research article use of zeolite zsm-5 for loading and release of … · 2019. 7. 31. · research...

Research ArticleUse of Zeolite ZSM-5 for Loading and Release of 5-Fluorouracil

Ruba A Al-Thawabeia and Hamdallah A Hodali

Department of Chemistry Faculty of Sciences The University of Jordan Amman 11942 Jordan

Correspondence should be addressed to Hamdallah A Hodali h-hodalijuedujo

Received 3 June 2015 Accepted 21 July 2015

Academic Editor Jose L Arias

Copyright copy 2015 R A Al-Thawabeia and H A Hodali This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Samples of zeolite ZSM-5 have been synthesized in both the sodium form (ZSM-5) and the acid activated form (H-ZSM-5) Inaddition each of these two forms was prepared in the two molar SiO

2Al2O3ratios of 169 and 15 All samples of these ZSM-5

derivatives were characterized by X-ray diffraction (XRD) nitrogen adsorption-desorption isotherms thermal gravimetric analysis(TGA) X-ray fluorescence (XRF) and scanning electron microscopy (SEM) The samples were successfully loaded with theanticancer drug 5-fluorouracil (5-FU) with loading capacities varying from 22 (for the sodium form having the lower molarSiO2Al2O3ratio of 15 ZSM-5-(15)) to 43 (for the corresponding acid form H-ZSM-5-(15)) Percent release of the drug-loaded

ZSM-5 samples into simulated body fluid (SBF) was measured at pH 74 and 37∘C The results showed a slight variation in the release within the range 84ndash93 while the first-order rate constant (k) varied from 22 hminus1 for ZSM-5-(15) to 39 hminus1 for H-ZSM-5-(15) It was interesting to note that at the higher molar SiO

2Al2O3ratios of 169 both the sodium form ZSM-5-(169) and the

acid form H-ZSM-5-(169) exhibit an intermediate efficiency in either loading (38) or first-order kinetic release constant (k =29 hminus1)

1 Introduction

Chemotherapy is the most commonly used route for cancertreatment employing organic- and inorganic-based drugsHowever most of these drugs are known for their poorphysicochemical properties such as low solubility low stabil-ity short circulating half-life and cytotoxicity [1] One of theproblematic drugs that have been widely used in anticancerchemotherapy is 5-fluorouracil (Figure 1)

5-Fluorouracil (5-FU) is a water-soluble pyrimidine ana-logue which is widely used in the treatment of various kindsof cancer especially colon head neck and ovary cancers [2]5-FU can be used in oral topical and aerosolized formula-tions [3] As a derivative of uracil it rapidly enters the cellwhere it is converted into activemetabolites that disrupt RNAsynthesis and acts as inhibitor of thymidylate synthase anucleotide synthesis enzyme [4] However the oral use of 5-FU exhibits a short plasma half-life (30min) as a result of itsrapid enzymatic metabolism [5] which demands continuoushigh doses thus leading to high toxicity incomplete andnonuniform oral distribution drug resistance by tumor cellsand nonselective action against normal cells [6 7]

Different delivery systems have been used to ensureprolonged and sustained release of 5-FU Examples includehydrogels [8] biodegradable polymers [9] layered inorganicnanocomposites [6] mesoporous organosilica [10] magneticnanocarriers [7] the clay mineral montmorillonite [11]organic-modified montmorillonite [12] hybrid TiO

2ZnO

nanotubes [13] porous silica calcium phosphate nanocom-posites [14] mesoporous silica systems [15] and thiol-func-tionalized mesoporous silica nanoparticles [16] Recentlyzeolites have been used in biomedical applications due totheir biocompatibility and low toxicity [17 18]The small poresize of zeolites (03ndash08 nm) that matches the size of smalldrug molecules in addition to the tunable properties thatcan be obtained by varying the molar SiO

2Al2O3ratio adds

more advantages for utilizing zeolites in the medicinal fieldZeolites have been used as delivery systems for different typesof drugs including the adsorption of sulfonamide antibioticsonto zeolite Y [19] the use of NaY zeolite for encapsulation ofthe anticancer drug 120572-cyano-4-hydroxycinnamic acid [20]the study of sustained release of the anticancer drug dox-orubicin from zeolite magnetite nanocomposites [21] andthe loading onto and release of aspirin from zeolite HY [22]

Hindawi Publishing CorporationJournal of ChemistryVolume 2015 Article ID 403597 9 pageshttpdxdoiorg1011552015403597

2 Journal of Chemistry

O

FHN

OHN

53Aring

49Aring

Figure 1 Chemical structure and molecular dimensions of 5-fluorouracil (5-FU)

Recently both zeoliteHY [23] and zeoliteNaX-FAU [24] havebeen explored as delivery systems for 5-FU

In this study zeolites ZSM-5 and H-ZSM-5 each pre-pared in two different molar SiO

2Al2O3ratios (169 and 15)

have been investigated as probable drug delivery systems for5-FU This choice of ZSM-5 zeolite derivatives for investi-gation as a possible drug carrier for 5-FU was dictated bytheir having a promising 3D-channel structure with a suitablepore size in addition to its reasonable good acid and thermalstability in comparison with low silica zeolites

2 Materials and Methods

21 Materials Tetrapropylammonium bromide (+98Acros Organics) aluminum sulfate Al

2(SO4)3sdot16H2O (Inter-

chem) sodium chloride (BDH) BaCl2sdot2H2O (Merck)

CaCl2sdot2H2O (Merck) MgCl

2sdot6H2O (SD Fine-Chem

Limited) sodiummetasilicate nonahydrate (Na2SiO3sdot9H2O)

(Aldrich) sulfuric acid (98 SD Fine-Chem Limited)ammonium nitrate (RPL) NaHCO

3(Merck) KCl (Riedel

de Haen) K2HPO4sdot3H2O (Merck) sodium hydroxide

pellets (BDH) Na2SO4(Merck) hydrochloric acid (35 SD

Fine-ChemLimited) nitric acid (95Merck) 5-fluorouracil(AcrosOrganics 99) and tris(hydroxymethyl)aminometh-ane (Merck) were used as received The simulated body fluid(SBF) was prepared following literature procedure [25]by dissolving the following salts into a 1 L solution withdeionized water 8036 g NaCl 0352 g NaHCO

3 0225 g

KCl 0230 g K2HPO4sdot3H2O 0311 g MgCl

2sdot6H2O 400mL

1M HCl 0388 g CaCl2sdot2H2O 0072 g Na

2SO4 and 6063 g

tris(hydroxymethyl)aminomethane The pH of solution wasadjusted to 74 by 1M HCl before being used

