OA10520A - Skin care compositions containing retinoids and liposomes - Google Patents

Abstract

This invention relates to a skin care composition containing a retinoid compound as an active ingredient, which is encapsulated in non-phospholipid liposomes and is chemically stable over a long period of time.

Description

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SKIN CARE COMPOSITIONS CONTAINING RETINOIDS AND LIPOSOMES

FIELD OF THE INVENTION 5

This invention relates to skin care comoositions containing retinoids whichgenerally improve the quality of The skin. parncuiarly human facial skin.More parncuiarly, trie présent invention relates to cnemtcally stable skincare compositions containtng a non-pnosDnolioid liDosome formulation anû 5 certain retinoids.

BACKGROUND OF THE INVENTION

Skin care compositions containing retinoids hâve become the focus of 10 great interest in recent years. Retmoic acid, also known as Vitamin A acidor tretinoin, is well-known for the treatment of such skin conditions asacné and proaucts containing retinoïc acid are commeroiaily avaiiable invarious forms. Sucn proaucts, for examoie, inciuae Retin A* créants, anoil-in-water émulsion of retinoïc acid containing an oii-soluble antioxidant. 15 butylated hyoroxytoiuene (BHTI; Retin A* liquid. commercially avaiiablefrom Ortho Pharmaceutical Corporation of Raritan. New Jersey, which isa solution of retinoïc acid in a polyetnyiene glycol/ethanol solventemploying BHT as an antioxidant; and Retin A* gel, which comprisesretinoic acid in a gel venicle comprising ethyl alcohol as the solvent, 20 hydroxYpropyi cellulose as the tnickener or getiing agent and BHT as anantioxidant. 010520

These retinoic acid containing products hâve oroven sraole and capable ofproviding active ingreaienrs after exrenaeo perioas of storage. Morerecently, however, wider use of rennoias has been suggested fortreatmenrs orner rhan acné such as, for example, the rrearmenr of skin 5 againsr phoroaging and sun damage. Many individuals who hâve had agood deal of sun exposure in chiidhood will show rhe following grosscutaneous alrerarions in larer adult life: wrinkling, learheriness, yellowing,looseness, rougnness, dryness, morrling (hyperpigmenrarionî and variouspremalignanr growrhs lofren subclinicat). These changes are most 10 prommenr in lighr-sKinnea persons who burn easiiy and ran poorly, Thesecumulative effecrs of sunlignr are orren referred ro as "phoroaging".Althougn rhe anaromicai dégradation of rhe skin is mosr advanced in theelderly, rhe destructive effecrs of excessive sun exposure are alreadyévident by rhe second decade. Serious microscopie alterations of the 15 epidermis and dermis occur décades before these become clinically visible.Wrinkling, yellowing, learheriness and loss of eiasticity are very latochanges. U.S. Patent No. 4,603.146 suggesrs rhe use of Vitamin A acid in an 20 emollienr vehicle as a rrearmenr for ameiioraung rhe effecrs ofphotodamage. Furrner, U.S. Patent No. 4,877,805, suggesrs that anumber of retinoius are useful for restonng and reversing sun damage ofhuman skin. 25 Certain retinoids suen as, for exampie. retinol (Vitamin A alcohal), retinai(Vitamin A aldehyae) and· retinyl esters such as retinyl acetare and retinylpalmirare may be preferade ro use in skin care compositions as opposedte retinoic acid. Retinol is an endogenous comoound naturallyoccurring in rhe human body and essenrial for good growth, (il 0520 - J - différentiation or epitheiial tissues and reDrooucnon. Retinoi is alsopreferred because ir is safer and tess irritating ro rhe skin rhan otherretinoids. such as retinoic acid. Addiiionatly, excess retinol is srored in thehuman body largeiy in an inactive ester form, e.g. retinyl paimitate and, 5 to some extern, retinyl acetate. The aidehyae. retinal, also a preferredform, is an active metaooiite of retinol and is neeaed for Visual function.

Accordingly, attention has turnea toward formulating skin carecompositions which contam tnese preferred, naturaliy occurring retinoids 10 which hâve simiiar prooerties to existing retinoïc acid formulations, i.e.,proviaing a comoosition wnicn is aestneticaily pieasma and which candeliver active ingrédients after a suDstantiai sheif life.

Typicaily, existing formulations containing retinoids are oil-in-water 15 émulsions in which the retinoic acid is carried within the oii phase and isprotected from oxidation by employing an oil-solubie antioxidant. QH-in-water émulsions are generally considérée préférable to water-in-oilémulsions oecause they are nonocciusive, non-greasy, compatible withother suen emuision prooucts. easy to remove from the skin and are 20 regarded as more aesthetically pleasing as weit as being moreeconomical to manufacture. Generally, the cnemical stability of the activeretinoic acid ingrédient is quite goou in thaï the oii phase orotects theretinoic acid, esoeciaily when an oil-soiuble antioxidant is présent. Thus,for example, the aforementioneo Retin A* cream is an oil-in-water 25 émulsion containing retinoic acid and BHT, an oil-soiuble antioxidant.In U.S. Patent 2,205,108 there is oisciosea an oil-in-wner émulsionof retinoic acid wnich may inciuce an oil-soiuble antioxidant suchas 3HT or dl-c-tocoonerol ano a c r. . c t. :t g agent e.g.etnyieneoiaminetetraacetic acid 1EDTA). In U.S. Patent 4,466,805, 010520 - 4 - a tanning comoosuion is described wnicn may include.among otheringrédients Vitamin A in an oil-in-water emuision containing Vitamin Eand cirric acid. In U.S. Patent 4.247,547 suit another form of aretinoic acid containing comoosition, namely a gel, is disclosed and isprotected by an antioxidant selected from the group consisting ofbutylated hydroxytoluene, butylated hydroxyanisote (BHA) , ascorbic acid(Vitamin Cl , propyl aallate. and <=-rocoonerol (Vitamin El. A number of skin care products hâve appeared in the marketpiaceincorporating other retinoios, including, for examole. retinol, retinal andretinyl esters sucn as retinyl scetate and retinyi palmitate.Unsurprisingly, these compositions emuiate the formulas of commercialretinoic acid compositions: they are oil-in-water émulsions protectedby oii-soiuble antioxidants. However. for reasons not yet cleariyunderstooa, the retinoids other tnan retinoic acid in such compositionsquickly lose their activity and either oxidize or isomerize to non-efficacious

Chemical forms with the resuit that the amount of retinoid acxuallyavailable to provide the oeneficial effects of the product is reduced. in anunacceptabiy snort penod of time. to an ineffective quanttty and eventuallyonly to trace quantities.

