|Title of Invention
ANTIPERSPIRANT OR DEODORANT COMPOSITIONS
|Antiperspirant or Deodorant Compositions The stability of antiperspirant or deodorant compositions comprising an aqueous solution of an antiperspirant or deodorant salt that has been thickened by a polyquaternium derivative of an hydroxycellulose and containing lypophylic organic material can be improved by employing a stabilising amount of propylene glycol, preferably selected in the range of from 1.5 to 5% by weight, thereby enabling the formulation to maintain its viscosity better or longer or under less favourable climatic conditions.
THE PATENTS ACT, 1970
(39 of 1970)
The Patents Rules, 2003
(See Section 10 and Rule 13)
ANTIPERSPIRANT OR DEODORANT COMPOSITIONS
HINDUSTAN LEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at Hindustan Lever House, 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India
The following specification particularly describes the invention and the manner in which it is to be performed
Antiperspirant or Deodorant Compositions
5 The present invention relates to antiperspirant or deodorant compositions and more particularly to aqueous compositions and to their preparation.
10 Background and Prior Art
Cosmetic, which is understood herein to mean non-therapeutic, antiperspirant or deodorant formulations are commonly available to the public for application topically
15 to the axilla (underarm) and less commonly to feet. Both contact and non-contact applicators are available, and habits differ from one country to another as which is the most popular. One class of applicators that is popular in parts of Europe, South East Asia and Latin America comprises
20 roll-ons in which a roll-ball distributes a mobile liquid from a reservoir by contact with skin.
In the past, a significant fraction of roll-on formulations have employed a solution of an antiperspirant active in
25 aqueous alcohol, typically aqueous ethanol. Whilst many find the cooling sensation from such formulations pleasurable, on account of alcohol evaporation, alcohol can sting, especially if the formulation is applied to broken or cut skin. Accordingly, the industry has sought alternatives
30 which do not require alcohol.
It is often desirable to incorporate a lypophylic organic liquid in antiperspirant or deodorant formulations, for example a fragrance. When the base composition is aqueous, it is convenient to employ a solubilising emulsifier or
5 surfactant to provide composition homogeneity.
Formulations that are intended for skin application via roll-on dispensers tend, in practice, to be significantly more viscous than water. The actual viscosity of the
10 formulation is often designed in conjunction with the gap between the roll ball and its housing so as to prevent an excessive flow of formulation, but at the same time enable sufficient formulation to be dispensed in a few strokes of the ball to control perspiration and/or malodour formation.
15 The viscosity of the formulation can be increased
conveniently by employing a thickener. Antiperspirant or deodorant products can often spend several months in the distribution chain or in users’ cabinets before or whilst they are being used. Accordingly, it is desirable that the
20 formulations remain stable until they are fully consumed.
One class of thickeners for aqueous solutions comprises a polyquaternium derivative of hydroxycellulose. However, the inventors have found that emulsion formulation that have
25 been thickened with that class of thickener demonstrate
signs of instability, which is evidenced by a reduction in the viscosity of the formulation over time. The rate of change is also increased by elevated temperatures which can occur, for example during storage in warehouses, especially
30 during the summer, or if the roll-on dispenser is exposed to strong sunlight. The roll-on bottle itself remains substantially unchanged during storage, so that the gap
between the roll ball and its housing remains unchanged, and a reduction in formulation viscosity increases the risk of the formulation flowing out undesirably quickly under gravity when the bottle is inverted (i.e. having the ball
5 below the bottle reservoir). It would desirable to improve the stability of such formulations, which is to say find a means to reduce the risk of such formulations suffering reduced viscosity or to increase the period before significant viscosity reduction occurs or to enable the
10 product to be stored or transported at higher temperatures without significant viscosity reduction occurring.
Summary of the Invention 15
According to a first aspect of the present invention, there is provided a formulation in accordance with claim 1 hereinafter.
20 By virtue of the incorporation of a stabilising amount of propylene glycol, the risk of the thickened compositions suffering reduced viscosity during storage or transportation is lessened or the period before any significant viscosity reduction occurring is increased or the product can be
25 stored or transported at higher temperatures without significant viscosity reduction occurring.
