-
Colloids and Surfaces B: Biointerfaces 117 (2014) 128134
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Colloids and Surfaces B: Biointerfaces
jo ur nal ho me p ag e: www.elsev ier .com/ locate /co lsur
fb
Curcum natreatm
Malathi SBalasubra Department ob Biomaterials
a r t i c l
Article history:Received 19 AReceived in reAccepted 8
FeAvailable onlin
Keywords:Poly (dl-lacticMelt
polycondElectrospinningNanoberCurcuminCarcinoma
A] co 10,0oadeon obing b
resuetics s Ko
drug dissolution and non-Fickian diffusion as a major drug
release mechanism. The effect of CPNF on cellviability was assessed
by the MTT (3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyltetrazolium
bromide) assayto examine the cytotoxic effect of released curcumin
on A431 cells in vitro.
2014 Elsevier B.V. All rights reserved.
1. Introdu
Melanomwith skin cmetastatic mortality ra12% of all cgrowth of
iand treatme1, 7-bis (4-ha polyphenolonga (turmsuch as
Indidiseases, wand is also eand pharm[4], antioxidhave been the
treatmepancreatic
CorresponE-mail add
http://dx.doi.o0927-7765/ ction
a and carcinoma are the main cause of death of patientsancer.
Melanoma is a cutaneous tumor and is fatal instage [1]. The
malignant melanoma has the highestte (1015%) among all skin
disorders and accounts forancer-related deaths among Caucasians.
The aggressivenvasive malignant melanoma calls for early
diagnosisnt. The natural curcumin [diferuloylmethane; (1E,
6E)-ydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione]lic pigment
isolated from the dry rhizomes of Curcumaeric), has found use in
traditional medicine in countriesa and China [2] for the treatment
of common cold, skinound healing, abdominal spasms and inammation
[3]mployed as a dietary herbal supplement. The biologicalacological
properties of curcumin such as antitumorant [58], anti-inammatory
[911] and anti-HIV [12]reported. There are several ongoing clinical
trials fornt of different types of cancers such as skin
cancer,cancer, multiple myeloma and colorectal cancer. The
ding author. Tel.: +91 4422202794.ress: [email protected] (B.
Sengottuvelan).
remarkable pharmacological activity of curcumin is attributed
toits ability to act on multiple intracellular targets and patients
withcolorectal cancer could achieve efcient chemopreventive
effect[1315]. The large dose of curcumin and frequent
administrationsshowed an increase in side effects and lower
compliance from theusers [16]. The factors that limit the use of
free curcumin for cancertherapy are its poor aqueous solubility,
poor absorption and rapidmetabolism [17,18]. In an effort to
improve the bioavailabilityof the hydrophobic drug curcumin, it was
encapsulated in PLGApolymeric nanoparticles or nanobers which are
known for theirbiodegradability [1921], biocompatibility,
solubility and goodmechanical strength [22,23]. Several delivery
systems have beenemployed to enhance the effectiveness of drug to
reduce thedosage and to overcome the problem of poor solubility of
the drugin water as well as its reduced bioavailability
[24,25].
The fabrication of nanobers can be achieved by a numberof
techniques such as template [26], self-assembly [27]
phaseseparation [28], melt-blown [29] and electrospinning [30].
Electro-spinning is an important technique for generating bers
directlyfrom polymers, composites, ceramic and metal nanobers. It
isa simple and versatile method to produce large scale
continuousbers and the ber diameter can be adjusted from nanometer
tomicron. Dalton et al. have reported that electrospun
PEO-block-PCLnanobers can eliminate the entry of cytotoxic solvents
into the
rg/10.1016/j.colsurfb.2014.02.0202014 Elsevier B.V. All rights
reserved.in loaded poly (lactic-co-glycolic) acident of
carcinoma
ampatha, Rachita Lakrab, PurnaSai Korrapatib,amanian
Sengottuvelana,
f Inorganic Chemistry, University of Madras, Guindy Campus,
Chennai 600 025, Indiadivision, CSIR-CLRI, TICEL Biopark, Chennai
600 113, India
e i n f o
pril 2013vised form 8 February 2014bruary 2014e 19 February
2014
-co-glycolic) acidensation
a b s t r a c t
Poly (dl-lactic-co-glycolic) acid [PLGmolecular weight (15,400,
11,000 andGPC and TGA-DTA studies. Curcumin lspinning in which no
visible aggregatiobtained from the topographical imagindicate that
an increase in GA contentin vitro release prole and release kinfrom
CPNF. The release prole follownober for the
polymers with different ratios (78/22, 68/32 and 61/39) and00
Da) were synthesized and characterized by 1H NMR, FTIR,d PLGA with
the size of 100300 nm were obtained by electro-served on the
surface. The diameter of CPNF (61/39) nanobery AFM is 160 10 nm.