Generaily then. products containing retinoids bave been ümited to oil-in-water émulsions and. with respect to those other than retinoic acid, hâvesuffered from Chemical instability. In a few instances, however, productsand/or suggestions for products hâve been made wnerein retinoids such asretinol, retinyl acetate and retinyl palmitate are formulata-d in water-in-oilémulsions. 010520 - 5 -

Thus. for example. ;n U.S. Patent 4,826.528 oescribes a stablecomoosition comorisma retinol. retinyl acetate and retinyl palmitate mayconsist or retinol in a water-in-oii émulsion w'nerein the émulsion furtberinclude two oil-soluble antioxidants. BHT ana BHA. 5

Further, Avon Proaucts. Inc., the assignée of U.S. 4,826,828, sells twoskin care products called Bioaavance and Bioaavance 2000. Each oftheseprooucts is suppliea in two bottles, portions of which are mixed togetherjust prior to use. The rirst bottle contains wnat is called a "skin lotion", 10 wnile the secono bottle contains what is callea a "fortifier”. The "skinlotion" is a water-m-oii émulsion navina a numoer of ingrédients whichinclude water, emulsifiers. silicone and vegetable oiis. preservatives,émollients and butylated hydroxytoluene {BHT) The "fortifier" is a non-aqueous solution which contains a number of ingrédients including 15 cyclomethicone (a silicone oil). denatured éthanol, an emulsifier(Polysorbate 20), retinol. retinyl acetate. retinyl palmitate, BHT and BHA.When a specifiea portion of tne "fortifier" is aaded to a specified portionof the "skin lotion" ano mixea, there results a water-m-oii émulsion whichcomprises retinol. retinyl acetate, retinyl palmitate. BHT and BHA, the latter 20 being oil-soluble antioxidants. The outer package in which Bioaavance issupplied carnes a statement which says "Because BIOADVANCE begins tolose effectiveness after one month, for maximum benefits, use a freshsupply each month". It would appear from this statement îhat theChemical staoiiity of the retinoids in the mixture of the "skin lotion" and the 25 "fortifier" is quite limiteo. The fact that in both the BIOADVANCE andBIOADVANCE 2000 products the "fortifier" ingrédients must be mixedwith the "skin lotion" ingrédients immediateiy prior to use indicates thatthe resulting water-in-oil émulsion which is applied to the skin also has 010520 - δ - limixed Chemical sxaDiiixy of one or more of ihe aoove-menxioneo rexinol,rexinyl acexaxe and rexinyl palmixaxe.

Furxner sxill. U.S. 4,720,353 xo Bell describes waxer-in-oil émulsion carriers 5 for various meaicamenxs and drugs inxenaed for xopicat applicaxion xo xheskin. Waxer soluble, miscible or dispersible drugs may be incorporaxed inxoxhe aqueous phase of xhe émulsion. Oil-soiuble. miscible or dispersibledrugs may be incorporaxed inxo xhe oil phase. Drugs which may beincorporaxed inxo xne émulsion include derivaxives of rexinoic acid. 10 Ingredienxs which may ooxionaily be added xo xhe emuision include apreservaxive sucn as mernyï paraoen. prooyi paraoen or imiaazolidinyl ureaor an anxioxiaanx sucn as buxytaxed hyoroxyanisole and a waxer or· oilsoluble vixamin such as vixamin C, xocopneroi linoleaxe and xhe like. 15 Still furxher, EP O 343 444- A2. xo Siemer ex al discloses cosmexicpreparaxions based on rexinyl palmixaxe. Example 3 discloses a nighx creamin xhe form or an waxer-in-oti xype émulsion comprising rexinyl palmixaxeand buxylaxea hyoroxyanisole (BHA1. Exampie 4 discloses a waxer-in-oilemuision comprising rexinyl acexaxe and a-Tocopnerol (Vixamin Eh 20

Still furxher. EP O 330 496 A2 xo Baxx is direcxed xo skin xreaxmenxcomposixions comorising a xopically accepxabie base and an enêcxiveamounx of ax leasx one esxer of rexinol. said composixions being useful inXhe xreaxmenx of phoxoaged skin. Examoie 6 disctoses a waxer-in-oil 25 emuision comprising Vixamin A prooionaxe and BHT, an oil solubleanxioxiaanx.

Unforxunaxely, none of xhese orior axxempxs xo emulaxe r.2 sxabilixy ci xherexinoic acid conxaming comoosmons hâve Deen successful for rexinoids 010520 - 7 - other than retinoïc scia sna in eacn case resuii in substantial andunacceDtable cnemicai instaoility of The retinoi, retinal or retinoïc estersemployée! therem. Accorotnaiy, there îs a neea for a composition in whichsuch non-retinoïc acid retinoids may be proviaea in a chemically stable 5 form.

Jonas C.T. Wang, et.ai in pending application USSN 719,754 filledNovemoer 15, 1993 aisciose the stabilization of retinol in a water-in-oiiémulsion, in wnicn retinol was dispersea and protected in oil phase. 10 However, oii-in-water emuisions are mucn more preferred than water-in-oiiémulsions Dasea on me cosmetic performance. This is due to the Tact thatoil-in-water émulsions, in générât, are less occlusive, less greasy,compatible witn maKe-uo ana easy to be removed from the skin leading toa more aesthetically pieasing feel. in addition, oil-in-water formulations are 15 less costly considering the ingrédient composition and the manufacturingprocess.

It is therefore aesiraole to aeveiop efficacious and also cosmeticaliy élégantskin care products containing retinoids including retinoïc acid, retinal, 20 retinol. and retinyi esters to ennance the oroaa usage of retinol for skintreatment.

It is another object of this invention to provide skin care compositionscontaining retinoids wnich hâve acceptable shelf-lives. 25

It is yet another ooiect of this invention to provide a skin care comoositioncontaining retinoias. which permits the controlled release of activeingrédients to the SKin over time. 010520 - 8 -

Anotner object of xhis invention is xo proviae a mexnoa for making a stableskin care composition contamina retinoios. which retains iis activity overa long lime oeriod. 5 II is yet another objecx of xhis invention xo provicie sxin care composixionswhich are relaxiveiy non-irritating and yex efficacious in delivering activeingrédient xo xhe skin.

Other objecxs of this invention will become clear througboutthe Description 10 proviaed. below.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a graph depicting the effect of pH on stability of retinol in non- 15 phosphoipid liposome formulations.

Ftgure 2 is a graph aepicting xhe amount of retinol released from theformulation of Example 8C comoarea with xhat of a water-in-oiiformulation. 20

Figure 3 is a graph ceptcting xne amount of active ingrédient whichpermeates xne eoidermts ana dermis from the formulations of Exemples 8Cand 6 in comparison with xhat of a water-in-oii formulation. 25 Figure A is a grapn aepicting xhe sensory perceptions of certainformulations of xhis invention in comparison with other skin carecompositions. 010520 - 9 -

5UMMAPY ΟΓ THE INVENTION ln accordance with The présent invention, it has now been aiscovered that.unexpectedly, certain retinoias may be successfuily stabiiizea against 5 Chemical dégradation by incorporating them into non-phospholipidliposomes using a specifically definea stabilizing System and process. Theretinoids which can be stabiiizea against Chemical dégradation inaccordance with the principles of the présent invention inctude retinol(Vitamin A alcoholl , retinat (Vitamin A aidehyael, retinyt acetate, retinyi 10 palmitate ano mixtures thereof.

