# US 5,352,693 A · Preservative mixtures

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- Number: US 5,352,693 A
- Document ID: US5352693A
- Status: Granted
- Kind: A
- Application number: 07/951,573
- Filed: 1992-09-25
- Granted: 1994-10-04
- Earliest claimed: 1992-09-25
- Assignees: Lonza Ltd.
- Inventors: Thomas E. Farina
- Web page: https://patentgrep.com/patent/US5352693A

## CPC

- A61K 8/4946: {Imidazoles or their condensed derivatives, e.g. benzimidazoles}
- A61Q 17/005: {Antimicrobial preparations}
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- A61Q: SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS

## Abstract

A solid composition comprising a dispersion of at least one alkyl ester of p-hydroxybenzoic acid in a hydroxymethyl-substituted dimethylhydantoin, its method of preparation, and its use as a preservative in shampoos, lotions, and cosmetics.

## Claims

### Claim 1

A solid preservative composition comprising a dispersion of an alkyl ester of p-hydroxybenzoic acid or mixtures of such esters in a hydroxymethyl-substituted dimethylhydantoin, wherein the aforesaid alkyl group has from 1 to 6 carbon atoms and the weight ratio of the hydantoin to the ester component is from 1:3 to 9:1.

### Claim 2 (depends on 1)

The solid composition of claim 1 wherein the esters of the p-hydroxybenzoic acid are the methyl, propyl, and butyl esters.

### Claim 3 (depends on 1)

The solid composition of claim 1 wherein the hydroxymethyl-substituted dimethylhydantoin is 1,3-bis(hydroxymethyl)-5,5-dimethylhydantoin.

### Claim 4 (depends on 2)

The solid composition of claim 2 wherein the ratio of the methyl to the propyl esters is from about 5:1 to 1:1.

### Claim 5

A method of preparing a solid preservative composition which comprises: melting a hydroxymethyl-substituted dimethylhydantoin and adding thereto an alkyl ester of p-hydroxybenzoic acid or a mixture of such esters, dispersing said ester in said hydantoin component, and thereafter cooling said dispersion to form a solid homogeneous compound, wherein the aforesaid alkyl group has from 1 to 6 carbon atoms and the weight ratio of the hydantoin to the ester component is from 1:3 to 9:1.

### Claim 6 (depends on 5)

The method of claim 5 wherein the solid compound is processed so as to form a comminuted mixture.

### Claim 7 (depends on 1)

A formulated cosmetic containing effective amounts of a cosmetic and a preservative comprising from 0.1% to 0.8% of the composition of claim 1 therein.

### Claim 8 (depends on 1)

A formulated shampoo containing effective amounts of a shampoo and a preservative comprising from 0.1% to 0.8% of the composition of claim 1 therein.

### Claim 9 (depends on 1)

A formulated lotion containing effective amounts of a lotion and a preservative comprising from 0.1% to 0.8% of the composition of claim 1 therein.