22 Instrumentation (Physical Measurements) X-ray powderdiffraction spectra were measured using a Philips 2KWmodel X-ray diffractometer (Cu-K120572 radiation source 120582 =15418 A) at a scan rate of 2∘Cmin Specific surface areaswere estimated through BET modeling using a nitrogenadsorptiondesorption instrument (Nova 2200e) UV-Visiblespectra were recorded using a Cary 100 Bio UV-Visible spec-trophotometer (Varian) FT-IR spectra (4000 to 400 cmminus14 cmminus1 spectral resolution KBr pellets) were measured usinga Thermo Nicolet NEXUS 670 FT-IR spectrometer Thermalgravimetric analysis (TGA) was conducted using a NetzschSta 409 PC instrument (Netzsch-Ger) and a Mettler-ToledoDSC823E instrumentThemorphologies of the solid sampleswere monitored by scanning electron microscopy (SEM)

using an FEI-FEG INSPEC F50 instrument The chemicalcomposition of samples was determined using an X-rayfluorescence spectrometer (SHIMADZUmodel XRF-1800)

23 Synthesis of ZSM-5 Samples of zeolite ZSM-5 with twodifferent molar SiO

2Al2O3ratios were prepared following

a literature procedure [26] with some modifications In atypical procedure the zeolite was prepared by mixing threesolutions 1 2 and 3 Solution 1 was prepared by dissolvingsodium silicate (Na

2SiO3sdot9H2O) (2525 g) with deionized

water (200mL) Solution 2 was prepared by dissolving a spe-cific amount of aluminum sulfate Al

2(SO4)3sdot16H2O (040 g or

300 g depending on the required molar SiO2Al2O3ratio)

and tetrapropylammonium bromide (159 g) in deionizedwater (100mL) Solution 3 was prepared by dissolvingsodium hydroxide (036 g) and sodium chloride (525 g) indeionized water (150mL)

Solutions 2 and 3 were mixed and then solution 1 wasadded dropwise After vigorous stirring (sim300min) the pHwas adjusted to the range 103ndash106 by adding concentratedsulfuric acid (98) The hydrogel formed was transferredinto an autoclave and heated for two days at 170∘C The solidproduct was filtered and washed with deionized water untilthe filtrate is sulfate-free (tested by BaCl

2) The zeolite was

dried at 110∘C for one hour and then calcined at 550∘C for 5 hto allow for the decomposition of the template

24 Acid Activation of Zeolite ZSM-5 The sodium zeoliteZSM-5 was acid activated into H-ZSM-5 using the followingtypical procedure a sample of ZSM-5 (100 g) was added to a20M solution of ammonium nitrite (500mL) and the mix-ture was placed in a thermostated water bathshaker at 80∘Cfor 24 h to obtain the ammonium exchanged zeolite NH

4-

ZSM-5 The ammonium form of the zeolite was transformedto the acid form (H-ZSM-5) by calcination at 500∘C for 4 h[27]

25 Loading of 5-FU into ZSM-5 5-FU was loaded intosamples of ZSM-5with two differentmolar SiO

2Al2O3ratios

via the following general procedure 5-FU (asymp0400 g) was dis-solved inwater (250mL) and then added to a flask containingZSM-5 (sim0200 g) The mixture was stirred in the dark atroom temperature for 24 h The drug-loaded carrier wasfiltered and dried under vacuum (30mmHg) for two hoursat 60∘C

The loading capacities of drug-loaded samples weredetermined by TGA measurements within the temperaturerange 25ndash1100∘C under nitrogen The drug loading capacitywas also determined by UV-Visible absorption spectropho-tometer in which a predetermined amount of drug-loadedcarrier (around 00100 g) was stirred with water (10000mL)for 24 hours at room temperature the solution was then fil-tered and the concentration of 5-FUwas determined bymea-suring the absorbance at 266 nm The total amount of drugcontained in the sample was calculated with reference to acalibration curve

26 5-FU Release Profiles The in vitro release of each 5-FU-loaded carrier was measured using the dialysis method

Journal of Chemistry 3

(dialysis bag diffusion technique) A 5-FU-loaded sample(sim00500 g) was introduced into a dialysis bag (MWCO =3500Da) containing SBF solution (200mL pH = 74) Thesealed dialysis bag was immersed in a flask containing 198mLSBF (pH = 74) The flask was covered and placed in athermostatic water bathshaker maintained at 37∘C and aconstant shaking rate of 120 rpm

At predetermined time intervals (160 560 05 10 2030 40 50 60 70 80 90 100 110 120 and 13 hours) analiquot (1000mL)waswithdrawn from the flask and replacedby a fresh sample of SBF (1000mL 370∘C) to maintain aconstant volumeThe release experiments were conducted intriplicate

The concentration of 5-FU released was determined bymeasuring the absorbance at 266 nm relative to a calibrationcurve of 5-FU in SBF The calibration curve covered theconcentration range of 050 to 2000 ppm

3 Results and Discussion

31 Synthesis of ZSM-5 and H-ZSM-5 ZSM-5 (sodium form)was prepared with two molar SiO


by using a constant amount of sodium silicate and changingthe aluminum content in the hydrogel (Table 1) Zeolite ZSM-5 was then acid activated into H-ZSM-5 via a two-stepprocedure the first step involves exchange of the sodiumion by ammonium ion to form NH

4-ZSM-5 which is then

transformed into the acid form (H-ZSM-5) by calcination

32 Characterization of ZSM-5 and H-ZSM-5

321 X-Ray Diffraction The XRD spectra of ZSM-5 sampleshaving the molar SiO

2Al2O3ratios of 15 and 169 appear

almost exactly the same Similarly the XRD spectra for theacid activated samples were in agreement with the typicalpattern for zeolite ZSM-5 thus confirming that the zeolitekeeps its structure and crystallinity upon acid activationas shown in the spectra of ZSM-5-(15) and H-ZSM-5-(15)depicted in Figure 2

322 Nitrogen Adsorption-Desorption Isotherms In an idealcase microporous materials should exhibit type I isothermaccording to IUPAC classification [27] A representativenitrogen adsorption-desorption isotherm of ZSM-5 samplesis shown in Figure 3 In the relative pressure 119875119875

0range

from 00 to 10 the adsorption increased gradually withrelative 119875119875

0due to monolayer adsorption of N

2onto the

microporous channels of ZSM-5 The desorption curve isvery close to the adsorption curve in the whole range of1198751198750 It was reported that highly siliceous ZSM-5 exhibits two

hysteresis loops one at high relative pressure and the otherat low relative pressure which eventually disappears as thealuminum content increases [28 29]

The specific surface areas of ZSM-5 derivatives wereestimated from the adsorption branch using the Brunauer-Emmett-Teller (BET) theory [30] The results (Table 2) indi-cate a higher surface area for the acid activated sample thanthat of the corresponding sodium form It also shows an

10 20 30 40

H-ZSM-5-(15)

ZSM-5-(15)

50

Figure 2 XRD spectra of ZSM-5 and H-ZSM-5 having a molarSiO2Al2O3ratio of 15

4400

000 020 040 060 080 100

52006000680076008400

AdsorptionDesorption

Volu

me a

t STP

(cc

g)

