FIELD OF INVENTION
It relates to a pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride in a single dosage form, designed to minimize interaction between the two drugs.
BACKGROUND OF THE INVENTION
Cetirizine is a second generation H1 histamine receptor antagonist. In its racemic form, it generally offers some significant advantages over the first generation antihistaminics.
US 5,698,558 discloses that the administration of optically pure enantiomer (-) cetirizine i.e. levocetirizine can reduce or avoid adverse side effects associated with the use of racemic cetirizine. These side effects include sedation, somnolence, headache, gastrointestinal disturbance, dizziness, nausea, cardiac arrhythmias, and other cardiovascular effects.
Montelukast is a leukotriene antagonists and inhibitor of leukotriene biosynthesis. US 5,565,473 discloses montelukast and use of montelukast in pulmonary disorders including diseases such as asthma, chronic bronchitis, and related obstructive airway diseases, allergies and allergic reactions such as allergic rhinitis, contact dermatitis, allergic conjunctivitis, inflammation such as arthritis or inflammatory bowel disease, pain, skin disorders such as psoriasis, atopic eczema, cardiovascular disorders such as angina, myocardial ischemia, hypertension, platelet aggregation and the like.
There have been several reports on the combination of cetirizine, or its enantiomer or salt with one or more leukotriene inhibitors provides synergistic effect for the treatment or prevention of inflammation, asthma or allergic disorder. Furthermore, said combination also avoids or reduces certain side effects associated with HI histamine receptor antagonists.
US 6,384,038 disclose a combination of cetirizine and a leukotriene inhibitor for the treatment or prevention of inflammation, asthma or allergic disorder.
WO 99/32125 discloses a combination of montelukast and antihistaminic drugs for the treatment of inflammation, asthma or allergic disorder and the like.
However, none of the prior art disclose a pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride.

In an attempt to prepare a pharmaceutical composition of montelukast sodium and levocetirizine dihydrochloride, we observed that incomplete in vitro release for montelukast sodium is attained when both the drugs are mixed and granulated together.
Unexpectedly, we have now found that desired in vitro release is attained when a combination of montelukast sodium and levocetirizine dihydrochloride is formulated in a single dosage form, in a manner to minimize observed interaction between the two drugs.
SUMMARY OF THE INVENTION
Hence, the present invention relates to a pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride.
According to one of the aspects, there is provided pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride in a single dosage form wherein there is minimum interaction between both the drugs and said pharmaceutical composition releases 95-99% of montelukast sodium in one hour when measured in USP type I apparatus, at 75 rpm in 900 ml water with 0.5%sodium lauryl sulphate,
In another aspect, there is provided process for the preparation of pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride in a single dosage form wherein there is minimum interaction between both the drugs and said pharmaceutical composition releases 95-99% of montelukast sodium in one hour when measured in USP type I apparatus, at 75 rpm in 900 ml water with 0.5%sodium lauryl sulphate,
In another aspect, there is provided process for the preparation of pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride in a single dosage form comprising the steps of:
i) Preparation of montelukast sodium blend/ granules
a) blending montelukast sodium with one or more pharmaceutically acceptable
excipients,
b) optionally, granulating the blend of step a),

c) lubricating the blend or granules of step a) or step b), ii) Preparation of levocetirizine dihydrochloride blend/ granules
a) blending levocetirizine dihydrochloride and one or more pharmaceutically
acceptable excipients,
b) optionally, granulating the blend of step a),
c) lubricating the blend/granules of step a) or step b),
iii) Compressing the granules or blend of step a) and step b) into a bilayer tablet.
wherein said pharmaceutical composition releases 95-99% of montelukast sodium in one hour when measured in USP type I apparatus, at 75 rpm in 900 ml water with 0.5%sodium lauryl sulphate.
In another aspect, there is provided process for the preparation of pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride in a single dosage form wherein said pharmaceutical composition is prepared by a process comprising the steps of:
i) Preparation of montelukast sodium tablet
a)blending montelukast sodium with one or more pharmaceutically acceptable excipients,
b)optionally, granulating the blend of step a),
c)lubricating the blend or granules of step a) or step b,
d) compressing the blend of step c),
ii) Preparation of levocetirizine dihydrochloride blend
a)blending levocetirizine dihydrochloride with one or more pharmaceutically acceptable excipients,
b)optionally, granulating the blend of step a), c)lubricating the blend or granules of step a) or step b), iii) coating blend of step ii) over the tablet of step i) into a compression coated tablet

