an embodiment of the present invention includes an immediate release unit - dose composition for the once - a - day administration of glimepiride , along with a thiazolidinedione , such as for example , pioglitazone or rosiglitazone , which is physically and chemically stable , and releases each drug from the unit - dose composition at a rate similar to that of the individually marketed products such as , for example , glimepiride from amaryl ™ ( aventis ), and pioglitazone from g - tase ™ ( unichem ) or rosiglitazone from avandia ™ ( smith kline beecham ). another embodiment of the present invention further includes processes for the preparation of such compositions and their use for the control of hyperglycemia in the treatment of niddm and associated conditions . in accordance with the invention , any salts , solvates , hydrates , polymorphs , complexes and such other products of glimepiride , may also be employed . according to an embodiment of the invention , the particle size of the glimepiride is such that the mean particle size is less than about 30 microns , and the particle size distribution is such that at least 90 % of the glimepiride particles are less than about 75 microns . preferably , the particle size of the glimepiride is such that the mean particle size is about 25 microns , and the particle size distribution is such that at least 90 % of the glimepiride particles are less than about 60 microns . according to another embodiment , the micronized glimepiride is evenly distributed over different sized sieve fractions of thiazolidinedione and other excipients resulting in a homogenous mixture . furthermore , during processing constituent segregation is minimized resulting in a powder blend with good content uniformity . the glimepiride of the invention is preferably present in an amount of from about 0 . 2 % to about 8 % by weight , more preferably from about 0 . 5 % to about 3 . 5 % by weight of the total composition . the thiazolidinediones that could be used in accordance with the unit - dose combinations of the present invention include , but are not limited to , pioglitazone and rosiglitazone , and other medicinally active and pharmaceutically acceptable forms from the glitazone class of compounds , including their salts , solvates , hydrates , polymorphs , complexes and such other products . preferably , the pharmaceutical composition of the invention includes each drug , glimepiride and the thiazolidinedione , in an amount that is typically administered for a given period of time . this amount includes a pharmaceutically effective amount of the drug , which is an amount large enough to significantly positively modify the condition to be treated , but small enough to avoid serious side - effects ( at a reasonable benefit / risk ratio ), within the scope of sound medical judgement . the thiazolidinedione of the invention is preferably present in an amount of from about 0 . 5 % to about 45 % by weight of the total composition . in those embodiments of the invention where the thiazolidinedione is pioglitazone or a pharmaceutically acceptable salt of pioglitazone , it is preferably present in an amount of from about 4 % to about 45 % by weight , more preferably from about 12 % to about 38 % by weight , of the total composition . in embodiments of the present invention where the thiazolidinedione is rosiglitazone or a pharmaceutically acceptable salt of rosiglitazone , it is preferably present in an amount of from about 0 . 5 % to about 10 % by weight , more preferably from about 1 . 5 % to about 7 % by weight , of the total composition . according to an embodiment of the present invention , the pharmaceutical composition may also contain other conventional pharmaceutically acceptable excipients known in the art of formulation development . the present invention is not to be construed as being limited to any particular excipient or class of pharmaceutical excipients . in addition , any adjuvants employed are preferably selected such that there is no interaction that would substantially reduce the pharmaceutical efficacy of the composition of the present invention . pharmaceutical excipients used are preferably of high purity and low toxicity to render them suitable for administration . the choice of these excipients and the amounts to be used is considered to be within the purview of one of ordinary skill in the art and would depend on the type of individual dosage form . such excipients include , but are not limited to , binding agents , diluents , disintegrants , glidants , wetting agents , lubricating agents , pigments , dyes and the like , and are known to persons skilled in the art of developing and manufacturing pharmaceutical solid oral dosage forms . examples of the binding agents which may be used in the present invention include , but are not limited to , hydroxypropyl cellulose , hydroxyethyl cellulose , sodium carboxymethyl cellulose , polyvinylpyrrolidone , alginates , starches , polysaccharides , and / or mixtures thereof . when present , the binder agent preferably comprises about 1 % to about 10 % by weight of the total composition . according to another embodiment of the present invention , the pharmaceutical composition may also contain one or more of a water - soluble and / or a water dispersible diluent . examples of water soluble diluents that may be used in the present invention include , but are not limited to , lactose , calcium sulphate , calcium phosphates , mannitol , dextrates , dextrin , dextrose , sucrose and the like . water dispersible diluents , which refer to water insoluble pharmaceutical excipients that disperse readily in water , include but are not limited to , cellulose based excipients such as microcrystalline cellulose , powdered cellulose , starches such as corn starch , pregelatinized starch , clays or clay minerals such as kaolin , bentonite , attapulgite , and the like . when present , the diluent preferably comprises about 15 % to about 85 % by weight of the total composition . suitable disintegrating agents that may be used in the present invention include but are not limited to starch , croscarmellose sodium , sodium starch glycolate , crospovidone , cross - linked carboxymethyl starch , magnesium aluminium silicate , polyacrylin potassium , and the like . when present , the disintegrating agent is preferably present in an amount of from about 1 % to about 10 % by weight of the total composition . in accordance with the present invention , other additives , such as for example , surface active agents , bioavailability modifiers , modifiers for absorption and the like , may also be present in the composition , and when present , they preferably comprise about 0 . 5 % to about 5 % by weight of the total composition . according to a further embodiment of the invention , the composition may optionally include a buffering agent , complexing agent and the like . according to the present invention , the pharmaceutical composition may be prepared in a variety of forms including , but not limited to , pellets , beads , granules , tablets or capsules . in those embodiments of the present invention wherein the pharmaceutical composition is in the form of a solid dosage form , it may contain in addition to the above ingredients , pharmaceutical - grade magnesium stearate or stearic acid and the like as a glidant , talc and the like as an anti - adherent , silicon dioxide or hydrogenated vegetable oil and the like as a lubricant , and ferric oxide and the like as a coloring agent . according to an embodiment of the present invention , the pharmaceutical composition may be optionally coated with a rapidly dissolving water - soluble film coat . the examples of water - soluble polymers include , but are not limited to , hydroxypropyl methylcellulose , hydroxypropyl cellulose , and the like . when such an optional coat is present , the solid unit dosage form in accordance with the present invention is preferably coated to a weight build - up of about 1 % to about 10 % by weight , more preferably from about 1 % to about 4 % by weight of the total composition . in those embodiments of the present invention wherein the pharmaceutical composition is in the form of a capsule dosage form , the capsule shell may be , for example , of a hard gelatin or a soft gelatin type . in accordance with an embodiment of the present invention , glimepiride is subjected to micronization using any milling apparatus whereby it is reduced to a very fine powder due to attrition of the particles by collisions between particles and between particles and machine surfaces . the micronization may be advantageously carried out in an accelerated air - jet mill wherein collision of drug particles with each other under a high pressure stream of air causes reduction of particle size and increases the specific surface area of the material , manifold . the period of milling may vary depending on the size of the mill , the velocity of the air , the type of feed material and the quantity of feed material . the effects of these variables are well known in the art , and the present invention may be processed over a range of these variables . however , the comminution operation is preferably carried out until the powder obtained is such that the mean particle size is less than 30 microns and the particle size distribution is such that at least 90 % of the particles are less than about 75 microns . in an embodiment of the method of the present invention , the pharmaceutical composition is prepared by blending drugs , such as glimepiride and a thiazolidinedione , with pharmaceutically acceptable excipients , such as inert diluents and the like . the blend is directly compressed into tablets or may be filled into capsules . in another embodiment for the process of preparing the composition of the present invention , the drugs are blended with excipients , and the blend is roll compacted and