As used herem. the "Chemical stabiiity" or "stability" of a retinoid isdefined in terms of the percentage of the specified retinoid which isretained in its original Chemical form after the composition has been stored 15 for a specified period of time et a specified température. Thus, if theoriginal concentration of all-trans retinol in an absolute éthanol solutionwere 0.20% by weight and, after two (2) weeks storage at roomtempérature (21 *C — 1*C1 , the concentration of all-trans retinol were0.18% by weignt, tnen the original solution of all-trans retinol in absolute 20 éthanol would be cnaractenzea as naving a Chemical stability of retinol of90% after two weeks storage at room température, ln the same fashion,if an non-phospholipid liposome formulation comprising all-trans retinol hadan initiai concentration of 0.30% by weight and after storage for 13 weeksat 50 *C had a concentration of atl trans-retinol of 0.24% by weight, then 25 the original émulsion would be characterized as havmg a Chemical stabilityof retinol of 80% after 13 weeks storage at 50"C.

For the spécifie retinoids wnich are tne subject of this invention the non-phospnoliDid liDosome form. in comoination with the sélection of a stability 010520 - 10 -

System from those described herein, will produce compositions having a

Chemical stabiiitv of 80% arter 13 weeks' storage at 5O*C. The présent invention also provides a System for stabilizing retinoids. unexpectedly, without the presence of a water-soluble antioxidant. 5

Accordingly there is provided. in accordance with the teachings of theprésent invention, a skin care composition comprising a non-phospholipidliposome and a retinoid selected from the group consisting of retinoi.retinal, retinyi acetate. retinyi palmitate and mixtures thereof, said 10 composition furtner comprising a stabilizing System selected from thegroup consisting of: a) an oii-soluble antioxidant; and bl a chelating agent and at least one oil-soluble antioxidant; 15 wherein said composition has a pH from at least about 5 to about 10, saidcomposition retaining at least about 80% of said retinoids after 13 weeksstorage at 50* C. 20 It was also discovereo unexpectedly mat the compositions of this inventioncan be endowea with material changes resulting in a controlled-releasa ofactive agent from the liposome carrier. The compositions of this inventionmay also be moderated in order ta ennance or diminish pénétration of theactive ingrédient into the skin. 25

Surprisingly, comoositions of the présent invention contaving a reiativelyhigh level of surfactants (e.g., > 8%1 exhibit irritation at the same level asthat experiencea by individuals exposea to a water-in-on cruam ce: taining2% surfactant. 010520 - 1 1

DETAILED DESCRIPTION OF THE INVENTION

As aescribed above. the composition of the invention is in The form of aparticular type of lioosome. nameiy, a non-pnospnolioid liposome. 5

Most commercial skin care compositions such as the ones containingreiinoic acid are oil-in-water émulsion Systems. In such oil-in-waterémulsion Systems, certain retinoid compounas, in particular, retinol, retinal,and. the retinyl esters teno to.be cnemically unstable. î.e. they dégradé, 10 either by way of oxiaation or isomerization. and are, therefore, notavailable to perform m their desirea manner. While this is not clearlyunderstood. it is believed that this dégradation occurs as a resuit of therapid diffusion of oxygen through the externat water phase to the internaioii phase containing the retinoid. The oxygen is readily available to dégradé 15 the retinoid. Because the diffusion of oxygen is greater in a water phasethan an oil phase, an oil-in-water System is more prône to suchdégradation.

The compositions of the présent invention overcome tnese difficuities and 20 instead, provide a non-phosoholipia -liposome composition containing atieast one retinoid comoound wnerein both the physical stability of theliposome and the cnemical stability of the active ingrédients are maintainedat high levels. 25 Liposomes are spnerical, self-closea structures composed of curved lipid bilayers wnich entrap part of the solvent, in whicn me. ireeiy float, into their interior. They may consist of one or several concentric membranes.

Liposomes are maoe preaominantiy from ampniphiies. a spécial class of surface active moiecuies. wnicn are cnaracterized by r.oving a hydrophilic 010520 -12- and a hydroonooic group on me same moiecuie. These molécules are notsoluble in water; and. ramer man forming solutions. they form colloïdaldispersions. 5 Until recently, liposome tecnnology has been concerned mostly withvesicles composed of phospholioia. Phospnolipias are labile and expensiveto purify or synthesize. In addition, manufacture of phospholipid liposomeis difficult and costly to scale up. For these reasons there has beenincreasing interest in non-pnospnolipid liposomes. Certain double-chain 10 synthetic surfactants with non-ionic polar heaas and single-chainsurfactants in mixture witn cnolesterol can form non-iomc liposome. Theyhâve increased cr.emical staoility over natural phospholipid and are easy tomake in large, commercial quantities. 15 Because of their solubility propèrties the structure of these aggregatesinvoives the ordering of lipid molécules: the hydrophilic part tends to be incontact with water while me hydroonobic hydrocarbon chains preferto behidden from water m the mterior of the structures. One of the mostfrequently encountereo aggregate structures is a lipid bilayer. On the 20 surface of either side are polar heaas which shield non-polar taiis in theinterior of the lameila from water. At higher lipid concentrations thesebilayers from lamellar crystalline phases wnere two-dimensionai planar lipidbilayers alternate with water layers. Upon dilution, these lipid biiayers formliposomes. These liposomes can entrap nyarophilic materials in the aqueous 25 compartiments and lipophilie materials in the bilayers. Molécules that areentrappea in the bilayers are sometimes referred to as "cargo molécules".Lipophilie entrapment is severety limited by the ability of the bilayer toentrap the cargo moiecuie. 010520 - 13 -

Liposomes can De large or small ana may be comoosea of from one xoseveral hunarea concenxric bilayers. Wixh respecr το xhe size and xhenumber of lameilae, xrxey are disxinguisnea as large multilameilar vesicles(MLV's) and large and small umlamellar vesicles (LUV's and SUV's 5 respecxively). Mosx of xhe researcn το daxe hâve cenxerea on abovemenxioned xype of vesicles.

Recenxly, Donald F.H Wallacn (U.S. Paxenx number 4,91 1,228) describedanoxher xype of lipid vesicles, xhe pauciiameilar lipid vesicles (PLV). The 10 invenxion aescribes xhe PLV's consisxing of 2 Xo 8 peripneral bilayersurrounaina a large unsxrucxured cenxral cavixy wnicn can oe filled wnollyor in parx wixh an apoiar oii or wax. The mulxiple lipid bilayer and an apolarcore of xhe PLV'S provide PLV'S wixh xhe capacixy xo xransporx a greaxeramounx of lipopnilic maxerials. 1 ci u

Sxill furxher, U.S. 5,147,723 xo Donald F. H. Wallacn describes xhe non-phospnolipid surfacxanxs wnich can form pauciiameilar lipid vesicles. Thesurfacxanx can be selecxeo from a grouo consisxing of poiyoxyexhylenefaxxy esxers navmg xhe formula R,-COO(C;H4O)nH wnere R, is a radical of 20 lauric. myrisxic. cexyl, sxearic or oleic acid ana n is an inxeger from 2 Xo 10;polvoxvexhytene faxxy acid exhers, having The formulawhere R;is a radical of lauric, myrisxic, or cexyl acids, single or doubleunsxauraxed ocxaaecyt acids, or double unsaxuraxed eicodienic acids and mis an inxeger from 2 xo 4; poiyoxyexhylene (20) sorbixan mono- or xrioleaxe; 25 and poiyoxyexhylene glyceryl monosxearaxe wixh from 1 xo 10poiyoxyexhylene grouos. AU xnese sxrucxures hâve many mxeresxing physix_ cud cnemicalprooerxies, sucn as osmoxic acxivixy, permeaoilixy of xneir memcranes xo 010520 - 1 4 - different solutés. solubiiizing power, interaction with various nyarophobicand hydrophilic solutés, or aggregation oenavior which can dépend ontempérature. Chemical composition and surface characteristics of Themembrane, and oresence of various agents. 5

The oil-soiuble antioxidants which are useful in the compositionsof the présent invention include butylated hydroxytoluene (BHT),ascorbyl palmitate, butylated hydroxyanisole (BHA), a-tocopherol, phenyl-a-naphthylamine, hyaroqumone, propyl gallate, nordihyaroguiaretic acid, 10 and mixtures thereof as well as any other known oil-solubleantioxidant comoatibie with the other comoonents of the compositions.

