P oceedings 2019, 41, 1; doi: 10.3390/ecsoc-23-06458 www.mdpi.com/jou nal/p oceedings
P oceedings
Syn hesis and Cha ac e iza ion o New
Biocompa ible Amino Amphiphilic Compounds
De i ed om Oleic Acid as Nano ec o s o D ug
Deli e y †
Vic o ia Valdi ia *, Chia a Paggia o and Inmaculada Fe nández
Depa amen o de Química O gánica y Fa macéu ica, Facul ad de Fa macia, Uni e sidad de Se illa,
41012 Se ille, Spain; chia apaggia [email protected] (C.P.); [email p o ec ed] (I.F.)
* Co espondence: aldi[email p o ec ed]; Tel.: +0034954556738
† P esen ed a he 23 d In e na ional Elec onic Con e ence on Syn he ic O ganic Chemis y, 15 No embe
2019–15 Decembe 2019; A ailable online: h ps://ecsoc-23.sci o um.ne /.
Published: 14 No embe 2019
Abs ac : Amphiphilic molecules ha e been ac i ely explo ed as p omising ma e ials in he ield o
bio and nano echnology. These molecules a e cons i u ed by a pola head and a lipophilic ail and
in an aqueous medium a e sel -assemble o o m di e en ypes o mac omolecula s uc u es such
as micelles, monolaye esicles, ba s, shee s and ubes. In his wo k, a con e gen syn he ic
app oach o he syn hesis o wo new amphiphilic compounds based on a e sa ile amino pola
head, a e ae hylene glycol space and a lipophilic ail de i ed om oleic acid has been de eloped.
Subsequen ly, a e a sel -assembly p ocess in aqueous medium, nanos uc u es as micelles ha e
been ob ained and cha ac e ized. Finally, a p ocedu e o he inclusion o he highly lipophilic d ug
Dexame hasone has been ca ied ou in o de o s udy he abili y o hese micelles o ac as
nano ec o s o d ug deli e y.
Keywo ds: amphiphilic compounds; sel -assembly; nano ec o s; d ug deli e y
1. In oduc ion
In he las yea s, amphiphilic molecules ha e been highly used in he de elopmen o
nanos uc u es, ep esen ing a g ea p omise o a ge ed deli e y, imp o ed bioa ailabili y, and
d ugs con olled elease 1–7]. These molecules consis o a pola head and a lipophilic ail ha a e
dis ibu ed in an aqueous medium o o m di e en ypes o s uc u es such as micelles, monolaye
esicles (also known as liposomes), ba s, shee s and ubes 8]. The cell memb ane o li ing cells,
o med by a bilaye sel -o ganiza ion is he mos illus a i e example o a complex nanosys em
o med om uni s o phospholipid. Among he di e en ypes o s uc u es o med by amphiphilic
compounds, micelles ha e ecei ed g owing scien i ic a en ion 9]. Micelles, in gene al, a e sel -
assembled pa icles composed o amphiphilic compounds 10]. In an aqueous en i onmen , hese
compounds a e dis ibu ed wi h he hyd ophobic ails in he cen e o he micelle, and he pola heads
owa ds he aqueous medium. In his way, hey au o-assemble o o m sphe oidal s uc u es wi h a
hyd ophilic shell and a hyd ophobic co e o minimize he con ac o he hyd ophobic segmen s wi h
he aqueous en i onmen by allowing a good g ade o s abili y 11]. CMC, c i ical micelle
concen a ion, is a ela i ely small ange o concen a ions sepa a ing he limi below which i ually
no micelles a e de ec ed and he limi abo e which i ually all addi ional amphiphilic molecules
o m micelles.
P oceedings 2019, 41, 1 10.3390/ecsoc-23-06458 2 o 14
Micelles ha e a pa icle size be ween 10 and 100 nm ha is impo an o allow a high s abili y
and a high bioa ailabili y. This size makes i possible o injec hese micelles in o sys emic ci cula ion
wi hou isk o blood essel blockage. The a e in i o o micelles depends on hei sizes, pa icles
unde 200 nm a e less phagocy osed by mac ophages a e he opsoniza ion, compa ed o hose wi h
la ge dimensions 12].
One o he ad an ages o using micelles in d ug deli e y is hei abili y o anspo d ugs wi h
di e en deg ees o pola i y hanks o hei s uc u e consis ing in a hyd ophilic shell and a
hyd ophobic co e.