then sized to obtain granules . the granules may be filled into capsules or compressed into tablets . in yet another embodiment for the process of preparing the composition of the present invention , the drugs are blended with above - mentioned excipients , and the blend is granulated with a solution of a binder . the granules so obtained are dried , sized and may be filled into capsules or compressed into tablets . in those embodiments of the present invention wherein the foregoing composition is , for example , a tablet dosage form , the glimepiride and the rosiglitazone or pioglitazone may be intimately dispersed in the same tablet matrix or a bilayered tablet may be prepared which encompass formulations where two separate layers are prepared by the compression of individual granules containing the two active agents , or one active agent is present in a coating which is formed on a core containing the second active agent . in those embodiments of the present invention wherein the foregoing composition is , for example , a capsule dosage form , it may contain a simple blend of the two active agents with the addition of suitable excipients or non - pareil sugar seeds and the like coated with the active ingredients filled into the capsule shells . of course , the use of a tablet of one active and a powder or granules of the other active , both filled into a capsule is well within the spirit or scope of this invention as well . in those embodiments of the present invention wherein the foregoing composition is in the form of spherical pellets or beads , such dosage forms may be produced by known techniques of extrusion and spheronisation techniques or techniques based on high shear granulation or fludized bed techniques , for example . furthermore , embodiments of the invention including single unit pellets can be produced on an industrial scale using lozenge and troches cutting machines . according to an embodiment of the invention , the combination unit - dose compositions could contain , for example , from about 0 . 5 to about 10 mg of glimepiride , and from about 5 to about 50 mg of pioglitazone or about 0 . 5 to about 10 mg of rosiglitazone . preferably , these combination unit - dose compositions could contain from about 1 to about 4 mg of glimepiride , and from about 15 to about 45 mg of pioglitazone or about 2 to about 8 mg of rosiglitazone . as would be understood by one of ordinary skill in the art , for any particular subject being treated , e . g ., a mammal , specific dosage regimens should be adjusted according to the individual need , and such individual dosage regimens are within the scope of the invention . it is further to be understood that the dosages set forth herein are examples only and they do not to any extent limit the scope of the practice of the present invention . preferably , the compositions of the invention are administered to the patients in need thereof either immediately before or after a meal in the morning or at night . that is , the preferred times for administering the compositions of the present invention are anytime within approximately 5 - 60 minutes before or after a meal in the morning , such as breakfast , or an evening meal , such as dinner . the following examples further illustrate this invention and are not to be construed as limiting the scope of the invention . the examples are illustrative only and are to be read in conjunction with the description above to provide a further understanding of the present invention , and an exemplary outline of the process for preparing the composition of the invention . this example illustrates the present invention in the form of unit - dose tablet containing glimepiride and pioglitazone as the active ingredients . the pharmaceutical composition of this example is given below in table 1 . in this example micronized glimepiride ( particle size of about 25 μ ) was mixed with a part of lactose monohydrate in geometric proportion . pioglitazone hydrochloride was added to the above blend and mixed well . microcrystalline cellulose and remaining part of lactose monohydrate were further added to the above mixture and granulated with a dispersion of polyvinylpyrrolidone in isopropyl alcohol . the dried granules were sifted through a 850 μm mesh ( british standard sieve ( bss ) no . 18 ). the sized granules were blended with crosslinked polyvinylpyrrolidone , magnesium stearate , talc and colloidal silicon dioxide prior to compression into tablets . hydroxypropyl methylcellulose and polyethylene glycol were dissolved in a mixture of methylene chloride and isopropyl alcohol . titanium dioxide was then dispersed in the above solution and homogenized . the tablets were film coated with this coating solution to a desired weight gain . the coated tablets prepared above according to example 1 were tested for the uniformity of content of pioglitazone and glimepiride . ten ( 10 ) sample tablets ( denoted below in table 2 as cu - 1 through cu - 10 ) demonstrated an assay of glimepiride of 101 . 