INTRODUCTION
Oral delivery is currently the gold standard in the pharmaceutical industry where it is regarded as the safest, most convenient and an economical method of drug delivery having the highest patient compliance [1]. Tablet is most popular among all dosage forms existing today because of convenience of self administration, compactness and easy manufacturing [2]. Many patients express difficulty in swallowing tablets and hard gelatin capsules, resulting in noncompliance and ineffective therapy [3].
To overcome this weakness, scientists have developed innovative drug delivery systems known as fast dissolving tablets [4]. United States Food and drug administration (FDA) defined fast dissolving tablet (FDT) as “a solid dosage form containing medicinal substance or active ingredient which disintegrate rapidly usually within a matter of seconds when placed up on the tongue”[5]. Their characteristic advantages such as administration without water, patient compliance, rapid onset of action, increased bioavailability and good stability make these tablets popular as a dosage form of choice in the current market [6]. Montelukast sodium is chemically designated as [R-(E)]-1-[[[1-[3-[2-(7-chloro-2-quinolinyl) ethenyl] phenyl]-3-[2-(1-hydroxy-1-methylethyl) phenyl] propyl] thio] methyl] cyclopropane acetic acid, monosodium salt, an orally administered drug of choice in the treatment of asthma in adults and children. Other problems like hand tremors, dysphagia in case of geriatric and non cooperative patients. To overcome these drawbacks mouth dissolving tablets or orally disintegrating tablets or fast dissolving tablets has emerged as an alternative oral dosage form [7]. Major challenge for tablets manufacturing comes from the flow properties of the materials to be compressed. Most of the formulations (> 70%) contain excipients at higher concentration than active drug[8]. In recent years drug formulation scientists have recognized that single-component excipients do not always provide the requisite performance to allow certain active pharmaceutical ingredients to be formulated or manufactured adequately[9]. Hence, there is a need to have excipients with multiple characteristics built into them such as better flow, low/no moisture sensitivity, superior compressibility and rapid disintegration ability [10]. Excipients with improved functionality can be obtained by developing new chemical excipients, new grade of existing materials and new combination of existing materials [11]. Many patients express difficult to swallow tablets and hard gelatin capsules and thus does not comply with prescription, which results in high incidence of non-compliance and ineffective therapy. Recent advances in novel drug delivery systems aim to enhance safety and efficacy of the drug molecules by formulating convenient dosage form for administration and to achieve better patient’s compliance. One such approach is fast dissolving tablets) FDT)[12-15]. New combinations of existing excipients are an interesting option for improving excipients functionality because all formulations contain multiple excipients. One such approach for improving the functionality of excipients is coprocessing of two or more excipients. Coprocessing is based on the novel concept of two or more excipients interacting at the sub particle level, the objective of which is to provide a synergy of functionality improvement as well as masking the undesirable properties of individual[16]. Co-processing excipients lead to the formulation of excipients granules with superior properties, compared with physical mixtures of components or individual components, like improved flow properties, improved compressibility, better dilution potential, fill weight uniformity, and reduced lubricant sensitivity[17]. Several co-processed superdisintegrants are commercially available: Ludipress (lactose monohydrate, polyvinyl pyrrolidone and crospovidone), Starlac (lactose and maize starch), Starcap 1500 (corn starch and pregelatinized starch), Ran Explo-C (microcrystalline cellulose (MCC), silica and crospovidone [CP]), Ran Explo-S (MCC, silica and sodium starch glycolate [SSG]), PanExcea MH300G (MCC, and CP)[18].