self-nanoemulsifying drug delivery system of tetrandrine

Research ArticleSelf-Nanoemulsifying Drug Delivery System of Tetrandrinefor Improved Bioavailability Physicochemical Characterizationand Pharmacokinetic Study

Chunxia Liu12 Li Lv2 Wei Guo3 LanMo3 Yaoxing Huang3

Guocheng Li 12 and Xingzhen Huang 3

1Department of Pharmacy Zengcheng District Peoplersquos Hospital of Guangzhou Guangzhou 511300 Guangdong China2Department of Pharmacy Sun Yat-Sen Memorial Hospital Sun Yat-Sen University Guangzhou 510120 Guangdong China3School of Pharmacy Guangxi Medical University Nanning 530021 Guangxi China

Correspondence should be addressed to Guocheng Li guochenglisyx126comand Xingzhen Huang huangxingzhengxmueducn

Received 10 May 2018 Accepted 27 August 2018 Published 27 September 2018

Academic Editor Sanyog Jain

Copyright copy 2018 Chunxia Liu et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The main purpose of this study was to investigate the potential of self-nanoemulsified drug delivery system (SNEDDS) to improvethe oral bioavailability of tetrandrine (Tet) SNEDDS was developed by using rational blends of excipients with good solubilizingability for Tet which was selected based on solubility studies Further ternary phase diagram was constructed to determine the self-emulsifying region The optimal formulation with the best self-nanoemulsified and solubilization ability consisted of 40 (ww)oleic acid as oil 15 (ww) SPC and 30 (ww)Cremophor RH-40 as surfactant and 15 (ww) PEG400 as cosurfactantThe averagedroplet size and zeta-potential of the optimal Tet SNEDDS were 1975plusmn037 nm and 187plusmn026mv respectivelyThe dissolute rate ofTet SNEDDS in various dissolution media was remarkably faster than Tet commercial tablet Moreover in vivo pharmacokineticstudy results show that significant increase (ple 005) in the peak concentration (Cmax) and the area under the curve (AUC) ofTet was observed after the oral administration of Tet SNEDDS and the absorption of Tet from SNEDDS resulted in approximately233-fold increase in oral bioavailability compared with the commercial tablet Our research suggests that the prepared Tet SNEDDScould be a good candidate for improved the dissolution and oral bioavailability of Tet

1 Introduction

Tetrandrine (Tet) is a bisbenzyltetrahydroisoquinoline alka-loid (Figure 1) which is found in the Chinese medicinal herbhan-fang-chi (or fen-fang-qi Stephania tetrandra SMoore)[1] The first pharmacological and toxicological study of Tetwas published in 1937 and demonstrated its hypotensiveand cardiodepressant effects [2] According to the literaturefor over half a century Tet has attracted large amount ofinterest because it shows a variety of pharmacological effectsincluding antiarrhythmia antiatherogenic antisilicosis anti-hypertension and immunomodulation effects [3ndash8] Tet hasbeen mainly used for early mild hypertension in clinicaltherapeutics and for severe hypertensive and hypertensivecrises The antihypertensive effect is made through a calcium

antagonist mechanism [9 10] In recent years Tet has alsoattracted much attention due to its obvious effect on exper-imental silicosis [11ndash15] There is a growing body of evidencethat Tet exerts anticancer effects against a variety of can-cers including leukemia hepatocellular carcinoma gastriccancer colon cancer lung cancer glioma nasopharyngealcarcinoma prostate cancer breast cancer and bladder cancer[16ndash21]

Although Tet has potentially considerable value in clinicsome problems have arisen that have limited its clinicalapplication In general a large dose (6 to 15 tablets per day)is required for the current commercially available tablets[22] Additionally Tetrsquos poor solubility in physiological envi-ronment (Tet saturation=0015 mgmL in pH 74 phosphatebuffered saline (PBS)) caused by the presence of a quaternary

HindawiBioMed Research InternationalVolume 2018 Article ID 6763057 10 pageshttpsdoiorg10115520186763057

2 BioMed Research International

O

O OO

N

N

O

H H

O

Figure 1 Molecular structure of tetrandrine (Tet)

ammonium cation [23] contributes to its low and variableoral bioavailability gastric intestine and kidney damageand bad patient compliance [24] In recent years manypharmaceutical methods have been investigated to improvethe bioavailability of Tet such as lipid nanocapsules nanopar-ticles ethosomes and microspheres [25] However most oftetrandrine based nanoparticles were used for injection andseldom used in oral administration

Investigation of novel drug delivery systems to enhancethe solubility and improve bioavailability of Tet is con-sidered a matter of urgency [26] In recent years variousstrategies have been considered to overcome the problemsassociated with oral absorption and bioavailability such asmicrosphere microcapsule nanoemulsified drug deliverysystem (SNEDDS) and nanoparticles [23] A high speeddisperser and a high pressure emulsifier generating particleswith an average diameter of about 200 nm in vitro has shownsome success for Tet encapsulation [27] and coencapsulateddoxorubicin and bromotetrandrine lipid nanoemulsions haveshown some potential of treatment in breast cancer animalmodels [28]

SNEDDS is an isotropic mixture of oils surfactanthydrophilic cosurfactant and drug substances which forma fine oil-in-water microemulsion when introduced intoaqueous media while being gently agitated by the digestivemotility of the stomach and intestine SNEDDS is a relativelyrecent term used to indicate formulations with a globulesize less than 100 nm [29] It has excellent efficiency inincreasing the dissolution rate promoting oral absorptionand increasing the bioavailability of poorly water-solubledrugs [30 31] and has shown a lot of success for herbal drugs[32] There are some commercially successful formulationssuch as Neoral (cyclosporine A) Fortovase (saquinavir)Agenerase (amprenavir) and Norvir (ritonavir) in clinicaluse

Extensive review of literature reveals lack of reports aboutthe bioavailability improvement of poorly water-soluble Tetusing SNEDDS Thus the objective of the present study wasto formulate Tet SNEDDS to improve Tetrsquos oral bioavail-ability To achieve this Tetrsquos solubility in various excipientswas evaluated and that with highest solubility of Tet wereselected oil surfactant and cosurfactant of Tet SNEDDSThe prepared Tet SNEDDS was evaluated for morphological

droplet size zeta-potential thermodynamic stability and invitro dissolution study Furthermore an in vivo pharma-cokinetic study was performed to study Tetrsquos pharmacoki-netic behavior and bioavailability enhancement after oraladministration