D ugs will be dis ibu ed di e en ly by chemical conjuga ion, physical en apmen o ionic
in e ac ions depending on he na u e o he d ug and he amphiphilic compound p ope ies:
Hyd ophilic d ugs will bind o he su ace (case 1), hose wi h di e en hyd ophilici y and
lipophilici y a ios will be be ween he pola pa and he lipophilic pa o he nanosys em (case 2),
and inally e y lipophilic d ugs will be dis ibu ed inside he micelle co e (case 3) (Figu e 1) 9].
Figu e 1. Possible pa e n o d ug associa ion wi h a micelle 9].
I is known ha abou 90% o d ugs a e lipophilic and a e cha ac e ized by a low solubili y in
wa e , his causing a di icul dis ibu ion and accumula ion in a y issues leading o a delayed
elease o he d ug and an inc ease o side e ec s. Micelles a e he e o e used o he anspo o
highly lipophilic d ugs, inc easing he solubili y o d ugs om 10 o 8400 imes and consequen ly
hei bioa ailabili y 13,14].
One o he mos success ul examples o micella o mula ion as al e na i e solubilizing agen s is
he o mula ion o pacli axel (PTX) in a poly (D, L-lac ide) MePEG diblock copolyme which inc eases
he solubilized PTX le els in wa e a ound 5000 imes 15].
Micelles can also be used in ac i e a ge ing, di ec ing he d ug owa ds he speci ic cell- issue-
o gan. Ligands such as ca bohyd a es 16], olic acid 17], an ibodies 18], p o eins 19], pep ides 20]
and ap ame s 21,22] ha e been used.
In summa y, he main ad an ages o micelles in d ug deli e y a e he ollowing:
i) high dynamic s abili y ha pe mi s hei applica ion in i o
ii) he hyd ophobic co e o micelles con e s hem he abili y o anspo highly lipophilic d ugs
iii) he hyd ophilic shell o micelles inc eases hei solubili y in wa e , esul ing in g ea e
bioa ailabili y and lowe oxici y o poo ly wa e -soluble d ugs.
i ) he possibili y o modi ying hei su ace wi h speci ic ligands con e s he abili y o di ec d ugs
o speci ic a ge s.
This wo k is placed in he ield o nano echnologies applied o d ug deli e y and speci ically
ocused on he syn hesis o amphiphilic compounds in o de o ob ain a new amily o micelles as
d ug nano ec o s wi hin he o ganism.
Bo h o hese amphiphilic compounds syn hesized p esen a e sa ile amino pola head, a space
and a lipophilic ail. The space in all cases is e ae hylene glycol, a polyme de i ed om
polye hylene glycol which p esen s wo impo an ad an ages: (i) an adequa e hyd ophilic-
hyd ophobic balance o he op imal o ma ion o he micelle and (ii) he abili y o a oid he
ac i a ion o he immune sys em. I has been disco e ed ha PEG de i a i es a e biocompa ible and
P oceedings 2019, 41, 1 10.3390/ecsoc-23-06458 3 o 14
hey a e no a acked by mac ophages escaping he opsoniza ion. Fu he mo e, he amphiphilic
compounds syn hesized p esen oleic acid as he lipophilic ail (Scheme 1).
Scheme 1. Gene al s uc u e o he amphiphilic compounds.
Micelles ha e been ob ained in wa e by a sel -assembly p ocess o he amphiphilic compounds
syn hesized. A e he cha ac e iza ion o micelles, he in e naliza ion o Dexame hasone, a syn he ic
highly lipophilic an i-in lamma o y co icos e oid d ug 23], has been s udied in o de o e i y he
ad an ages o he use o ou micelles in d ug deli e y (Scheme 2).
Scheme 2. Fo ma ion o micelles by sup amolecula sel -assembly o amphiphilic compounds and
in e naliza ion o Dexame hasone.
2. Me hod
2.1. Ma e ials and Techniques
Unless o he wise s a ed, he s a ing ma e ials, eagen s, and sol en s we e pu chased as high-
g ade comme cial p oduc s om Sigma-Ald ich. THF, CH2Cl2, DMF and Toluene we e d ied using
molecula sie es, and highes quali y sol en s we e used. All non-aqueous eac ions we e pe o med
unde an a gon a mosphe e in o en-d ied glasswa e.