The water contact angle measurementslts in increase in the
hydrophilicity of the PLGA copolymer. Thefrom the CPNF demonstrated
a sustained release of curcuminrsmeyerPeppas model suggesting a
combination of surface
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M. Sampath et al. / Colloids and Surfaces B: Biointerfaces 117
(2014) 128134 129
human broblasts cells when the bers are deposited directly
ontobroblasts [31]. The polymeric nanobers are employed as
carriersfor controlled drug delivery, wound healing, biocatalysts
and alsoas active components for biosensing [32] due to their large
sur-face area to volume ratio and also they exhibit good capability
ofsupporting cell adhesion and differentiation.
Fibers can interact with skin at cellular level as an
adjuvant.The nanoberskin interaction can be used to enhance
immuneresponse for topical applications. The nanobers can
facilitate slowrelease of curcumin for its wound healing and
antimicrobial activ-ities [33]. The curcumin released from nanober
not only inhibitsmicrobial proliferation, but also accelerates
wound healing. Thiscontrolled release of curcumin while the
nanobers remain on theskin surfaceery systems
Langer arelease of pof antiangioPLGA degratrolled by tmolecular
wtallinity. In by followinsion througenvironmendation.
Curcumiexhibit gooreports on cof curcuminis to synthemolar
ratiosby melt polynanobers
2. Experim
2.1. Materi
dl-Lacticdichloromemethanol (Stannous oreported prout the expout
at pH 7.microbiologand were u
2.2. Method
2.2.1. Melt PLGA w
(80.025kPand glycoli70/30 and
connected to a liquid nitrogen trap. Stannous octoate was
addedin catalytic amount. The mixture of lactic acid and glycolic
acidwas dehydrated at 120 C for 6 h at 8.0 kPa. In the second
stage, thecondensation of LA and GA occurs with the elimination of
waterresulting in the formation of the ester when the mixture of
lacticand glycolic acid was heated at 150 C for 12 h under high
vacuum(2.5 kPa). In the third stage viscous and brous polymer
wasproduced under very low pressure (0.025 kPa). The crude
brousPLGA was soluble in chloroform and precipitated with
diethylether as a non-solvent. The precipitate was dried under
vacuum toyield transparent yellow ber. The PLGA copolymers with
differentcompositions were prepared using the same procedure.
Prepa encrriedlutioer in issolvmoguouse nan
to he n
solvber wThe fm [E
electforceed ong prry trie 2)
Chara drutomer Tratic Red o
wehlororpho
FielHITAHI). Ted bof ther donio
cm ed aremeer suh m
copoly highlights one of the most successful topical drug
deliv-.nd Folkman were the rst to demonstrate the controlledroteins
using polymers which enabled the developmentgenic drug delivery
systems for cancer therapy [34].dation and drug release kinetics
can be precisely con-he physicochemical properties of the polymer,
such aseight, polydispersity index, hydrophobicity and
crys-general, drugs can be released in a controlled mannerg Fickian
or non-Fickian kinetics due to drug diffu-h the polymeric matrix,
or be triggered in response total stimuli or released in the course
of chemical degra-
n loaded PLGA nanoparticles have been reported tod anticancer
activity [35,36]. However, there are nourcumin loaded PLGA nanobers
for controlled delivery
in squamous carcinoma. The aim of the present studysize a series
of lactic/glycolic acid polymers with various
of lactic to glycolic acid and various molecular
weightscondensation method and study their curcumin loaded
for the treatment of squamous carcinoma.
ental
als
acid and glycolic acid (Merck), curcumin (Sigma),thane, acetone,
diethyl ether (Fischer Scientic),SRL) were used as such without
further purication.ctoate was prepared with slight modication of
theocedure in Ref. [37]. Deionized water was used through-eriment.
The in vitro release measurement was carried4 in PBS medium.