2 Materials and Methods

21Materials Tet (puritygt980)was obtained as a gift sam-ple from Beihai Sunshine Pharmaceutical co Ltd (BeihaiChina) A Tet tablet (containing 20mg Tet in one tablet withexcipients including starch dextrin andmagnesium stearate)was manufactured by Beihai Sunshine Pharmaceutical coLtd (Beihai China) Oleic acid Tween 60 and Tween 80 werepurchased from Tianjin Damao Chemical Reagent Factory(Tianjin China) Soybean oil isopropyl acetate olive oilethyl linoleate cremophor RH-40 and isopropyl myristate(IPM)were purchased fromChengdu Gracia Chemical Tech-nology co Ltd (Chengdu China) Ethyl oleate butyl oleateand soybean phosphatidylcholine (SPC) were purchasedfrom Tianjin Xing Fu Fine Chemical Industry ResearchInstitute (Tianjin China) Isopropanol glycerol absolutealcohol and PEG400 were purchased from Chengdu KelonChemical Reagent Factory (Chengdu China) Methanol andacetonitrile (chromatographic grade) were from ThermoFisher Scientific (China) Co Ltd All other chemicals usedwere of analytic grade

22 Determination of Tet Solubility The solubility of Tet wasdetermined in selected oils surfactants and cosurfactants bypouring an excess of Tet into 1mL of each excipient Theobtained mixtures were mixed using a vortex mixer Andthen the mixture was kept in a water bath at 37plusmn05∘C for72 hours After equilibrium was achieved the equilibratedsamples were centrifuged at 3000 rpm for 15min and excessinsoluble Tet was discarded by filtration using a 045 120583mmembrane filterThe concentration of Tet was determined bya high performance liquid chromatography (HPLC) methoddescribed below The experiments were performed in tripli-cate

23 HPLC Analysis The amount of Tet in various excip-ients was quantified by a validated HPLC method [33]equipped with an ultraviolet detector (Agilent 1260 LiquidChromatography American) Tet was separated on a RP-C18column (ODS C18 200mmtimes46mm 5 120583m) using methanol-acetonitrilendashwater (3 1 1 v v v) plus 006 diethylamineas mobile phase at a flow rate of 10mLmin with thedetection wavelength at 282 nm The column temperaturewas maintained at 25∘C

24 Preparation of SNEDDS For preparation of TetSNEDDS the content of Tet was fixed at a constant level(10 ww of excipients) Firstly Tet was dissolved bycosurfactant and then the mixture containing the calculatedamount of oil and surfactant was mixed by gentle stirringfor 10min and vortex mixing until the microemulsionformulation was obtained

BioMed Research International 3

25 Pseudo-Ternary Phase Diagram Study The pseudo-ternary phase diagrams were constructed with oil surfactantand cosurfactant using the water titration method at roomtemperature each of them representing an apex of the trian-gle and the total of themwas kept at 100Themixture oil andsurfactantcosurfactant at certain weight ratio were titratedwith water and mixed by magnetic stirring until equilibriumwas reached The mixtures which were clear or slightlybluish appearance were determined as microemulsions Inthe SNEDDS oleic acid was used as the oil a mixture of SPCand cremophor RH-40 was used as surfactant and PEG400was used as cosurfactantThe ratios of SPC to cremophorRH-40 by weights 1 1 2 1 and 1 2 were studied by constructinga ternary phase diagram The key factor for SNEDDS is theratio of surfactant to cosurfactant Phase diagrams at specificratios of surfactant to cosurfactant by weights 1 1 3 2 2 1and 3 1 were taken Mixtures of surfactantcosurfactant (at aspecific ratio) with oil were prepared at ratios 9 1 8 2 7 36 4 5 5 4 6 3 7 2 8 and 1 9 by weight Eachmixture wastitrated with water and visually observed for phase clarityThe microemulsion regions in the diagrams were plottedAlso themicroemulsion formulationswere selected at desiredcomponents ratios

26 Characterization of SNEDDS

261 Morphological Characterization The morphology ofSNEDDS was observed by transmission electron microscopy(Hitachi transmission electron microscope H7650 Japan)SNEDDS was diluted with distilled water and mixed byslightly shaking One drop of diluted samples was depositedon a film-coated 200mesh copper specimen grid and allowedto stand for 20min after which any excess fluid was removedwith the filter paper The grid was later stained with onedrop of 2 phosphotungstic acid and dried for 15min beforeexamination with the transmission electron microscope

262 Determination of Droplet Size and Zeta-Potential 1mLSNEDDS was diluted with 50mL distilled water in a glassflask and gently stirredThedroplet size distribution and zeta-potential of the resultant microemulsions were determinedby dynamic light scattering with particle size apparatus(Malvern Zetasizer Nano ZS90 UK) Each sample wasanalyzed in triplicate

263 Thermodynamic Stability Study The objective of ther-modynamic stability is to evaluate the phase separation andeffect of temperature variation on SNEDDS formulation Thestability was evaluated by centrifugation a heating-coolingcycle and a freeze-thaw cycle Briefly Tet was diluted withaqueous medium followed by centrifugation at 15000 rpmfor 15min and then the mixture was observed visually forphase separation after SNEDDS formulations were dilutedwith deionized water (1 50) and subjected to freeze-thawcycles (-20∘C for 2 days) followed by heated to 40∘C for 2 daysthe phase separation and appearance were observed

264 In Vitro Dissolution Study The in vitro dissolutionbehaviors of Tet from commercial tablet of Tet and Tet

SNEDDS were assessed using the Chinese pharmacopoeia(2010 version) paddle method The SNEDDS containing Tet(10 ww of the excipients) were added into hydroxy-propylmethyl cellulose (HPMC) capsules ldquosize 0rdquo A Tet SNEDDShard capsuletablet was put into a sinker Thus the sinkerwas loaded with 900mL of simulated gastric fluid withoutenzymes (pH 12) phosphate buffer pH 68 and distilledwater (containing 05 of sodium dodecyl sulfate to increasedissolution) at 37plusmn05∘Cwith a paddle speed of 100 rpmusinga dissolution tester (ZRS-8G Tianjin University ElectronicsCo Ltd Tianjin China) 50mL sample was withdrawn at 510 20 30 45 60 90 120 and 180min and replaced with freshdissolution medium to keep the volume constant The releaseof Tet from the SNEDDS formulation was compared withcommercial tablets containing the same quantity of drugTheconcentration of Tet in the released sample was determinedby the HPLC method described in the above section ldquo23HPLC analysisrdquo