Relative pressure PP0

Figure 3 A typical nitrogen adsorption-desorption isotherm forZSM-5-(15)

increase in the surface area with an increase in the molarSiO2Al2O3ratio for both forms [31]

As to the effect of variations in acid activation andormolar SiO

2Al2O3ratio on the specific surface area of ZSM-5

zeolite the following three observations are evident

(i) For the acid activated form H-ZSM-5 increasing themolar SiO

2Al2O3ratio from 15 to 169 raises the

specific surface area by asymp50 (247 up to 369m2g)(ii) For the sodium form ZSM-5 increasing the molar

SiO2Al2O3ratio from 15 to 169 raises the specific

surface area by asymp70 (194 up to 326m2g)(iii) For the sodium form ZSM-5 a combination of acid

activation and increase in themolar SiO2Al2O3ratio

from 15 to 169 raises the specific surface area by asymp90(194 up to 369m2g) Therefore a combination ofincreasingmolar SiO

2Al2O3ratio and acid activation

of ZSM-5 yields the highest specific surface area

323 Scanning Electron Microscopy (SEM) Micrographs ofZSM-5 Estimates of the sizes of ZSM-5 and H-ZSM-5 par-ticles and their morphologies were obtained through SEMmicrographs All micrographs depict homogeneous distri-bution of particles with no significant effect of molar


Table 1 ZSM-5 sample preparation with molar SiO2Al2O3ratios of 169 and 15

Samplelowast NaSiO3sdot9H2Omass (g) Al

2(SO4)3sdot16H2Omass (g) SiO

2Al2O3

lowastlowast

ZSM-5-(169) 2525 0400 169ZSM-5-(15) 2525 3000 15lowastThe number in brackets refers to the molar SiO2Al2O3 ratiolowastlowastMolar ratios determined by XRF

Table 2 Specific surface area (119860) for the synthesized zeolite ZSM-5

Zeolite sample SiO2Al2O3(molar ratio) 119860 (m2g)

ZSM-5-(15) 15 194ZSM-5-(169) 169 326H-ZSM-5-(169) 169 369H-ZSM-5-(15) 15 247

SiO2Al2O3ratio or acid activation on their size or shape

Some of the particles have elongated cubic shapes while oth-ers have hexagonal prismatic units with particle size distribu-tions in the range of 04ndash08 120583m Examples of these micro-graphs are depicted for ZSM-5-(15) and H-ZSM-5-(15) inFigure 4

33 Loading and Release of 5-FU331 5-FU Loading into Zeolite ZSM-5 With the dimensionsshown in Figure 1 5-FU is expected to enter the micro-pores of ZSM-5 readily 5-FU was loaded into samples ofzeolites ZSM-5 and H-ZSM-5 with the two different molarSiO2Al2O3ratios 169 and 15 by the impregnation method

The optimum conditions to obtain the highest loadingwere attained using an aqueous 2500mL of 1600mgmLsolution of 5-FU and 020 g of the zeolite carrier (2 1 mass

ratio of drug to carrier) and a stirring period of 24 hoursLoading of the drug into the ZSM-5 was confirmed byFTIR-spectrometry and XRD spectra Inspection of the FTIRspectra of ZSM-5 5-FU and loaded ZSM-5 in the region2000ndash1500 cmminus1 confirms the presence of the drug in theloaded zeolite The strong band centered at about 1770 cmminus1in the spectrum of free 5-FU (which is absent from thespectrum of unloaded ZSM-5) appears as a very weak bandin the spectra of loaded ZSM-5 and loaded H-ZSM-5 Suchdrastic decrease in intensity is characteristic of compoundsenclosed by porous materials [23] Drug loading was alsoconfirmed by the appearance of the 5-FU characteristic peakat 2120579 = 29∘ in the XRD-spectrum of the drug-loaded ZSM-5(Figure 5) This is an indication of 5-FU crystallization in thecarrier pores

The zeolite loading capacity for 5-FU was determinedfrom the TGA thermograms of pure ZSM-5 and ZSM-5loaded with 5-FU Figure 6(a) shows decomposition of 5-FUwithin the range 280ndash350∘C (mp of 5-FU = 282ndash286∘C)However one of the drug-loaded samples 5-FU-ZSM-5-(15)lost about 40 of its mass below 400∘C but eventually endedwith 50 residual mass at 1100∘C thus indicating the thermalstability of the silicate carrier

The zeolite loading capacity was also estimated by UV-Visible spectrophotometry according to the following equa-tion

Drug loading =Mass of drug loaded into carrier (estimated by UV absorption)

Mass of loaded carriertimes 100 (1)

Table 3 lists loading of 5-FU into the sodium form ofzeolite (ZSM-5) and the corresponding acid activated form(H-ZSM-5) for each of the two molar SiO

2Al2O3ratios 169

and 15 Inspection of the table indicates that the estimates of loading obtained for each of the four zeolite derivativesfrom TGA thermograms and UV absorption are equivalentwithin experimental error

In view of data presented in Table 3 a lower molarSiO2Al2O3ratio plus acid activation of the sodium form

of ZSM-5 yields the highest loading capacity for 5-FU Forexample at the lower molar SiO

2Al2O3ratio of 15 acid

activation of ZSM-5 doubles the loading of 5-FU (22up to43)

332 5-FU Release from Zeolite ZSM-5 The in vitro cumu-lative release of 5-FU loaded into three different samplesof zeolite ZSM-5 was studied The effects of variation in

the molar SiO2Al2O3ratio on the release profiles of 5-FU

that was loaded into ZSM-5 having a molar SiO2Al2O3ratio

of 15 and also into ZSM-5 having a molar ratio of 169 weremeasured In addition the effect of acid activation of zeoliteon the release profile from ZSM-5 and H-ZSM-5 having thesame molar SiO

2Al2O3ratio (15) was also measured The

release was evaluated utilizing the dialysis bag diffusiontechnique in which dialysis bags with MWCO of 3500Dawere usedThe dialysis bags retain the carrier particles withinthe bag but allow the released free drug molecules to diffuseinto the simulated body fluid (SBF) medium at pH 74 and37∘C

At predetermined time intervals (as specified in theexperimental section) aliquots were withdrawn from thereleasemedium andwere readily replaced by fresh samples ofSBF at the same conditions in order to maintain a constantSBF volume The release experiments were conducted in


(a) (b)

Figure 4 SEM micrographs of (a) ZSM-5-(15) and (b) H-ZSM-5-(169)

0

200000

400000

600000

0

5000

10000

8000

6000

4000

2000

010 20 30 40 50 60

Inte

nsity

(cou

nts p

er se

cond

s) (a) 5-FU

(b) 5-FU-ZSM-5

(c) ZSM-52120579 (deg)

Figure 5 XRD of (a) 5-FU (b) ZSM-5-(15) loaded with 5-FU and(c) unloaded ZSM-5-(15)

triplicate and corresponding data averages of the threeexperiments were used for nonlinear regression analysis

