Drug – bio-affecting and body treating compositions – Dentifrices
Patent
1997-04-03
1999-03-16
Rose, Shep K.
Drug, bio-affecting and body treating compositions
Dentifrices
414 52, A61K 716, A61K 718
Patent
active
058826300
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP95/02826 Jul. 18, 1995.
The present invention relates to a dentifrice composition, in particular to a non-aqueous (anhydrous) dentifrice composition. Such non-aqueous compositions may then suitably contain other materials which are unstable and incompatible with an aqueous environment.
There are many materials which have limited solubility in or even react with the aqueous systems of typical dentifrice formulations. One way of overcoming this problem during formulation is to encapsulate these water sensitive materials to prevent them from interacting with the aqueous component(s) present in the dentifrice formulation. Although encapsulation is a well known and used technique that can be usefully employed in the formulation of dentifrice compositions, it does not completely solve the problem as the encapsulated material frequently contacts water in the remainder of the product due to diffusion or `capsule fracture`.
Other methods of improving the stability of these materials have been suggested and these include the use of anhydrous compositions.
U.S. Pat. No. 4,988,500 (Hunter et al) which has been assigned to The Procter & Gamble Company discloses and claims an anhydrous oral composition comprising a carboxyvinyl polymer, a neutralising agent, a peroxide or perborate compound and an anhydrous humectant. It is however necessary to neutralise the carboxyvinyl polymer in order to obtain dentifrice compositions that provide acceptable viscosity characteristics.
U.S. Pat. No. 4,647,451 (Piechota) which has been assigned to Colgate-Palmolive Company describes an anhydrous dentifrice containing a polysaccharide gum and a glycerine humectant. Polyethylene glycol is optionally added as a dispersion agent.
It has now been discovered that the problems associated with formulating and administering a dentifrice with ingredients that are incompatible with the aqueous phase may be solved by the use of an improved non-aqueous formulation that is as acceptable as conventional dentifrice formulations.
Accordingly, the present invention provides a non-aqueous dentifrice composition comprising a carboxyvinyl polymer, a humectant, a polyethylene glycol and a dentally acceptable abrasive.
The carboxyvinyl polymer is used in the acid form, and does not necessarily require any form of neutralising.
Carboxyvinyl polymers will thicken humectant materials and also provide the necessary rheology in order to suspend any required abrasive material.
The term `rheology` as used herein is intended to reflect the flow characteristics of the formulation.
Suitable carboxyvinyl polymers for use in dentifrices of the invention are copolymers of acrylic acid cross-linked with polyallylsucrose, for example Carbopol 974 and 934 or cross-linked with divinyl glycol, for example Noveon AA-1. Carbopol polymers are manufactured by B.F. Goodrich Company. Carbopol 974 is preferred.
The carboxyvinyl polymer may be present in the range of from 0.1 to 7.5% w/w, preferably from 0.3 to 1.0%, more preferably about 0.35% by weight of the dentifrice.
Suitable humectants for use in the present invention include glycerine, sorbitol and propylene glycol or mixtures thereof. It is well known that commercially available glycerine may contain between 0.5-2.0% by weight of water which is in association with the glycerine. Typically this amount is between 0.5-1.0% by weight. This small amount of water if bound to the glycerine and is therefore not available to the other ingredients. The skilled person would still consider a composition containing glycerine as being non-aqueous. The humectants should in any case be as anhydrous as possible and preferably used in solid form.
Glycerine is the preferred humectant.
As the humectant is used to make the formulations up to 100%, the humectant may be present in the range of from 20 to 90% by weight of the dentifrice. Preferably the humectant is present from 35 to 75%, more preferably from 45 to 70% by weight of the dentifrice.
The polyethylene glycol is selected so that it will reduce any sti
REFERENCES:
patent: 3939261 (1976-02-01), Barth
patent: 3954962 (1976-05-01), Prussin
patent: 4837008 (1989-06-01), Rudy et al.
patent: 4988500 (1991-01-01), Hunter et al.
patent: 5213789 (1993-05-01), Degenhardt
Bannon Martin Edward
Gates Cheryl Teresa
Rose Shep K.
SmithKline Beecham p.l.c.
Stein-Fernandez Nora
Williams Janice E.
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