27 Pharmacokinetic Study The pharmacokinetic experi-ment was designed to compare the Tet SNEDDS formulationand the Tet commercial tablet The male Wistar Albino rats(180-220 g)were purchased fromGuangxiMedicalUniversityLaboratoryAnimalCentre ChinaTheywere allocated to twogroups at random the first group received the Tet commercialtablet which was prepared by Tet suspension (025 wvcarboxymethyl cellulose sodium (CMC-Na)) according tothe following method ten tablets were ground to a finepowder with a mortar The powder was weighed and mixedwith 025 CMC-Na solution to make a suspension Thesuspension was made and used when needed The secondgroup received the Tet SNEDDS formulation Each groupconsisted of six rats Tet SNEDDS formulation was givenorally or gavage at the same dose of 10mgkg body weightThe dose was based on the median of the clinical dose ofTet tablets which is between 80 and 120mgdaypersonBased on an average weight of 60 kg per person thedose will be 167mgkgday Thus for the rat model thedose was 10mgkgday All rats were dosed following anovernight fast Food was supplied to the rats after 4 hof the dose administration In vivo study was approvedby the Animal Ethics Committee of Guangxi MedicalUniversity

Blood samples (approximately 03mL) were collectedfrom the retroorbital plexus with a heparinized tube at pre-dose and 025 05 1 2 3 4 6 8 12 24 48 and 72 h postdoseBlood samples were centrifuged at 6000 rpm for 10min5120583L demethyltetrandrine (internal standard IS) solution(10120583mL) 01mL acetonitrile and 04mL ether were addedto 01mL upper plasma After vortex mixing for 3min andcentrifugation at 3000 rpm for 15min the upper organic layerwas transferred and the plasma was extracted by 04mLether again The combined organic phase was evaporated todryness at 40∘C Then the residue was dissolved in 100120583Lmethanol and centrifuged at 10000 rmp for 10min [34] Aftercentrifugation 2120583L of clear supernatant was injected intoUPLC-MS-MS system for analysis

The concentration of Tet was determined by UPLC-MS-MS according to the following HPLC analysis was performed


Table 1 Result of solubility studies with Tet in various excipients (n=3)

Sample Excipient Function in SNEDDS Solubility(mgmL)1 Oleic acid Oil 8674plusmn00562 Soybean oil Oil 2372plusmn00913 Isopropyl acetate Oil 2291plusmn01174 Olive oil Oil 2124plusmn00655 Ethyl linoleate Oil 3326plusmn01776 Isopropyl myristate (IPM) Oil 4348plusmn01987 Ethyl oleate Oil 1185plusmn00668 Butyl oleate Oil 1194plusmn00649 Tween-60 Surfactant 4216plusmn020810 Tween-80 Surfactant 6793plusmn032411 SPC Surfactant 10238plusmn019912 Cremophor RH-40 Surfactant 12645plusmn025213 Isopropanol Co-surfactant 2564plusmn008814 Glycerol Co-surfactant 3455plusmn010015 PEG400 Co-surfactant 9584plusmn022516 Absolute alcohol Co-surfactant 8449plusmn0165

using the Dionex UltiMate 3000 with a binary pump an on-line degasser an auto-sampler and a column temperaturecontroller Chromatographic separations were performed ona Hypersil GOLD C18 column (100mm times 21mm 19 120583m)protected by a C18 guard column (10mm times 21mm 5 120583m) at35∘CThemobile phase consisted of methanolndashwater (50 50vv) The flow rate was set at 02mLmin

MS analysis was carried out on a Thermo ScientificTSQ Quantum Access MAX triple stage quadrupole massspectrometer with an electrospray ionization (ESI) sourcerunning in a positive-ionization modeThe typical ion sourceparameters were spray voltage 3500V sheath gas pressure(N2) 30 units auxiliary gas pressure (N2) 10 units ion trans-fer tube temperature 400∘C collision gas (Ar) 15mTorrQ1Q3 peak resolution 07Da scan width 0002Da sampleswere analyzed via selective-reaction monitoring (SRM) withmonitoring ion pairs at mz 623 997888rarr 381 for Tet mz 609997888rarr 367 for IS The scan dwell time was set at 01s forevery channel All data collected in centroid mode wereacquired and processed using Xcalibur 22 software (ThermoFisher Scientific Inc USA) Peak area ratio of Tet to ISwas calculated and the calibration curve was establishedwith the ration as Y-axis while the corresponding nominalconcentrations of Tet as X-axis

28 Data Analysis Statistical evaluation was performed byStudent t-test of paired observations to analyze different con-centrations of Tet The pharmacokinetic data were processedby noncompartmental analysis using the DAS 20 softwarepackage (Chinese Pharmacological Society)

3 Results

31 Solubility Studies of Tet in Various Excipients The objec-tive of solubility studies is to identify the most suitable oilsurfactant and cosurfactant which have a good solubiliz-ing capacity for Tet The concentration of Tet in various

excipients at 37∘C was determined by HPLC and solubilityresults are presented in Table 1 If excipients with highdrug solubility are chosen to prepare SNEDDS formulationthen the amount of formulation to be administered will besmall It is clear from the table that the highest solubility ofTet is in oleic acid as the oil and in the surfactants SPCand cremophor RH-40 with the cosurfactant PEG400 andabsolute alcohol However absolute alcohol was not selectedas cosurfactant due to its volatility that would result inprecipitation or crystallization of drugs So in the preparationof SNEDDS oleic acid was used as oil SPC and cremophorRH-40 were used as surfactant and PEG400 was used ascosurfactant

32 Construction of Pseudo-Ternary Phase Diagrams Pseu-do-ternary phase diagrams were constructed to identify themicroemulsion regions for optimizing the concentrations ofoil surfactant cosurfactant and their mixing ratios Thevisual test measured the apparent spontaneous of emulsionformation Screening of the mixed surfactant was based onthe pseudo-ternary phase diagram As shown in Table 1for surfactant Tet had the highest solubility in cremophorRH-40 followed by SPC The maximum region of self-microemulsion was obtained when mixture of SPC andcremophor RH-40 in the ratio of 1 2 was used Thereforethe optimal of SPC to cremophor RH-40 was selected tobe 1 2 The phase diagrams containing oleic acid SPC andcremophor RH-40 and PEG400 were shown in Figure 2As shown in Figure 2 microemulsion formation area wasincreased with an increase in 3 1 (the ratio of surfactantto cosurfactant) and 3 2 (the ratio of mixtures includingsurfactant and cosurfactant to oil) There will be a loss offlow if the surfactant to cosurfactant ratio is more than3 1 According to these results the following SNEDDSformulation was established 40 (ww) oleic acid as oil 15(ww) SPC and 30 (ww) Cremophor RH-40 as surfactantand 15 (ww) PEG400 as cosurfactant


