Vehicle and Enhancer Effects on Human Skin Penetration Of

8/2/2019 Vehicle and Enhancer Effects on Human Skin Penetration Of

1/10

j. Cosmet. ci., 58, 245-254 (May/June 2007)

Vehicle and enhancer effects on human skin penetration ofaminophylline rom cream formulations: Evaluation n vivo

LAI-HAO WANG, CHIA-CHEN WANG, andSU-CHING KUO, Department f Applied Chemistry, hia NanUniversity f Pharmacy nd Science, ainan 71710, Taiwan R.O.C.

Acceptedor p/blication arch 6, 2007.

Synopsis

The effects f four essential ils rosemary, lang, ilacin, and peppermint ils), and hree plant oils jojobaoil, corn germ oil, and olive oil) on the permeation f aminophylline ere studied using human skin. Thepermeation ffects f these ils were compared ith those f three chemical enetration nhancers. lthoughall oils enhanced he permeation f aminophylline, heir effects were ess han that of ethanol. ojoba oilwas ound o be the most active, ausing bout a 32% peak height decrease f N-H bending bsorbancesin comparison ith the control, while peppermint, ilacin, rosemary, nd ylang oils caused 8%, 24%, 18%,and 12% peak height decreases, espectively. icroemulsions ontaining 0% jojoba oil and 30% corn germoil were ound o be superior ehicles or the percutaneous bsorption f aminophylline. omparision ithresults btained rom high-performance iquid chromatography hows ood agreement.

INTRODUCTION

Theophylline s a xanthene erivative. When theophylline s combined with ethylenediamine n anhydrous lcohol, t forms he compound minophylline 1). Aminophyllinehas been eported o break down at and cellulite rom cells by triggering nzymes hat

help the body o release at from stores n certain areas f the body. t works well on thethighs and buttocks of women and has a smoothing ffect on the skin. However, someindividuals suffer rom allergic reactions o ethylenediamine ydrochloride 2). Theaminophylline ream has been studied by Fourier ransform nfrared FTIR (3), electro-chemical etection 4), reversed-phase igh-performance iquid chromatography HPLC)(5), and spectral nalysis 6). There was only one study applied o aminophylline ream,in which permeation hrough rat skin in vitro was performed n a two-compartmentdiffusion cell to a select enhancer 7). Human skin is usually he preferred kin mem-brance o use n an absorption tudy. No animal model gives bsorption alues denticalto those obtained n human skin (8). The stratum corneum as ong been consideredmajor barrier to the penetration of topically applied chemicals. Studies have

Address ll correspondence o Lai-Hao Wang.

245


2/10

246 JOURNAL OF COSMETIC SCIENCE

shown hat most compounds ave ow permeabilities hrough the skin. Consequently,some transdermal drug delivery systems have utilized enhancers o accelerate rugpermeability 9). Although many studies on the essential ils in topical dermal prepa-rations, cosmetics, nd toiletries and also n experimental ermopharmacy) s penetra-tion enhancers ave been reported 10,11), no attenuated otal reflection Fourier trans-form infrared ATR-FTIR) spectroscopy nd stratum corneum tripping study dealingwith the interaction of aminophylline cream with human skin in the presence ndabsence f essential ils and chemical penetration nhancers as appeared n the litera-ture. The aim of this study was to investigate kin absorption, amely essential il andsoft lipophilic skin) penetration nhancers, ncorporated n w/o emulsions, espectively.The preparations ere applied o the human skin i, vivo, and after 30 to 60 rain, theamount of aminophylline n the stratum corneum ayers was determined using ATR-FTIR and HPLC.