Detailed Description of the Invention
The instant invention relates to a means for stabilising an
aqueous solution of an antiperspirant active containing a
solubilised lypophylic liquid and thickened with a polyquaternium derivative of an hydroxycellulose comprising the introduction of an effective amount of propylene glycol. It is effective, i.e. a stabilising amount, if it lessens
5 the extent to which a corresponding propylene-glycol-free composition would suffer from a reduction in viscosity during storage, for example in a test after 4 weeks at 23°C, and particularly lessens the viscosity reduction by at least 5% preferably at least 10% and advantageously at least 20%
10 in the test.
Desirably, the composition contains at least 1.5% by weight often at least 2% and in at least some preferred compositions at least 2.5% by weight. Stabilisation tends
15 to increase with increasing concentration of propylene glycol, and this propensity is especially noticeable at lower concentrations, such as up to 3 or 3.5% by weight. The concentration of propylene glycol is advantageously less than 10%, often less than 7.5% and preferably not more than
2 0 5% by weight of the composition. Although the incorporation of propylene glycol improves the stability of the composition, it has unfortunately been found simultaneously to increase negative sensory attributes perceived by users. For example, increased propylene glycol induces a perception
25 of increased stickiness. Consequently, a balance can be struck between the increased stability and increase in stickiness, a window of opportunity in which a valuable increase in stability can be obtained without an excessive impairment of stickiness. The concentration of propylene
3 0 glycol is consequentially often chosen in the range of from
2 to 5% by weight, and in many preferred compositions from 2 or 2.5 to 3 or 3.5% by weight.
The polyquaternium derivative of hydroxycellulose is commonly a derivative of an hydroxyethylcellulose. Of the various derivatives available listed in the International Cosmetic Ingredient Dictionary and Handbook, 8th Edition
5 published by the CTFA (Cosmetic Toiletry and Fragrance Association) in 2000, including Polyquaternium 4, polyquaternium 10 and polyquaternium 23, the preferred material is polyquaternium 10. The proportion of polyquaternium thickener to employ depends to at least some
10 extent on the viscosity desired in the composition and can also vary according to the grade of the thickener. The concentration of the thickener is often selected in the range of from at least 0.3% and in many instances is at least 0.4%. The concentration of thickener is commonly not
15 greater than 2.5% and conveniently is not greater than 2% by weight. In some embodiments, the thickener concentration is not more than 0.8%. A particular desirable range for at least some thickeners is from 0.45 to 0.7% by weight. In some other desirable embodiments, the weight proportion of
20 thickener is from 1 to 2%.
It is often desirable to employ the propylene glycol and the thickener in a weight ratio of from 4:1 to 7.5:1, and in some particularly preferred embodiments from 5:1 to 6:1.
The antiperspirant or deodorant compositions herein contain one or more antiperspirant or deodorant actives.
The composition preferably contains an antiperspirant active 30 and more preferably in an amount of from 0.5-60%,
particularly from 5 to 30% or 40% and especially from 5 or 10% to 30 or 35% of the weight of the composition. In some
desirable embodiments, the compositions contain from 10 to 2 0% by weight antiperspirant active. In other desirable compositions, the proportion of antiperspirant active is from 6 to 10%, and especially when the active is an
5 aluminium zirconium chlorohydrate or an Al/Zr chlorohydrex complex with glycine.
Antiperspirant actives for use herein are often selected from astringent active salts, including in particular
10 aluminium, zirconium and mixed aluminium/zirconium salts, including both inorganic salts, salts with organic anions and complexes. Preferred astringent salts include aluminium, zirconium and aluminium/zirconium halides and halohydrate salts, such as especially a chlorohydrate.
15 Activated aluminium chlorohydrates can be incorporated, if desired, commonly having a higher Band 3 content. Some literature employs alternative terminology, such as basic aluminium chloride for aluminium chlorohydrate, and aluminium chlorhydrex for complexed chlorohydrate. In some
20 suitable actives, the chlorohydrate on introduction is complexed with a glycol, particularly propylene glycol.
Aluminium halohydrates are usually defined by the general formula Al2 (OH)xQy.wH20 in which Q represents respectively
25 chlorine, bromine or iodine, (and especially chlorine to
form a chlorohydrate) x is variable from 2 to 5 and x + y = 6 while wH2O represents a variable amount of hydration.