00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08

Oleic acid (ww)water (ww)

surfactantco-surfactant (ww)

10

(a)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(b)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(c)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(d)

Figure 2 Pseudo-ternary phase diagram consisting of oleic acid the mixture of surfactant (SPCcremophor RH-40 1 2) and PEG400 withsurfactantcosurfactant ratios of (a) 1 1 (b) 3 2 (c) 2 1 and (d) 3 1 The blank region represents oilwater microemulsion formation area


331 Morphological Characterization In order to observethe oily droplets the SNEDDS of Tet was turned intomicroemulsion by diluting with distilled water A represen-tative transmission electron microscope picture is shown inFigure 3 From the figure it is evident that all the oil dropletswere of spherical in shape

332 Droplet Size and Zeta-Potential Analysis As shownin Figure 4 the mean droplet sizes of diluted SNEDDSpreconcentrates were very low and all were found to be inthe nanometric range (lt100 nm) The average droplet size ofTet microemulsion was 1975plusmn037nm and showed Gaussiandistribution The SNEDDS of Tet was diluted with distilledwater The resultant zeta-potential was 187plusmn026 mv whichindicated that the microemulsion droplets had no charge (seeFigure 5)

333 Thermodynamic Stability Studies For lipid-based dos-age forms stability is crucial to their performances which

Figure 3 Transmission electron microscopy photo of Tet microe-mulsion (times100000)


Number Distribution Data ()

0

5

10

15

20

25

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(a)


0

5

10

15

20

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(b)


0

5

10

15

20

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(c)

Figure 4 (andashc) Droplet size distribution by intensity (n=3)

can make an adverse effect in the form of precipitation ofthe drug in the excipient matrix In thermodynamic stabilitystudies formulation selected was subjected to stress test likecentrifugation (at 15000 rpm for 15min) and freeze-thaw test(-20∘C for 2 days followed by +40∘C for 2 days)The SNEDDSformulation was found to be stable under these stressedconditions Since the Tet SNEDDS formulation was stable ametastable formation is thus avoided and frequent tests neednot be performed during storage

334 In Vitro Dissolution Study An in vitro dissolutionprofile of the optimized Tet SNEDDS formulation was per-formed to compare with the commercial tablet and thedissolution of drug from various media was evaluated The

Zeta Distribution Data

020000400006000080000

100000120000140000160000180000

Tota

l Cou

nts

minus150 minus100 minus50 0 50 100 150 200minus200Zeta Potential (mV)

(a)


0

5000

10000

15000

20000

25000

30000

Tota

l Cou

nts


(b)


0

20000

40000

60000

80000

100000

120000

140000

Tota

l Cou

nts


(c)

Figure 5 (andashc) zeta- potential distribution (n=3)

dissolution of Tet from SNEDDS and Tet commercial tabletformulation in various medium were presented in Figure 6and showed that the Tet SNEDDS formulation allowed 85dissolution of Tet within 20min whereas the commercialtablet showed less than 80 of Tet within 180min Thedissolute rate of the Tet SNEDDS formulation in variousdissolution media was remarkably faster than commercialtablet due to the small droplet size In order to establish thekinetics of drug dissolution various mathematical modelsincluding zero-order first-order Higuchi Korsmyer-PeppasHixson-Crowell and Weibull were used The assessment ofthe models is presented in Table 2 that provides the modelselection criteria (MSC) by selecting the model with thehighest MSC it was found that the drug dissolution from


Dissolution Profile

0

20

40

60

80

100

120

Cum

ulat

ive D

rug

Dis

solv

ed (

)

30 60 90 120 150 1800Time (Mins)

pH 68 phosphate buffer SNEDDS simulate gastric fluid(pH12) SNEDDSdistilled water SNEDDSpH 68 phosphate buffer commercial tabletsimulate gastric fluid(pH12) commercial tabletdistilled water commercial tablet

Figure 6 In vitro profiles of Tet from SNEDDS and Tet commercialtablet formulation in various medium at 37∘C with a paddle speedof 100 rpm using a dissolution tester (ZRS-8G Tianjin UniversityElectronics Co Ltd Tianjin China) Each value represents themeanplusmn SD (n=6)

Table 2 The model selection criteria of various mathematicalmodels for the drug dissolution from SNEDDS

Mathematical models Model selection criteria (MSC)Zero-order -13324First-order 16415Higuchi -02989Korsmyer-Peppas 30797Hixson-Crowell -02690Weibull 57438

SNEDDS best fitted with Weibull Distribution Mode 119910 =567 times 106 times (1 minus 119890(minus(119909 minus 499)005(799 times 104))) r2 = 09996

34 Pharmacokinetic Study Figure 7 presents the plasmaconcentration vs time curve for Tet SNEDDS formulationand Tet commercial tablet after a single dosage of oraladministration in male rats At all the indicated time pointsTet blood concentrations in rats treated with Tet SNEDDSwere significantly higher than those treated with Tet com-mercial tablet Pharmacokinetic parameters are shown inTable 3 The results indicated that the average of Tmax ofthe SNEDDS formulation and commercial tablet was 38 hand 66 h respectively which meant that the Tet SNEDDSformulation showed a faster rate of absorption than the Tetcommercial tablet The peak plasma concentration (Cmax)and the area under the curve (AUC0-72 h) of SNEDDS of

0

200

400

600

800

1000

1200

1400

1600

Tet c

once

ntra

tion

(ng

mL)

20 40 60 800Time (h)

Tet SNEDDS formulationTet commercial tablet

Figure 7 Plasma concentration profile of Tet after oral administra-tion in male rats Each value represents the mean plusmnS D (n=6 and10mgkg)