Nutrient agar (Himedia) was used forical tests. All other reagents
were of analytical gradesed as received.
s
poly condensation of PLGA copolymersas synthesized in three
stages under vacuum
a) (Scheme 1). In the rst stage, dl-lactic acid (0.08 M)c acid
(0.02 M) with different molar ratio (80/20,60/40) were placed in a
ask with a distillation head
2.2.2. The
was camer sopolymwas dthe hocontinpreparappliedfrom tnied
bynanoment. of 10 cstrongtional collectresultilimina(Schem
2.2.3. The
trophoFourieMagnerecordspectraated cThe mousing a6600,
HITACexaminbicity of watangle gfoil (1preparmeasuthe bfor eac
Scheme 1. Synthesis of the PLGA ration of curcumin loaded PLGA
nanobersapsulation of PLGA copolymer with curcumin (10:1)
out by electrospinning technique. The PLGA copoly-n was prepared
at room temperature by dissolving the40% chloroform under gentle
stirring for 2 h. Curcumined in 60% methanol and was gradually
poured intoeneous polymer solution. The solution was sonicatedly
for 1 h and it was lled in a 5 mL plastic syringe. Toobers by
electrospinning, a high voltage (24 kV) wasthe polymer solution and
a charged jet is driven outeedle which undergoes
stretching/thinning accompa-ent evaporation (Supporting
information, Fig. SF1). Theas collected on a drum, which is
attached to the instru-eed-rate was 0.4 mL/h, with a
tip-to-collector distancespin Nano]. The electrospinning process is
governed byrical forces, viscoelastic forces, surface tension,
gravita-s and frictional force of the air drag [38]. The ber wasn
an aluminum foil and was dried under vacuum. Theoduct was stored in
a freezer for further studies. Pre-als were carried out to adjust
the processing parameters.
cterizationg concentration was determined by UVvisible spec-try
at 425 nm. The polymer was characterized bynsform Infrared
Spectroscopy (FTIR) and Nuclearesonance spectroscopy (1H-NMR). FTIR
spectra weren a Bruker Tensor 27 IR spectrometer and 1H-NMRre
obtained on a Bruker NMR spectrometer in deuter-form with
tetramethylsilane as an internal standard.logy of curcumin loaded
PLGA nanober was analyzedd Emission Scanning Electron Microscope
(FESEM, SU-CHI) and Scanning Electron Microscope (SEM, S3400,he
bers were coated with a thin layer of gold and theny FESEM and SEM.
The hydrophilicity and hydropho-e CPNF was measured by contact
angle relaxationroplet by Kruss easy drop method using a
contactmeter (KRUSS, DSA II GmbH, Germany). The aluminum
1 cm) containing electrospun nanober was freshlynd then attached
to a glass slide for contact anglents. A droplet of deionized water
was pipetted ontorface and the contact angle was measured at 25
C
easurement. The images of the solution droplet were
mers.
-
130 M. Sampath et al. / Colloids and Surfaces B: Biointerfaces
117 (2014) 128134
ded PL
obtained usvalues werwas ascertaBruker X-ration
sourcegravimetriccarried out lyzer, underrate of 10 Croughness
dSystem Atonanobers by non-con
2.2.4. DeterCurcumi
rately weigmethanol iwere then tor (Remi ofor 2 h afte1 h, for
comthreefold wspectrophospectrophosulation ef
Encapsulati
2.2.5. In vitThe CPN
at pH 7.4. TThe sampleincubator. intervals atcumin fromof
methanoThe concena calibratio
2.2.6. ReleaThe drug
the followin
1) Higuchi 2) Power la
where Q is ing the desreleased at nent. The nIf the n valu
on, aFicki
Cytot celyl) armin. Thech 8
wit and t samn 5% owthas dxprestand
ults
direus oc
efcc acid
undeiffereigh
andmersrom2). Wease ed. Wolect al. tio o/50 a
inhsperser r
encytocodicald. ThScheme 2. Schematic illustration of curcumin
loa
ing a high speed digital camera and the contact anglee
determined. The crystalline nature of the polymerined by powder
X-ray diffraction measurements usingy diffractometer with a Cu
K-monochromatic radia-
( = 1.5406 A) operating at 30 kV and 15 mA. Thermo (TG) and
differential thermal analysis (DTA) wereon a Pyris 1 TGA (Perkin
Elmer) thermo gravimetric ana-
nitrogen atmosphere, with 4 mg of sample, at a heating/min in
the temperature range from 40 to 600 C. Theata were obtained from
the images recorded by Parkmic Force Microscope (AFM) XE 100. The
drug loadedwere coated on to a mica substrate and scanned in
airtact mode for the AFM studies.