EXPERIMENTAL

APPARATUS

Infrared spectra were recorded with a Perkin Elmer System 000/IRDM FTIR spectro-photometer with an attenuated otal reflection ATR) (accessory rom Grase by SpecacInc.) system. An ATR-crystal (ZnSe; dimensions, cm x 1 cm; incident angle, 45 )enabled horizontal ositioning f the subject's orearm ventral). Spectra btained ep-resented naverage ften scans, ollected t a resolution f4 cm . Subsequent pectralanalysis was performed using a Spectrum 2.0 (Perkin Elmer Ltd.). HPLC was per-formed with a Hitachi model L-7100 pump and a model 7125 injector equipped witha 20-pl sample oop and a model L-7455 photodiode rray detector DAD). Chromato-grams were acquired nd peak areas alculated y means ofa D-7000 chromatogram ataintegrator.

REAGENTS AND MATERIALS

Aminophylline was purchased rom Sigma (USA). All other chemicals were analyticalreagent grade. The chemicals nvestigated n this study were 1-methyl-2-pyrrolidone,IB-cyclodextrin ydrate, and ricaprylin Cs) purchased rom Tedia and Aldich. Samplesof plant oils (jojoba oil, corn germ oil, olive oil), essential ils (rosemary il, ylang oil,lilacin oil, peppermint oil), and cosmetics ere bought from a number of retail outletsin the south of Taiwan. Oil/water microemulsions f four essentials ils, three plant oils,and three chemical skin penetration nhancers ontaining Span and Tween as emulsi-fying agent were prepared. These systems were used as vehicles or the percutaneousabsorption of aminophylline. The effects of microemulsions ontaining B-cyclodextrinhydrate and 1-methyl-2-pyrrolidone n the percutaneous bsorption of aminophyllinewere compared with a control ormulation consisting of 50% ethanol solution.

PROCEDURES

ATR-FTIR spectroscopy. recent eport by the European Center or Ecotoxicology ndToxicology of Chemicals ECETOC) states hat general-purpose osmetic creams are


3/10

SKIN PENETRATION OF AMINOPHYLLINE 247

typically pplied o skin t 1 mg/cm (12).Therefore, oreach ormulation 0.25-5.0%),six normal healthy subjects mean age, 22 + 1.0 years) were investigated. ATR-FTIRmeasurements ere recorded t the site of application before reatment. These measure-ments served as pretreatment control values. Taking into account he aminophylline

content of the formulation approx. 0.3 g cream), t was weighed accurately nd spreadover 14 cm area f forearm 7 cmx 2 cm). The ormulation as maintained n contactwith the skin for 30 min and 60 min without occlusion, espectively. he marked skinarea of the forearm was pressed n the ZnSe crystal the window of the Skin Analyzer)by its own weight. After each measurement, he window was cleaned with alcohol. Allin vivo spectra were obtained under ambient aboratory onditions nd recorded t t: 0(before mulsion pplication) nd at t: 30 min and t-60 min after application. At eachtime, he values f the absorption and ntegrations erenoted or N-H (1557 cm absorbance) or both treated and non-treated arms.

Stripping method. ix normal healthy subjects mean age, 22 + 1.0 years) were investi-gated before drug-free) and after 30-min and 60-min periods of treatment with aformulation f fat-burning ream. n the middle of each orearm, wo sites f 14 cmwere delineated. One forearm received no treatment and was used as a control. On the

other one, the stratum corneum ayer was removed by stripping, performed by applyinga piece of adhesive ape (Scotch 3M TM)8 cm in length for 15 seconds, nder a constantweight. The tape was hen torn off. This operation was repeated everal imes. The skinwas not occluded; herefore, he vehicles were allowed o evaporate s hey would duringconditions of normal use.

Determination y /iqzdd chromatography. standard tock solution was prepared by dis-solving 10 mg of aminophylline n 10 ml of methanol. Working standard olutions wereprepared rom a standard tock olution n methanol n the range 10-80 mg 1 .RP-HPLC was performed n a Phenomenex una Cs (5u, 250 x 4.6 mm) column-eluted methanol-phosphate uffer (20:80, v/v, pH 5.50) as the mobile phase at 1 mlrain , and DAD was set at 270 rim. By means f the injection alue, 0 ll of theprepared sample solution and standard solution was chromatographed nder the oper-ating conditions described bove. Quantitation was based on the peak height of thesample.