Analy ical TLC was un on silica gel pla es suppo ed by alluminio Alu am® Sil.G / V245
Me ck di 0.25 nm. Pla es elu ed and d ied wi h 5% o phosphomolybdic acid in e hanol.
Flash ch oma og aphy was pe o med on glass column using silica gel ype 60 (pa icle size
230–400 mesh, Me ck). The composi ion o he eluen used is di e en o each compound, as
indica ed.
1H- and 13C- spec a we e eco ded on a B uke AMX-500 e B uke Ad ance DRX-500 (500
MHz) ins umen a a he cen e o Resea ch, Technology and Inno a ion o he Uni e si y o
P oceedings 2019, 41, 1 10.3390/ecsoc-23-06458 4 o 14
Se ille’s NMR co e acili y. Chemical shi s (δ) a e exp essed in pa s pe million ela i e o he
esidual sol en peak o 1H and 13C nucleus (ace one-d6: δH = 2.05, δC = 29.84; CDCl3: δH = 7.26,
δC = 77.16; DMSO-d6: δH = 2.50, δC = 39.52; me hanol-d4: δH = 3.31, δC = 49.00); coupling cons an s
(J) a e in he z (Hz). The ollowing abb e ia ions a e used o desc ibe peak pa e ns when
app op ia e: s (single ), d (double ), ( iple ), q (qua e ), sex (sex uple ), m (mul iple ), app
(appa en ), and b (b oad).
High esolu ion mass spec ome y (HRMS) was ca ied ou on a K a os MS-80-RFA
spec ome e and in a Au oSpec mic o-mass spec ome e a he cen e o Resea ch, Technology and
Inno a ion o he Uni e si y o Se ille.
2.2. Syn hesis o he Amphiphilic De i a i es
Syn hesis o he Fi s Amphiphilic De i a i e
1,11-mesyl-3,6,9- ioxaundecane (1)
To a solu ion o e ae hylene glycol (8.90 mL, 15.49 mmol) in d y THF (200 mL) unde a gon
a mosphe e, and E 3N (17.9 mL, 128.71 mmol) was added MsCl (9.96 mL, 128.71 mmol) d op by d op
a 0°C and was s i ed o 1 h. A e his ime he mix u e was allowed o wa m slowly a oom
empe a u e. Then he sol en was e apo a ed and he mix u e was dissol ed in CH2Cl2 (50 mL) and
washed 3 imes wi h NH4Cl (3 × 15 mL), a e wa ds was neu alized wi h NaHCO3 (15 mL) and
washed wi h b ine (15 mL). The o ganic ex ac was d ied o e anhyd ous Na2SO4, il e ed, and
e apo a ed o ob ain he p oduc 1 as a yellowish oil (5.42 g, 15.48 mmol, 99.97%).
R (CH2Cl2/MeOH 9:1): 0.62
1H NMR (500 MHz, CDCl3): δ 4.383–4.365 (m, 4H, CH2CH2OMs), 3.776–3.677 (m, 4H, CH2CH2OMs),
3.671–3.633 (m, 8H, OCH2CH2O), 3.066 (s, 6H, CH3).
13C NMR (125.7 MHz, CDCl3): δ 70.752, 70.620 (CH2O), 69.331, 69.128 (CH2CH2OSO2), 52.689
(CH2OSO2), 37.769 (OSO2CH3).
HRMS calcd o C10H22O9S2 [M + H] +: 351.0778; ound 351.0778.
1,11-diazido-3,6,9- ioxaundecane (2)
To a solu ion o 1 (18.80 g, 53.66 mmol) in d y E OH (35.8 mL) was added sodium azide (8.72 g,
134.15 mmol). The mix u e was allowed o e lux du ing 24 h, unde a gon a mosphe e and a e his
ime, was added NaCl (50 mL) o deac i a e he sodium azide. Then he sol en (E OH) was emo ed
by o a y e apo a ion. Successi ely he mix u e was ex ac ed wi h CH2Cl2 in o de o ob ain he
p oduc in he o ganic phase, and a e all, was e apo a ed he sol en . Then he c ude p oduc was
pu i ied by lash ch oma og aphy column on silica gel wi h AcOE : Hexane (1:2), o yield 2 as a
yellowish oil (11.9 g, 48.71 mmol, 91%).
R (AcOE /Hexane 3:1): 0.58
1H NMR (500 MHz, CDCl3): δ 3.694–3.654 (m, 12H, OCH2CH2O and CH2CH2N3), 3.386 ( , J = 5 Hz,
4H, CH2N3).