mination of drug encapsulation efciencyn was extracted from CPNF
by suspending an accu-hed amount (10 mg) of curcumin loaded CPNF in
10 mln well-closed screw-capped 15 ml vials. The samplesmaintained
at 37 C in a shaker (100 rpm) incuba-rbital shaker). The samples
were stirred continuouslyr the incubation and were sonicated
continuously forplete drug dissolution. A 1-ml sample was
dilutedith methanol, and curcumin content was
determinedtometrically in methanol at 425 nm using UVvisibletometer
(Perkin Elmer -35). The percentage of encap-ciency was calculated
using the following equation:
on efciency (%) = Weight of drug in CPNFTheoretical drug
loading
100
ro drug releaseF (100 mg) was dispersed in 100 ml phosphate
bufferhe solution was distributed in 1.5 ml eppendorf tubes.s were
then maintained at 37 C in a shaker (100 rpm)The solution was
centrifuged at predetermined time
4000 rpm for 10 min to separate the released cur- CPNF. The
released curcumin was dissolved in 1 mll, and then analyzed
spectrophotometrically at 425 nm.tration of the released curcumin
was determined fromn curve of curcumin in methanol.
se kinetics release kinetics and mechanism were investigated byg
mathematical models.
diffusia non-
2.2.7. The
diphento detegrowthin whitreatedcuminThe tes37 C itive grcells)
wwere eples
3. Res
Thestannoits highglycolifor 4 hwith dtheir w11,000copolytive
chFig. SFa decrobservwith mZhou efeed raand 50
Thepolydimonomused toof its cbiomemethoModel Q = Kt1/2.w (or)
KorsmeyerPeppas model Mt/M = Ktn.
the cumulative drug release, K is the constant reect-ign
variables of the system. Mt/M is fraction of drugtime t, K is the
rate constant and n is the release expo-
value is used to identify different release mechanisms.e is 0.45
or less, the release mechanism follows Fickian
such as confrom the suoptimized chloroforma medium tis also
highformation oout with dithe conditiGA nanober (CPNF).
nd higher values 0.45 < n < 0.89 for mass transfer
followan model (anomalous transport).
oxicity studiesl viability MTT (3-(4,5-dimethyl
thiazol-2-yl)-2,5-ssay was carried out with skin cancer (A431) cell
linese the effect of curcumin loaded PLGA nanobers on cell
inhibition in cell growth was determined by MTT assay000
cells/well were taken in a 48-well plate and wereh 10, 25, 50, 100
and 250 m concentration of free cur-equivalent doses of
curcumin-loaded PLGA nanobers.ples were kept in triplicate. The
plate was incubated at
CO2. The assay was terminated after 48 h and the rela-
inhibition compared to that of control cells (untreatedetermined
spectrophotometrically at 570 nm. The datassed as mean absorbance
value (OD) of triplicate sam-ard deviation of the mean.
and discussion
ct melt polycondensation of LA and GA was initiated bytoate as a
catalyst. This catalyst was chosen because ofiency in promoting the
polymerization of lactic acid and. The polymerization reaction was
carried out at 150 Cr reduced pressure (0.025 kPa). PLGA was
synthesizedent molar feed ratios (78/22, 68/32 and 61/39) andt
average molecular weights were found to be 15,400,
10,000 Da respectively. The molecular weights of the were
determined by GPC method and the representa-atogram is reproduced
(vide: Supporting information,hen the ratio of glycolic acid
monomer was increased,in the molecular weight of the PLGA copolymer
wasang et al. have reported the direct synthesis of PLGA
ular weight ranging from 900 to 1400 Da [39]. Recently,have
reported the direct synthesis of PLGA with molarf dl-lactic acid to
glycolic acid 100/0, 85/15, 75/25, 65/35nd its application in
protein delivery systems[40].erent viscosity, melting point,
molecular weight andity index of a series of PLGA copolymer with
differentatios are tabulated (Table 1). The PLGA nanober
wasapsulate curcumin in the present investigation
becausempatibility, biodegradability and suitability for
various
applications. The CPNF was obtained by electrospinninge control
over different electrospinning parameters
centration, applied voltage, distance of source
electrodebstrate, temperature, and solvent volatility have beenfor
good spinnability to get nanobers. A mixture of
and methanol in the ratio 40/60 (v/v) was chosen aso dissolve
PLGA and curcumin and this solvent mixturely volatile. When
curcumin content was increased, thef nanobers was difcult. The
experiment was carriedfferent concentration of curcumin in order to
optimizeon for forming smooth nanobers and nally the ratio
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M. Sampath et al. / Colloids and Surfaces B: Biointerfaces 117
(2014) 128134 131
Table 1Feed monomer ratio, calculated monomer ratio, inherent
viscosity, molecular weight and polydispersity index of the PLGA
copolymer.