The oil-soluble antioxidants useful in the compositions of this inventionshould be utilized in. a stabiiizing effective arnount and may range 1 c

I «J 20 vvciyi11 the total composition, preferaDly from about O.Ol to about 1%. Thearnount of antioxidants utilizea in the compositions of the présentinvention is depenaent in part on tne spécifie antioxidants seiected, thearnount of and soecific retinoid being protectea and the Processingconditions. For examole, a retinol formulation should include BHT in thearnount of from about 0.01% to about 1% bv weiqht. A retinalformulation should incluae BHT in the arnount of from about 0.01% toabout 1% by weight. 25 In certain asoects of this invention, the comDositions may inciudea chelating agent during the scale-up process to iv-'iumize meta! ioncontamination. The retinoid compounas of this invention are sensitiveto métal ions and in particuiar to bi- and tri-vaiem. cations andin certain instances, appear cegraae raoialy in their presence. The WO 96/31194 PCT/US96/04557 010520 • 15 - chelating agent forms a comptex with ;he métal ions therebyinactivating them ana preventina tnem from affecting the retinoidcomoounas. Chelating agents wnicn are useful in tne compositions of theprésent invention mcluae ethyleneatamme tetraacetic acid (EDTA) and 5 dérivatives and salts tnereof. dihyaroxyethyl glycine, citric acid, tartaricacid, and mixtures tnereot. The cnelating agents snould be utilized in astabiiizing effective amount and may range from about 0.01 to about 2%based on the weight of the total composition, preferably from about 0.05to about 1 %. 10

The retinoia comoounas wnicn are useful in tne compositions of theprésent invention consist of Vitamin A aicohol (retinol) , Vitamin Aaldehyoe (retinal) ana Vitamin A esters (retinyl acetate and retinylpalmitate). These retinoids are utilizea in the compositions of the présent 15 invention in a therapeuticaiiy effective amount that may range from about0.001 to about 5% by weight of the total compositions, preferably fromabout 0.001 to about 1 %.

The sxin care comoositions of the présent invention comprising a non- 20 phospnolipio can be in tne format of cream or lotion formulations, asdesired. by varying tne relative puantities of the lipid and water phases ofthe émulsion. The pH of the compositions snould be in the range of fromat least about 5 to aoout 9. ana preferaoly from about 5 to about 7. 25 Any of the many formulations or compositions of the cream or lotion type currently utilizea in skin care préparations can be empioyed pruviced that it is in a non-onosonoliDid ana is cnemically compatible with the retinoid comoounas. The ratio of the oii phase of the non-pnospnolipid lioosome to the water pnase can oe from aoout 5:25 to aoout 40:60. The actual ratio 010520 of The two phases wiil depena on tne aesired final proauct.

The advanTages of The invention ana spécifie emoodimenTs or The skin carecomposiTions preparea in accordance with The presenT invention, as weilas comparisons with composiTions ourside The scope of The ciaimedinvendon are illustrated by The foilowing examples. Ιΐ will be undersxood,however, Thar The invendon is ηοτ confinea το The spécifie limitations setforth in The individual examples, buî raTher το The scope of The appendeddaims. COMPARISON EXAMPLE 1

Three oii-in-water émulsions of rexinol (Vitamm A alcohoi) were preparedhaving The % w/w composiTions set forth in Table 1. In Table 1, Theappellaiion "o/w" indicaTes an σΐΐτίη-waxer composition. These émulsionswere prepared according το The foilowing procedure. The ingrédientsshown under tne neaaing "Aqueous Phase Ingrédients" were added to afirst gtass container eauippea with a stainless steei sttrrer and heated withstirring to 75 " C-35 ‘ C unoer an argon gas blanket. The ingrédients shownunder the neaaing "üil Phase Ingrédients" were added to a second glass

Cûûtaiûêr eguippeu wixri a stainiess steei stirrer and heated with sdrring toabout from 85*C To 9O'C under an argon gas blankei. The ingrédientsshown under The heading "Retinoid Mixxure" were added το a third glasscontainer equippea with a stainless Steel stirrer and stirred at roomtempérature under a blanxet of argon gas. Stirring was continued in ailinstances until uniformity was achievea. The Aqueous P^aze ingrédientsat 75"C-35 "C were then added to tne Oïl Phase Ingrédients. Durtng thisaddition step, The Oil Phase Ingrédients were maintamc-d a; 35'3-30*C with stirring unoer an argon gas blanket. The mixture of ;r.e Aqueous 010520 - 17 -

Phase Ingrédients and Oil Phase ingrédients was stirrea. a: a températurein the range of 90 " C ana unaerthe argon gas blanKet until a uniform oil-in-water émulsion was obtaineo. After the resulting émulsion was cooled toabout 5O'C-53’C, the Retinoid Mixture was added with stirring. The 5 émulsion was blanketed under argon gas and the température wasmamtainea at about 5O*C-53'C during the addition of the RetinoidMixture. After the addition of the Retinoid Mixture was completed, theémulsion was graaually cooled. with sttrring and under an argon blanket,to room température (approximately 21 "Ci. The finisnea émulsion was 10 then transferreo unoer argon gas bianxeting to btind eno aluminum tubes(2 ounce sizel wnicn were oromptly crimoeo and tightly capped. Theclosed tubes were tnen set astde for détermination of retmol stability afterstorage for various time periods at various températures. Retinol dégradésunder the influence of UV light. Accordingly, care must be taken at ail 15 stages of the émulsion préparation process to prctect the retino! irontexposure to UV light. This can be accompiished by turning out the lightsin the Processing area cr by conductmg the various handling andProcessing steos under yeilow light. 20 TABLE 1

Sarnpla Désignation A B C

Water. q.s 100% — -- - J Propyiene Glvcol 4.00 4.00 4.00 [| Carbomer 234 0.50 0.50 0.50 | 010520 . 18 -

Qi) Inargdienxs 10 15 20

Mixture A 8.75 8.75 | 8.75 Il Polvsorbato 61 iTween 61) 1.20 1.20 1.25 Il Dlmoxhicone 1.00 | 1.00 1 1.00 I Il Sorbitan Stéarate 0.80 0.80 0.80 Retinoid Mixture T i Accorbic Acid 0.00 0.00 0.10 EDTA 0.00 0.10 0.10 Benrvl Alcohol 0.30 0.30 0.30 50% NaOH. c.s. cH a.7 — — — Methyl Paranen 0.15 0.15 0.15 | Praoyl Paranen 0.10 0.10 0.10 J" - ' -.1.-" - - Butvl Paranen Û.Û5 0.05 | 0.05 BHT 0.02 0.02 0.02 Fragrance 0.25 0.25 0.25 | Rexinoi (ail transi. USP 1.00 0.86 0.86 I Emulsion Typa o/w o/w | o/w