The withdrawn samples were analyzed for 5-FU concen-tration by measuring the absorbance at 120582max = 266 nm fol-lowing appropriate dilution and using a blank sample for base

Temperature (∘C)

TG (

)(e)

(d)(c)

(a)

(b)

10

200 400 600 800 1000 1100

20

30

40

50

60

70

80

90

100

Figure 6 TGA thermograms of (a) 5-FU which shows a residualmass of 695 (b) 5-FU-ZSM-5-(15) with a residualmass of 5002(c) 5-FU-ZSM-5-(169) with a residual mass of 5869 (d) 5-Fu-H-ZSM-5-(169) with a residual mass of 6472 and (e) 5-Fu-H-ZSM-5-(15) exhibiting a residual mass of 7196

line correctionThe concentration of 5-FU (119862) was estimatedwith reference to a calibration curve of 5-FU in SBF at thesame conditions according to

1198625-FU (ppm) = 195380304 times 119860266 nm minus 00519868 (2)

The measured concentration of 5-FU (in ppm) released intothe buffer solution was used to estimate the cumulative drugrelease 119876

119905 at time 119905 The cumulative release represents the

total amount of drug released (inmg) from the ZSM-5 carrierinto the releasemedium whichwas kept at a constant volumeof 200mL For each sampling time 119905 the amount of drug in allpreviously withdrawn samples is added to the amount of thedrug in the release medium measured at time 119905 thus givingrise to the cumulative drug release 119876

119905

The first-order kinetic model was used to simulate thekinetics of the drug release process Nonlinear regressionanalysis was used to fit the experimental cumulative drugrelease (119876

119905) against time 119905 to the first-order drug release

model given by the following equation [32]

119876119905

119876119898

= 1 minus 119890minus119896119905 (3)


Table 3 The measured loading of 5-FU into the four zeolitesamples

Sample loading (TGA data) loading (UV data)ZSM-5-(169) 38 380H-ZSM-5-(169) 40 391ZSM-5-(15) 21 220H-ZSM-5-(15) 45 430

where 119876119905is the cumulative drug release (in mg) 119876

119898is the

maximum amount of drug (in mg) that is released into themedium 119896 is the release rate constant in hminus1 and 119905 is thesampling time in hours

Both 119876119898

and 119896 were used as floating parameters innonlinear regression of 119876

119905against 119876

119898(1 minus 119890

minus119896119905) and the best

parameter estimates thus obtained were used to obtain a cor-responding estimate of the best data fitThe release was cal-culated by the normalization of the cumulative drug release ofdrug estimated for each time interval (119876

119905) into the total quan-

tity of drug in the loaded ZSM-5 zeolite sample Plots of release against time profiles for the three systems are depictedin Figure 7 where solid lines represent the best data fits

The kinetic parameters for the release of 5-FU from thethree carriers ZSM-5-(15) H-ZSM-5-(15) and ZSM-5-(169)are listed in Table 4 Analysis of those data indicates thatupon acid activation the first-order release rate constant (119896)increases from 22 hminus1 for ZSM-5-(15) to 39 hminus1 for H-ZSM-5-(15) The effect of molar SiO

2Al2O3ratio can be seen by

comparing the 119896 values for ZSM-5-(15) and ZSM-5-(169)which are 22 hminus1 and 29 hminus1 respectively This might beattributed to the corresponding decrease of the aluminumcontent which is responsible for the stronger attractiveinteraction forces between 5-FU and the zeolite ZSM-5 poresurface thus impeding drug release These results are inagreement with those reported for the release of 5-FU fromzeolite HY [23]

The Higuchi square root time model [33] which is basedon Fickian diffusion was also applied to the initial first burstof drug release This model assumes that the drug releasevaries with the square root of time (11990512) which typicallyoccurs relatively fast compared with subsequent release andis given by the relation

119876119905

119876119898

= 11989611986711990512+ 119888 (4)

where 119876119905is the mass of drug released at time 119905 119876

119898is the

maximum mass released 119896119867(hminus12) is the Higuchi constant

and 119888 is a constant characteristic of the drug and host beingformulated Plots of release of 5-FU from zeolite ZSM-5against 11990512 are depicted in Figure 8

In addition estimates of the individual contributions ofdrug diffusion (119860) and drug erosion (119861) to 5-FU first burstwere obtained through nonlinear regression analysis of datausing Kopcharsquos model [34] according to

119876119905

119876119898

= 11986011990512+ 119861119905 (5)

5-FU-ZSM-5-(15)

00

20

40

60

80

100

2 4 6 8 10 12 14

5-FU-H-ZSM-5-(15)5-FU-ZSM-5-(169)

Time (h)

Rele

ase (

)

Figure 7 Percent release profiles of 5-FU from 5-FU-ZSM-5-(15)(triangles) 5-FU-H-ZSM-5-(15) (squares) and 5-FU-ZSM-5-(169)(circles) Solid lines passing through experimental data representnonlinear regression into first-order release kinetics

00

20

40

60

80

100

1 2 3 4

Rele

ase (

)

5-FU-ZSM-5-(15)5-FU-H-ZSM-5-(15)5-FU-ZSM-5-(169)

Time12 ((h)12)

Figure 8 A plot of the release against 11990512 of 5-FU from differentsamples of zeolite ZSM-5 all loaded with 5-FU into SBF solution atpH 74 and 37∘C

The119860119861 ratios thus obtained (Table 4) indicate that diffusionis the principal mechanism for release of 5-FU from zeoliteZSM-5 with different molar SiO

2Al2O3ratios both in the

sodium and acid activated formsTable 5 lists the loading and release results of 5-

FU obtained in this work in addition to related data onmicro- and mesoporous silicates that have been publishedin the literature Inspection of the data reveals the followingobservations

(i) Successful use of zeolite ZSM-5 as a carrier for 5-FUwith a relatively high loading capacity (ge40) canbe partially attributed to the close matching between


Table 4 Kinetic parameters of 5-FU release from sodium zeolite (ZSM-5) and the corresponding acid activated form (H-ZSM-5) Modelingof release (119876

119905119876119898) was carried out utilizing each of the following models the first-order release model [119876

119905119876119898= 1 minus 119890

minus119896119905] Higuchirsquos first

burst model [119876119905119876119898= 11989611986711990512+ 119888] and Kopcharsquos model [119876

119905119876119898= 11986011990512+ 119861119905]

