FIELD OF THE INVENTION

The invention relates to the field of dermal fillers.

BACKGROUND

It is well known to inject hyaluronic acid under the dermis for cosmetic reasons. SUMMARY OF THE INVENTION

Forming one aspect of the invention is an improved dermal filler of the type having particles of cross-linked hyaluronic acid. The improvement comprises: at least 10% of the particles having a diameter greater than 800 um; the particles can absorb 5-7 times their weight in water; and the degree of cross-linking is about 7%.

According to another aspect, about half of the particles can have a diameter above 500μητ

According to another aspect, the filler can be adapted such that an extrusion force of about 2 lbs is sufficient to force the filler at a rate of 4 ml/hr through a 27 Gauge needle.

A consumer package containing more than 1 ml of the improved filler forms another aspect of the invention.

Use of the improved filler for non-face augmentation procedures forms another aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A is a photograph of a sample of the exemplary filler;

FIG. 1 B is the volume-weighted size distribution of the particles of FIG. 1 A; FIG. 2A is a photograph of another sample of the exemplary filler;

FIG. 2B is the volume-weighted size distribution of the particles of FIG. 2A;

FIG. 3A is a photograph of another sample of the exemplary filler;

FIG. 3B is the volume-weighted size distribution of the particles of FIG. 3A;

FIG. 4A is a photograph of another sample of the exemplary filler;

FIG. 4B is the volume-weighted size distribution of the particles of FIG. 4A;

FIG. 5A is a photograph of another sample of the exemplary filler;

FIG. 5B is the volume-weighted size distribution of the particles of FIG. 5A;

FIG. 6A is a photograph of another sample of the exemplary filler;

FIG. 6B is the volume-weighted size distribution of the particles of FIG. 6A;

FIG. 7A is a photograph of another sample of the exemplary filler;

FIG. 7B is the volume-weighted size distribution of the particles of FIG. 7A;

FIG. 8A is a photograph of another sample of the exemplary filler;

FIG. 8B is the volume-weighted size distribution of the particles of FIG. 8A;

FIG. 9A is a photograph of another sample of the exemplary filler;

FIG. 9B is the volume-weighted size distribution of the particles of FIG. 9A;

FIG. 10A is a photograph of another sample of the exemplary filler;

FIG. 10B is the volume-weighted size distribution of the particles of FIG. 10A;

FIG. 1 1 A is a photograph of another sample of the exemplary filler;

FIG. 1 1 B is the volume-weighted size distribution of the particles of FIG. 1 1 A;

FIG. 12A is a photograph of another sample of the exemplary filler;

FIG. 12B is the volume-weighted size distribution of the particles of FIG. 12A.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

Figures 1A-12A show the filler according to the exemplary embodiment.

More particularly, twelve samples of the filler were taken, at random, and photographed under high magnification: these photographs constitute Figures 1A-12A. As will be seen, the filler is characterized by a relatively high average diameter particle size.

The particles in the photographs were counted and measured, such that a volume- weighted size distribution could be produced, as shown by Figures 1 B-12B.

From these results, the filler can be characterized in that:

• at least 10% of the hyaluronic acid particles are greater than 800 urn in diameter

• about half of the particles in the gel have a particle size above 500 m.

Further measurements were also taken, from which it was determined that:

• the particles can absorb 5-7 times their weight in water

• the degree of cross-linking is about 7%

• an extrusion force of about 2 lbs is sufficient to force gel at a rate of 4 ml/hr

through a 27 Gauge needle.

It has been found useful to inject gel according to the invention into the hips of patients; more particularly, it has been found that the gel has a sufficient low viscosity such that the relatively large volumes needed [above 40 ml] for non-facial [large volume] augmentation can be injected without undue discomfort. 60 ml was injected into the legs of an individual in less than 3 hours without causing any pain or adverse reactions. Accordingly, a consumer package containing more than 1 ml of the gel has been found to be useful.