Tet were higher than the Tet commercial tablet by 1378and 1341 respectively The relative bioavailability of theTet SNEDDS formulation was 233-fold compared withthe Tet commercial tablet This indicated better systemicabsorption of Tet from the SNEDDS formulation comparedto the commercial tablet The Tet SNEDDS formulationdemonstrated almost similar mean residence time (MRT)(396 h) compared to the Tet commercial tablet MRT (399 h)Therefore no prolonged action was found in the SNEDDSformulation It was reasonable to conclude that SNEDDSenhances the absorption in vivo significantly

4 Discussion

In our research the potency of a self-microemusifying drugdelivery system was successfully investigated in order toprovide an effective system for delivery of Tet Based onthe results of the solubility tests in various excipients weselected the optimal oil cosolvent surfactant and cosur-factant Through the construction of a ternary phase dia-gram the optimal formulation of SNEDDS containing Tetwas found to be the following 40 (ww) oleic acid asoil 15 (ww) SPC and 30 (ww) Cremophor RH-40 assurfactant and 15 (ww) PEG400 as cosurfactant Theparticle size zeta-potential stability in vitro dissolutionand in vivo bioavailability of the resultant emulsion afterself-emulsification were determined The average dropletsize of the optimal formulation was 1975plusmn037 nm andthe average zeta-potential was 187plusmn026 mv With othernew formulations of Tet such as nanoparticles (Tet-loadedPVP-b-PCL nanoparticles) [35] nanocapsules (tetrandrine-phospholipid complex loaded lipid nanocapsules) [22] andmicrosphere (tetrandrine-loaded chitosanmicrosphere) [25]


Table 3 Pharmacokinetic parameters of Tet SNEDDS formulation and Tet commercial tablet after single dose administration (n=6)

Parameters Unit SNEDDS TabletAUC0-72 h ngmL h 338556plusmn20243lowast 144594plusmn31314AUC0-infin ngmL h 410784plusmn36212lowast 176040plusmn43373Tmax h 38plusmn12lowast 66plusmn16Cmax ngmL 12348plusmn397lowast 5193plusmn268MRT h 396plusmn102 399plusmn121Relative bioavailability 2333lowast119901lt005 compared to the Tet commercial tablet

SNEDDS-Tet has a smaller particle size (size ranges ofnanocapsules andmicrosphere from 40 nm to 15 120583m) equiv-alent solubility (solubility of nanocapsules in water 828 plusmn037120583gmL) and a longer mean residence time (MRT ofnanocapsules nanocapsules 839 plusmn 1532 h)

Encapsulation of drugs that are poorly soluble and havehydrophobic properties and poor distribution has been stud-ied quite widely [31 36] This study has some advantagesover previous studies into the delivery of Tet because theSNEDDS-Tet can form a microemulsion spontaneously andthe diameter of SNEDDS-Tet was smaller than those usedpreviously [27] which might allow it to be more easilydelivered into cells or to pass across some barriers Recentlyin order to overcome high cost of SNEDDS a new supersat-urable self-emulsifying drug delivery system (S-SEDDS) wasdeveloped [37] But some preparation methods of S-SEDDScannot be used for Tet because of its thermal instabilityTherefore the focus of our research for Tet concentrates onSNEDDS

Using mixed surfactants can achieve a rational valueof hydrophile-lipophile balance (HLB) that using a singlesurfactant cannot achieve The mixture of cremophor RH-40and SPC can adjust the arrangement of the surfactant in theoil-water interface and improve the structure of the interfacialfilm increase mobility and stability of the film and soallow easier formation of a microemulsion [38] In additionselecting the appropriate surfactant HLB value can reduce theappearance of crystallization The expected HLB of SNEDDSis usually within the range of 14-18 and the HLB of SNEDDSwas 14-16 in this study In vitro dissolution experimentsrevealed that the dissolution of Tet from SNEDDS was fasterthan the commercial tablet The relative bioavailability of TetSNEDDS was enhanced by 233 In addition to improvingthe solubility of the drug there are a number of otherbiopharmaceutical properties that can affect the bioavailabil-ity of hydrophobic drugs Surface active agents dispersedparticle size lymphatic transport lipolysis and inhibition ofintestinal metabolism can improve bioavailability Thus thesystem developed here could be used as an effective approachfor enhancing the solubility and bioavailability of Tet and theTet SNEDDS is worthy of further investigation

5 Conclusion

In summary self-nanoemulsifying drug delivery systemcomposed of 40 (ww) oleic acid as oil 15 (ww) SPC and

30 (ww) Cremophor RH-40 as surfactant and 15 (ww)PEG400 as cosurfactant was used to prepare the Tet SNEDDSThe results of in vitro dissolution study show that the disso-lute rate of the prepared Tet SNEDDS in various dissolutionmedia was remarkably faster than commercial tablet due tothe small droplet size And the results of pharmacokineticstudy show that the prepared Tet SNEDDS achieved anapproximately 233-fold increase in bioavailability comparedwith the commercial tablet It could be concluded that self-nanoemulsifying drug delivery system of tetrandrine has thepotential to improve the dissolution and oral bioavailabilityof poor water-soluble Tet

Data Availability

The data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Authorsrsquo Contributions

Chunxia Liu and Li Lv contributed equally to this work

Acknowledgments

This work was supported by National Natural Science Foun-dation of China (Grant no 81503001) Guangdong NaturalScience Foundation (Grant no 2016A030313330) Guang-dong province science and technology plan project publicwelfare fund and ability construction project (Grant nos2017A020215081 2016A020215069 and 2016A020215063)Yixian Scientific Research Project Set Sail (Grant noYXQH201706) Medical Scientific Research Foundation ofGuangdong Province (Grant no A2017062) the Scienceand Technology Foundation of Guangzhou (Grant no201707010103) Guangxi Provincial Department of science ampTechnology (Grant no 1346011-22) and Nanning Science ampTechnology (Grant no 20123117)

References

[1] Y-T Huang and C-Y Hong ldquoTetrandrinerdquo CardiovascularDrug Reviews vol 16 no 1 pp 1ndash15 1998


[2] K Chen A Chen R Anderson and C Rose ldquoThe pharma-cological action of tetrandrine an alkaloid of han-fang-chirdquoChinese Journal Of Physiology vol 11 pp 13ndash34 1937

[3] G Wang J R Lemos and C Iadecola ldquoHerbal alkaloidtetrandrine From an ion channel blocker to inhibitor of tumorproliferationrdquo Trends in Pharmacological Sciences vol 25 no 3pp 120ndash123 2004

