FORMULATION AND EVALUATION OF MOUTH DISSOLVING TABLETS OF MONTELUKAST SODIUM

Convenience of administration and patient compliance are gaining significant importance in the design of dosage forms. Despite of tremendous innovations in drug delivery, the oral route remains the preferred route for administration of therapeutic agents because of accurate dosage, low cost therapy, self medication, non invasive method and ease of administration leading to high level of patient compliance . US-FDA: United States Food and Drug Administration defined orally disintegrating tablets as “A solid dosage form containing medicinal substance or active ingredients which disintegrate rapidly usually within a matter of seconds when placed upon the tongue”. These results to a rapid onset of action and greater bioavailability of the drug than those observed from conventional tablet dosage forms . These are novel types of tablets that disintegrate/dissolve/disperse in saliva .They are also suitable for the mentally ill and bed ridden patients who do not have easy access to water. The benefit in terms of patient compliance, rapid onset of action, increased bioavailability and good stability makes these tablets popular as a dosage form of choice in the current market.


INTRODUCTION
Mouth dissolving tablets are those that disintegrate and dissolve rapidly in saliva within a few seconds without the need of chewing and drinking water. A mouth dissolving tablet usually dissolves in oral cavity within 15 sec to 3min. [1][2][3] Mouth dissolving tablets (MDT) or Fast dissolving tablets or melt in mouth or rapid dissolving tablet is the name coined for these tablets. MDTs are the most widely preferred commercial products to obviate the problems associated with conventional dosage forms. Mouth dissolving tablets have been developed having good hardness, dose uniformity, easy administration, and serves as the first choice of dosage form for paediatrics, geriatrics, and travelling patients. 4,5 The technologies used for mouth dissolving tablets are freeze drying, spray drying, tablet molding, sublimation, sugar-based excipients, tablet compression and disintegrant addition. [6][7][8]

MATERIAL AND METHODS
Montelukast sodium was obtained as a gift sample from Ind Swift Pvt. Ltd. Crosscarmellose Sodium and sodium starch glycolate were obtained from Loba chem. Pvt. Ltd and Crosspovidone and Microcrystalline cellulose were obtained from Signet Chem Pvt. Ltd, Mumbai. All the other raw materials were of pharmacopoeial grade.

Pre-formulation study
Standardization of drug was carried out using phosphate buffer 6.8 by UV spectrophotometer. Solubility analysis of drug in various solvents like distilled water and phosphate buffer pH 6.8 was carried out.

PREPARATION OF MOUTH DISSOLVING TABLETS BY DIRECT COMPRESSION METHOD
Mouth dissolving tablets of Montelukast sodium were prepared firstly using different excipients ( diluents and superdisintegrants) and then evaluated for various parameters like wetting time, friability, hardness, disintegration time and dissolution studies to select the best combination for the preparation of Montelukast sodium tablets.

EVALUATION OF TABLETS
Tablets were evaluated for various parameters such as hardness, friability, weight variation, wetting time, disintegration time and in vitro release. Hardness was measured by Monsanto hardness tester. Disintegration test was performed on six tablets using disintegration test apparatus using distilled water as disintegrating medium at 37 • C±2 • C.Friability was determined in Roche friabilator by taking ten tablets. Drug release was carried out using USP Type 2 apparatus in phosphate buffer pH 6.8 with sample withdrawn at regular intervals and analysed using UV/Vis spectrophotometer at wavelength of 287nm.

RESULTS AND DISCUSSION
The results of preformulation studies indicated that the drug was of acceptable standards with 99.8% purity. For the preparation of mouth dissolving tablets of Montelukast sodium and various superdisintegrants were screened for the best formulation. All the tablets passed weight variation test. Disintegration time of all the tablets was found varying from 65sec to30 secs all the tablets were found within the specification limit of FDA ( i.e., less than 3 min). All the tablets were having hardness more than 3 kg/cm 2 . Friability of tablets of all the batches were less than 1% w/w.
In this study three superdisintegrants have been used that is crosscarmellose sodium, crosspovidone and sodium starch glycolate. Out of these three sodium starch glycolate has been found to be relatively better because it releases the drug at faster rate because of its rapid and enormous swelling index and tablets were wetted earlier prepared with sodium starch glycolate.

CONCLUSION
In the present research work, an attempt was made to formulate and evaluate mouth dissolving tablets of Montelukast sodium for the treatment of asthma. Oral drug delivery has been known for decades as most utilized route of administration among all the routes that have been explored for systemic delivery of drug. Oral route of drug administration has wide acceptance upto 50-60% of total dosage form because of self medication, pain avoidance and most important the patient compliance. One important drawback of this dosage form for some patients is difficult to swallow, motion sickness and in allergic conditions. Montelukast Sodium has been selected as choice of drug because of its lower bioavailiblity and need of faster onset of action in case of asthamatic patients and chronic allergic conditions. So, it can be concluded that mouth dissolving tablets of montelukast sodium is the better option to control the risk of asthma because such tablets would release the drug immediately when placed upon tongue.