In xhû naovc Table 1. Uie ingrédient in tne Uil Phase fngrQaianxs dcaignntnda> Mixture A cünsisxea ûf I.SO g mvnstyi mynsxaxe: 1.25 g oleic acid(Emoraol 223); 1,25g giycervl stéarate (Emerest 2400); 1.25 g sxoaric acid(Emercol 1321; 1.00 a isocropyl palmlxaie: 1.00 staaroxytnmetnylsiiana 5 (Dow Corning 530 Wexl; 0.50 synxnetic beaswax: O.5Ü g sxearvi alcohol;and 0.50 g cetvi alconol, Mixture A was creoared by mixlng ΙΠΘ indicatadingreaients in a atacs container, sxirring witn beat uni·’. ·ι'·Ι mgreaients vzera 010520 - 19 - liquefied ano umformly mixea; pouring me uaueried mixture into shallowcontainers; and allowmg the mixture to cooi to ambtent temoerature.

Concentrations or all-trans retmol in oil-in-water samples A, B and C in5 Table 1 were determined after storage for various time periods at varioustempératures. Concentrations of retinol and other retinoids such as retinal (vitamin A aldéhyde), retinyl acetate and retinyl palmitate can bedetermined by any suitable analytical procedure. As reported herein, wedetermined retinoid concentrations by a stability indicating high TO performance liauid chromatography IHPLC) procedure in which thechromatograpn was eauippea with a reversed phase 5 micron C-3 column(25 cm in length x 4.6 mm in diameter) and a UV detector at 340nm. Thesample to be analyzea was dilutea with a solution of 50% by weightmethanol and 50% by weight ethyl acetate to a concentration of 18 15 micrograms/ml and the retinoi!± was detected at 340nm. The gradientmobile phase consisted of an organic portion composed of 5 percenttetrahydrofuran in acetonitrile and an aqueous portion consisting of 0.05Nammonium acetate. The solvent program has an initial composition of70% orgamc/30% aaueous which increases lineariy to 80% organic/20% 20 aqueous at 13 minutes, then again increases lineariy to 100% organic at15 minutes, where it stays until 19 minutes. After injecting 15microiiters of samole solution into the chromatograph, the analyticalconditions were run at a flow rate of 2 ml/min and thermostaticallyregulated at 40"C. The rétention time of retinol (Vitamin A alcohol) 25 is about 6.4 minutes. The rétention times of retinal (Vitamin Aaldehyae), retinyl acetate, and retinyl palmitate are uocut 7.5 mins.10.1 mins. and 13.7 mins. , respectiveiy. The HPLC results were 010520 - 20 - founa to be reproaucible to better tnan a 3% range of standarddéviation.

The results were as follows: 5

For Samnle A: After twenty-six (26) weeks aging ai roomtempérature (2VC - 10*0. only 39% of the original amount of all-trans retinol was found in the émulsion. After twenty-six (26) weeksaging at 40’C, only three percent (3%) of the original amount of 10 all-trans retinoi was founa in the emulsion.lt is concluded that anoil-in-water émulsion comprising retinol ana butylatedhyoroxytoluene iBHT). an oil-soluble antioxidant. does not hâve acceptableretinol Chemical stability. 15 For Sample B: After thirteen (13) weeks aging at room température,87.% of the original amount of all-trans retinol was found in theémulsion. After thirteen (13) weeks aging at 40*C, just four percent(4%) of the original amount of ail-trans retinol was found in theémulsion. After tnirteen ( 1 3) weexs aging at 50*C, no amount of all- 20 trans-retinoïc acid was detected in Sampie B. After twenty-six (26) weeks aging at room température, fifty-seven percent (57.%) of the original amount of all-trans retinol was found in the émulsion.

It is concluded that Chemical stability of all-trans retinol in an oil-in-water 010520 - 21 - émulsion comprising all-trans retinol. EHT ano disoaium EDTA (a chelatingagent) does not hâve acceotaole cnemicai staoility.

For Sample C: A fier thirteen (13] weeks aging ai room Température, sixTy5 percent (60%) of The initial amount of all-trans retinol was found in Theémulsion, while after tmrteen (13) weeks aging at 40*C, twenty-threepercent (23%) all-trans retinol was detected. No amount of ail trans-retinol was detectea aner Sample C was stored for thirteen (13) weeks at 5O*C. 10

After twenty-six 126) weexs aging at room température, forty-two percent(42%) of the initial amount of all-trans retinol was found in Sample C; afterfifty-two (52) weeks aging at room température, thiny-one percent (31 %)of the initiai concentration of all-trans retinol remained in Sample C. 15

From the foregoing aging results, it is concluded that the Chemical stabilityof all-trans retinol in an oii-in-water émulsion comprising all-trans retinol,an oii-soluble antioxidant (BHT) , a water-solubie antioxidant (ascorbicacid)and a chelating agent (ethyleneaiaminetetraacetic acid) is chemicaily 20 unacceptable. COMPARISON EXAMPLE 2 A phospnolipid liposomal formulation of retinol (Vitamin A alcohol) was25 prepared having the % w/w composition set forth in Table 2 at CILAG AG.

After four weexs aging at 50* C, oniy 64.37% of the original amount ofretinol was founo in t'ne formulation wnich does not meet the stability criteria. 010520 - 22 - 10 15

Table 2:

ÇQMPARISON EXAMPLE 3 20 A phospnolipid liposomal formulation of rexinol (Vixamin A alcohol) wasprepared by BioZone according xo U.S Paxenxs Nos. 4,485.054- and4,751,238. Afxer four weeks aging ax 50'C. only 64.61 % of The originalamounx of 010520 - 23 - rexinol was founa in ine formulaxion wnicn does nox meex xhe sxabilixycrixeria. CQMPARISON EXAMPLE 4 5 A non-phospnolipid liposomal formulaxion of rexinol (Vixamin A alcohol)was prepared by Micro Vesicuiar Sysxems, Inc. of New Jersey accordingxo U.S. Paxenx No. 4,911,928. Afxer 12 weeks aging ax 50"C, 40‘C androom xemperaxure only 53.1% , 79.4% and 89.3% respecxively of The 10 original amounx of rexinol was found in xhe formulaxion whicb does noxmeex xbe sxaoilixy crixeria.

The resulxs ciearly demonsxraxed xbax rexinol was more sxable in boxhphospholipid and non-phosonolipid liposome xype formulaxion xhan in the Q ii-i ΓΊ- vV3ΐ£ Γ £ îTi U ! 3 IG u .