RESULTS AND DISCUSSION

The ATR-FTIR observed minophylline bsorbances n the spectra of the fat-burningcream on the human skin and is shown n Table I. Figure 1 is the infrared absorbancespectra of human skin before a) and after (b and c) contact with fat-burning creamcontaining % aminophylline. he bands t 2915 cm 1 2847 cm 1 and 1701 cm 1correspond o C-H and C=O vibrations, espOctively. he strong C--O band n the 1700

-1

cm range s mainly due to the C=O bonds present n the aminophylline, plant oil,essential il, and fatty acids; his can be demonstrated y the lack of the characteristicC=O band of the applied fat-burning cream n the skin print. In addition to a strongN-H stretch 3400 cm-t), here s also weak N-H bond t approximately 557cm 1in the stratum corneum. The intensity of the N-H bond n the skin spectra fter contactwith the fat-burning cream s much lower in the N-H bonds. The presence f spectralbands t frequencies haracteristic f N-H bonds provides vidence or the adsorption fthe aminophylline on the skin. t is therefore oncluded hat the adsorbed minophylline


4/10


Table I

Aminophylline Absorbances bserved n Spectra ATR-FTIR) of Fat-Burning Sample on Human Skin

Absorption requenciesFunctionality (cm- )

Absorbance band chosen for

quantitative analysis

N-H Primary amine stretch 3493, 3380 --Primary amine bend 1557 1557

O-H Stretch (broad) 3398 --C-H Aliphatic carbon tretch 2921, 2849 --C=O Ring 1701 --

Ring conjugated 1649 --C=C Ring benzene 1605, 1525, 1495 --

95.1 90

80.

70

60

50%T

40

30

20.

10.

4.0

2000.0

C=(

,'oo ,a'oo

Figure 1. ATR-FTIR spectra of human skin treated with and without fat-burning cream containing 5%aminophylline/30% corn germ oil. (a) Untreated cream. b) Treated cream at 0 min for N-H bendingcharacteristic. c) Treated cream at 60 min for N-H bending characteristic.

is largely responsible or the N-H bond n the spectra of skin treated with fat-burningcream.

In order to quantify the amount of adsorbed minophylline, calibration was needed.For calibrating absorbance easurements, n area of 7 cm x 2 cm was marked on theforearm. A 0.3-g amount of aminophylline ream was spread on the marked area. Effortwas made o keep he distribution f the solution niform over he 14 cm area(0.05-0.64 mg/cm2). fter one hour, an IR scan f the area was obtained. ith theabsorbance t 1557 cm (N-H from skin), he percentage fdecrease n signal trengthwas plotted vs the mg/cm of aminophylline ream pplied o the skin. A linearcalibration Figure 2), y = 0.8901 x + 0.0538 (correlation oefficient, R = 0.9902) was

obtained.

The approach o determining he amount of drug remaining on the skin has been usedfor many years. n this experiment, we evaluated he amount of aminophylline bsorbed


5/10


0.300

0.200

" 0.100

0.000

R = 0.9902

Y .8901.0538 oo

o

I I I a I

0.000 0.100 0.200

Aminophyilinemg cm skin)

0.300

Figure 2. Aminophylline amounts n the stratum corneum 60 min after application.

percutaneously y recovering nd measuring he amount of aminophyltine hat remainedon the skin surface. he FTIR spectra rom 2000 to 700 cm of aminophylline nstratum corneum reated with 30% corn germ oil/10% essential il are shown n Figure3. Figure 4 shows he percent change n the peak heights of the N-H bending absor-bances f plant oils and essential ils, respectively. hese reatments decreased he peakheights of the N-H bending absorbances n comparison ith the control an aqueousvehicle). ojoba oil was ound to be the most active, causing bout a 32% peak heightdecrease, hile peppermint, ilacin, rosemary, nd ylang oils caused 8%, 24%, 18%and 12% peak height decreases, espectively. lant oils such as ojoba oil contain estersof unsaturated igher alcohols s atty acids and terpenes nd terpenoids n essential ils,and can disturb ntercellar ipid packing, ncreasing he flux of aminophylline 13-15).Treatment with plant oils and essential oils in comparison with 5% aminophyllinesignificantly ncreased he permeability of the stratum corneum o aminophylline ncomparison with treatment with 5% aminophylline alone. The 30% corn germ oil/10%jojoba oil produced he greatest enhancement n the permeability of the epidermis oaminophylline among the four essential ils studied.