wherein said pharmaceutical composition releases 95-99% of montelukast sodium in one hour when measured in USP type I apparatus, at 75 rpm in 900 ml water with 0.5%sodium lauryl sulphate.
In another aspect, there is provided a method of symptomatic treatment of seasonal and perennial allergic rhinitis, the method comprising administering to a subject a pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride in a single dosage form wherein there is minimum interaction between both the drugs and said pharmaceutical composition releases 95-99% of montelukast sodium in one hour when measured in USP type I apparatus, at 75 rpm in 900 ml water with 0.5%sodium lauryl sulphate,
DETAILED DESCRIPTION
We have found that there is an improved in vitro release of montelukast sodium when a formulation in a single dosage form is designed to minimize interaction between the two drugs than the formulations in which both the drugs are mixed and granulated together and compressed as single tablet.
This incomplete dissolution of montelukast sodium, as given in Table 1 (comparative example 1 and 2), may be due to the dihydrochloride salt of levocetrizine which converts montelukast sodium into montelukast base. Montelukast base so formed has a reduced solubility as compared to the sodium salt.
"Levocetirizine" as employed herein means (-) cetirizine dihydrochloride, substantially free of its (+) stereoisomer. Levocetirizine may be used in any of the polymorphic forms.
"Montelukast" as employed herein includes montelukast sodium. It may also include any of the polymorphic form or cis and trans form of a montelukast sodium or mixture thereof.
Pharmaceutical composition may in the form of tablet, capsule or pills.
The pharmaceutical composition may further comprise one or more "pharmaceutically acceptable excipients". They include binders, diluents, lubricant/glidant, disintegrating agent, antioxidants and coloring agents. These excipients may be present as intragranularly or extragranularly.

Specific examples of "binders" include methyl cellulose, hydroxypropyl cellulose (HPC-L), hydroxyl propyl methycellulose, polyvinylpyrrolidone, gelatin, ethyl cellulose, polyvinyl alcohol, pregelatinized starch, carboxymethyl cellulose, sodium alginate, microcrystalline cellulose or mixtures thereof.
The term "diluents" as used herein includes calcium carbonate, calcium phosphate-dibasic, calcium phosphate-tribasic, calcium sulfate, microcrystalline cellulose, cellulose powdered, dextrates, dextrins, dextrose excipients, fructose, kaolin, lactitol, lactose, mannitol, sorbitol, starch, sucrose and mixtures thereof.
Specific examples of lubricants/glidants include colloidal silicon dioxide, stearic acid, magnesium stearate, calcium stearate, talc, hydrogenated castor oil, and mixtures thereof.
Disintegrants may be selected from starches or modified starches such as starch, modified starch, croscarmellose sodium, crospovidone and sodium starch glycolate, cross linked sodium carboxymethylcellulose, hydroxypropyl cellulose (L- HPC) and mixtures thereof.
Coloring agent may be selected from FDA approved colorants and such as Iron oxide, Lake of Tartrazine, Allura red, Lake of Quinoline yellow, Lake of Erythrosine, Titanium dioxide and the like.
The pharmaceutical composition may further be coated with a functional or non functional coating. One or more film-formers such as hydroxy-propylmethyl cellulose (HPMC), HPC, PVA, ethyl cellulose, cellulose acetate, polyvinyl alcohol-maleic anhydride copolymers, and acrylic copolymers may be used. Coating formulation may further comprise one or more plasticizers, such as polyethylene glycol, triethyl citrate, diethyl phthalate, propylene glycol, glycerin, butyl phthalate, castor oil and the like.
The composition may further comprise antioxidant, to protect the drug from oxidative degradation. Antioxidants may be selected from group consisting of ascorbic acid, sodium pyrosulphite, glutathion or sorbic acid, BHT, BHA and propyl gallate.
The pharmaceutical composition may be provided in the form of bilayer tablet wherein first layer comprises montelukast sodium and second layer comprises levocetirizine dihydrochloride .