Sl. no Feed monomerratio (LA/GA)
Calculated monomerratio (LA/GA)a
Inherentviscosity (dL/g)
Melting point(C)
Molecularweight (Da)
Poly dispersityindex (Mw/Mn)
1 80/20 78/22 0.23 96 2 70/30 68/32 0.18 52 3 60/40 61/39 0.16
nd
nd: not detected. Inherent viscosity was determined using
tetrahydrofuran as solvent with a solution ca Calculated by
NMR.
of curcumin and PLGA was maintained at 1:10. Said et al.
havereported fusidic acid loaded PLGA ultrane bers for
antimicrobialand wound bacterial studies [41].
Fig. 1 shows the characteristic FTIR spectrum of PLGA
copoly-mer. A strong band at 1759 cm1 is due to the C O
stretchingfrequency of ester group and the bands at 3002 and 2987
cm1
are attributed to CH stretching frequency. The strong band
at3558 cm1 is assigned to the OH stretching frequency. The bandsat
1463 and 862 cm1 are assigned to OH in-plane and out-of-plane
bending vibrations respectively. The bands at 1202 and1097 cm1 are
assigned to CO stretching while the band at750 cm1 is assigned to
out-of-plane bending vibration of CH. Thisspectral study conrms the
formation of PLGA copolymer.
The FTIR spectrum of curcumin (Fig. 1) shows the
characteristicpeak at 3500 cm1 which can be attributed to phenolic
OH stretch-ing vibration [42] and this band was observed at 3661
cm1inCPNF. The bands at 1510 and 1426 cm1 are due to the
stretchingvibrations of CC of benzene ring and olenic bending
vibrationof CH group bound to the benzene ring of curcumin
respectively[43]. These peaks were shifted to1524 and 1454 cm1 in
CPNF andthus, conrming the curcumin was encapsulated by PLGA
poly-mer. The peak at 865 cm1 is due to the stretching vibration
ofCO in CCPNF. A strbonyl stretcAll major b
Fig. 1. F
frequenciestogether tomation, Tab
NMR spPLGA copolcidated bydifferent ra(vide: Suppof PLGA
coassigned tois assigned observed a61/39) is caton signals.GA from
theCH2 peak nCH2, CH proare tabulate
The LA/Gthe integral(CH, LA), ac[45]. The ar
.79 pere o
wer encrting
therin thhe co
of th00
Suppted iopolre shopolted t
lacti therserie
XRD as se) and). Th9.7, mainses wOCH3. The phenyl ring was
observed at 871 cm1 inong and sharp peak at 1750 cm1 is attributed
to car-hing (C O) which was shifted to1752 cm1 in CPNF.ands of both
curcumin and PLGA are shifted to higher
7.117tons wprotoning theSuppo
Theascertaity of tcurvesup to 6(vide: presenPLGA cperatuPLGA
cattribution ofhigherof the
Theas well(68/32mation19.1, 2the redecreaTIR spectra of (A)
Curcumin (B) PLGA copolymer and (C) CPNF.
informationPLGA (68/3
Several gthe surfacetact anglescontact angfaces with 15400
2.011000 2.310000 2.1
oncentration of 0.1 g/dL.