5-FU loading data 5-FU kinetic release modelsrsquo dataZeolite 119876

119905119876119898= 1 minus 119890

minus119896119905

119876119905119876119898= 11989611986711990512+ 119888 119876119905

119876119898= 11986011990512+ 119861119905

119882119878

a (mg) loading 119882119863

b (mg) 119876119898

c (mg) released 119896e (hminus1) 119896

119867

f (hminus12) 119860119861g

ZSM-5-(15) 492 22 108 1047 97 22 12 110H-ZSM-5-(15) 502 43 216 198 92 39 14 225ZSM-5-(169) 506 38 192 162 85 29 11 24a119882119878 = average mass of the drug-loaded sample

b119882119863 = average mass of the drug in the loaded sample (obtained from loading)

c119876119898 = maximum mass of drug released into the SBF buffer solution

d release = 100 times 119876119905119882119863e119896 = first-order rate constant

f119896119867 = Higuchi first burst constantg119860119861 = ratio of diffusion-to-erosion contributions to drug release

Table 5 A comparison of loading release and kinetic model parameter data of 5-FU obtained in this work as well as related data onsiliceous carriers published literature for comparison

5-FU kinetic release modelsrsquo dataSiliceous material 119876

119905119876119898= 1 minus 119890

minus119896119905119876119905119876119898= 11989611986711990512+ 119888 Reference

loading release 119896 (hminus1) 119896119867(hminus12)

ZSM-5-(15) 22 97 after 3 hrs 22 12This workH-ZSM-5-(15) 43 92 after 3 hrs 39 14

ZSM-5-(169) 38 85 after 3 hrs 29 11Zeolite NaX-FAU 16 83 after 3min (01MHCl) mdash mdash [24]Zeolite HY-60 9 63 after 5 hrs 90 mdash [23]MCM-41 86 45 after 1 hr 95 after 26 hrs 024 33

[16]Thiol-functionalized MCM-41 99 20 after 2 hrs 95 after 18 hrs 01 206

the size of ZSM-5 micropores and that of the 5-FUmolecule

(ii) Enhancements on the loading capacity and the first-order rate constant (119896) were observed upon acidactivation of ZSM-5 and also upon increasing themolar SiO

2Al2O3ratio from 15 to 169

(iii) A relatively high release of 5-FU was achieved withthe highest release exhibited by ZSM-5 having amolar SiO

2Al2O3ratio of 169 (ge85)

(iv) The first-order rate constant (119896) increases withincreasing the molar SiO

2Al2O3ratio from 22 hminus1

for Na-ZSM-5-(15) to 29 hminus1 for Na-ZSM-5-(169) andincreases upon acid activation (from 22 hminus1 for Na-ZSM-5-(15) to 39 hminus1 for H-ZSM-5-(15))

(v) Diffusion is the principal process governing 5-FUrelease from zeolite ZSM-5

4 Conclusion

In this research work zeolite ZSM-5 was synthesized withtwo different molar SiO

2Al2O3ratios which were both acid

activatedThe acid activated ZSM-5 with a molar SiO2Al2O3

ratio of 169 shows the highest loading and release Asshown in Table 5 ZSM-5 exhibits about fourfold loading

capacity and about twofold release of 5-FU as comparedwith zeolite YWith its relative good thermal and acid stability(compared with low silica zeolites) in addition to its high loading (sim40) and release (sim85) ZSM-5 may serve as apotential carrier for 5-FU

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors acknowledge the fruitful discussions of kineticdata with Professor M Zughul The authors gratefullyacknowledge the financial support provided by the Deanshipof Academic Research The University of Jordan AmmanJordan and Scientific Research Support Fund (Grant noBas2022012) Amman Jordan

References

[1] H Zhu J Cao S Cui Z Qian and Y Gu ldquoEnhanced tumortargeting and antitumor efficacy via hydroxycamptothecin-encapsulated folate-modified N-succinyl-N1015840-octyl chitosan


micellesrdquo Journal of Pharmaceutical Sciences vol 102 no 4 pp1318ndash1332 2013

[2] S Yan J Zhu Z Wang J Yin Y Zheng and X Chen ldquoLayer-by-layer assembly of poly(l-glutamic acid)chitosan microcap-sules for high loading and sustained release of 5-fluorouracilrdquoEuropean Journal of Pharmaceutics and Biopharmaceutics vol78 no 3 pp 336ndash345 2011

[3] J L Arias ldquoNovel strategies to improve the anticancer action of5-fluorouracil by using drug delivery systemsrdquo Molecules vol13 no 10 pp 2340ndash2369 2008

[4] D B Longley D P Harkin and P G Johnston ldquo5-Fluorouracilmechanisms of action and clinical strategiesrdquo Nature ReviewsCancer vol 3 no 5 pp 330ndash338 2003

[5] R C Mundargi V Rangaswamy and T M Aminabhavi ldquoAnovel method to prepare 5-fluorouracil an anti-cancer drugloaded microspheres from poly(N-vinyl caprolactam-co-acryl-amide) and controlled release studiesrdquoDesignedMonomers andPolymers vol 13 no 4 pp 325ndash336 2010

[6] B D Kevadiya T A Patel D D Jhala et al ldquoLayered inorganicnanocomposites a promising carrier for 5-fluorouracil (5-FU)rdquoEuropean Journal of Pharmaceutics and Biopharmaceutics vol81 no 1 pp 91ndash101 2012

[7] J L Arias M Lopez-Viota A V Delgado and M A RuizldquoIronethylcellulose (coreshell) nanoplatform loaded with 5-fluorouracil for cancer targetingrdquo Colloids and Surfaces BBiointerfaces vol 77 no 1 pp 111ndash116 2010

[8] N P Bayramgil ldquoSynthesis characterization and drug releasebehavior of poly(1-vinyl 124-triazole) hydrogels prepared bygamma irradiationrdquo Colloids and Surfaces B Biointerfaces vol97 pp 182ndash189 2012

[9] X Cai Q Zhao Y Luan Y Jiang J Shi and W Shao ldquoPolymerfibrous materials composed of sodium carboxymethylcelluloseand poly(vinyl alcohol) for a hydrophilic anticancer drugreleaserdquo Journal of Dispersion Science and Technology vol 33no 6 pp 835ndash839 2012

[10] M S Moorthy S-S Park D Fuping S-H Hong M Selvarajand C-S Ha ldquoStep-up synthesis of amidoxime-functionalisedperiodic mesoporous organosilicas with an amphoteric ligandin the framework for drug deliveryrdquo Journal of MaterialsChemistry vol 22 no 18 pp 9100ndash9108 2012

[11] F H Lin Y H Lee C H Jian J-M Wong M-J Shieh andC-Y Wang ldquoA study of purified montmorillonite intercalatedwith 5-fluorouracil as drug carrierrdquo Biomaterials vol 23 no 9pp 1981ndash1987 2002

[12] S Garea AMihai A Ghebaur C Nistor andA Sarbu ldquoPorousclay heterostructures a new inorganic host for 5-fluorouracilencapsulationrdquo International Journal of Pharmaceutics vol 491no 1-2 pp 299ndash309 2015

[13] HAM Faria andAAA deQueiroz ldquoAnovel drug delivery of5-fluorouracil device based on TiO