AiÎuOugft feüuui wdb pdikïdiΟ hÎabiiized by formulaxion xype change from o/w xo non-phospnolipid liposome, xhe shelf-life ax ambienx xemperaxure was only 12 weeks. xhax is sxill chemicallyunaccepxable. 20 EXAMPLE 5 and 6:

Rexinol was encaosulaxea in xhe non-phosonolipid liposome formulationwith xhe following comoosixion in accordance wixh xhe procedure set forthbelow. The pH of xhe final formulaxion was aboux 5.6. 25 010520 24 -

Examoie 5 Example 6

Oil Phase: %W/W %WZW Caprylic Caoric Triglycéride 10.00% 10.00% 5 Cholesxerol 5.55% 6.80% Glyceryl Disxearaxe 4.33% 5.30% Stearyl Alconol 3.90% 4.75% Stearexh-10 3.28% 4.00% Glyceryl Monosxearaxe 2.08% 2.55% 10 Polysoroaxe 80 1.00% 1.05% Tocoonerol Acexaxe 0.15% 0.34% 15 Buxylaxeo Hyoroxy Toluene Waxer Phase: 0.05% 0.05% Deiomzed Waxer 68.14% 83.90% Citric Acid 0.13% 0.12% Sodium Hydroxiae 0.03% 0.07% Mexhyl Paracen 0.20% 0.20% 20 Propyl Paracen 0.03% 0.03%

Active Ingredieni:

Rexinot (45% W/W) 1.12% 0.34%

Under a yellow iiahx ana inside an argon blanxex. wnicn served xo oiminishXhe amounx of oxygen in me rormulaxion. xhe oil phase comoonenxs weremixed xogexner ana heaxea xo a xemoeraxure ox aboux 55°C. The waxer 010520 - 25 - phase components were xhen mixed xogexner and heaxea xo a xemperaxureof aboux 85°C and xhen cooled xo 6O°C before phasina. xhe waxer phasewas xhen purgea wixh argon xo remove oxygen. A Novosome liposomemaker, commercially avaiiable from Micro Vesicular Sysxems of New Jersey 5 and described in U.S Paxenx Numoer A,895,4521 was equilibraxed xo axemperaxure of aboux 6O°C by pumDing xhe waxer phase xhrough xheequipmenx. 1.13% of rexinol (45% acxive was added xo xhe oil phase.Boxh xhe waxer phase and xhe oii phase were pumped xhrough xheNovosome maker and xhe producx was coilecxed in a sxainless sxeei 10 jackexed kexxie imanufacxured by frymai wnic'n had been blankexed wixhargon. The Kexxie was eauiopea wixh a scraoer-sxirrer. xooxhed coiloid mill,dissoiver and vacuum oeaeraxton sysxem. The producx was vacuumedunxil Xhe pressure in xhe kexxie dropped xo 0.8 mBar. The producxs weredispensed inxo proper packages under xhe argon blankex. Proper packages 15 roay be seiecxed from aluminunrxubes, cans, pumps and/or sprays.

The sxabilixy resulxs snown in Table 3 ana 4 cleariy illusxraxe xhax rexinol ismore sxable in exampie 5 and 6 xhan in exampie 4 and also meer xhesxabilixy crixena 80% remaimna ax 50°C afxer 13 weeks of sxorage. Thereis no sigmficanx différence on xne sxaoiiixy of rextnol as ixs concenxraxion ischanged from 0.153% xo 0.504%. 20 010520 - 26 - 10 15

Table 3. Retinol Stabilises in Example 5 at Various Températures. %

Retinol % Initial

pH

Initial 0.5059 100 5.53 3 weeks

50*C 8 weexs

40’C

5Q‘C 0.44-98 0.4704 0.4636 88.91 92.98 91.64 5.32 5.36 5.32 1 «U 1»L.p,UO 30'C 0.4884 97.0 5.37 40 ’C 0.4566 90.69 5.33 50'C 0.4355 86.5 5.22 26 weeks 1 ~ . 1 JU c U.4/34- U J.a / 5.4o i 40*C 0.4454 88.04 5.28 20 010520 - 27 -

Table 4. Reîinol Stabilities in Example G at Various Températures. % Retinol % Initiai pH I Initial 0.153 100 5.64 5 4 weeks 40 'C 0.143 93.46 5.65 5O‘C 0.142 92.81 5.61 10

8 weeks40 "C

5O‘C 0.1275 0.1355 89.87 88.56 5.60 5.56 13 weeks 40'C 50"C 04 335 0.1275 87 = 25 83.33 5.55 1 5.55 20 weeks 1 30"C 0.1375 89.87 5.69 40'C 0.1295 84.64 5.62 50'C 0.1220 79.74 5.56 » iiii 20 28 - 010520 EXAMPLE 7: Το îurther improve the formulations of this invention, a formulation with a 5 water soluble antioxidant ascoroïc acid ana a cnelating agent disodium EDTAwas préparée in dark room without an Argon blanket set forth below..

The data summarizeo in Table 5 suggest that the stabiiity of retinoi inExample 7 was comoaraole to Example 5 wnicn was prepared without 10 ascorbic acid ano disooium EDTA but under yellow light and Argon blanket.The results also suggest tnat tne addition of ascoroïc acid/disooium EDTAmignt ennance tne cnemicai stabiiity of retinoi in Novasome’ liposomeswithout the need for using an argon blanket. Thus. water-solubleantioxidants may also be utilizea in the compositions of this invention such 15 as ascorbic acid, sodium sulfite,· sodium metabisulfite, sodium bisulfite,sodium thiosulfite, sodium formaldéhyde sulfoxylate. isoascorbic acid,thiogtycerol, thiosoroitol. thiourea. thioglycoiic acid, cysteine hydrochloride.1-4-diazobicycio-i2.2.2)octane ano mixtures thereof. 010520 - 29 % w/w

Glycerai Distearate 2.80%

Cholesierol 1.00% POE-10 Stearyl Alcohol 1.40% 5 Stearyl Alcohol and Ceteareth-20 1.50%

Cetearyl Alconol and Ceteareth-20 1.00%

Cetyl Acetate ano Acetylatea Lanolin Alconol 1.00%

Dow Corning 344· Fluid Silicone Oil 5.00%

Tocopherol 0.15% 10 Butytated Hyaroxv Toluene 0.05%

Glycérine 10.00%

Methyl Paraoen 0.20%

Propyl Paraoen 0.03%

Sodium Chloride 0.10% 15 Polysorbate 80 0.75%

Ascorbic Acid 0.10%

Disodium EDTA 0.10%

Butylène Glycoi 10.00%i

Cl 2-1 5 Alkyl Benzoate 6.70% 20 Retinol (45% W/W) 1.12% 10 mM Citnc Acid Buffer 57.00% 010520 - 30 -

Table 5. Retinol Stability in Exampie 7. %RETlNOL | %INITIAL j pH INITIAL 0.491 100 5.55 5O'C 3 weeks 0.459 93.48 5.55 7 weeks 0.449 91.45 5.47 12 weeks 0.407 82.89 5.50 • 31 - 010520 EXAMPLE 8: Το improve the cosmetic elegance of The reiinol formula, the non-5 phospholiDÎd liposomal formulation of retinol (Example 8A ) was physicallymixed with various proportions of 30% w/w cyclometPicone loaded non-pPospholipid liposome (ExamDle 8BÎ. The stabiiity results are summarized in