Zirconium actives can usually be represented by the empirical
30 general formula: ZrO (OH) 2n-nzBz.wH20 in which z is a variable in the range of from 0.9 to 2.0 so that the value 2n-nz is zero or positive, n is the valency of B, and B is selected from the
group consisting of chlorine (to form a chlorohydrate), other halide, sulphamate, sulphate and mixtures thereof. Possible hydration to a variable extent is represented by wH20 . Preferably, B represents chlorine and the variable z lies in
5 the range from 1.5 to 1.87. In practice, such zirconium salts are usually not employed by themselves, but as a component of a combined aluminium and zirconium-based antiperspirant.
The above aluminium and zirconium salts may have co-
10 ordinated and/or bound water in various quantities and/or
may be present as polymeric species, mixtures or complexes.
In particular, zirconium hydroxy salts often represent a
range of salts having various amounts of the hydroxy group.
Zirconium aluminium chlorohydrate may be particularly 15 preferred.
Antiperspirant complexes based on the above-mentioned astringent aluminium and/or zirconium salts can be employed. The complex often employs a compound with a
20 carboxylate group, and advantageously this is an amino
acid. Examples of suitable amino acids include dl-tryptophan, dl-β-phenylalanine, dl-valine, dl-methionine and β-alanine, and preferably glycine which has the formula CH2(NH2)COOH.
It is highly desirable to employ complexes of a combination of aluminium chlorohydrates and zirconium chlorohydrates together with amino acids such as glycine, which are disclosed in US-A-3792068 (Luedders et al). Certain of
30 those Al/Zr complexes are commonly called ZAG in the
literature. ZAG actives generally contain aluminium, zirconium and chloride with an Al/Zr ratio in a range from
2 to 10, especially 2 to 6, an Al/Cl ratio from 2.1 to 0.9 and a variable amount of glycine. Actives of this preferred type are available from Westwood, from Summit and from Reheis.
The selection of zirconium aluminium salts, including zriconium aluminium complexes, is advantageous in certain embodiments in that a similar level of antiperspirant efficacy can be attained using a lower concentration of
10 antiperspirant active than for aluminium chlorohydrates.
The use of less of an ingredient releases formulation space for other constituents and can reduce the likelihood of visible deposits upon axillary application of the composition. None the less, it will also be recognised
15 that the latter antiperspirant salts can be employed in other embodiments that are practically useful.
The antiperspirant salts can be introduced in the form of powders or in the form of pre-formed solutions, commonly in
20 water. Such powders may, if desired, comprise an adduct
with propylene glycol, and pre-formed solutions can likewise contain propylene glycol, to provide not more than the desired proportion of propylene glycol in the fully-formed formulation.
Other actives which may be utilised include astringent titanium salts, for example those described in GB 2299506A.
Herein, in calculating the weight of the active
30 antiperspirant salt, any water of hydration is ignored.
The antiperspirant active salts can be incorporated by employment of preformed aqueous solutions obtainable from the producers, with subsequent dilution as needed with water, optionally or alternatively a fraction of the
5 antiperspirant active can be incorporated from a preformed solution in propylene glycol or an aqueous /propylene glycol mixture. If desired, solid antiperspirant active can be dissolved in water or the aqueous/propylene glycol mixture.
10 At least some preferred compositions herein contain at least 65% by weight water, often at least 67.5% by weight water and particularly in certain formulations at least 75% by weight water. The weight proportion of water is commonly not more than 87.5% and in many embodiments is up to 85% by
The combined weight of water and antiperspirant active is desirably selected in the range of from 85 to 95% by weight and in a number of highly desirable compositions is at least
20 88% by weight. In such or other formulations, such combined weight is conveniently up to 93%.
The compositions herein advantageously contain a fragrance material in the form of a lypophylic organic material. Such
25 materials provide a characteristic perfume to the
composition, but lypophylic materials are not readily dissolved in the aqueous antiperspirant solution. The fragrance is commonly employed at a concentration of from 0.25 to 2.5% by weight of the composition and in many
30 instances in an amount of at least 0.5%. The proportion is sometimes not greater than 1.5% by weight.