According to one of the embodiment, there is provided a process for the preparation of bilayer tablet comprising montelukast sodium and levocetirizine dihydrochloride, wherein the process comprises the steps of:
a. Blending montelukast sodium with other pharmaceutically acceptable
excipients,
b. granulating the blend of step a) with a binder solution or granulating fluid,
c. blending levocetirizine dihydrochloride and other pharmaceutically acceptable
excipients,
d. compressing granules of step b) and blend of step c) into bilayer tablet,
e. Optionally, coating the compressed tablets.
According to another embodiment, there is provided a process for the preparation of bilayer tablet comprising montelukast sodium and levocetirizine dihydrochloride, wherein the process comprises the steps of:
a) Blending montelukast sodium with other pharmaceutically acceptable
excipients,
b) granulating the blend of step a),
c) blending levocetirizine dihydrochloride and other pharmaceutically acceptable
excipients,
d) granulating the blend of step c),
e) compressing both the granules of step b) and d) into bilayer tablet,
f) Optionally, coating the compressed tablets.
The pharmaceutical composition may be provided in the form of a compression coated tablet which includes a core comprising montelukast sodium and coating comprising levocetirizine dihydrochloride
According to another embodiment, there is provided a process for the preparation of compression coated tablets comprising montelukast sodium and levocetirizine dihydrochloride, wherein the process comprises the steps of:

a. Blending montelukast sodium with other pharmaceutically acceptable
excipients,
b. optionally, granulating the blend of step a),
c. lubricating the blend or granules of step a) or step b),
d. compressing granules or a blend into suitable size tablet,
e. blending levocetirizine dihydrochloride and one or more pharmaceutically
acceptable excipients,
f. optionally, granulating the blend of step e),
g. lubricating the blend/granules of step e) or step f),
h. Compressing levocetirizine dihydrochloride blend of step g) over the montelukast sodium tablet of step d) to form compression coated tablet.
Alternatively, the pharmaceutical formulation composition may be provided in the form of a compression coated tablet which includes a core comprising levocetirizine dihydrochloride and coat comprises montelukast sodium
According to another embodiment, there is provided a process for the preparation of compression coated tablets comprising montelukast sodium and levocetirizine dihydrochloride, wherein the process comprises the steps of:
a. Blending levocetirizine dihydrochloride with other pharmaceutically acceptable
excipients,
b. optionally, granulating the blend of step a),
c. lubricating the blend or granules of step a) or step b),
d. compressing granules or a blend into suitable size tablet
e. blending montelukast sodium and one or more pharmaceutically acceptable
excipients,
f. optionally, granulating the blend of step e),
g. lubricating the blend/granules of step e) or step f),

h. Compressing montelukast sodium blend of step g) over the levocetirizine dihydrochloride tablet of step d) to form compression coated tablets.
According to another embodiment, there is provided a process for the preparation of film coated tablet comprising montelukast sodium and levocetirizine dihydrochloride, wherein the process comprises the steps of:
a. Blending montelukast sodium with other pharmaceutically acceptable
excipients,
b. optionally, granulating the blend of step a),
c. lubricating the blend or granules of step a) or step b),
d. compressing granules or a blend into suitable size tablet,
e. blending levocetirizine dihydrochloride and one or more pharmaceutically
acceptable excipients,
f. dispersing or dissolving the blend of step e) in a suitable solvent,
g. coating montelukast sodium tablet of step d) with dispersion or solution of
levocetirizine dihydrochloride of step f).
Alternatively, the pharmaceutical formulation composition may be provided in the form of a film coated tablet which includes a core comprising levocetirizine dihydrochloride and coating comprising montelukast sodium
The pharmaceutical composition may be provided in the form of capsules wherein one of the active ingredients is in the form of mini tablet and other in the form of the powder blend.
In another embodiment, there is provided a process for the preparation of a pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride, comprising the steps of
a. Blending montelukast sodium and one or more pharmaceutically acceptable
excipients,
b. optionally, granulating the blend step a),
c. lubricating the blend or granules step a) or step b),