21 % of label claim ( 1 mg per tablet ) with a uniformity of content of 101 . 04 %± 5 . 48 % and an assay of pioglitazone of 100 . 16 % of label claim ( 15 mg per tablet ) with a uniformity of content of 101 . 88 %± 5 . 43 %. the content uniformity of each tablet studied in this example is given below in table 2 . the dissolution profile of the unit - dose combination composition as prepared above according to example 1 , was compared to the profiles of each of the individually marketed products contained therein . the dissolution profile for pioglitazone from the unit - dose combination composition of example 1 above was compared to that obtained for pioglitazone ( 15 mg ) from its individually marketed form ( g - tase ™ ( unichem )). the dissolution results are recorded in table 3 and the profiles are given in fig1 . as shown in fig1 which plots the data from table 3 , the unit - dose combination composition of example 1 releases the pioglitazone at a substantially similar rate to that of the individually marketed product . furthermore , the dissolution profile for glimepiride from the unit - dose combination composition of example 1 was compared to that of glimepiride from its individually marketed form ( amaryl ™ ( aventis )). the dissolution results are recorded in table 4 and the profiles are given in fig2 . as shown in fig2 which plots the data from table 4 , the unit - dose combination composition of example 1 releases the glimepiride at substantially the same rate as the individually marketed product . the unit - dose combination composition of example 1 , was also subjected to accelerated stability testing by storing the product in controlled temperature chambers at 40 ° c . and 75 % relative humidity for three ( 3 ) months . there was no change in the physical properties of the tablets such as color and shape . furthermore , there was no chemical degradation of the active agents as seen from the assay values at three months , which were 100 . 68 % and 99 . 11 % of the respective label claims of pioglitazone and glimepiride . thus , this example 1 , which employs pioglitazone hydrochloride and glimepiride as the active agents of the composition , shows that the novel unit - dose combination composition of the present invention is physically and chemically stable under accelerated stability testing conditions of elevated temperature and humidity . this example illustrates the present invention in the form of unit - dose tablet containing pioglitazone ( 15 mg ) and a higher dose of glimepiride ( 2 mg ) than was used in example 1 . the pharmaceutical composition of this example is given below in table 5 . the coated tablets of example 2 were tested for the uniformity of content of pioglitazone and glimepiride . ten ( 10 ) sample tablets ( denoted below in table 6 as cu - 1 through cu - 10 ) demonstrated an assay of glimepiride of 100 . 22 % of label claim ( 2 mg per tablet ) with a uniformity of content of 99 . 44 %± 3 . 73 % and an assay of pioglitazone of 100 . 63 % of label claim ( 15 mg per tablet ) with a uniformity of content of 100 . 37 %± 3 . 56 %. the content uniformity of each tablet studied in this example is given below in table 6 . the dissolution profile for pioglitazone and glimepiride from the unit - dose combination composition of example 2 was studied as described previously in example 1 . the dissolution results for pioglitazone as recorded in table 7 and as plotted in the profiles given in fig3 reveal that pioglitazone is released from the unit - dose combination composition of example 2 at a substantially similar rate to that of the individually marketed product . the dissolution results for glimepiride as recorded in table 8 and as plotted in the profiles given in fig4 reveal the release of glimepiride from the unit - dose combination composition of example 2 is at substantially the same rate as the individually marketed product . the unit - dose combination composition of example 2 , was also subjected to accelerated stability testing as described in example 1 . the results reveal no change in the physical properties of the tablets such as color and shape . further , results indicated no chemical degradation of the active agents as seen from the assay values at three months , which were 98 . 47 % and 98 . 42 % of the respective label claims of pioglitazone and glimepiride . thus , this example 2 , which employs pioglitazone hydrochloride and higher dose of glimepiride shows that the novel unit - dose combination composition of the composition is physically and chemically stable under accelerated stability testing conditions of elevated temperature and humidity . this example illustrates the present invention in the form of unit - dose tablet containing glimepiride ( 1 mg ) and higher dose of pioglitazone ( 30 mg ) than was used in examples 1 or 2 , and a lower amount of diluent was used to regulate the release profiles . the pharmaceutical composition of this example is given below in table 9 . the coated tablets prepared above were tested for the uniformity of content of pioglitazone and glimepiride . ten ( 10 ) sample tablets ( denoted below in table 10 as cu - 1 through cu - 10 ) demonstrated an assay of glimepiride of 99 . 