The fragrance, and/or any other lypophylic liquid can be solubilised by employment of a solubilising emulsifier or surfactant. Such solubilisers are often selected from nonionic surfactants, and particularly from polyalkylene
5 oxide-containing nonionic surfactants. Desirable emulsifiers include polyethylene oxide derivatives containing from 10 to 100 and especially from 15 to 50 PEG units. The surfactants can comprise as hydrophobic moiety one or more long chain hydrocarbon or hydrofluorocarbon
10 groups, conveniently containing at least one chain of at
least 10 carbons and often from 12 to 25 carbons. Suitable hydrophobic moieties include cetyl, palmityl, stearyl, oleyl, and behenyl. The hydrophobic moiety can comprise a simple entity as exemplified hereinbefore or can comprise a
15 more complex entity such as a derivative of a hydrocarbon chain that is substituted by an hydroxyl group as in derivatives of castor oil. The hydrophobic moiety can be linked directly to the hydrophylic polyalkylene oxide moiety via an ester or in many instances via an ether linkage. The
20 emulsifier can be derived from a polyol such as sorbitol or glycerol, if desired. Illustrative emulsifiers comprise ceteth-20, ceteth-25, ceteth-30, ceteth-35, ceteth-40, glycerol, if desired. Illustrative emulsifiers comprise ceteth-20, ceteth-25, ceteth-30, ceteth-35, ceteth-40,
25 steareth-20, steareth-25, steareth-30, steareth-35,
steareth-40, ceteareth-20, ceteareth-25, ceteareth-30, ceteareth-35, ceteareth-40. Preferred solubilisers include PEG derivatives of castor oil. A mixture of emulsifiers can be employed, such as a mixture of the castor oil derivative
30 with a steareth or ceteareth emulsifier, for example in a weight ratio of thrice the weight of the castor oil-based solubiliser.
The proportion of the solubiliser to employ is often selected in the range of from 1.5 to 8% of the composition, and in a number of instances from 1.5 to 5% by weight. Desirably, the solubiliser is employed at a weight ratio to
5 lypophylic oil in the range of from 1:1 to 6:1 and particularly from 1:1 to 4:1.
The compositions herein can additionally comprise an amino preservative. Materials such as particularly an
10 alkanolamine or an aminopolycarboxylic acid/salt chelating agent act as preservatives during storage whilst providing functional benefits on topical application. Trialkanolamines are especially desirable, for example triethanolamine. The aminopolycarboxylic acids such as EDTA
15 (ethylene diaminotetramethylenecarboxylic acid) or DTPA
(diethylenetriaminopentamethylenecarboxylic acid) or their water-soluble salts are suitable alternatives. The proportion of the amino preservative is often up to 1.0% by weight, for example from 0.25 to 0.75% by weight chelating
The formulations herein can comprise one or more deodorant actives in addition to or instead of the aforementioned chelating preservatives, including chlorinated aromatics, of
25 which materials known as triclosan, and chlorhexidine
warrant specific mention. Yet another class of suitable deodorant actives comprises polymeric biguanide salts such as available under the trademark Cosmosil™. These two classes may be employed in amounts selected in the range of
30 from 0.001 to 1%, and particularly from 0.1 to 0.5% by
weight. Yet other suitable deodorant actives include zinc salts such as zinc oxide, hydroxide, carbonate, phenol
sulphonate or ricinoleate and particular salts that are soluble in the formulation.
In some especially chosen embodiments of the present
5 invention, the compositions comprise one or more of the following:-
from 80 to 95% by weight together of water plus an aluminium or aluminium/zirconium astringent antiperspirant salt, preferably containing from 67.5 to 80% by weight of water
10 plus 15 to 25% of the astringent antiperspirant salt;
preferably selected from an aluminium chlorohydrate, an aluminium zirconium chlorohydrate and an aluminium zirconium chlorohydrate complex with glycine; or from 75 to 85% or 87.5% by weight of water and from 6 to 10% by weight of an
15 aluminium zirconium chlorohydrate and an aluminium zirconium chlorohydrate complex with glycine
from 0.4 to 0.8% by weight of a polyquaternium derivative of a hydroxycellulose, preferably polyquaternium-10; from 0.5 to 2% by weight of a lypophylic oil, preferably a
20 fragrance oil;
oil solubiliser and emulsifier, preferably from 3 to 6% by weight, advantageously comprising an ethoxylated nonionic emulsifier and especially containing at least 1% by weight of an ethoxylated castor oil optionally hydrogenated
25 optionally together with a further ethoxylated nonionic emulsifier
from 2 to 5% by weight of propylene glycol and optionally up to 1% by weight of an aminoalkanol, preferably triethanolamine, or an aminopolycarboxylic acid or salt,
30 preferably EDTA or DTPA.