Three chemical enhancers ethanol, -cyclodextrin, nd 1-methyl-2-pyrrolidone) estedenhanced he absorption of aminophylline compared o a control cream containing oilphase, 30% corn germ oil/10% jojoba oil/10% tricaprylin, water phase 5%, aminophyl-line, and surfactants. ne hour after application of fat-burning cream A (containing 50%ethanol), ream B (containing -cyclodextrin nhancer), ream C (containing -methyl-2-pyrrolidone enhancer), and the control cream (without chemical enhancers), he ami-


6/10


107.8.

90. '"''"".

70.

60.

%T50.

40_

30.

20

10

4.0

2000.0 1900 1800 1700 li00 15'00

Figure 3. ATR-FTIR spectra f aminophylline n stratum orneum fter 60-min treatment with plant andessential ils. (a) 5% aminophylline/30% orn germ oil. (b) 10% peppermint oil/30% corn germ oil. (c)10% jojoba oil/30% corn germ oil.

4O

35

30

20

'15

o

Corn germ Olive Jojoba Peppermint Ylang Lilacin Rosemary

Oil enhancers

Figure 4. Comparative alues of peak height decrease f aminophylline n the stratum comeurn fter60-min treatment with plant and essential ils.


7/10


'"'4O

e 20

Cream A Cream E Cream C

Forfnulation,Figure 5. Comparative alues of peak height decrease f aminophylline n the formulations: Cream A

(containing 50% ethanol), cream B (containing 3-cyclodextrin nhancer), nd cream C (containing1-methyl-2-pyrrolidone nhancer).

nophylline components ad penetrated he stratum corneum Figure 5), and N-Habsorbance t 1557 cm decreased 4.43%, 17.27%, nd 27.9% or creams , B, andC, respectively.

The enhancement ffect of 50% ethanol demonstrated he largest ncrease n perme-ability when the three chemical nhancers ere used, since ethanol directly affects heskin's modification f the formulation. hus, t can modify he intercellular ipid do-mains o reduce he barrier resistance f the bilayer ipids. In addition, penetrationenhancement an be indirect by modification of the thermodynamic ctivity of thevehicle. Rapid permeation of a good solvent rom the donor solution, such as ethanol, canleave he permeant n a more thermodynamically ctive state han when the solvent waspresent 16). A study also eports linear elationship etween he flux and thermody-namic activity of the drug in the vehicle with various concentrations f ethanol (17).

However, the high delivery rate of ethanol enhancers ften produces kin irritation.Aminophylline absorption sing 1-methyl-2-pyrrolidone as ess han with 50% etha-nol by a factor 1.6, and greater han with [3-cyclodextrin y a factor of 1.6. One-methyl-2-pyrrolidone has a heterocyclic ing structure, which is a five-membered ing, and[3-cyclodextrin onsists f six, seven r eight glucose nits inked together nto a ring.One-methyl-2-pyrrolidone, hich has a smaller ing and polar molecule, s thought toallow easier ntercalation on the tightly packed ipids of the stratum corneum and agreater disruption of these ipids, increasing ipid fluidity. Based on previous studies


8/10


(16-18), pyrrolidones were utilized as solvents, nd the drug was generally present nsolution form. In the present study, the enhancers were used at a low concentration(


9/10


Table II

Determination f Aminophylline fter 60-min Treatment with Cream C by Stripping Method

% Decrease

Analytical methods Determinations AverageLC-UV 19.70, 19.20, 20.90, 20.56, 19.93, 19.69 20.01 -+ 0.69ATR-FTIR 22.48, 20.98, 22.47, 18.87, 22.4, 22.82, 23.5 21.92 -+ 1.52