d. compressing the blend or granules of step c) to obtain mini tablets,
e. optionally, coating the compressed mini tablet of step d)
f. blending levocetirizine dihydrochloride and one or more pharmaceutically
acceptable excipients and,
g. Filling the montelukast mini tablet of step d) or step e) and levocetirizine
dihydrochloride blend of step f) into a capsule.
In another embodiment, there is provided a process for the preparation of a pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride comprising the steps of:
a. Blending levocetirizine dihydrochloride and one or more pharmaceutically
acceptable excipients,
b. optionally, granulating the blend,
c. lubricating the blend or granules,
d. compressing into a suitable size mini tablet,
e. optionally, coating compressed mini tablet of step d)
f. blending montelukast sodium and one or more pharmaceutically acceptable
excipients and,
g. Filling the levocetirizine dihydrochloride mini tablet of step d) or step e) and
montelukast sodium blend of step f) into a capsule.
It is also possible that tablet of montelukast sodium and levocetirizine dihydrochloride are filled in '0' size capsule.
In another embodiment, there is provided a process for the preparation of a pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride comprising the steps of:
a. Blending levocetirizine dihydrochloride and one or more pharmaceutically
acceptable excipients,
b. granulating the blend of step a),

c. lubricating the granules of step b),
d. blending montelukast sodium and one or more pharmaceutically acceptable
excipients and,
e. granulating the blend step d),
f. lubricating the granules of step e)
g. Filling the granules of step c) or step f) into a capsule.
Granules can be prepared by dry granulation or wet granulation. Wet granulation may be carried out using granulating fluid or binder solution. Dry granulation may be carried out by roller compaction or slugging.
The solvent used for granulation and coating may be selected from water, alcohols like methyl alcohol, ethyl alcohol or isopropyl alcohol, acetone, and mixture thereof.
The following examples are illustrative of the invention and are not to construed as limiting invention.
EXAMPLES
Comparative Example 1

(Table Removed)

Procedure
a. Montelukast sodium, Levocetirizine dihydrocloride, Lactose monohydrate, HPC-L
and microcrystalline cellulose were blended together
b. Blend of step a) was granulated with purified water
c. Granules of step b) were dried and sifted
d. Crosscarmellose sodium was added to granules and lubricated using magnesium
stearate.
e. Lubricated blend is then compressed into suitable size tablet.
Comparative Example 2
Montelukast sodium granules

(Table Removed)
Levocetirizine dihydrochloride granules
(Table Removed)

Procedure
I) Preparation of montelukast sodium blend
a. Montelukast sodium, Lactose monohydrate, HPC-L and microcrystalline
cellulose were blended together
b. Blend of step a) was granulated with purified water
c. Granules of step b) were dried and sifted
d. Crosscarmellose sodium was added to granules and lubricated using
magnesium Stearate.
II) Preparation of levocetirizine dihydrochloride granules
a. Levocetirizine dihydrochloride, lactose, colloidal silicon dioxide and
microcrystalline cellulose were sifted and blended together
b. Blend of step a) was granulated by slugging
c. Slugs of step b) were desluggged and sized
d. Granules were lubricated using magnesium Stearate
III) Final blending
a. Granules of montelukast sodium of step I) and levocetirizine dihydrochloride of
step II) were blended together
b. Blend of step a) was compressed into suitable size tablet
c. Compressed tablets were coated using white opadry (non aqueous coating).

Example 1
Montelukast sodium granules

(Table Removed)
Levocetirizine dihydrochloride blend

(Table Removed)
Procedure
I) Preparation of montelukast sodium blend
a. Montelukast sodium, lactose monohydrate, HPC-L and microcrystalline cellulose
were blended together
b. Blend of step a) was granulated with purified water
c. Granules of step b) were dried and sifted
d. Crosscarmellose sodium was added to granules and lubricated using magnesium stearate.
II) Preparation of levocetirizine dihydrochloride blend
a. Levocetirizine dihydrochloride , lactose , colloidal silicon dioxide and
microcrystalline cellulose were sifted and blended together
b. Blend of step a) was lubricated with magnesium stearate
III) Granules of montelukast sodium step I) and blend of levocetirizine dihydrochloride
step II) were compressed into bilayered tablet
VI) Compressed tablets of step III) were coated using opadry dispersion in isopropyl alcohol and water
Example 2
It has similar composition and method of preparation as example 1. Instead of opadry dispersion in isopropyl alcohol and water as example 1, opadry dispersion in water was used to coat bilayer tablets.
All the above examples (comparative example 1, 2 and example 1 and 2) were subjected to dissolution study in 900 ml water with 0.5%sodium lauryl sulphate, at 75 rpm using USP type I method. Results (given in table 1 and 2) indicate there was observed an incomplete dissolution of montelukast sodium in comparative example 1 and 2; however dissolution of levocetirizine dihydrochloride was unaffected in these examples. On the other hand example 1 and 2 showed desired release profile w.r.t both the drugs.
Table 1: Dissolution profile of montelukast sodium