in CPNF indicating that curcumin and PLGA are bound form more
stable nanobers (vide: Supporting infor-le ST1).ectroscopy was used
to analyze the composition of theymers. The structure of the PLGA
copolymers was elu-1H NMR spectrum. The 1H NMR spectra of PLGA
withtios viz. (61/39), (68/22) and (78/22) are reproducedorting
information, Fig. SF3). The 1H NMR spectrumpolymer (78/22) shows a
signal at 5.16 ppm which is
CH protons of GA unit while the signal at 1.50 ppmto CH3 protons
of LA unit. The CH2 protons of GA ist 4.76 ppm. The ratio of LA/GA
of PLGA (78/22, 68/32,lculated from the intensities of CH(LA) and
CH2(GA) pro-
Wang et al. have determined the molar ratio of LA and integral
data of the CH peak near 5.19 ppm and that ofear 4.85 ppm [44]. The
chemical shift values of the CH3,tons observed in the 1H NMR
spectra of the copolymersd (vide: Supporting information, Table
ST1).A monomer ratio of the copolymer was calculated using
values of the peak at 4.29 ppm (CH2, GA) and 4.51 ppmcording to
the method described by Gilding and Reedomatic protons of curcumin
exhibit a signal in the regionpm. However, in the case of CPNF, the
aromatic CH pro-bserved at 7.35 ppm while the CH2 (GA) and CH (LA)e
observed at 4.35 and 4.7 ppm respectively indicat-apsulation of
curcumin in the PLGA copolymer (vide:
information, Fig. SF4).mal behavior of PLGA copolymers was
investigated toe inuence of the monomer ratio on the thermal
stabil-polymers. The weight loss and differential weight losse
copolymers were obtained by heating the samples
C at the rate of 10 C/min under nitrogen atmosphereorting
information, Fig. SF5) and the relevant data aren Table ST2
(Supporting information). The TGA plots forymers are similar, with
the initial decomposition tem-ifting to higher values as the GA
component increases inymer (Supporting information, Fig. SF5). This
process iso the decomposition of PLGA copolymer with the forma-de
and glycolide monomers. The PLGA (68/32) exhibitsmal stability when
compared to that of other monomerss.
pattern of the copolymers indicates their amorphousmi
crystalline nature. The XRD results of PLGA (78/22),
(61/39) are reproduced in Fig. SF6 (Supporting infor-e PLGA
(78/22) exhibits ve peaks (2 = 17.5, 18.2,and 30.8), whereas the
peak intensity decreases ining copolymers indicating that polymer
crystallinityith increase in the glycolic acid ratio (vide:
Supporting
, Fig. SF6). The PLGA78/22 is semi crystalline whereas2) and
(61/39) are amorphous in nature.roups have employed experimental
results to compare
roughness of nanomaterial with the observed con- [46,47] and it
has been suggested that surfaces withle < 90 exhibit hydrophilic
properties whereas sur-contact angle > 90 exhibit hydrophobic
properties.
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132 M. Sampath et al. / Colloids and Surfaces B: Biointerfaces
117 (2014) 128134
Fig. 2. Water cresults are giv
The hydropwith the incCPNF nanothe GA contact angle oindicating
i60.1 0.89 (78/22) resin these twhydrophobiof lactic
achydrophobiF-108 can cpared to tha
The SEM images of CPNF (61/39) (Fig. 3) and other ratios
arereproduced in supporting information (Fig. SF7A and B). The
effectof curcumin content of PLGA (1:2, 1:10) on the morphology
of
s observed in these photographs. As decreasing curcumint
resulted in progressively reduced beading, increased berter, and
reduced diameter distribution were observed andorphology of the ber
was smooth without the presence
beads. The images observed in the SEM indicate that the
non-uniform because of its lower thermal stability (vide:rting
information, Fig. SF8A and B), which is reected byelting of
nanobers on the SEM grid itself. The polymerbers employed in the
present investigation essentially hasolecuLGA.o 10/curc
showses wCPNF icontendiamethe mof anyber isSuppothe mnanolow
mmer P1000 tof PLAwhichdecreaontact angle measurements of (A)
78/22, (B) 68/32 and (C) 61/39. Theen in degrees as a mean value
standard deviation (n = 5).
hilic nature of PLGA nanobers increases substantiallyrease in GA
content. The contact angle measurements ofbers indicate the change
in surface hydrophilicity whentent in the copolymer was increased
(Fig. 2). The con-f water droplets containing CPNF (61/39) is 51.5
0.18ts hydrophilic nature. The contact angle increases toand 88.1
0.97 in the case of CPNF (68/32) and CPNFpectively suggesting that
the hydrophilicity decreaseso systems. PLGA copolymer exhibits a
wide range ofc/hydrophilic property depending on the molar ratioid
and glycolic acid. Vasita et al. have reported thatc PLGA ber
meshes blended with hydrophilic pluronicause a decrease in the
surface contact angle when com-t of pure PLGA meshes [48].
