Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Nitrogen containing other than solely as a nitrogen in an...
Patent
1998-12-29
2000-11-14
Weddington, Kevin E.
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Nitrogen containing other than solely as a nitrogen in an...
514946, 514947, A61K 3118
Patent
active
061471186
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to the field of topical compositions comprising sphingoid bases functioning as antimicrobial agents.
BACKGROUND OF THE INVENTION
Healthy human skin is colonized by a number of different microorganisms responsible for maintaining the natural microbial equilibrium of the skin. However, outgrowth of certain species within the skin microflora can easily occur, thereby causing cosmetically and dermatologically undesirable phenomena, like unpleasant body odour, and in a worser case, infections. Several skin conditions are known which are associated with unwanted microbial growth. For instance, wounded or diseased skin especially is prone to superinfections by Staphylococcus aureus, a bacterium which also is the most important infective agent in patients suffering from atopic eczema. In addition, acne is associated with outgrowth of the bacterium Propionibacterium acnes. Also, fungal skin infections (mycoses) are known to occur frequently.
It has been known for several decades that skin surface lipids contain one or more lipid compounds possessing antimicrobial activity against gram-positive bacteria (Burtenshaw (1942), J. Hyg. 42, 184-209). These antimicrobial lipid compounds were thought to be mainly the free fatty acids released from sebaceous triglycerides by lipases from the normal microflora (Kearney et al. (1984), Br. J. Dermatol. 110, 593-599). Only recently, attention has been focused on the role of sphingolipids in this respect.
In a recent series of papers, Bibel et al. attribute an antimicrobial activity to sphingoid bases. In a first paper, test mixtures containing about 0.0005 to 0.005% of a sphingoid base were described to inhibit in vitro microbial growth (Bibel et al. (1992), J. Invest. Dermatol. 98, 269-273). However, high concentrations of ethanol were additionally present in these mixtures and ethanol is known as a solvent which itself substantially contributes to antimicrobial activity. Furthermore, no or a very low activity against gram-negative bacteria was observed. In in vivo experiments (Bibel et al. (1992), supra; Bibel et al. (1995), Clin. Exper. Dermatol. 20, 395-400), sphingoid bases were applied in much higher concentrations, i.e. as an 1.6% ethanolic solution or as a suspension of an 1.5% ethanolic solution in petrolatum. However, these formulations are not considered to enable an effective delivery of an active ingredient to the skin. For instance, Bibel et al. (1995) reported granulation of sphinganine upon drying, resulting in a decreased availability of this compound.
The present invention discloses compositions for the inhibition of topically-occurring microbial growth which comprise an effectively formulated sphingoid base, i.e. a sphingoid base which is formulated without ethanol in a high concentration.
DESCRIPTION OF THE INVENTION
The present invention discloses that sphingoid bases have a potent antimicrobial activity in the absence of inhibiting concentrations of an antimicrobial solvent like ethanol. Effective formulations are disclosed which are suitable for topical application on various skin conditions associated with undesired microbial growth.
The present invention further discloses that the concentration of a sphingoid base necessary to obtain a substantial antimicrobial effect in vitro in the absence of inhibiting concentrations of ethanol should be at least about 0.005 wt %. When higher concentrations are used, i.e 0.01, 0.02, 0.04 or 0.08 wt %, the antimicrobial effect of a sphingoid base increases.
Throughout the invention, the terms "antimicrobial activity/effect" or "growth-inhibitory activity/effect" are used synonymously.
Microorganisms which are susceptible to the antimicrobial activity of sphingoid bases include bacteria, yeasts and fungi.
When using a concentration of at least about 0.005% of a sphingoid base, the present invention discloses that sphingoid bases also display a growth-inhibitory activity on gram-negative bacteria. In particular, the present invention discloses that sphingoid bas
REFERENCES:
patent: 5149860 (1992-09-01), Zysman et al.
patent: 5578641 (1996-11-01), Jackson et al.
patent: 5627056 (1997-05-01), Casey et al.
patent: 5693677 (1997-12-01), Lambers et al.
Bibel et al., "Topical Sphingolipids in Antisepsis and Antifungal Therapy" Clin. Exper, Dermatol. 20:395-400 (1995).
Bibel et al., "Sphingosines: Antimicrobial Barriers of the Skin" Acta Derm Venereol (Stockh) 73:407-411 (1993).
International Search Report dated Nov. 17, 1998.
Lambers Johannes Wilhelmus Jacobus
Streekstra Hugo
DSM N.V.
Weddington Kevin E.
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