(Table Removed)

Table 2: Dissolution profile of levocetirizine dihydrochloride

(Table Removed)
While several particular formulations have been described above, it will be apparent that various modifications and combinations of the formulations detailed in the text can be made without departing from the spirit and scope of the invention. For example, additional exemplary pharmaceutical compositions are given below.
Example 3
Montelukast sodium tablet

(Table Removed)

Levocetirizine dihydrochloride blend

(Table Removed)
Procedure
I) Preparation of montelukast sodium tablet
a. Blend montelukast sodium, lactose monohydrate, HPC-L and microcrystalline
cellulose together
b. Granulate blend of step a) with purified water
c. Dry and sift granules of step b)
d. Add crosscarmellose sodium and yellow iron oxide to granules and lubricate
using magnesium stearate.
e. Compress granules of step d) into suitable size tablet
f. Coat compressed tablets of step e) using aqueous dispersion of opadry white
II) Preparation of levocetirizine dihydrochloride blend
a. Blend levocetirizine dihydrochloride, lactose monohydrate, colloidal silicon
dioxide and microcrystalline cellulose together
b. Lubricate blend of step a) with magnesium stearate
III) Compress levocetirizine dihydrochloride blend of step II) over the montelukast
sodium tablet of step I) to form compression coated tablet.

Example 4
Montelukast sodium blend

(Table Removed)
Levocetirizine dihydrochloride tablet

(Table Removed)
Procedure
I) Preparation of montelukast sodium blend
a. Blend montelukast sodium, lactose monohydrate, HPC-L and microcrystalline
cellulose together
b. Granulate blend of step a) with purified water
c. Dry and sift granules of step b)
d. Add crosscarmellose sodium and yellow iron oxide to granules and lubricate
using magnesium Stearate.
II) Preparation of levocetirizine dihydrochloride tablet

a. Blend levocetirizine dihydrochloride, lactose, colloidal silicon dioxide and
microcrystalline cellulose together
b. Lubricate blend of step a) with magnesium stearate
c. Compress blend of step b) into a suitable size tablet
d. Coat compressed tablets of step c) using aqueous dispersion of opadry white
III) Compress montelukast sodium granule blend of step I) over the levocetirizine dihydrochloride tablet step of II) to form compression coated tablet.
Example 5
Montelukast sodium mini tablet

(Table Removed)

Levocetirizine dihydrochloride blend

(Table Removed)

Procedure
I) Preparation of montelukast sodium mini tablet
a. Blend montelukast sodium, lactose monohydrate, HPC-L and microcrystalline
cellulose together
b. Granulate blend of step a) with purified water
c. Dry and sift granules of step b)
d. Add crosscarmellose sodium and yellow iron oxide to granules and lubricate
using magnesium stearate.
e. Compress granules of step d) into a mini tablet
f. Coat compressed mini tablets of step e) using aqueous dispersion of opadry
white
II) Preparation of levocetirizine dihydrochloride blend
a. Blend levocetirizine dihydrochloride, lactose, colloidal silicon dioxide and
microcrystalline cellulose blended together
b. Lubricate blend of step a) with magnesium stearate
III) Fill capsule with mini tablets of step I) and blend of step II).
Example 6
Montelukast sodium blend

(Table Removed)
Levocetirizine dihydrochloride mini tablet

(Table Removed)
I) Preparation of montelukast sodium blend
a. Blend montelukast sodium, lactose monohydrate, HPC-L and microcrystalline
cellulose together
b. Granulate blend of step a) with purified water
c. Dry and sift Granules of step b)
d. Add crosscarmellose sodium and yellow iron oxide to granules and lubricate
using magnesium stearate.
II) Preparation of levocetirizine dihydrochloride mini tablet
a. Blend levocetirizine dihydrochloride, lactose, colloidal silicon dioxide and
microcrystalline cellulose together
b. Lubricate blend of step a) with magnesium stearate
c. Compress blend of step b) into a mini tablet
d. Coat compressed mini tablets of step c) using aqueous dispersion of opadry
white
III) Fill capsule with blend of step I) and mini tablets of step II).