mainly attrexplained bmore solubthe curcumshaped, non
The AFMof CPNF (61The scan raAFM [50,51ent molecupresence ofof
electrospticles encapdescribed bimage of AFSurface rousurface
comsurface rousurface rouRp-v (peaksured from variation ingated
usingdue to the fimage showsurface. Thsurface of tdistributionwith
a mea
The rele37 C in PBSdrug was dmeasured adays with nincreases
tstrength anelectrospinrmed the study. The
Table 2Surface roughThe results are
Sample code
CPNF 78/22 CPNF 68/32 CPNF 61/39 lar weight and also has lower
ratio of LA in the copoly- The average diameter of nanober
decreased from0 nm. Lin et al. [49] have reported average
diameterumin composite nanobers between 756 and 971 nm,s that the
average diameter of composite nanoberith increase in curcumin
content. The results were
ibuted to the solubility of the curcumin, and can bey the fact
that curcumin is hydrophobic drug and isle in
PLGA/dichloromethane/methanol solution. Whenin content is higher,
the nanobers formed are beaduniform and unstable.
non-contact mode two and three dimensional images/39) are shown
in Fig. SF9 (Supporting information).nges are 5 m 5 m and 5 m 5 m
respectively.] lets one to qualitatively visualize the surface
depend-lar event in 3D on a nanometer spatial resoltuion in the
oxygen. Xu et al. have studied the structural evolutionun
nanobers using AFM [52]. Chitosan/siRNA nanopar-sulated in PLGA
nanobers for siRNA delivery has beeny Chen et al. [53]. It is
evident from the topographicalM that the curcumin is impregnated in
the PLGA matrix.ghness (Ra) analysis provides a method of assessing
theposition and the drug distribution of the ber mats. Theghness
parameters of the CPNF (61/39) viz., Ra (averageghness), Rq (root
means square surface roughness) and
to valley surface roughness) of the system (SF9) mea-the 2D
images are 115, 140 and 497 nm respectively. The
wettability due to the surface roughness was investi- water
contact angle measurement (Table 2). Lower Raaster internalization
and the corresponding amplitudeed the presence of only a few
particles on the ber
e Ra value shows that most of the drug is beneath thehe ber and
to a lesser extent on the surface. The size
curve from the AFM image indicates the size of bern diameter of
160 10 nm.ase kinetics of curcumin from CPNF was observed at
(pH 7.4). At predetermined time intervals, the releasedissolved
in 1 ml of methanol and its absorbance wast 425 nm. Curcumin
release was sustained at least for 8o burst effect. The absence of
beads in the nanobershe surface area to volume ratio, better
mechanicald also the drug compatibility with the
polymer/solventning solution while the sustained release pattern
con-structural reliability of the nanobers throughout therelease
kinetics of curcumin from the PLGA nanobers
ness parameters using AFM and water contact angle measurements.
given in degrees, as a mean value and standard deviation (n =
5).
Ra (nm) Rq (nm) Rp-v (nm) Contact angle ()
320 371 1392 88.1 0.97235 282 1121 60.1 0.89115 140 397 51.5
0.18
-
M. Sampath et al. / Colloids and Surfaces B: Biointerfaces 117
(2014) 128134 133
Fig. 3. SEM images of (A) CPNF bead (1:2) and (B) CPNF (61/39)
nanober (1:10).
Table 3Drug loading and release prole of curcumin loaded PLGA
nanobers (CPNF). Theloading efciency and drug release data
presented as percentage. Data are presentedin mean value and
showing standard deviation (n = 3).
Sl. no Sample code Drug releasetime (h)
Drug loadingefciency (%)
Drug release(%)
1 CPN2 CPN3 CPN
was followenanober wCurcumin isin hydrophloading ef78/22 (81%)in
GA conteity of the m(Table 3) orelease rateof rifampiciage of
drugin the amouin glycolic aPLGA with ysis becaussterically
hemployed cemulsicatidrug loadinnanoparticlrelease for 7
The kinebetween drvalues of retting the ralong with
vitrond sho
ationST3)., was evaluated from the regression coefcients
obtained byi and KorsmeyerPeppas (power law) kinetic models. Thee
indicates that the KorsmeyerPeppas model is best suited
release kinetics of curcumin. The release exponent value
sustained release of curcumin is 0.45 < n > 0.89, which
lies
the limits of KorsmeyerPeppas model (vide: Supportingation,
Table ST3). The release exponent is a clear indicationomalous
diffusion (non-Fickian model) could be the princi-ase mechanism for
curcumin, which is due to the combinedf diffusion and erosion
mechanism for drug release [59].F 78/22 264 81 0.57 25 0.11F 68/32
264 70 1.50 45 0.50F 61/39 264 66 1.00 96 1.02
d for more than 10 days. The drug content (%) of theas
calculated and the values are tabulated (Table 3).
