TITE: A DISINTEGRATING TABLET FOR PRODUCING STABLE NANO-DISPERSION IN WATER.
FIELD OF INVENTION:
This invention relates to a disintegrating tablet for producing stable nano-dispersion in water.
BACKGROUND OF THE INVENTION:
Nanofluids are prepared using nanoparticles in powder form. However, the tablet form has several advantages over the powder form, such as relative and shipment and convenience in use and in storing for retailers.
US Patent WO/2005/110376 discloses a similar application for medicinal use of an orally-administered, rapidly disintegrating tablet. The tablet comprises: titanium dioxide; a super disintegrant; and a sugar alcohol. When immersed in water the tablet has a friability of less than about 2% and disintegrates in less than about 60 seconds.
This present innovation uses titanium dioxide in its nano-crystalline form, which no existing patent has disclosed. This innovation also discloses a novel application of this rapidly disintegrating tablet to prepare stable nanofluids for heat transfer and other applications. The precursor form of titanium dioxide (nano-crystalline form) and the application to prepare nanofluid are the novelty associated with the present invention.

OBJECTS OF THE INVENTION:
An object of this invention is to propose a disintegrating tablet for producing stable nano-dispersion in water;
Another object of this invention is to propose a tablet which, when immersed in water has a friability of less than about 2% and disintegrates in less than about 60 seconds;
Still another object of this invention is to propose a method for preparing a disintegrating tablet for producing stable nano-dispersion;
Yet another object of this invention is to propose a disintegrating tablet that can remain intact during the periods of storage and transportation until being finally delivered to the end-user;
Further, object of this invention is to propose a disintegrating tablet that has friability of less than 2%.
BRIEF DESCRIPTION OF THE INVENTION:
According to this invention there is provided a disintegrating tablet for
producing stable nano-dispersion in water comprising:
10 to 80% by wt titanium dioxide nano particles;
20 to 80% by wt of an organic acid;
20 to 80% wt of an organic base; and
1 to 30% by wt of a binder.

In accordance with this invention there is provided a method for
preparing a rapidly disintegrating tablet comprising:
Removing the lumps from the ingredients by passing through a 20 mesh
sieve;
mixing the ingredients such as titanium dioxide, the organic base,
organic acid and the binder in a blender for few minutes;
subjecting the mixture to Piccola rotary tablet press to form tablet.
DETAILED DESCRIPTION OF THE INVENTION:
Nanofluids are prepared using nanoparticles in powder form. However, the solid, compacted tablet form has several advantages over the powder form, such as relative ease in packaging and shipment and convenience in use and in storing for retailers and consumers alike. The compressed tablet form is particularly well-suited for preparing nanofluids. However, the tablet must disintegrate rapidly in water instantaneously so that the active ingredient Ti02 is delivered to the base fluid (water) to prepare in-situ nanofluids in a minimal time. The present invention includes a rapidly disintegrating tablet comprising (a) about 10% to about 80% titanium dioxide nanoparticles (10 to 100 nm average particle size), (b) about 20% to about 80% of an organic acid, (b) about 20% to about 80% of an organic base and (c) about 1% to about 30% of a binder. All parts, percentages and ratios used herein are expressed by weight unless otherwise specified.
Titanium dioxide provides dual functionality to the rapidly disintegrating as well as the active ingredient for preparing the nanofluids. Titanium dioxide nanoparticles may be in rutile or anatase forms, which are often derived from ilmenite or leuxocene ores. A suitable source of titanium