Formulations according to the invention and especially those of the aforementioned especially chosen embodiments have the advantage of being translucent, and often sufficiently so to be transparent, whilst at the same time demonstrating
5 significantly improved stability against thinning without incurring excessive sensory negative attributes, such as stickiness, and without being based on ethanol.
Compositions according to the present invention can be made 10 by mixing the ingredients together in the desired
proportions in a suitable mixing vessel. Conventional low shear mixers can be employed. Advantageously, the process can be conducted at or about ambient temperature, by which is contemplated a temperature of from about 15 to 3 0°C or at
15 an elevated temperature, such as up to 70°C. Although the order of introduction of the ingredients is at the convenience of the producer, it is often of practical advantage to introduce water or an aqueous solution into the production vessel first and thereafter introduce remaining
2 0 ingredients into a bulk material. One convenient method
comprises hydrating the thickener at an elevated temperature of from for example 50 to 70°C, and thereafter introducing the remaining constituents, possibly without continued heating. It is often convenient to premix the fragrance
25 with the solubiliser and to introduce the resultant mixture last, preferably when the temperature of the remainder of the composition is or has fallen to below 40°C.
Advantageously, by dissolving the various constituents of
3 0 the invention compositions to form homogenous mixtures,
translucent and comparatively stable formulations are obtained.
Compositions according to the present invention are particularly suitable for application to human skin in a non-therapeutic method of controlling perspiration or odour employing a roll-on or similar dispenser. Such dispensers
5 include those described WO 00/64302 WO 00/49908 or US 6511243.
In a further aspect of the present invention there is provided a non-therapeutic method for controlling
10 perspiration or odour by applying topically to human skin a composition in accordance with the first aspect of the invention, and especially to armpits.
Having described the invention in general terms and
15 preferred embodiments thereof, specific embodiments are now given in more detail by way of example only.
Materials Table 1
INCI name Trade Name Supplier Function
Polyquaternium 10 Ucare JR30M Dow Thickener
Sorbeth-3 0 Atlas G-2330 Uniqema emulsifier
PEG-40 hydrogenated castor oil Cremophor RH40 BASF Solubiliser
Triethanolamine BASF preservative
Aluminium ZirconiumtetrachlorhydrexGly Rezal 36GC Reheis antiperspirant astringent active salt
Examples 1 and 2 and comparison A
This comparison and Examples demonstrate stability-improvement. The compositions in accordance with the summary in the Table 2 below were prepared by introducing water into a mixing vessel at laboratory ambient temperature
5 water, heating it to about 60°C, introducing the thickener and maintaining the temperature and stirring until the thickener was hydrated. Then, the stabiliser, emulsifier and amine were introduced, and followed by the antiperspirant active salt and stirring was continued until
10 dissolution was complete. Thereafter, the remaining
ingredients were introduced and mixing continued until the composition had an homogenous appearance. Finally, when the composition temperature had fallen below 40°C, the fragrance which had been pre-mixed with the solubiliser was introduced
15 with stirring. The compositions were then poured into
dispensers described in WO 0 0/64302, the cap fitted and the bottles were stored in the dark in a cabinet maintained at 45°C. The viscosity of the compositions was tested at laboratory ambient temperature (about 23°C) both prior to
20 storage and at intervals during storage in order to identify the extent to which the composition resists thinning and periodically inspected to determine whether the compositions had altered their appearance.
Comp A Ex 1 Ex 2
% by weight
Water 78.5 75.5 74.0
antiperspirant active 17.4 17.4 17.4
thickener 0.6 0.6 0.6
propylene glycol 0 3.0 5.0
triethanolamine 0.5 0.5
Emulsifier 3.0 3.00 3.0
% reduction in viscosity (4 weeks) 95 34 33
Comparison A and Examples 1 and 2 were all translucent and had desirable sensory properties, for example as regards 5 their stickiness on topical application, and the presence of . little or no visible deposits. The three formulations had an initial viscosity in the region of 740 to 8 00 mPa.s However, Examples 1 and 2 demonstrated substantially increased resistance to a loss of viscosity during storage,
10 a reduction of about l/3rd of the initial viscosity compared with Comp A which lost virtually all its initial viscosity. Thus, Examples 1 and 2 exemplify a window within which stability is significantly improved without significantly impairing sensory properties.