[4] N Sekiya H Hikiami K Yokoyama et al ldquoInhibitory effectsof Stephania tetrandra S Moore on free radical-induced lysis ofrat red blood cellsrdquoBiological ampPharmaceutical Bulletin vol 28no 4 pp 667ndash670 2005

[5] L-H Fang Y-H Zhang andB-S Ku ldquoFangchinoline inhibitedthe antinociceptive effect of morphine in micerdquo Phytomedicinevol 12 no 3 pp 183ndash188 2005

[6] L Pang and J R S Hoult ldquoCytotoxicity to macrophagesof tetrandrine an antisilicosis alkaloid accompanied by anoverproduction of prostaglandinsrdquo Biochemical Pharmacologyvol 53 no 6 pp 773ndash782 1997

[7] R-L Bian ldquoAntiallergic effect and its mechanism of tetran-drinerdquo European Journal of Pharmacology vol 183 no 2 p 2271990

[8] H Wang S D Luo and H S C Chin ldquoResearch progress inpharmacological actions of tetrandrinerdquo Chinese Pharmaceuti-cal Association no 12 pp 10ndash12 2000

[9] H Takemura K Imoto H Ohshika and C-Y K WanldquoTetrandrine as a calcium antagonistrdquo Clinical and Experimen-tal Pharmacology and Physiology vol 23 no 8 pp 751ndash7531996

[10] G Wang and J Lemos ldquoTetrandrine a new ligand to blockvoltage-dependentCa2+andCa(+)-activatedK+channelsrdquoLifeSciences vol 56 no 5 pp 295ndash306 1994

[11] P L Schiff ldquoBisbenzylisoquinoline alkaloidsrdquo Journal of NaturalProducts vol 50 no 4 pp 529ndash599 1987

[12] Y C Shen C J Chou W F Chiou and C F Chen ldquoAnti-inflammatory effects of the partially purified extract of radixStephaniae tetrandrae comparative studies of its active princi-ples tetrandrine and fangchinoline on human polymorphonu-clear leukocyte functionsrdquoMolecular Pharmacology vol 60 no5 pp 1083ndash1090 2001

[13] R Man-Ren ldquoEffects of tetrandrine on cardiac and vascularremodelingrdquo Acta Pharmacologica Sinica vol 23 no 12 pp1075ndash1085 2002

[14] R H Reist R D Dey J P Durham Y Rojanasakul and VCastranova ldquoInhibition of proliferative activity of pulmonaryfibroblasts by tetrandrinerdquo Toxicology and Applied Pharmacol-ogy vol 122 no 1 pp 70ndash76 1993

[15] N Bhagya andK R Chandrashekar ldquoTetrandrinemdashAmoleculeof wide bioactivityrdquo Phytochemistry vol 125 pp 5ndash13 2016

[16] T Chen B Ji and Y Chen ldquoTetrandrine triggers apoptosis andcell cycle arrest in human renal cell carcinoma cellsrdquo Journal ofNatural Medicines vol 68 no 1 pp 46ndash52 2014

[17] Q Chen Y Li Y Shao et al ldquoTGF-1205731PTENPI3K signalingplays a critical role in the anti-proliferation effect of tetrandrinein human colon cancer cellsrdquo International Journal of Oncologyvol 50 no 3 pp 1011ndash1021 2017

[18] K Guo and J Cang ldquoPharmacodynamic evaluation of noveltetrandrine-loaded chitosan microspheresrdquo Letters in DrugDesign and Discovery vol 14 no 6 pp 686ndash689 2017

[19] W Qiu A-L Zhang and Y Tian ldquoTetrandrine triggers analternative autophagy in DU145 cellsrdquo Oncology Letters vol 13no 5 pp 3734ndash3738 2017

[20] M Yao B Yuan X Wang et al ldquoSynergistic cytotoxic effects ofarsenite and tetrandrine in human breast cancer cell line MCF-7rdquo International Journal of Oncology vol 51 no 2 pp 587ndash5982017

[21] L Ye S Hu H Xu et al ldquoThe effect of tetrandrine combinedwith cisplatin on proliferation and apoptosis of A549DDP cellsand A549 cellsrdquo Cancer Cell International vol 17 no 1 2017

[22] Y-Q Zhao L-P Wang C Ma K Zhao Y Liu and N-P FengldquoPreparation and characterization of tetrandrine-phospholipidcomplex loaded lipid nanocapsules as potential oral carriersrdquoInternational Journal of Nanomedicine vol 8 pp 4169ndash41812013

[23] C Shi S AhmadKhan KWang andM Schneider ldquoImproveddelivery of the natural anticancer drug tetrandrinerdquo Interna-tional Journal of Pharmaceutics vol 479 no 1 pp 41ndash51 2015

[24] C Fan X Li Y Zhou et al ldquoEnhanced topical delivery oftetrandrine by ethosomes for treatment of arthritisrdquo BioMedResearch International vol 2013 Article ID 161943 13 pages2013

[25] K Guo and J Cang ldquoA novel tetrandrine-loaded chitosanmicrosphere Characterization and in vivo evaluationrdquo DrugDesign Development andTherapy vol 10 pp 1291ndash1298 2016

[26] W Tan Y Li M Chen and YWang ldquoBerberine hydrochlorideanticancer activity and nanoparticulate delivery systemrdquo Inter-national Journal of Nanomedicine vol 6 pp 1773ndash1777 2011

[27] X Tian J-B Zhu J-S Wang and T-F Li ldquoPreparationof tetrandrine lipid emulsion and its therapeutic effect onbleomycin-induced pulmonary fibrosis in ratsrdquo Journal of ChinaPharmaceutical University vol 36 no 3 pp 225ndash229 2005

[28] X Cao J Luo T Gong Z-R Zhang X Sun and Y Fu ldquoCoen-capsulated doxorubicin and bromotetrandrine lipid nanoemul-sions in reversing multidrug resistance in breast cancer in vitroand in vivordquoMolecular Pharmaceutics vol 12 no 1 pp 274ndash2862015

[29] S Bandopadhyay B Singh R Kapil R Singh and O P KatareldquoSelf-emulsifying drug delivery systems (SEDDS) formula-tion development characterization and applicationsrdquo CriticalReviews in Therapeutic Drug Carrier Systems vol 26 no 5 pp427ndash521 2009

[30] A R Patel and P R Vavia ldquoPreparation and in vivo evaluationof SMEDDS (self-microemulsifying drug delivery system) con-taining fenofibraterdquoThe AAPS Journal vol 9 no 3 pp E344ndashE352 2007