Example 7
Montelukast sodium tablet

(Table Removed)
Levocetirizine dihydrochloride tablet

(Table Removed)
I) Preparation of montelukast sodium mini tablet
a. Blend montelukast sodium, lactose monohydrate, HPC-L and microcrystalline
cellulose together
b. Granulate blend of step a) with purified water
c. Dry and sift granules of step b)

d. Add crosscarmellose sodium and yellow iron oxide to granules and lubricate
using magnesium stearate.
e. Compress granules of step d) into a mini tablet
f. Coat compressed mini tablets of step e) using aqueous dispersion of opadry
white
II) Preparation of levocetirizine dihydrochloride mini tablet
a. Blend levocetirizine dihydrochloride, lactose, colloidal silicon dioxide and
microcrystalline cellulose together
b. Blend of step a) is lubricated with magnesium stearate
c. Compress blend of step b) into a mini tablet
d. Coat compressed mini tablets of step c) using aqueous dispersion of opadry
white
III) Fill capsule with mini tablet of step I) and mini tablet of step II).

WE CLAIM:
1. A pharmaceutical composition comprising montelukast sodium and levocetirizine
dihydrochloride in a single dosage form wherein there is minimum interaction
between the montelukast sodium and levocetirizine dihydrochloride and said
pharmaceutical composition releases 95-99% of montelukast sodium in one hour
when measured in USP type I apparatus, at 75 rpm in 900 ml water with
0.5%sodium lauryl sulphate.
2. The pharmaceutical composition according to claim 1 wherein said
pharmaceutical composition may further comprises one or more
pharmaceutically acceptable excipients selected from the group consisting of
binders, diluents, lubricant/glidant, disintegrating agent, antioxidants and coloring
agents.
3. The pharmaceutical composition according to claim 1 wherein pharmaceutical
composition is a tablet, capsule or pills.
4. The pharmaceutical composition according to claim 3 wherein tablet is a
bilayered tablet or coated tablet.
5 The pharmaceutical composition according to claim 4 wherein bilayered tablet comprises montelukast sodium in first layer and the second layer comprises levocetirizine dihydrochloride.
6. The pharmaceutical composition according to claim 4 wherein coated tablet is
film coated tablet or compression coated tablet and core comprises montelukast
sodium and coating comprises levocetirizine dihydrochloride.
7. The pharmaceutical composition according to claim 3 wherein capsule
comprises separate granules, separate mini tablets or separate tablets of
montelukast sodium and levocetirizine dihydrochloride.

8 A pharmaceutical composition according to claim 1 wherein said pharmaceutical composition is prepared by a process comprising the steps of:
i) Preparation of montelukast sodium blend/ granules
a)blending montelukast sodium with one or more pharmaceutically acceptable excipients,
b)optionally, granulating the blend of step a), c)lubricating the blend or granules of step a) or step b), ii) Preparation of levocetirizine dihydrochloride blend/ granules
a)blending levocetirizine dihydrochloride and one or more pharmaceutically acceptable excipients;
b)optionally, granulating the blend of step a),
c) lubricating the blend/granules of step a) or step b),
iii) Compressing granules or blend of step i) and step ii) into a bilayer tablet.
9. A pharmaceutical composition according to claim 1, wherein said pharmaceutical composition is prepared by a process comprising the steps of:
i) Preparation of montelukast sodium tablet
a)blending montelukast sodium with one or more pharmaceutically acceptable excipients,
b)optionally, granulating the blend of step a),
c) lubricating the blend or granules of step a) or step b),
d) compressing the blend of step c) into suitable size tablet,
ii) Preparation of levocetirizine dihydrochloride blend/granules
a)blending levocetirizine dihydrochloride with one or more pharmaceutically acceptable excipients,

b)optionally, granulating the blend of step a),
c)lubricating the blend or granules of step a) or step b),
iii) coating blend of step ii) over the tablet of step i) into a compression coated tablet.
10. A pharmaceutical composition comprising montelukast sodium and levocetirizine dihydrochloride in a single dosage form as described herein.