13C NMR (125.7 MHz, CDCl3): δ 70.856 (CH2O), 70.162 (CH2CH2N3), 50.846 (CH2N3).
HRMS calcd o C8H16N6O3Na [M + Na] +: 267.1176; ound 267.1179
11-azido-3,6,9- ioxaundecan-1-amine (3)
To a solu ion o 2 (7.83 g, 32.04 mmol) in HCl 1M (96.10 mL) and e hyl ace a e (56.91 mL) a 0 °C,
was added d opwise a solu ion o iphenylphosphine (9.24 g, 35.24 mmol) in e hyl ace a e (85.36
mL). A e wa ds, he empe a u e was allowed o each oom empe a u e and s i ed o e 7 h. The
mix u e was sepa a ed in a sepa a o y unnel, and in he aqueous phase was added NaOH un il PH
>14 (5 mL). Successi ely was added CH2Cl2 (30 mL) and sepa a ed he o ganic phase which was d ied
o e anhyd ous Na2SO4. The sol en was emo ed by o a y e apo a ion and he esidue was
P oceedings 2019, 41, 1 10.3390/ecsoc-23-06458 5 o 14
pu i ied by a lash column ch oma og aphy on silica gel elu ing wi h AcOE : Hexane (1:1), o ob ain
p oduc 3 (4.70 g, 21.52 mmol, 72%), as a colo less oil.
R (AcOE /Hexane 1:1): 0
1H NMR (500 MHz, CDCl3): δ 3.687–3.619 (m, 10H, OCH2CH2O and CH2CH2N3), 3.515 ( , J = 5 Hz,
2H, CH2CH2NH2), 3.388 ( , J=5 Hz, 2H, CH2N3), 2.881–2.861 (m, 2H, CH2NH2), 1.806 (s, 2H, NH2).
13C NMR (125.7 MHz, CDCl3): δ 73.387 (CH2CH2NH2), 70.851, 70.801, 70.772, 70.422, 70.162 (CH2O)
50.841 (CH2N3), 41.857 (CH2NH2).
HRMS calcd o C8H18N4O3 [M + H]+: 219.1452; ound 219.1447
N-(2-p opin-1-yl) oleamide (4)
A solu ion o p opa gylamine (0.15 mL, 2.34 mmol) and dime hylaminopy idine (0.066 g, 0.54
mmol) in d y CH2Cl2 (4 mL) was added o a solu ion o oleoyl chlo ide (0.50 g, 1.8 mmol) and
diisop opylca bodiimide (0.4 mL, 2.7 mmol) in d y CH2Cl2 (4 mL), unde a gon a mosphe e and was
s i ed o e nigh . A e wa ds he eac ion was dissol ed in CH2Cl2 hen was ea ed wi h HCl 4N (2
× 7 mL), neu alized wi h NaHCO3 (7 mL) and inally washed wi h b ine (7 mL). The o ganic phase
was d ied o e anhyd ous Na2SO4, and he sol en e apo a ed o a o d he c ude p oduc . To ob ain
he pu e p oduc 5 (0.505 g, 1.34 mmol, 57%), as a whi e solid, he c ude was pu i ied wi h column
ch oma og aphy on silica gel using AcOE : Hexane (1:5).
R (Hexane/AcOE 3:1): 0.55
1H NMR (500 MHz, CDCl3): δ 5.579 (bs, 1H, NHCO), 5.390–5.353 (m, 2H, CH=CH), 4.079 (m, 2H,
HCCCH2NHCO), 2.249–2.230 (m, 1H, HCCCH2NHCO), 2.225–2.194 (m, 2H, HNCOCH2), 2.051–2.011
(m, 4H, CH2CH=CHCH2), 1.673–1.644 (m, 2H, HNCOCH2CH2), 1.326–1.292 (m, 20H, CH2), 0.905 ( ,
3H, J = 7 Hz, CH3).
13C NMR (125.7 MHz, CDCl3): δ 170.37 (COO), 155,67 (CONH), 79.967 ( -BuC), 70,729, 70.683, 70.662,
70.049, 68.914, 64.361, 60.365, 53.401, 50.712, 42.429 (BocNHCH2COO), 28.313.
HRMS calcd o C21H37NONa [M + Na] +: 342.2753, ound 342.2767.