[31] C J H Porter C W Pouton J F Cuine and W N CharmanldquoEnhancing intestinal drug solubilisation using lipid-baseddelivery systemsrdquo Advanced Drug Delivery Reviews vol 60 no6 pp 673ndash691 2008

[32] L Zhang L Zhang M Zhang et al ldquoSelf-emulsifying drugdelivery system and the applications in herbal drugsrdquo DrugDelivery vol 22 no 4 pp 475ndash486 2015

[33] A Karthik G Subramanian A Ranjith Kumar and N UdupaldquoSimultaneous estimation of paracetamol and domperidonein tablets by reverse phase HPLC methodrdquo Indian Journal ofPharmaceutical Sciences vol 69 no 1 pp 142ndash144 2007

[34] F X I L LI Zhonghong C A I I Ing Y Zhihong Y I JianandD G Q I Guifen ldquoPharmacokinetics of fangch inoline andtetrandrine in ratsrdquo China Journal of Chinese Materia Medicavol 34 no 23 pp 3110ndash3113 2009

[35] H Xu Z Hou H Zhang et al ldquoAn efficient Trojan delivery oftetrandrine by poly(N-vinylpyrrolidone)-block-poly(epsilon-caprolactone) (PVP-b-PCL) nanoparticles shows enhanced


apoptotic induction of lung cancer cells and inhibition of itsmigration and invasionrdquo International Journal of Nanomedicinevol 9 no 1 pp 231ndash242 2014

[36] T Liu X Liu and W Li ldquoTetrandrine a Chinese plant-derivedalkaloid is a potential candidate for cancer chemotherapyrdquoOncotarget vol 7 no 26 pp 40800ndash40815 2016

[37] D H Lee D W Yeom Y S Song et al ldquoImproved oral absorp-tion of dutasteride via Soluplus-based supersaturable self-emulsifying drug delivery system (S-SEDDS)rdquo InternationalJournal of Pharmaceutics vol 478 no 1 pp 341ndash347 2015

[38] B Bahloul M A Lassoued and S Sfar ldquoA novel approachfor the development and optimization of self emulsifying drugdelivery system using HLB and response surface methodologyApplication to fenofibrate encapsulationrdquo International Journalof Pharmaceutics vol 466 no 1-2 pp 341ndash348 2014

Medicinal ChemistryInternational Journal of

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Arthritis

Neurology Research International


StrokeResearch and TreatmentHindawiwwwhindawicom Volume 2018

Drug DeliveryJournal of



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Tropical MedicineJournal of


AddictionJournal of



BioMed Research International

Emergency Medicine InternationalHindawiwwwhindawicom Volume 2018


Anesthesiology Research and Practice

Journal of


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Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Infectious Diseases and Medical Microbiology


Canadian Journal of


Autoimmune DiseasesScientica



MEDIATORSINFLAMMATION

of

Submit your manuscripts atwwwhindawicom


O

O OO

N

N

O

H H

O

Figure 1 Molecular structure of tetrandrine (Tet)

ammonium cation [23] contributes to its low and variableoral bioavailability gastric intestine and kidney damageand bad patient compliance [24] In recent years manypharmaceutical methods have been investigated to improvethe bioavailability of Tet such as lipid nanocapsules nanopar-ticles ethosomes and microspheres [25] However most oftetrandrine based nanoparticles were used for injection andseldom used in oral administration

Investigation of novel drug delivery systems to enhancethe solubility and improve bioavailability of Tet is con-sidered a matter of urgency [26] In recent years variousstrategies have been considered to overcome the problemsassociated with oral absorption and bioavailability such asmicrosphere microcapsule nanoemulsified drug deliverysystem (SNEDDS) and nanoparticles [23] A high speeddisperser and a high pressure emulsifier generating particleswith an average diameter of about 200 nm in vitro has shownsome success for Tet encapsulation [27] and coencapsulateddoxorubicin and bromotetrandrine lipid nanoemulsions haveshown some potential of treatment in breast cancer animalmodels [28]

SNEDDS is an isotropic mixture of oils surfactanthydrophilic cosurfactant and drug substances which forma fine oil-in-water microemulsion when introduced intoaqueous media while being gently agitated by the digestivemotility of the stomach and intestine SNEDDS is a relativelyrecent term used to indicate formulations with a globulesize less than 100 nm [29] It has excellent efficiency inincreasing the dissolution rate promoting oral absorptionand increasing the bioavailability of poorly water-solubledrugs [30 31] and has shown a lot of success for herbal drugs[32] There are some commercially successful formulationssuch as Neoral (cyclosporine A) Fortovase (saquinavir)Agenerase (amprenavir) and Norvir (ritonavir) in clinicaluse

Extensive review of literature reveals lack of reports aboutthe bioavailability improvement of poorly water-soluble Tetusing SNEDDS Thus the objective of the present study wasto formulate Tet SNEDDS to improve Tetrsquos oral bioavail-ability To achieve this Tetrsquos solubility in various excipientswas evaluated and that with highest solubility of Tet wereselected oil surfactant and cosurfactant of Tet SNEDDSThe prepared Tet SNEDDS was evaluated for morphological

droplet size zeta-potential thermodynamic stability and invitro dissolution study Furthermore an in vivo pharma-cokinetic study was performed to study Tetrsquos pharmacoki-netic behavior and bioavailability enhancement after oraladministration

2 Materials and Methods

21Materials Tet (puritygt980)was obtained as a gift sam-ple from Beihai Sunshine Pharmaceutical co Ltd (BeihaiChina) A Tet tablet (containing 20mg Tet in one tablet withexcipients including starch dextrin andmagnesium stearate)was manufactured by Beihai Sunshine Pharmaceutical coLtd (Beihai China) Oleic acid Tween 60 and Tween 80 werepurchased from Tianjin Damao Chemical Reagent Factory(Tianjin China) Soybean oil isopropyl acetate olive oilethyl linoleate cremophor RH-40 and isopropyl myristate(IPM)were purchased fromChengdu Gracia Chemical Tech-nology co Ltd (Chengdu China) Ethyl oleate butyl oleateand soybean phosphatidylcholine (SPC) were purchasedfrom Tianjin Xing Fu Fine Chemical Industry ResearchInstitute (Tianjin China) Isopropanol glycerol absolutealcohol and PEG400 were purchased from Chengdu KelonChemical Reagent Factory (Chengdu China) Methanol andacetonitrile (chromatographic grade) were from ThermoFisher Scientific (China) Co Ltd All other chemicals usedwere of analytic grade