78 % of label claim ( 1 mg per tablet ) with a uniformity of content of 100 . 37 %± 3 . 53 % and an assay of pioglitazone of 101 . 37 % of label claim ( 30 mg per tablet ) with a uniformity of content of 100 . 28 % 2 . 73 %. the content uniformity of each tablet studied in this example is given below in table 10 . the dissolution profile for pioglitazone and glimepiride from the unit - dose combination composition of example 3 was studied as described previously in example 1 . the dissolution results for pioglitazone as recorded in table 11 and as plotted in the profiles given in fig5 reveal that pioglitazone is released from the unit - dose combination composition of example 3 at a substantially similar rate to that of the individually marketed product . the dissolution results for glimepiride as recorded in table 12 and as plotted in the profiles given in fig6 reveal that the release of glimepiride from the unit - dose combination composition of example 3 is at substantially the same rate as the individually marketed product . the unit - dose combination composition of example 3 was subjected to accelerated stability testing as described previously in example 1 . the results reveal no change in the physical properties of the tablets such as color and shape . further , results indicated no chemical degradation of the active agents as seen from the assay values at three months which were 99 . 84 % and 98 . 04 % of the respective label claims of pioglitazone and glimepiride . thus , example 3 , which employs glimepiride and higher dose of pioglitazone hydrochloride than was used in examples 1 or 2 , with lower amounts of diluent , shows that the combination composition of this example is physically and chemically stable under accelerated stability testing conditions of elevated temperature and humidity . this example illustrates the present invention in the form of unit - dose tablet wherein higher dose of both glimepiride ( 2 mg ) and pioglitazone ( 30 mg ) was used . the pharmaceutical composition of this example is given below in table 13 . the coated tablets of example 4 were tested for the uniformity of content of pioglitazone and glimepiride . ten ( 10 ) sample tablets ( denoted below in table 14 as cu - 1 through cu - 10 ) demonstrated an assay of glimepiride of 100 . 32 % of label claim ( 2 mg per tablet ) with a uniformity of content of 101 . 23 %± 2 . 94 % and an assay of pioglitazone of 100 . 68 % of label claim ( 30 mg per tablet ) with a uniformity of content of 100 . 95 %+ 3 . 00 %. the content uniformity of each tablet studied in this example is given below in table 14 . the dissolution profile for pioglitazone and glimepiride from the unit - dose combination composition of example 4 was studied as described previously in example 1 . the dissolution results for pioglitazone as recorded in table 15 and as plotted in the profiles given in fig7 reveal that pioglitazone is released from the unit - dose combination composition of example 4 at a substantially similar rate to that of the individually marketed product . the dissolution results for glimepiride as recorded in table 16 and as plotted in the profiles given in fig8 reveal the release of glimepiride from the unit - dose combination composition of example 4 at substantially the same rate as the individually marketed product . the unit - dose combination composition of example 4 was subjected to accelerated stability testing as described previously in example 1 . the results reveal no change in the physical properties of the tablets such as color and shape . furthermore , results indicated no chemical degradation of the active agents as seen from the assay values at three months which were 99 . 32 % and 98 . 83 % of the respective label claims of pioglitazone and glimepiride . thus , example 4 , which employs higher doses of glimepiride and pioglitazone hydrochloride shows that the novel unit - dose combination composition of the present invention is physically and chemically stable under accelerated stability testing conditions of elevated temperature and humidity .
a unit - dose pharmaceutical composition for the treatment of non - insulin dependent diabetes mellitus includes a combination of glimepiride and a thiazolidinedione insulin sensitizer , providing for the simultaneous release of each drug at rates substantially similar to those obtained with the separate administration of immediate release dosage forms of glimepiride and the thiazolidinedione . in addition , processes for the preparation of such combination unit - dose compositions and the use of such compositions for improving glycemic control are described .