Tables 6 througn 8. 10 010520 32 -

Exampie 8A

% W/W

Water 54.95% Caprylic Capric Triglycéride 6.00% 5 Glycerin 96% 10.00% Butylène Glyccl 10.00% Cholestérol 3.95% Glyceryl Distearate 3.15% Stearyl Alconol 2.85% 10 Stearetn-10 2.50% Tocopnerol Acetate 2.00% Glyceryl Monostearate 1.58% Poiysorbate 80 1.00% Retinol (45% W/W) 0.75% 15 Citric Acid 0.50% Sodium Hydroxide 0.25% Methyl Paraoen 0.20% Disooium EDTA 0.10% Butylated Hyaroxy Toluene 0.10% 20 Ascorbic Acid 0.10% Propyl Paraoen 0.03% 010520 - 33 -

Examnte 8B (30% w/w Cyclomexhicone Loaded Non-phospholipid Liposome)

% W/W

Waxer 5 Cyclomexbicone

Glyceryl DisxearaxeGlycerin 96% 1,3-Buxylene GlycoiStearexh-10 10 Cholesxeroi

Sodium CitraxePolysorbaxe 80Citric AcidMethyl Paraoen 15 Tocopheroi AcexateAscorbic AcidDisodium 6DTAPropyl Paraoen 40.10% 30.00% 7.95% 7.00% 7.00% 3.98% 1.97% 0.95% 0.52% 0.16%0.14%0.11 % 0.07% 0.07% 0.02% 010520 • 34 -

Table 6. Exampie 8C 150% Example 8A St 50% Example 8B) °/a Rexinol % lnixial PH 5 lnixial | 0.1735 100 | 5.56 | 4 weeks 5.54 40'C 0.1705 98.27 5.54 5O‘C 0.1690 97.41 I 8 weeKs 10 40'C 0.1 690 97.41 5.53 5O'C 0.1 670 96.25 5.56 1 3 weeks r\ rrr\ ne co c c n | O kj VJ. 1 uuu 23 .J . U U J.J2. I 40*C 0.1650 95.10 5.58 15 50*C 0.1580 91.07 5.57 | 20 weeks 30'C 0.1715 98.84 5.61 40'C 0.1655 95.39 5.60 50' C j Ο7Τ55Ό j 89.34 5.60 20 010520 - 35

Table 7. Exampie 8D (60% Example 8A and 40% Example 8B) % Rerinol % Initial | PH j 5 Inixiai J 0.1900 100 5.62 4- weeks 40*C 0.1869 98.37 5.57 5O'C 0.1831 96.37 | 5.57 8 weeks 10 3O'C 0.1 896 99.77 5.57 40*C 0.1858 97.78 5.64 5O*C 0.1816 95.59 5.62 I 13 weeks I 3O*C 0.1867 98.26 5.65 15 40 "C 0.1809 95.21 5.64 1 5°'c j 0.1750 92.11 5.64 1 010520 - 35 -

Table 8. Examnie 8E (70% ExamDie 8A and 20% Example SB) % Rexinoi % Initiai P H j 5 L Initial 0.2235 100 | 5.64 4 weeKS 40*C 0.2201 98.50 5.64 50’C 0.2151 96.70 5.62 j 8 weeKS 10 30 *C 0.2213 99.04 5.62 40*C 0.2181 97.53 5.67 mm n ?nn qt; ς nn I 13 weeks ! : 30*C 0.2205 98.65 5.66 15 40*C 0.2146 96.02 5.66 50 "C 1 0.2075 92.84 5.67

The data suggesx xnax xnere are no significanx cnanges in sxabilixy of a non-20 phospnoiioid liposomal rextnoi formulation wnen ix is mixea wixh 30-50% of 30%cyclomexnicone loaaea non-pnasonoiioip liposome formulation xo render cosmexicelegance xo xne primarv formula. This was of greax sigr.iricance because xhe elegance cnaracxerisxic :s of ororounc importance for cust".·".:: compliance. 010520 - 37 -

Examole 9:

The Effect of oH on Stability of Retinol in a Non-Phospholipjd Liposom

Formulation. 5

To aefine the pH range most useful for retmoi-containing compositions ofthis invention, the pH of Example 8D was adjusted to pH's ranging from 3.6to 7.4 with dilute hydrochloric acid or dilute sodium hydroxide. The sampteswere stored at different températures (4*C. 30'C, 4O*C and 5O*C). 10 Samoles were taken oerioatcally for both physical ano Chemical évaluation.

The results in Figure 1 cieariy showea that optimal pK range for retinolcream at 50* C was aoove 5 . EXAMPLE 9: 15

In-virro Bîoavailability of Liposome Formulations

Skin bioavaiiabilitv, wnich is defineo by the avaiiability of drug released fromthe formulation as weil as the extern of skin pénétration after application, 20 usually serves as a good indicator for drug efficacy. The in-virrabioavailability of retinol was determined by standard in-vitro release and skinpénétration tests using FRANZ diffusion cells. For the release study, aweighea amount of cream was applied on a synthetic membrane mountedon each of the FRANZ diffusion cells. The synthetic membrane functioned 25 as a cream supporter and did not cause significant résistance to the drug release. Sampies were taken from the receptor chamoer at predetermined intervais. The amount of retinol released from the formulation to the receptor solution was determined by Hign Pressure Liau.d Chromatography 010520 - 38 - (HPLC1. The resuits in Figure 2 cleariy showed Thaï The reiease of retiraifrom non-phosDholiDia lioosome Exampie 8C is mucn faster than Thaï fromRoC s.a (water-in-oil, 0.1 5% retinoi) formulation, a stable retinol water-in-oilcream produced accoraing to Wang, et.al. pending patent on the market. 5 At the end of 7 hours. approximatelY 10% and 5% of retinol were releasedfrom non-phosphoiioid liposome and RoC s.a respectiveiy.

The in-vicro skin pénétration studv was conducted usine a simiiar protocol asthe reiease studv except that human cadaver skin was used instead of a 10 synthetic membrane. At the end of 48 hrs of experiment. the skin surface wasthorougnlv cleaned and the amount of retinoi penetrated was analvzed bvHPLC. It was found that non-phosp'noiipid liposome formulations cnn beengineered to provide a wide range of bioavailabilitv. For exampie, Exampie8C (which is a 50:50 mixture of 0.34% retinoi loaded non-phosphoiipid 15 liposome and 30% cyclomethicone loaded non-phospnolipid) yieidcd muchhigher retinoi skin pénétration compared to the RoC s.a proauct. On the otherhand. Exampie 6 (0.15 % reunol loaded non-pnospnolipid) provided simiiar skinpénétration to RoC s.a product (Figure 3). 20 EX AMPLE 10:

Dermal Irritation Test:

Retinol-containing non-phospnolipid liposome formulations were evaluated for25 dermal irritation and were also compared with a watcr-in-oil retinoi formulation. - 33 010520 Sçope and Procedure

The modified Draize Rabbit Primary Dermai Irritation Tesi is a procedure forpredicting the abilitv of lest articles to elicit inflammatorv responses upon 5 proionged occiuded contact with intact and intentionailv-abraded New Zeaiandwhite rabbit skin. Following a timed exposure period. the test articles areremoved and the application sites were evaluated. From this data, a PrimaryDermai Irritation (PDI) Index is caiculated for each test article and aclassification is assigned. 10