a hydrophobic drug and hence it is expected to resideobic LA
domain of the PLGA copolymer. The curcuminciency of the polymer is
in the following order: CPNF:
> CPNF: 69/31 (70%) > CPNF: 61/39 (66%). The increasent of
the polymer results in increase in the hydrophilic-atrix and it is
reected in lesser loading percentage
f the hydrophobic drug curcumin and also its faster (Fig. 4). A
similar observation has been made in the casen which is also a
hydrophobic drug [54]. The percent-
release in the CPNF nanober increases with increasent of GA
content in the PLGA copolymers. The increasecid percentage results
in faster degradation, whereas
higher lactic acid content is less susceptible to hydrol-e the
pendant methyl group on the lactic acid moietyinders the attack of
water molecules. Tsai et al. haveurcumin loaded PLGA nanoparticles
by high-pressureon-solvent evaporation method and found that theg
efciency was 46.9%. The release prole of curcumines was found to be
an initial burst followed by sustaineddays [55].
Fig. 4. Invalues a
informTable (CPNF)HiguchR2 valufor thefor thewithininformthat
anpal releeffect otic modeling on drug release shows the
relationshipug dissolution and drug release pattern [5658].
Thelease constant and release exponent (n) determined byelease data
into their respective mathematical models,regression coefcient (R2)
are provided in supporting
A431 cemeric nanoand Vishwagested thatpotential a
Fig. 5. Cytotoxicity prole of CPNF (61/39). Data are presented
as mean valu drug release prole of PLGA copolymers. Data are
presented as meanwing standard deviation (n = 3).
(vide: Supporting information, Figs. SF10SF15 and The curcumin
release prole from nanober matrixlls were used to assess the
potential of PLGA poly-bers as anticancer drug delivery vehicle.
Mukerjeenatha formulated curcumin-loaded PLGA NPs and sug-
a nanoparticle-based formulation of curcumin has highdjuvant
therapy in prostate cancer [60]. Cell viability
es and showing standard deviation (n = 3).
-
134 M. Sampath et al. / Colloids and Surfaces B: Biointerfaces
117 (2014) 128134
(MTT) assays were performed using equivalent dosages of free
cur-cumin and curcumin-loaded PLGA nanober (CPNF: 61/39). ThePLGA
(61/39) nanober was taken as blank and untreated cellsserved as
controls. The cell death was maximum when the unboundcurcumin
content was increased from 10 to 250 M while CPNFexhibits only
marginal decrease in cell death when curcumin con-tent was
increased indicating the controlled release of curcuminfrom the
polymer matrix (Fig. 5). However, the PLGA did not showany effect
on the cell viability. The assay was terminated after 48 hand the
colthat curcumgrowth of ccancer cell PLGA nanop
4. Conclus
The biodwith low mdensation m1HNMR, GPfree
curcumelectrospincurcumin cacterized bmeasuremeconcentraticumin
loadhydrophilicrelease rateage diamethigh drug estudies
fromsustained mThe cell viananobers CPNF is capcontrolled m
Acknowled
The nafully acknoNanosciencMadras for
Appendix A
Supplemfound, in th2014.02.02
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Curcumin loaded poly (lactic-co-glycolic) acid nanofiber for the
treatment of carcinoma1 Introduction2 Experimental2.1 Materials2.2
Methods2.2.1 Melt poly condensation of PLGA copolymers2.2.2
Preparation of curcumin loaded PLGA nanofibers2.2.3
Characterization2.2.4 Determination of drug encapsulation
efficiency2.2.5 In vitro drug release2.2.6 Release kinetics2.2.7
Cytotoxicity studies
3 Results and discussion4 ConclusionsAcknowledgementsAppendix A
Supplementary dataAppendix A Supplementary data