[(Z)-4-Oc adec-9-enoic-amidome hyl-1H-(1,2,3-T iazol-1-yl)]-3,6,9- ioxaundecan-amine (5)
A solu ion o 3 (0.25 g, 0.71 mmol) and 4 (0.23 g, 0.71 mmol), in CH2Cl2 (6 mL), was added o a
solu ion o CuSO4 (0.018 g, 0.11 mmol) and sodium asco ba e (0,059 g, 0.30 mmol) in wa e (8 mL).
A e wa ds, he eac ion mix u e was s i ed igo ously o e h ee days. Then he mix u e was
sepa a ed and he o ganic phase was d ied o e anhyd ous Na2SO4. The CH2Cl2 was emo ed by
o a y e apo a ion o yield he c ude p oduc . The iazole de i a i e, was isola ed by lash column
ch oma og aphy on silica gel, elu ing wi h a CH2Cl2:MeOH (9:1) mix u e. Thus, p oduc 5 was
ob ained as a whi e solid (0.34 g, 0.51 mmol, 30%).
R (CH2Cl2/MeOH 9:1): 0.08
1H NMR (500 MHz, MeOD): δ 7.802 (s, 1H, H- iazol), 5.388–5.232 (m, 2H, CH=CH), 4.473 ( , J = 6,
2H, CH2CH2 iazole), 4.254 (s, 2H, NHCH2- iazol), 3.796 ( , J=5 Hz, 2H, CH2- iazol), 3.606–3.596 (m,
2H, CH2CH2NH2), 3.550–3.503 (m, 8H, OCH2CH2O), 3.032 (s, 2H, CH2NH2), 2.121 ( , J= 7.5 Hz, 2H,
CH2CO), 1.934–1.922 (m, 4H, CH2CH=CHCH2), 1.7914–1.733 (m ,2H, NH2), 1.513 (m, 2H, CH2), 1.220–
1.194 (m, 20H, CH2 oleic acid), 0.799 ( , J = 7 Hz, 3H, CH3).
13C NMR (125.7 MHz, MeOD): δ 176.191 (C=O), 130.871, 130.772 (C=C), 124.903, 71.496, 71.354, 71.342,
71.224, 70.373, 68.152, 51.376, 36.965, 35.543, 33.026, 30.807, 30.5272, 30.406, 30.330, 30.309, 30.298,
30.216, 28.123, 28.104, 26.916, 23.702, 14.438.
HRMS calcd o C29H55N5O4 [M + H] +: 538.43; ound 538.43.
(Z)-(1-azido-3,6,9- ioxaundecan)-oleamide (6)
To a solu ion o 3 (0.10 g, 0.46 mmol) in d y CH2Cl2 (0.58 mL), unde a gon a mosphe e, E 3N
(0.042 mL, 0.56 mmol) and oleoyl chlo ide (0.066 mL, 0.46 mmol) we e added, and he eac ion was
igo ously s i ed o 1 day a oom empe a u e. Then, CH2Cl2 (10 mL) was added and ex ac ed
P oceedings 2019, 41, 1 10.3390/ecsoc-23-06458 6 o 14
wi h HCl 1N (3 × 5 mL). The o ganic phase was washed wi h a sa u a ed aqueous NaHCO3 solu ion
(5 mL). The o ganic phase was d ied o e anhyd ous Na2SO4. The sol en was e apo a ed and he
p oduc was pu i ied by lash column ch oma og aphy on silica gel wi h CH2Cl2:MeOH (15:1) o yield
compound 6 (0.123g, 57 %), as a whi e solid.
R (CH2Cl2/MeOH 9:1): 0.60
1H NMR (500 MHz, CDCl3): δ 5.986 (s, 1H, NHCO), 5.353–5.328 (m, 2H, CH=CH), 3.690–3.60 (m, 10H,
OCH2CH2O and CH2CH2N3), 3.459 ( , J = 5 Hz, 2H, OCH2CH2NHCO), 3.470–3.449 (m, 2H,
CH2CH2NHCO), 3.390 ( , J = 5, 2H, CH2N3), 2.168 ( , J = 7.5 Hz, 2H, CH2CO), 2.024–1.986 (m, 4H,
CH2CH=CHCH2), 1.638–1.609 (m, 2H, CH2CH2CO), 1.300–1.253 (m, 20H, CH2 oleic acid), 0.892 ( , J =
6.5 Hz, 3H, CH3).
13C NMR (125.7 MHz, CDCl3): 173.380 (C=O), 130.132, 129.905 (C=C), 70.886, 70.787, 70.738, 70.399,
70.226, 70.121, 50.836, 39.294, 36.889, 32.044, 29.913, 29.878, 29.837, 29.665, 29.457, 29.314, 27.365,
27.336, 25.886, 22.820, 14.249.
