This invention relates to the encoding of data on gelatine capsules used for human and animal ingestion.

The use of gelatine as a concentrated protein product is well known as indeed is its use to form a thin capsule shell having a 5. conventional wall thickness within the range of 0.1 to 0.2 millimetres.

For gelatine useful for this purpose it is preferable that this material should have a high molecular weight and generally a bloom count of approximately 250 is indicated for a suitable material for this purpose.

iQ. As the gelatine is actually consumed by the user for this purpose, treatment of the material must conform to acceptable pharmaceutical standards but furthermore, the material must not be degraded or reduced in effectiveness by any marking procedure for instance by making a part of the shell so thin as to cause a fracturing of the shell and the integrity is.. therefore of the shell as a container.

The discovery of this invention is that the use of a very high energy light pulse for a very short duration will cause a pyrolysing of the surface of some of the gelatine material which does not appear to substantially degrade the surface thickness, does not provide mal-odour, 0- any taste intrusion and which furthermore creates in the samples treated in this way thusfar a white clearly visible marked finish.

Such a high energy light pulse is most effectively achieved by using an appropriate laser source which conveniently provides coherent light but more importantly provides a pulse of such leading edge 25. characteristic and duration together with power concentration such that this effect is achieved.

It is to be noted that in the ordinary heating or even burning of gelatine this will not apparently cause a clearly defined white surface and it is therefore the discovery that by using extremely high 3d. temperature effects but for a very limited time, causes the material to

form a different character which in the preferred instance creates a relatively hardened white specular surface.

The invention can be said in one form then to reside in a method of marking a gelatine capsule which comprises subjecting the surface of 5. the capsule to a high intensity short duration of light.

The term "light" presumes that this can include ultra-violet and infrared sources and it therefore in its broadest sense not intended to be limited simply to optically visible light.

In preference, it is the external surface of the gelatine capsule o. which is marked and the surface is subjected to light with sufficient intensity to ensure the formation of a white residue, and for a duration less than that which may cause undue penetration through the thickness of the capsule wall.

The invention can also reside in a capsule comprises of gelatine is- which has been marked by being subjected to a high intensity short duration of light.

In preference such a capsule has the surface marking visible by a white specular finish. In preference, the gelatine is chosen so that it is appropriate as an edable gelatine and it is further chosen so as to have a 20. bloom count of approximately 250.

in preference, the method of marking the gelatine capsules includes locating a capsule within a target area triggering a pulse of light through a mask the light being in the form of high intensity light and being effected for a very short duration, and then ejecting the Z5-. capsule from the target position.

In the preferred embodiment, a carbon-dioxide laser which uses a mixture of helium, carbon-dioxide, carbon-monoxide and nitrogen is used to provide a light pulse which has an approximate energy concentration within the range of 1 to 3 multiplied by 10 ¹⁰ joules per square 30. centimetre with a leading edge rise time in the approximate range of 1 to 10 nanoseconds and with a pulse duration of 10 microseconds.

This pulse for this period is focused through a mask containing appropriate indicia with the light then being focused onto a surface of a gelatine capsule having a bloom count of 250.

The effect is to cause with temperatures raised to the - approximate level of 15,000° Celcius a pyrolising of the surface of the gelatine capsule having a 0.2 millimetres shell thickness.

With the rapid rise time, a plasma is created providing free electrons and free ions such as to provide apparently substantial energy separation to limit further melting and burning of the gelatine surface ^Q - but providing for such surface as is immediately contacted, that this is converted into a white brittle expanded material which then protrudes slightly from the surface of the gelatine.

Such a surface has a white slightly crystal ine and therefore perhaps specular type surface finish which is easily visible for those 5- subsequently needing to refer to the marking information.

The white pyrolised surface material on such examination as can be conducted has shown itself to be stable and substantially long lasting and substantially adhering to the remaining surface of the gelatine.

It does not appear to provide any mal-odour and does not appear to 20- be noxious and therefore the gelatine remains an edible component and suitable for pharmacological and suitable physiological purposes.

As an alternate marking system, further development is being conducted using a rare gas halide laser source which will provide a light source in the ultraviolent range which provides a duration in the range of 25- ιo to 20 nanoseconds with a rise time in the range of 1 to 10 nanoseconds and with an intensity of the range of 1 to 3 by 10 ¹⁰ joules per square centimetre.

A repetitive cycle rate of as much as 500 hertz can be appropriate and on such investigation as has been thus far conducted, this would 30. provide also an effective marking method.

in a further example, a solid state so called VAG laser can be used providing for a 50 cycle per second repetition rate but once again from experiments thus far conducted, this will also provide an appropriate surface marking in accord with the previous descriptions.

£.. The advantage of being able to provide an edible gelatine which is able to be efficiently marked with an easily changeable marking provides for an extremely advantageous result especially where the edible container may be required to contain drugs having a limited shelf life so that a batch number or a date maybe efficiently marked thereon.

^Q - The marking in fact is easily visible, is white so that it does look satisfactory for consumer purposes and as previously stated would appear to comply with any foodstuff regulations.