Furthermore, when the proportion of propylene glycol in the formulation was increased to 10% by weight, with a corresponding reduction of water content, the resultant formulation exhibit impaired sensory properties and in
20 particular significantly greater stickiness.
Examples 3 to 9
These Example compositions were made in the same way as Example 1. 5
Ex 3 Ex 4 Ex 5 Ex 6 Ex 7 Ex 8 Ex 9
Ingredient % by weight
Water 73.0 76.1 73.5 72.5 82.5 77.3 69.0
antiperspirant active 17.4 17.4 17.4 17.4 8.0 10.0 21.0
thickener 0.6 0.5 0.6 0.6 0.6 0.7 0.8
propylene glycol 3.0 3.0 3.0 3.0 3.0 3.5 2.7
Fragrance 1.2 1.2 0.6 1.2 1.2 1.2 1.2
triethanolamine 0.5 0.5 0.5 0.5 0.5
Emulsifier 3.0 3.0 3.0 3.0 3.0 3.0
Solubiliser 1.8 1.8 1.4 1.8 1.8 1.8 1.8
The compositions of Examples 3 to 9 all enjoyed a combination of acceptable sensory properties, translucency
10 and stability.
Compositions having similar stability and sensory properties to the corresponding compositions are obtained by introducing aluminium chlorohydrate (ACH-303 [50% aqueous
15 solution, Summit]) or aluminium zirconium chlorohydrate
(Zirconal-50 [50% aqueous solution, B K Giulini]) instead of the antiperspirant active of Examples 1 to 9.
1 An antiperspirant or deodorant formulation comprising a
lypophilic organic liquid,
5 an emulsifier to solubilise the organic liquid an aqueous solution of an antiperspirant active, a thickener comprising a polyquaternium derivative of an hydroxycellulose,
and a stabilising amount of propylene glycol.
2 A composition according to claim 1 in which the amount
of propylene glycol is at least 1.5% by weight, and
preferably not more than 5%.
15 3 A composition according to claim 2 in which the amount of propylene glycol is from 2 to 3.5% by weight.
4 A composition according to any preceding claim in which
the proportion of polyquaternium thickener is from 0.5
20 to 2.5% by weight.
5 A composition according to any preceding claim in which
the polyquaternium thickener is polyquaternium 10.
25 6 A composition according to any preceding claim in which the antiperspirant active is selected from an aluminium chlorohydrate, an aluminium zirconium chlorohydrate or a complex of either with glycine.
30 7 A composition according to any preceding claim in which the antiperspirant active is present in a concentration of from 5 to 30% by weight.
8 A composition according to claim 7 in which the antiperspirant active is present in a concentration of from 15 to 25% by weight.
9 A composition according to claim 7 in which the antiperspirant is an aluminium zirconium chlorohydrate, optionally complexed with glycine, present at a concentration of from 6 to 10% by weight.
10 A composition according to any preceding claim in which the lypophylic organic liquid comprises fragrance material.
11 A composition according to any preceding claim in which the emulsifier is present in an amount of from 1.5 to 8% by weight.
12 A composition according to any preceding claim in which the lypophylic organic liquid and emulsifier are present in a weight ratio of from 0.5-2 to 1.5-8.
13 A composition according to any preceding claim in which the emulsifier comprises a nonionic ethoxylated ether.
14 A composition according to claim 13 in which the emulsifier comprises an ethoxylated castor oil, optionally hydrogenated.
15 A non-therapeutic method of reducing perspiration or controlling odour comprising applying topically to skin a composition according to any preceding claim.
Dated this 7th day of November 2006
HINDUSTAN LEVER LIMITED
Senior Patents Manager
|Indian Patent Application Number
|PG Journal Number
|Date of Filing
|Name of Patentee
|HINDUSTAN UNILEVER LIMITED
|HINDUSTAN LEVER HOUSE, 165-166,BACKAY RECLAMATION, MUMBAI 400 020
|PCT International Classification Number
|PCT International Application Number
|PCT International Filing date