HRMS calcd o C26H50N4O4Na [M + Na] +: 505.3724; ound 505.3718
1-amino-3,6,9- ioxaundecan-(Z)-9-Oc adecenamide (7)
To a solu ion o he azide 9 (0.423 g, 0.88 mmol) in d y THF (3.83 mL), unde a gon a mosphe e,
and cooled o 0 °C, 1.75 mL (1.75 mmol) o a 1M LAH solu ion in THF was added. A e s i ing a 0
°C o 1 h, he eac ion mix u e was quenched wi h sa u a ed Na2SO4 aqueous solu ion (0.62 mL), and
s i ed o 30 min, a oom empe a u e. The whi e p ecipi a e (aluminium sal s) o med, was il e ed
o e celi e and washed wi h e he (5 × 10 mL) and hen wi h CH2Cl2 (10 mL). The combined o ganic
phases we e d ied o e anhyd ous Na2SO4, il e ed and concen a e. The esidue was pu i ied by
lash column ch oma og aphy on silica gel using CH2Cl2: MeOH (15:1) as eluen , o yield he p oduc
7 (0.261 g, 0.57 mmol, 65%), as a colo less oil.
R (CH2Cl2/MeOH 15:1) = 0
1H NMR (500 MHz, CDCl3): δ 6.632 (s, 1H, NHCO), 5.350–5.325 (m, 2H, CH=CH), 3.657–3.557 (m,
10H, OCH2CH2O and OCH2CH2NH2), 3.482–3.436 (m, 2H, CH2CH2NHCO), 3.036–3.031 (m, 2H,
CH2NHCO), 2.985–2.957 (m, 2H, CH2NH2), 2.937–2.924 (m, 2H, NH2), 2.204–2.174 (m, 2H, CH2CO),
2.022–1.984 (m, 4H, CH2CH=CHCH2), 1.634–1.605 (m, 2H, CH2CH2CONH), 1.298–1.266 (m, 20H, CH2
oleic acid), 0.878 ( , J = 7 Hz, 3H, CH3).
13C NMR (125.7 MHz, CDCl3): δ 173.682 (C=O), 130.118, 129.906 (C=C), 70.603, 70.560, 70.303, 70.248,
39.308, 36.808, 32.036, 29.908, 29.888, 29.834, 29.791, 29.657, 29.484, 29.467, 29.444, 29.333, 27.363,
27.340, 25.930, 22.811, 14.237
HRMS calcd o C26H52N2O4 [M + H] + : 457.71; ound 457.40
3. Resul s and Discussion Sec ion
3.1. Syn hesis o he Amphiphilic Compounds
The i s syn hesized amphiphilic compound, 5, has a e ae hylene glycol chain as a space , he
e sa ile amine g oup as a pola head and he oleic acid agmen as a lipophilic ail. I was ob ained
h ough a i e s eps sequence (Scheme 3).
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Scheme 3. Syn hesis o he amphiphilic compound 5.
Mesyla ion o e ae hylene glycol wi h mesyl chlo ide ga e he dimesyla ed de i a i e 1, which
was ans o med in o diazide 2 by subs i u ion wi h sodium azide, and hen educed wi h
iphenylphosphine o yield compound 3. The linking o 3 o he lipidic pa o he amphiphilic
compound was ca ied ou h ough a Cu (I) ca alyzed Huisgen eac ion. Whi h his pu pous, he
co esponding alkynyl de i a i e o oleic acid 4 was p e iously p epa ed by amida ion o oleic acid
wi h p opa gylamine, and he Huisgen eac ion was ca ied ou wi h he co esponding azide 3,
ob aining he inal compound 5. The p esence o he amine g oup in 5, as a e sa il pola head, may
cons i u e a binding si e o o he speci ic unc ional g oups as a d ug, a ecogni ion ligand o an
anionic g oup like phosphona e.
In he case o he second syn hesized amphiphilic compound 7, wi h a s uc u e simila o ha
o compound 5, he connec ion be ween he pola head and he lipophilic chain is an amide g oup
ins ead o a iazole one (Scheme 4).
