, he alues on y-axis a e only o 100 nm.
0
50
100
150
200
250
300
I/DCM I/AC II/DCM II/AC
X
90
[nm]
API / Excipien concen a ion [%]
5%
10%
0
50
100
150
200
250
300
5% 10%
X
90
[nm]
Excipien concen a ion [%] / API
I/DCM
I/AC
II/DCM
II/AC
A B
0
10
20
30
40
50
60
70
80
90
100
I/DCM I/AC II/DCM II/AC
X
90
[nm]
API / Excipien concen a ion [%]
5% 10%
0
10
20
30
40
50
60
70
80
90
100
5% 10%
X
90
[nm]
Excipien concen a ion [%] / API
I/DCM I/AC II/DCM II/AC
A B
Molecules 2012, 17 13227
Figu e 4. Dependence o pa icle size (x90 [nm]) o model APIs I, II on concen a ion [%]
o mac ogol 6000 in dichlo ome hane (DCM) o ace one (AC). (A) Samples a e g ouped
acco ding o APIs; (B) samples a e g ouped acco ding o excipien pe cen age. Fo cla i y
sake, he alues on y-axis a e only o 300 nm.
Figu e 5. Dependence o pa icle size (x90 [nm]) o model APIs I, II on concen a ion [%]
o sodium ca boxyme hyl cellulose in dichlo ome hane (DCM) o ace one (AC).
(A) Samples a e g ouped acco ding o APIs; (B) samples a e g ouped acco ding o
excipien pe cen age. Fo cla i y sake, he alues on y-axis a e only o 100 nm.
Figu e 6. Dependence o pa icle size (x90 [nm]) o model APIs I, II on concen a ion [%]
o sodium ca boxyme hyl dex an in dichlo ome hane (DCM) o ace one (AC).
(A) Samples a e g ouped acco ding o APIs; (B) samples a e g ouped acco ding o
excipien pe cen age. Fo cla i y sake, he alues on y-axis a e only o 100 nm.

0
50
100
150
200
250
300
I/DCM I/AC II/DCM II/AC
X
90
[nm]
API / Excipien concen a ion [%]
5% 10%
0
50
100
150
200
250
300
5% 10%
X
90
[nm]
Excipien concen a ion [%] / API
I/DCM I/AC II/DCM II/AC
A B
0
10
20
30
40
50
60
70
80
90
100
I/DCM I/AC II/DCM II/AC
X
90
[nm]
API / Excipien concen a ion [%]
5% 10%
0
10
20
30
40
50
60
70
80
90
100
5% 10%
X
90
[nm]
Excipien concen a ion [%] / API
I/DCM I/AC II/DCM II/AC
A B
0
10
20
30
40
50
60
70
80
90
100
I/DCM I/AC II/DCM II/AC
X
90
[nm]
API / Excipien concen a ion [%]
5% 10%
0
10
20
30
40
50
60
70
80
90
100
5% 10%
X
90
[nm]
Excipien concen a ion [%] / API
I/DCM
I/AC
II/DCM
II/AC
A B
Molecules 2012, 17 13228
Figu e 7. Dependence o pa icle size (x90 [nm]) o candesa an cilexe il (I) on
concen a ion [%] o Tween 80 (TW), sodium dodecyl sul a e (SDS), mac ogol 6000
(PEG), sodium ca boxyme hyl cellulose (SCMC), sodium ca boxyme hyl dex an (SCMD)
in dichlo ome hane (DCM) o ace one (AC). Fo cla i y sake, he alues on y-axis a e only
o 50 nm.
Figu e 8. Dependence o pa icle size (x90 [nm]) o a o as a in calcium (II) on
concen a ion [%] o Tween 80 (TW), sodium dodecyl sul a e (SDS), mac ogol 6000
(PEG), sodium ca boxyme hyl cellulose (SCMC), sodium ca boxyme hyl dex an (SCMD)
in dichlo ome hane (DCM) o ace one (AC). Fo cla i y sake, he alues on y-axis a e only
o 50 nm.