The test article was applied with 0.25-0.30g to 25mm Hilltop Chamberscontaining non-woven Webrii pads. The chambers were then applied to theappropriate test sites and held in place with strips of Dermicel tape. The trunkof the animais were wrapped to occiude the sites and to keep the test articles 15 in place. After the 4 hours of exposure, the test articles were removed andrcadings were taken after one hottr in order to allow the skin to equilibratc.After the équilibration period, the sites were examined and then againreexamined after 72 hours of application for signs of dermai irritation and weregraded usina a scaie as follows: 20 PDI Index 0.0 0.1 - 2.0 2.1 - 5.0 5.1 - 3.0 ÇlassificaVQp

Non-irritantMîld IrritantModerate irritantScvere Irritant 25 - 40 - 010520

Table 9: PDI Classification J Formulation 0.9 j Mild irritant 6(0.15% Retinol) Study I Placebo (négative 0.7 Mild Irritant control) w/o-I (0.15% 1.7 Mild Irritant 1 Retinol 0.5 Mild Irritant i mixuu (ΐη-^αιιγ^ control)

Study Π Formulation 8C (0.15% Retinol) 3.0 Moderate Irritant ( np et ·□ r t 0 n X A rvrt f* r-n r îmtont 1 &amp; 1 U ». 1- kj W \l 1 >- i. U k 1 1 control) w/o-ll (0.15% Retinol) 2.4 Moderate Irritant 1 Placebo (négative control) 1.2 Mild Irritant 010520 • 41 ln general, the irritancv of topical formulation anses from both the active andthe surfactants. The results in Table 9 show that 0.15% retinol w/oformulations, which contatn approximatelv 2% surfactants, exhibit mild ormarginally moderate irritancv. Surprisingiy, 0.15% retinol non-phospholipid 5 liposome formulations, which contain more than 8% surfactants, show similarirritancv as that of w/o formulation tested. The results suggest that non-phospholipid liposome formulations mav hâve a potential to reduce the irritancyfrom the ingrédients of the formulations. 10 EX AMPLE 11:

Evaluation of Cosmetic Performance:

Thrcc non-phospholipid liposomal formulations and a water-in-oil émulsion (a 15 stable retinol product marketed bv RoC s.a.) containing 0.15% retinol wercevaluated for quantitative descriptive analysis (QDA). The commercial productNignt of Olav'5 from Procter &amp;. Gambie was used as a controi. The objectiveof this évaluation was to détermine the overail cosmetic attributes of the retinolcréants. The évaluation was performed by a trained panei of scicntists. The 20 parameters which werc evaluated werc appcarancc in cup, feel between fingers.feel during application and skin feel after application.

The results for the various éléments after application arc shown in Figure 4along with the same for Night of Olav for easv comparison. The results suggest 25 that retinol liposome formulations werc preferred over retinol in watcr-ïn-oil.The results also suggest that greasiness which is a big drawoack for water-in-oil 010520 - 42 - émulsion can be controlled with slig'nt modification of lhe liposomalformulation without compromising the stability of retinol. The rcsults ofcomparisons of the formulations of Exampies ô. S and two commercialcompositions are set t’orth in Fig. 4. 5

According to above observations, the products of this invention unexpectediyprovide Chemical stability enhancement. bioavaiiability programmability ofretinoids to the skin. as well as improvement of the cosmetic elegance of thevehicle. which can ali be achieved in a single non-p'nospholipid liposome 10 formulation.

Claims (14)

1. 010520 - 43 - WHAT IS CLAJGMED IS:

   1. A composition ror skin care comprising a non-phosphoiipid liposome anda retinoid selected from the group consisting of retinol. retinai. rctinyi 5 acetate. retinvi paimitate and mixtures thereof, said composition further comprising a stabilizing svstem selected from the group consisting of: a) an oil-soluble antioxidant; and b) a cheiating agent and at least one oil-soluble antioxidant; 10 wherein said composition nas a pH from at least about 5 to about 10,said composition retaining at least 80% of said retinoids arter 13 weeks’storage at 500C, 15 2. A composition according to claim i wherein said rednoid is Vitamin A alcohol.
2. 3. A composition according to claim 1 wherein said retinoid is Vitamin Aacid. 20
3. 4. A composition according to claim 1 wherein said retinoid is Vitamin Aaldéhyde.
4. 5. A composition according to claim 1 wherein said oil-soluble antioxidant 25 is selected from the arouo consistins of butvlated hvdroxvtoluene. 010520 - 44 - ascorbvl paimitate. butylated hvdroxvanisole, a-tocopnerol, phenyl-a-naphthvlamine and mixtures thereof.
5. 6. A composition according to claim 1 wherein said chelating agent is 5 seiected from the group consisting of ethvlenediamine tetraacetic acid and dérivatives and saits thereof. dihydroxvethyl glycine, citric acid,tanaric acid, and mixtures thereof.
6. 7. A composition according to claim ό wnerein said chelating agent is 10 seiected form the group consisting of ethvlenediamine tetraacetic acid and dérivatives and saits thereof.
7. 8. A composition according to claim 1 wherein the pH of said compositionis from about 5 to about 7. 15
8. 9. A skin care composition comprising a non-phospholipid liposome and arctinoid seiected from the group consisting of rctinol. rctinai, rctinylacetate. retinvi paimitate and mixtures thereof. said composition furthercomprising a stabilizâng System comprising an oil-soluble antioxidant, 20 wherein said composition has a pH from at least about 5 to about 10, said composition retaining at least 80% of said retinoids after 13 wecks’storage at 500C.
9. 10. A composition according to claim 9 wherein said o·'.·soluble antioxidant 25 is seiected from the group consistins of butvlated hydroxvtoluene. 010520 - 45 - ascorbyl paimiiate. butvlated hvdroxvanisoie. cx-tocopnerol, p'nenvi-o:-naphthyiamine and mixtures thereof.
10. 11. A skin care composition comprising a non-p’nosphotipid liposome and a5 retinoid selected from the group consisting of retinol. rednal, rcdnyl acetate. rettnyi palmitate and mixtures thereof. said composition furthercomprising a stabilizing System comprising at least one oil-soluble antioxidant and a cnelating agent, wherein said composition bas a pHfrom at least about 5 to about 10. said composition retairting at least 10 80% of said retinoids after 13 weeks’ storage at 50OÇ.
11. 12. A composition according to ciaim 11 wherein said oii-soluble antioxidantis selected from the group consisting of butylated hydroxytoluenc,ascorbyl palmitate, butylated hydroxyanisole, cx-tocopheroi, phcnyi-ix- 15 naphthylamine and mixtures thereof.
12. 13. A composidon according to ciaim 11 wherein said cheladng agent isselected form the group consisung of ethylènediamine tetraaccdc acidand derivadves and salis thereof. dihydroxyethyl glycine, citric acid. 20 tartaric acid, and mixtures thereof.
13. 14. A composidon according to ciaim 9 wherein said rednoid is Vitamin Aaicohol. 25 15. A composition according to ciaim 11 wherein said rednoid is Vitamin A aicohol. 010520 - 46 - 16. · A composition according to ciaim 9 wncrein lhe pH is from about 5 toabout 7.
14. 17. A composition according to daim 11 w'nerein lhe pH is from about 5 to5 about 7.