2ZnS nanotubesrdquoMaterials

Science and Engineering C vol 56 pp 260ndash268 2015[14] A El-Ghannam K Ricci A Malkawi et al ldquoA ceramic-based

anticancer drug delivery system to treat breast cancerrdquo Journalof Materials Science Materials in Medicine vol 21 no 9 pp2701ndash2710 2010

[15] I S Carino F Testaa F Puocib L Pasquaa and R AielloaldquoPolymer coated silica-based mesoporous materials for con-trolled drug releaserdquo in Proceedings of the 4th InternationalFEZA Conference PIII-A66 Paris France September 2008

[16] B Murugan L N Ramana S Gandhi S Sethuraman and UM Krishnan ldquoEngineered chemoswitchable mesoporous silica

for tumor-specific cytotoxicityrdquo Journal of Materials ChemistryB vol 1 no 28 pp 3494ndash3505 2013

[17] A Petushkov J Intra J B Graham S C Larsen and A KSalem ldquoEffect of crystal size and surface functionalization onthe cytotoxicity of silicalite-1 nanoparticlesrdquo Chemical Researchin Toxicology vol 22 no 7 pp 1359ndash1368 2009

[18] S C Larsen ldquoNanocrystalline zeolites and zeolite structuressynthesis characterization and applicationsrdquo Journal of Phys-ical Chemistry C vol 111 no 50 pp 18464ndash18474 2007

[19] I Braschi S Blasioli L Gigli C E Gessa A Alberti and AMartucci ldquoRemoval of sulfonamide antibiotics from water evi-dence of adsorption into an organophilic zeolite Y by its struc-tural modificationsrdquo Journal of Hazardous Materials vol 178no 1ndash3 pp 218ndash225 2010

[20] N Vilac R Amorim O Martinho et al ldquoEncapsulation of 120572-cyano-4-hydroxycinnamic acid into a NaY zeoliterdquo Journal ofMaterials Science vol 46 no 23 pp 7511ndash7516 2011

[21] M Arruebo R Fernandez-Pacheco S Irusta J Arbiol M RIbarra and J Santamarıa ldquoSustained release of doxorubicinfrom zeolite-magnetite nanocomposites prepared by mechani-cal activationrdquoNanotechnology vol 17 no 16 article 4057 2006

[22] A Datt D Fields and S C Larsen ldquoAn experimental andcomputational study of the loading and release of aspirin fromzeolite HYrdquo Journal of Physical Chemistry C vol 116 no 40 pp21382ndash21390 2012

[23] A Datt E A Burns N A Dhuna and S C Larsen ldquoLoadingand release of 5-fluorouracil from HY zeolites with varyingSiO2Al2O3ratiosrdquoMicroporous andMesoporousMaterials vol

167 pp 182ndash187 2013[24] M Spanakis N Bouropoulos D Theodoropoulos et al ldquoCon-

trolled release of 5-fluorouracil from microporous zeolitesrdquoNanomedicine Nanotechnology Biology and Medicine vol 10no 1 pp 197ndash205 2014

[25] A Oyane H-M Kim T Furuya T Kokubo T Miyazaki andT Nakamura ldquoPreparation and assessment of revised simulatedbody fluidsrdquo Journal of Biomedical Materials ResearchmdashPart Avol 65 no 2 pp 188ndash195 2003

[26] S Ahmed M Z El-Faer M M Abdillahi M A B Siddiquiand S A I Barri ldquoInvestigation of the rapid crystallizationmethod for the synthesis of MFI-type zeolites and study of thephysicochemical properties of the productsrdquoZeolites vol 17 no4 pp 373ndash380 1996

[27] A Saito and H C Foley ldquoHigh-resolution nitrogen and argonadsorption on ZSM-5 zeolites effects of cation exchange andSiAl ratiordquoMicroporous Materials vol 3 no 4-5 pp 543ndash5561995

[28] K Sing ldquoReporting physisorption data for gassolid systemsrdquoPure and Applied Chemistry vol 54 no 11 pp 2201ndash2218 1982

[29] J Cejka H VanBekkum andC Schueth Introduction to ZeoliteMolecular Sieves Elsevier Science New York NY USA 3rdedition 2007

[30] H Feng C Li and H Shan ldquoEffect of calcination temperatureof kaolin microspheres on the in situ synthesis of ZSM-5rdquoCatalysis Letters vol 129 no 1-2 pp 71ndash78 2009

[31] L Shirazi E Jamshidi and M R Ghasemi ldquoThe effect of SiAlratio of ZSM-5 zeolite on its morphology acidity and crystalsizerdquo Crystal Research and Technology vol 43 no 12 pp 1300ndash1306 2008

[32] THeikkila J Salonen J Tuura et al ldquoEvaluation ofmesoporousTCPSi MCM-41 SBA-15 and TUD-1 materials as API carriersfor oral drug deliveryrdquoDrug Delivery vol 14 no 6 pp 337ndash3472007


[33] T Higuchi ldquoMechanism of sustained-action medicationTheo-retical analysis of rate of release of solid drugs dispersed in solidmatricesrdquo Journal of Pharmaceutical Sciences vol 52 no 12 pp1145ndash1149 1963

[34] E ChevalierM Viana A Artaud S Haddouchi andD ChulialdquoA novel application of the T-cell for flow-through dissolutionthe case of bioceramics used as ibuprofen carrierrdquo Talanta vol77 no 4 pp 1545ndash1548 2009

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


O

FHN

OHN

53Aring

49Aring

Figure 1 Chemical structure and molecular dimensions of 5-fluorouracil (5-FU)

Recently both zeoliteHY [23] and zeoliteNaX-FAU [24] havebeen explored as delivery systems for 5-FU

In this study zeolites ZSM-5 and H-ZSM-5 each pre-pared in two different molar SiO


have been investigated as probable drug delivery systems for5-FU This choice of ZSM-5 zeolite derivatives for investi-gation as a possible drug carrier for 5-FU was dictated bytheir having a promising 3D-channel structure with a suitablepore size in addition to its reasonable good acid and thermalstability in comparison with low silica zeolites

2 Materials and Methods

21 Materials Tetrapropylammonium bromide (+98Acros Organics) aluminum sulfate Al

2(SO4)3sdot16H2O (Inter-

chem) sodium chloride (BDH) BaCl2sdot2H2O (Merck)

CaCl2sdot2H2O (Merck) MgCl

2sdot6H2O (SD Fine-Chem

Limited) sodiummetasilicate nonahydrate (Na2SiO3sdot9H2O)

(Aldrich) sulfuric acid (98 SD Fine-Chem Limited)ammonium nitrate (RPL) NaHCO

3(Merck) KCl (Riedel

de Haen) K2HPO4sdot3H2O (Merck) sodium hydroxide

pellets (BDH) Na2SO4(Merck) hydrochloric acid (35 SD

Fine-ChemLimited) nitric acid (95Merck) 5-fluorouracil(AcrosOrganics 99) and tris(hydroxymethyl)aminometh-ane (Merck) were used as received The simulated body fluid(SBF) was prepared following literature procedure [25]by dissolving the following salts into a 1 L solution withdeionized water 8036 g NaCl 0352 g NaHCO