Scheme 4. Syn hesis o he amphiphilic compound 7.
The eac ion be ween compound 3 and oleoyl chlo ide yielded he amide 6, and he subsequen
egioselec i e educ ion o he azide g oup wi h LAH ga e compound 7, wi hou educing he amide
unc ion.
P oceedings 2019, 41, 1 10.3390/ecsoc-23-06458 8 o 14
3.2. P epa a ion and Cha ac e iza ion O Micelles
In all cases, he ange o CMC ob ained was [0.01 mM–0.08 mM] using he py ene me hod 24],
e y simila o he CMC alues o polyme ic micelles 25–27].
Micelles we e o med in wa e solu ions a a concen a ion o 1.25 mg/mL (0.02 M in he case o
compound 7) much g ea e han CMC. Micelle o ma ion p ocess was p e iously op imized and
consis s on he dispe sion o he amphiphilic compound in MilliQ wa e . Then, he sample was
ul asonica ed by a sonic ip (Digi al ul asonic sonica o Q500 o 500 wa s), o 30 min. A e
sonica ion, a mic o il a ion p ocess was ca ied ou wi h a 30 mm memb ane il e (In e lab L d.
Cus omables sy inge il e s) in o de o elimina e suspended pa icles.
Micelles we e hen cha ac e ised by DLS and TEM. Figu e 2 ep esen s wo elec onic
ansmission mic oscope pic u es wi h di e en magni ica ion o micelles ob ained om amphiphilic
compound 5 (M5). As i can be seen, micelles a e monodispe se, he e o e agg ega es a e no p esen ,
and hey ha e sizes in a ange o 50–89 nm.
Figu e 2. TEM images o M5.
In addi ion o mic oscopic analysis, he sample was analysed by DLS (Dynamic ligh sca e ing)
in o de o de e mine hei hyd odynamic size. In he case o M5, i was o 99.80 nm (Figu e 3).
Figu e 3. DLS Analysis o M5.
As can be seen, bo h echniques de e mined simila micelles size.
Figu e 4 ep esen s a TEM pho og aph o micelles om compound 7 (M7) wi h diame e s
be ween 70–120 nm and DLS esul s wi h hyd odynamic size o 40 nm.
P oceedings 2019, 41, 1 10.3390/ecsoc-23-06458 9 o 14
Figu e 4. TEM and DLS Analysis o M7.
In his case, one mo e ime, bo h echniques con i m he p esence o micelles.
3.3. Inclusion o Dexame hasone in Micelles
Dexame hasone (Dexa) was in oduced in he syn hesized micelles, in o de o e i y he abili y
o hese nanoca ie s o con ain a highly insoluble d ug. This es was pe o med using syn hesized
micelles o compound 5 (M5) and 7 (M7) (Table 1).
A p ocedu e in 3 s eps has been ca ied ou :
(i) Addi ion o he solid d ug (5.9 mg) di ec ly o he p e iously p epa ed wa e solu ion o micelles
and s i ing 72 h a 50 °C. Du ing his ime, he sample was co e ed wi h an aluminum oil o
p e en he deg ada ion o he pho osensi i e d ug Dexame hasone.
(ii) Cen i uga ion a 2000 pm du ing 15 min, ob aining a p ecipi a e, which ep esen s he d ug
no included, and a solu ion con aining he micelles wi h he d ug inside.
(iii) Lyophiliza ion o he elimina ion o wa e om he samples.
Table 1. D ug and micelles quan i ies (in mg) be o e and a e he inclusion p ocess.
Ini ial mg o
Dexa
Ini ial mg o
Amphiphile
mg o Dexa
as a
P ecipi a e
Mg o Micelle +
Dexa
mg o Dexa
Included in
Micelles
% o Included
D ug (Pa i ion
Coe icien )
5.9 mg 10 mg o 5
(in 8 mL H
2
O milliQ) 2.7 mg 13.2 mg 3.2 mg 54.2%
6.2 mg 10 mg o 7
(in 10 mL H
2
O miliQ) 1.6 mg 14.6 mg 4.6 mg 74.2%
To con i m he inclusion o he d ug in he micelle, he analysis o he samples by
1
H-NMR using
di e en deu e a ed sol en s has been ca ied ou and he esul s ob ained a e shown in Figu e 5.
(a)
8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 ppm