Figu es 2–6 illus a e he dependence o pa icle size exp essed as he cumula i e dis ibu ion x90
[nm] o he APIs I, II on he concen a ion [%] o an indi idual excipien , whe eas in Figu es A
samples a e g ouped acco ding o indi idual APIs I, II, while in Figu es B indi idual APIs a e always
sepa a ed acco ding o he pe cen age o he excipien . The pa icle size x90 was used o e alua ion o
he me hod success, since his alue ep esen s 90% o he cumula i e pa icle size dis ibu ion in he
measu ed sample. The dispe si y is a measu e/deg ee o he homogenei y/he e ogenei y o sizes o
pa icles in a mix u e/sys em. I is possible o see his ea u e on he wid h o he pa icle-size
dis ibu ion, which is desc ibed as di e ences be ween cumula i e dis ibu ion x10 and x90, see Tables
1–5. Acco ding o he esul s, when mic o-size samples (3, 21, 22, 38) we e elimina ed, he a e age
ela ion o he cumula i e dis ibu ion x10/x90 anged om 0.6 o 0.9. I is possible o suppose ha
DCM
AC
0
10
20
30
40
50
TW 5% TW 10% SDS 5% SDS 10% PEG 5% PEG 10% SCMC 5% SCMC 10% SCMD 5% SCMD 10%
1
219
2
16
9
99
10
3
17
3
18
3
25
13
26
4
33
2
34
1
3
6531
4
3
11
512
2
19
3
20
206
27
2
28
35
35
4
36
43
Sol en
X90 [nm]
Excipien concen a ion [%]
DCM
AC
0
10
20
30
40
50
TW 5% TW 10% SDS 5% SDS 10% PEG 5% PEG 10% SCMC 5% SCMC 10% SCMD 5% SCMD 10%
5
142
6
213
13
2
14
99
21
1804
22
5755
29
574
30
2
37
2
38
10281
7
111
8
415
2
16
4
23
824
6
31
7
32
30
39
3
40
77
Sol en
X
90
[nm]
Excipien concen a ion [%]
Molecules 2012, 17 13229
nanopa icles a e sphe es, because he size in dynamic ligh sca e ing ep esen s he hyd odynamic
diame e o he pa icle. All samples we e dispe sed by ul asonics di ec ly be o e he measu emen o
a oid possible e-agglome a ion. S abiliza ion o he dispe sed samples was achie ed by su ac an s
and by he cons an empe a u e. The measu ing cell was equilib a ed a 25 °C, so he B own mo ion o
nanopa icles is in luenced jus by hei size.
F om Figu es 2A–6A i can be s a ed ha gene ally pa icle size is no dependen on he ype o
model API, bu i is pa ially in luenced by he ype and concen a ion o he excipien u ilized.
Ne e heless, i can be supposed ha in he case o candesa an cilexe il (I) smalle pa icles we e
ound, especially when a o as a in calcium (II) and SDS, PEG and SCMC in dichlo ome hane we e
used, as i is illus a ed in Figu es 7 and 8, whe e he dependences o he pa icle size o indi idual
APIs I and II on he concen a ions o indi idual excipien s a e shown. This ac is p obably caused by
he sol en used, because dichlo ome hane has less ad an ageous p ope ies in compa ison wi h
ace one, as discussed below.
Table 6 summa izes esul s o all he samples o nanopa icles unde 900 nm size depending on
sol en s and he ype and amoun o excipien s. As he aim o his con ibu ion is speci ica ion o
sui able condi ions o nanopa icles p epa a ion, in Table 6 gene a ed nanopa icles a e no di ided
acco ding o used APIs.
Table 6. View o o med samples o nanopa icles (≤900 nm) depending on sol en s and
ype and amoun o excipien s. (conc. = concen a ion; excp. = excipien ; dichlo ome hane =
DCM; ace one = AC; Tween 80 = TW; sodium dodecyl sul a e = SDS; mac ogol 6000 =
PEG; sodium ca boxyme hyl cellulose = SCMC; sodium ca boxyme hyl dex an = SCMD).
Excp.
conc./ ype
DCM
Sum
o al
O e all
a e age
x90 [nm]
AC
Sum
o al
O e all
a e age
x90 [nm]
5% 10% 5% 10%
numbe o
nanop. samples
numbe o
nanop. samples
TW 2 2 4 147 1 2 3 39
SDS 2 2 4 51 2 2 4 3
PEG 1 1 2 3 2 2 4 56
SCMC 2 2 4 148 2 2 4 18
SCMD 2 1 3 2 2 2 4 32
Sum o al 9 8 17 351 9 10 19 148
O e all
a e age
x90 [nm]
117 42 160 70
80 16 41 57 30
29
A e summa ion o all he esul s i can be concluded ha om 40 p epa ed mix u es 36 samples
con ained nanopa icles (see Tables 1–5), om which 32 samples con ained nanopa icles smalle han
200 nm (see Tables 1–5, bolded alues). Nanopa icles unde 10 nm we e de e mined in 22 samples
om 32, see Tables 1–5 (as e isked bolded alues).
Based on he esul s lis ed in Table 6 and Figu es 7 and 8 i can be gene ally s a ed ha he sol en
used plays he c ucial ole in gene a ion o nanopa icles. This ac was no so e iden in he p e ious
s udy, whe e only s e oid-like compounds we e in es iga ed [26]. This e ec o sol en was signi ican
in he case o a o as a in calcium (II), which is a sal and hus by i s chemical na u e absolu ely