22 Determination of Tet Solubility The solubility of Tet wasdetermined in selected oils surfactants and cosurfactants bypouring an excess of Tet into 1mL of each excipient Theobtained mixtures were mixed using a vortex mixer Andthen the mixture was kept in a water bath at 37plusmn05∘C for72 hours After equilibrium was achieved the equilibratedsamples were centrifuged at 3000 rpm for 15min and excessinsoluble Tet was discarded by filtration using a 045 120583mmembrane filterThe concentration of Tet was determined bya high performance liquid chromatography (HPLC) methoddescribed below The experiments were performed in tripli-cate

23 HPLC Analysis The amount of Tet in various excip-ients was quantified by a validated HPLC method [33]equipped with an ultraviolet detector (Agilent 1260 LiquidChromatography American) Tet was separated on a RP-C18column (ODS C18 200mmtimes46mm 5 120583m) using methanol-acetonitrilendashwater (3 1 1 v v v) plus 006 diethylamineas mobile phase at a flow rate of 10mLmin with thedetection wavelength at 282 nm The column temperaturewas maintained at 25∘C

24 Preparation of SNEDDS For preparation of TetSNEDDS the content of Tet was fixed at a constant level(10 ww of excipients) Firstly Tet was dissolved bycosurfactant and then the mixture containing the calculatedamount of oil and surfactant was mixed by gentle stirringfor 10min and vortex mixing until the microemulsionformulation was obtained


















3 Results





00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(a)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(b)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(c)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(d)









0

5

10

15

20

25

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(a)


0

5

10

15

20

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(b)


0

5

10

15

20

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(c)





020000400006000080000

100000120000140000160000180000

Tota

l Cou

nts


(a)


0

5000

10000

15000

20000

25000

30000

Tota

l Cou

nts


(b)


0

20000

40000

60000

80000

100000

120000

140000

Tota

l Cou

nts


(c)




Dissolution Profile

0

20

40

60

80

100

120

Cum

ulat

ive D

rug

Dis

solv

ed (

)

30 60 90 120 150 1800Time (Mins)







0

200

400

600

800

1000

1200

1400

1600

Tet c

once

ntra

tion

(ng

mL)

20 40 60 800Time (h)




4 Discussion








5 Conclusion



Data Availability






Acknowledgments


References
















































Arthritis










AddictionJournal of







Journal of


Pharmaceutics



Volume 2018



Canadian Journal of






of



















3 Results





00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(a)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(b)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(c)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(d)









0

5

10

15

20

25

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(a)


0

5

10

15

20

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(b)


0

5

10

15

20

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(c)





020000400006000080000

100000120000140000160000180000

Tota

l Cou

nts


(a)


0

5000

10000

15000

20000

25000

30000

Tota

l Cou

nts


(b)


0

20000

40000

60000

80000

100000

120000

140000

Tota

l Cou

nts


(c)




Dissolution Profile

0

20

40

60

80

100

120

Cum

ulat

ive D

rug

Dis

solv

ed (

)

30 60 90 120 150 1800Time (Mins)







0

200

400

600

800

1000

1200

1400

1600

Tet c

once

ntra

tion

(ng

mL)

20 40 60 800Time (h)




4 Discussion








5 Conclusion



Data Availability






Acknowledgments


References
















































Arthritis










AddictionJournal of







Journal of


Pharmaceutics



Volume 2018



Canadian Journal of






of



00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(a)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(b)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(c)

00 02 04 06 08 10

000

025

050

075

100 00

02

04

06

08



10

(d)









0

5

10

15

20

25

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(a)


0

5

10

15

20

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(b)


0

5

10

15

20

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(c)





020000400006000080000

100000120000140000160000180000

Tota

l Cou

nts


(a)


0

5000

10000

15000

20000

25000

30000

Tota

l Cou

nts


(b)


0

20000

40000

60000

80000

100000

120000

140000

Tota

l Cou

nts


(c)




Dissolution Profile

0

20

40

60

80

100

120

Cum

ulat

ive D

rug

Dis

solv

ed (

)

30 60 90 120 150 1800Time (Mins)







0

200

400

600

800

1000

1200

1400

1600

Tet c

once

ntra

tion

(ng

mL)

20 40 60 800Time (h)




4 Discussion








5 Conclusion



Data Availability






Acknowledgments


References
















































Arthritis










AddictionJournal of







Journal of


Pharmaceutics



Volume 2018



Canadian Journal of






of




0

5

10

15

20

25

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(a)


0

5

10

15

20

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(b)


0

5

10

15

20

Inte

nsity

()

1 10 100 1000 1000001size (dnm)

(c)





020000400006000080000

100000120000140000160000180000

Tota

l Cou

nts


(a)


0

5000

10000

15000

20000

25000

30000

Tota

l Cou

nts


(b)


0

20000

40000

60000

80000

100000

120000

140000

Tota

l Cou

nts


(c)




Dissolution Profile

0

20

40

60

80

100

120

Cum

ulat

ive D

rug

Dis

solv

ed (

)

30 60 90 120 150 1800Time (Mins)







0

200

400

600

800

1000

1200

1400

1600

Tet c

once

ntra

tion

(ng

mL)

20 40 60 800Time (h)




4 Discussion








5 Conclusion



Data Availability






Acknowledgments


References
















































Arthritis










AddictionJournal of







Journal of


Pharmaceutics



Volume 2018



Canadian Journal of






of



Dissolution Profile

0

20

40

60

80

100

120

Cum

ulat

ive D

rug

Dis

solv

ed (

)

30 60 90 120 150 1800Time (Mins)







0

200

400

600

800

1000

1200

1400

1600

Tet c

once

ntra

tion

(ng

mL)

20 40 60 800Time (h)




4 Discussion








5 Conclusion



Data Availability






Acknowledgments


References
















































Arthritis










AddictionJournal of







Journal of


Pharmaceutics



Volume 2018



Canadian Journal of






of








5 Conclusion



Data Availability






Acknowledgments


References
















































Arthritis










AddictionJournal of







Journal of


Pharmaceutics



Volume 2018



Canadian Journal of






of
















































Arthritis










AddictionJournal of







Journal of


Pharmaceutics



Volume 2018



Canadian Journal of






of


self-nanoemulsifying drug delivery system of tetrandrine

Documents