% Decrease n peak height or peak area = {(peak height or peak area due o treatment--peak height or peakarea due to control)/peak eight or peak area due to control} x 100.Cream C contains 1-methyl-2-pyrrolidone nhancer.

standard deviations re slightly higher than with HPLC because TIR detection s notas sensitive s UV and the samples ere not pretreated nd run on the ZnSe crystal. Thereproducibility f the peak area of aminophylline s poor. However, he data n a sampleare obtained y both LC-UV and FTIR. Thus LC-UV can be used or quantitation ndFTIR for qualitative detection and spectroscopic dentification of aminophylline n amixture.

CONCLUSIONS

In vivo indings on skin with an ATR crystal or a stripping method, n which thedecrease n the peak height of the permeating minophylline s determined n the creamreceiving phase, can be evaluated nd considered n preformulation tudies. The resultsof this study suggest hat the choice f the proper combination f oil phase ipids mayallow achieving rug-controlled elivery rom a topical o/w microemulsion, nd may beemployed with limited success hen ormulated nto a matrix-type ransdermal atch orin a gel.

ACKNOWLEDGMENTS

Financial support of this work by the Chia Nan University of Pharmacy nd Science sgratefully acknowledged CNAC-92-06).

REFERENCES

(1) J. s. Artz, and M. I. Dinner, Can. J. Plast. Surg., 3, 190 (1995).(2) J. W. Petrozzi and R. N. Shore, Arch. Dermatol. 112, 525 (1976).(3) M. Baan, J. Madarasz, G. Pokol, and S. Gal, Solid State onics, 72, 587 (2004).(4) L.-H. Wang and C.-C. Wang, Microchimica cta, 153, 95 (2006).(5) J.-E. Haky, W. M. Foss, nd B. L. Marks, J. Liq. Chromatogr. el. Technol., 0, 2399 (1997).(6) B. L. Marks, L. M. Katz, J. E. Haky, W. M. Foss, nd D. J. Torok, nt. J. Obesity, 3, 198 (1999).(7) J.P. Liu and N. Zhou, Chinese harm. ., 36(8), 534 (2001).(8) R. L. Bronaugh nd J.J. Yourick, C&T, 115, 47 (2000).(9) M. Hori, S Satoh, and H. I. Maibach, "Classification of Percutaneous enetration Enhancers: A Con-

ceptual Diagram," n Percutaneous bsorption, . L. Bronaugh nd H. I. Maibach, Eds. Marcel Dekker,New York, 1989), p. 197.

(10) D. Abdullah, O. N. Ping, and J. G. Liu, Yaoxue uebao, 1,214 (1996).(11) D. Monti, P. Chetoni, S. Burgalassi, . Najarro, M. F. Saettone, nd E. Boldrini. nt. J. Pharm., 237,

209 (2002).


10/10


(12) ECETOC, Consumer xposam CETOC Technical Report No. 58: Assessment f Non-OccupationalExposure o Chemicals ECETOC, Brussels), p. 9-39 (1994).

(13) M.L. Francoeur, G. M. Golden, and R. O. Potts, Pharm. Res. 7, 621 (1990).(14) V. R. Sinha and P. K, Maninder, Drug. Der. Inc/. Pharm. 26, 1131 (2000).(15) K. Kazunori, T. Osamu, M. Rakan, M., Setsuko, A. Tetsuya, K. Masawo, and K. Tamotsu., Chem.

Pharm. Bulletin 40, 3097 (1992).(16) A. C. Williams and B. W Barry, Adv. Dr/g Del. Rev., 56, 603-618. (2004).(17) P. R. Rao, K. B. Chalasani, . S. Chauhan, A. K. Jain, P. V. Diwan, and M. K. Ram, Drug Delivery,

13, 207 (2006).(18) R.J. Babu, Drug Delivery, 12, 165 (2005)

Vehicle and Enhancer Effects on Human Skin Penetration Of

Documents

Transcript of Vehicle and Enhancer Effects on Human Skin Penetration Of