3 0225 g

KCl 0230 g K2HPO4sdot3H2O 0311 g MgCl

2sdot6H2O 400mL

1M HCl 0388 g CaCl2sdot2H2O 0072 g Na

2SO4 and 6063 g

tris(hydroxymethyl)aminomethane The pH of solution wasadjusted to 74 by 1M HCl before being used

22 Instrumentation (Physical Measurements) X-ray powderdiffraction spectra were measured using a Philips 2KWmodel X-ray diffractometer (Cu-K120572 radiation source 120582 =15418 A) at a scan rate of 2∘Cmin Specific surface areaswere estimated through BET modeling using a nitrogenadsorptiondesorption instrument (Nova 2200e) UV-Visiblespectra were recorded using a Cary 100 Bio UV-Visible spec-trophotometer (Varian) FT-IR spectra (4000 to 400 cmminus14 cmminus1 spectral resolution KBr pellets) were measured usinga Thermo Nicolet NEXUS 670 FT-IR spectrometer Thermalgravimetric analysis (TGA) was conducted using a NetzschSta 409 PC instrument (Netzsch-Ger) and a Mettler-ToledoDSC823E instrumentThemorphologies of the solid sampleswere monitored by scanning electron microscopy (SEM)

using an FEI-FEG INSPEC F50 instrument The chemicalcomposition of samples was determined using an X-rayfluorescence spectrometer (SHIMADZUmodel XRF-1800)

23 Synthesis of ZSM-5 Samples of zeolite ZSM-5 with twodifferent molar SiO

2Al2O3ratios were prepared following

a literature procedure [26] with some modifications In atypical procedure the zeolite was prepared by mixing threesolutions 1 2 and 3 Solution 1 was prepared by dissolvingsodium silicate (Na

2SiO3sdot9H2O) (2525 g) with deionized

water (200mL) Solution 2 was prepared by dissolving a spe-cific amount of aluminum sulfate Al

2(SO4)3sdot16H2O (040 g or

300 g depending on the required molar SiO2Al2O3ratio)

and tetrapropylammonium bromide (159 g) in deionizedwater (100mL) Solution 3 was prepared by dissolvingsodium hydroxide (036 g) and sodium chloride (525 g) indeionized water (150mL)

Solutions 2 and 3 were mixed and then solution 1 wasadded dropwise After vigorous stirring (sim300min) the pHwas adjusted to the range 103ndash106 by adding concentratedsulfuric acid (98) The hydrogel formed was transferredinto an autoclave and heated for two days at 170∘C The solidproduct was filtered and washed with deionized water untilthe filtrate is sulfate-free (tested by BaCl

2) The zeolite was

dried at 110∘C for one hour and then calcined at 550∘C for 5 hto allow for the decomposition of the template

24 Acid Activation of Zeolite ZSM-5 The sodium zeoliteZSM-5 was acid activated into H-ZSM-5 using the followingtypical procedure a sample of ZSM-5 (100 g) was added to a20M solution of ammonium nitrite (500mL) and the mix-ture was placed in a thermostated water bathshaker at 80∘Cfor 24 h to obtain the ammonium exchanged zeolite NH

4-

ZSM-5 The ammonium form of the zeolite was transformedto the acid form (H-ZSM-5) by calcination at 500∘C for 4 h[27]

25 Loading of 5-FU into ZSM-5 5-FU was loaded intosamples of ZSM-5with two differentmolar SiO

2Al2O3ratios

via the following general procedure 5-FU (asymp0400 g) was dis-solved inwater (250mL) and then added to a flask containingZSM-5 (sim0200 g) The mixture was stirred in the dark atroom temperature for 24 h The drug-loaded carrier wasfiltered and dried under vacuum (30mmHg) for two hoursat 60∘C

The loading capacities of drug-loaded samples weredetermined by TGA measurements within the temperaturerange 25ndash1100∘C under nitrogen The drug loading capacitywas also determined by UV-Visible absorption spectropho-tometer in which a predetermined amount of drug-loadedcarrier (around 00100 g) was stirred with water (10000mL)for 24 hours at room temperature the solution was then fil-tered and the concentration of 5-FUwas determined bymea-suring the absorbance at 266 nm The total amount of drugcontained in the sample was calculated with reference to acalibration curve

26 5-FU Release Profiles The in vitro release of each 5-FU-loaded carrier was measured using the dialysis method
















0range



2onto the




10 20 30 40

H-ZSM-5-(15)

ZSM-5-(15)

50


4400

000 020 040 060 080 100

52006000680076008400


Volu

me a

t STP

(cc

g)





















2Al2O3

lowastlowast




ZSM-5-(15) 15 194ZSM-5-(169) 169 326H-ZSM-5-(169) 169 369H-ZSM-5-(15) 15 247











2Al2O3ratios 169














(a) (b)


0

200000

400000

600000

0

5000

10000

8000

6000

4000

2000

010 20 30 40 50 60

Inte

nsity

(cou

nts p

er se

cond

s) (a) 5-FU

(b) 5-FU-ZSM-5

(c) ZSM-52120579 (deg)




Temperature (∘C)

TG (

)(e)

(d)(c)

(a)

(b)

10

200 400 600 800 1000 1100

20

30

40

50

60

70

80

90

100







119905




119876119905

119876119898

= 1 minus 119890minus119896119905 (3)





119898is the


Both 119876119898


119905against 119876

119898(1 minus 119890









119876119905

119876119898

= 11989611986711990512+ 119888 (4)


119898is the




119876119905

119876119898

= 11986011990512+ 119861119905 (5)

5-FU-ZSM-5-(15)

00

20

40

60

80

100

2 4 6 8 10 12 14

5-FU-H-ZSM-5-(15)5-FU-ZSM-5-(169)

Time (h)

Rele

ase (

)


00

20

40

60

80

100

1 2 3 4

Rele

ase (

)


Time12 ((h)12)










119905119876119898= 1 minus 119890



119905119876119898= 11986011990512+ 119861119905]


119905119876119898= 1 minus 119890

minus119896119905

119876119905119876119898= 11989611986711990512+ 119888 119876119905

119876119898= 11986011990512+ 119861119905

119882119878

a (mg) loading 119882119863

b (mg) 119876119898


119867

f (hminus12) 119860119861g








119905119876119898= 1 minus 119890

minus119896119905119876119905119876119898= 11989611986711990512+ 119888 Reference














4 Conclusion








Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of
















0range



2onto the




10 20 30 40

H-ZSM-5-(15)

ZSM-5-(15)

50


4400

000 020 040 060 080 100

52006000680076008400


Volu

me a

t STP

(cc

g)





