dioxide nanoparticles are the Aeroxide titanium dioxide (P 25) available from Degussa Inc, Germany. The organic acid base provide the chemical reaction of effervescence that helps the tablet to disintegrate and release the active ingredient in water. The binder aids in binding the active ingredients, organic acids and bases. The list of such binders are those given in the Encyclopedia of Chemical Technology, Vol. 23, 4th Edition, Mary Howe-Grant, editor, John Wiley & Sons, New York, NY (1997) pages 93-113, which is incorporated herein by reference, and include erythritol, xylitol, sorbitol, maltitol, mannitol, lactitol, and the like, used singly and in combinations, with mannitol and sorbitol. The chemical reaction of effervescence facilitates the break-up of a tablet when it is placed in an aqueous environment, such in a nanofluid. Preferably effervescence is provided by reaction of a carbonate salt such as calcium carbonate, sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate with an acid such as citric acid, tartaric acid or malic acid. All tablet formulation ingredients, are weighed together and mixed. Thereafter, the tablets are then manufactured by using a compacting process. A standard single stroke or a rotary press may be used. The tablets prepared according to this invention may be of any geometrical shape, such as round, square, triangular or caplet-shaped, and of any size suitable for any use to prepare nanofluids of any concentration and use. The invention will now be described in more detail with respect to the following, specific, non-limiting examples. Tablets were prepared by weighing all formulation ingredients together on a weighing pan. Typically, a tablet formulation was 100 mg to 1000 mg total weight. Tablets were produced comprising: 10 to 80% by wt titanium dioxide nano particles; 20 to 80% by wt of an organic acid; 20 to 80% wt of an organic base; and 1 to 30% by wt of an binder. The

combined ingredients were passed through a 20 mesh (850pm) sieve to remove any lumps and then bag blended, by gentle inversion in a plastic bag for about 30 seconds of the formulation ingredients previously weighed. The resulting mixture was transferred to a blender (twin shell dry blender) and mixed for 10 minutes. Tablets were formed from the resulting formulation on a 8 -station Piccola rotary tablet press, fitted with 10mm standard concave die punches compacting over a range of compression forces. Tablet weight can be set at 100 to 1000 mg by adjusting the tablet press. All tablets were prepared 24 hours before testing hardness, disintegration time and friability. Tablet hardness (H) expressed in kP, for each formulation, was measured. Tablet disintegration time was determined, according to the USP test. The tablets were repeatedly immersed in 37°C deionized water at a rate of 30 strokes/min. until the tablets disintegrated, as detected and recorded by the instrument. The disintegrating time was less than 10 seconds for each tablet. Tablet friability was determined by placing tablets in a Friabilator set for 100 revolutions. Friability was less than 2% for each tablet.
It seen from above that all formulations provided tablets that could be compressed to an acceptable hardness providing friability of less than 2% and rapid disintegration times of no greater than about 10 seconds. This small friability percentage reflects the fact that the tablets, despite their very fast disintegration times, are also strong and have excellent physical integrity. This means that they can remain intact during the periods of storage and transportation until being finally delivered to the end-user.

It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

WE CLAIM:
1. A disintegrating tablet for producing stable nano-dispersion in water
comprising:
10 to 80% by wt titanium dioxide nano particles; 20 to 80% by wt of an organic acid; 20 to 80% wt of an organic base; and 1 to 30% by wt of a binder.
2. The disintegrating tablet as claimed in claim 1, wherein the average particle size of titanium dioxide is around 10 to 100 mm.
3. The disintegrating tablet as claimed in claim 1, wherein the said binder is selected from erythritol, xylitol, sorbitol, maltitol, mannitol, lactitol, and the like, used singly and in combinations, with mannitol and sorbitol.
4. The disintegrating tablet as claimed in claim 1, wherein the said organic acid is selected from citric acid, tartaric acid and malic acid.
5. The disintegrating tablet as claimed in claim 1, wherein the said organic base is selected from sodium bicarbonate and potassium bicarbonate.
6. A method for preparing a rapidly disintegrating tablet comprising: removing the lumps from the ingredients by passing through a 20 mesh sieve;
mixing the ingredients such as titanium dioxide, the organic base, organic acid and the binder in a blender for few minutes;

subjecting the mixture to Piccola rotary tablet press to form tablet.
7. The method as claimed in claim 1, wherein the titanium dioxide in nano-crystalline form.

A disintegrating tablet for producing stable nano-dispersion in water comprising: 10 to 80% by wt titanium dioxide nano particles; 20 to 80% by wt of an organic acid; 20 to 80% wt of an organic base; and 1 to 30% by wt of an binder.