2Al2O3

lowastlowast




ZSM-5-(15) 15 194ZSM-5-(169) 169 326H-ZSM-5-(169) 169 369H-ZSM-5-(15) 15 247











2Al2O3ratios 169














(a) (b)


0

200000

400000

600000

0

5000

10000

8000

6000

4000

2000

010 20 30 40 50 60

Inte

nsity

(cou

nts p

er se

cond

s) (a) 5-FU

(b) 5-FU-ZSM-5

(c) ZSM-52120579 (deg)




Temperature (∘C)

TG (

)(e)

(d)(c)

(a)

(b)

10

200 400 600 800 1000 1100

20

30

40

50

60

70

80

90

100







119905




119876119905

119876119898

= 1 minus 119890minus119896119905 (3)





119898is the


Both 119876119898


119905against 119876

119898(1 minus 119890









119876119905

119876119898

= 11989611986711990512+ 119888 (4)


119898is the




119876119905

119876119898

= 11986011990512+ 119861119905 (5)

5-FU-ZSM-5-(15)

00

20

40

60

80

100

2 4 6 8 10 12 14

5-FU-H-ZSM-5-(15)5-FU-ZSM-5-(169)

Time (h)

Rele

ase (

)


00

20

40

60

80

100

1 2 3 4

Rele

ase (

)


Time12 ((h)12)










119905119876119898= 1 minus 119890



119905119876119898= 11986011990512+ 119861119905]


119905119876119898= 1 minus 119890

minus119896119905

119876119905119876119898= 11989611986711990512+ 119888 119876119905

119876119898= 11986011990512+ 119861119905

119882119878

a (mg) loading 119882119863

b (mg) 119876119898


119867

f (hminus12) 119860119861g








119905119876119898= 1 minus 119890

minus119896119905119876119905119876119898= 11989611986711990512+ 119888 Reference














4 Conclusion








Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





2Al2O3

lowastlowast




ZSM-5-(15) 15 194ZSM-5-(169) 169 326H-ZSM-5-(169) 169 369H-ZSM-5-(15) 15 247











2Al2O3ratios 169














(a) (b)


0

200000

400000

600000

0

5000

10000

8000

6000

4000

2000

010 20 30 40 50 60

Inte

nsity

(cou

nts p

er se

cond

s) (a) 5-FU

(b) 5-FU-ZSM-5

(c) ZSM-52120579 (deg)




Temperature (∘C)

TG (

)(e)

(d)(c)

(a)

(b)

10

200 400 600 800 1000 1100

20

30

40

50

60

70

80

90

100







119905




119876119905

119876119898

= 1 minus 119890minus119896119905 (3)





119898is the


Both 119876119898


119905against 119876

119898(1 minus 119890









119876119905

119876119898

= 11989611986711990512+ 119888 (4)


119898is the




119876119905

119876119898

= 11986011990512+ 119861119905 (5)

5-FU-ZSM-5-(15)

00

20

40

60

80

100

2 4 6 8 10 12 14

5-FU-H-ZSM-5-(15)5-FU-ZSM-5-(169)

Time (h)

Rele

ase (

)


00

20

40

60

80

100

1 2 3 4

Rele

ase (

)


Time12 ((h)12)










119905119876119898= 1 minus 119890



119905119876119898= 11986011990512+ 119861119905]


119905119876119898= 1 minus 119890

minus119896119905

119876119905119876119898= 11989611986711990512+ 119888 119876119905

119876119898= 11986011990512+ 119861119905

119882119878

a (mg) loading 119882119863

b (mg) 119876119898


119867

f (hminus12) 119860119861g








119905119876119898= 1 minus 119890

minus119896119905119876119905119876119898= 11989611986711990512+ 119888 Reference














4 Conclusion








Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(a) (b)


0

200000

400000

600000

0

5000

10000

8000

6000

4000

2000

010 20 30 40 50 60

Inte

nsity

(cou

nts p

er se

cond

s) (a) 5-FU

(b) 5-FU-ZSM-5

(c) ZSM-52120579 (deg)




Temperature (∘C)

TG (

)(e)

(d)(c)

(a)

(b)

10

200 400 600 800 1000 1100

20

30

40

50

60

70

80

90

100







119905




119876119905

119876119898

= 1 minus 119890minus119896119905 (3)





119898is the


Both 119876119898


119905against 119876

119898(1 minus 119890









119876119905

119876119898

= 11989611986711990512+ 119888 (4)


119898is the




119876119905

119876119898

= 11986011990512+ 119861119905 (5)

5-FU-ZSM-5-(15)

00

20

40

60

80

100

2 4 6 8 10 12 14

5-FU-H-ZSM-5-(15)5-FU-ZSM-5-(169)

Time (h)

Rele

ase (

)


00

20

40

60

80

100

1 2 3 4

Rele

ase (

)


Time12 ((h)12)










119905119876119898= 1 minus 119890



119905119876119898= 11986011990512+ 119861119905]


119905119876119898= 1 minus 119890

minus119896119905

119876119905119876119898= 11989611986711990512+ 119888 119876119905

119876119898= 11986011990512+ 119861119905

119882119878

a (mg) loading 119882119863

b (mg) 119876119898


119867

f (hminus12) 119860119861g








119905119876119898= 1 minus 119890

minus119896119905119876119905119876119898= 11989611986711990512+ 119888 Reference














4 Conclusion








Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





119898is the


Both 119876119898


119905against 119876

119898(1 minus 119890









119876119905

119876119898

= 11989611986711990512+ 119888 (4)


119898is the




119876119905

119876119898

= 11986011990512+ 119861119905 (5)

5-FU-ZSM-5-(15)

00

20

40

60

80

100

2 4 6 8 10 12 14

5-FU-H-ZSM-5-(15)5-FU-ZSM-5-(169)

Time (h)

Rele

ase (

)


00

20

40

60

80

100

1 2 3 4

Rele

ase (

)


Time12 ((h)12)










119905119876119898= 1 minus 119890



119905119876119898= 11986011990512+ 119861119905]


119905119876119898= 1 minus 119890

minus119896119905

119876119905119876119898= 11989611986711990512+ 119888 119876119905

119876119898= 11986011990512+ 119861119905

119882119878

a (mg) loading 119882119863

b (mg) 119876119898


119867

f (hminus12) 119860119861g








119905119876119898= 1 minus 119890

minus119896119905119876119905119876119898= 11989611986711990512+ 119888 Reference














4 Conclusion








Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




119905119876119898= 1 minus 119890



119905119876119898= 11986011990512+ 119861119905]


119905119876119898= 1 minus 119890

minus119896119905

119876119905119876119898= 11989611986711990512+ 119888 119876119905

119876119898= 11986011990512+ 119861119905

119882119878

a (mg) loading 119882119863

b (mg) 119876119898


119867

f (hminus12) 119860119861g








119905119876119898= 1 minus 119890

minus119896119905119876119905119876119898= 11989611986711990512+ 119888 Reference














4 Conclusion








Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

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