Orally disintegrating tablets also called as fast dissolving or mouth dissolving tablets are such kind of dosage forms which when placed in mouth disintegrates rapidly in a matter of seconds(1). They are different from lozenges or buccal tablets which require more than a minute to get dissolved in mouth(1). Any dosage form or a novel drug delivery system which improves patient compliance is of great interest to scientists in which orally disintegrating tablets stands first among them. Market studies indicated that 70% of the population ask their doctors or prefer to purchase orally disintegrating tablets over conventional tablets or liquids(1). They are more advantageous in case of geriatric or pediatric patients who feel difficulty in swallowing tablets or capsules(1). They are also useful in disease conditions like motion sickness, repeated emesis or coughing where it is difficult to swallow tablet(1).
Many patents have appeared recently describing various formulation approaches for orally disintegrating tablets. Some Orally disintegrating tablets are also available commercially. Many approaches are like cotton candy process, Freeze drying, spray drying compression, wet granulation compression, direct compression followed by sublimation, multiparticulate compression were reported in literature(2). Each of the approaches has their own advantages as well as limitations.
The strategy of compressing multiparticulates or microparticles or crystals into an orally disintegrating tablet is of more interest due to its ease in technology and cost effectiveness. Taste masking is of prime importance in formulating an orally disintegrating tablet. One of the applications of microencapsulation is taste masking(2). Microcapsules or pellets can be compressed into a tablet that can disintegrate in less than a minute(2). Recently, Ethypharm, a drug delivery technology company announced the launch of ODT version of Allegra (Fexofenadine) by applying its proprietary Flashtab(r) technology in US(3). Tramadol, the 4th most prescribed analgesic is available as orodispersible tablet under the brand names Zamadol(r) and Travex(r) in US(3). They generated annual excess sales of 300 million dollars in US in 2006(3). This clearly indicates the potential of orally disintegrating tablets in generating income and extension of product life cycle.
1) William R. Pfister, Tapash K.Ghosh Orally disintegrating tablets Pharmaceutical Technology, October 2, 2005.
2) Honey Goel et. al Orally Disintegrating systems: Innovations in Formulation and Technology Recent Patents on Drug Delivery & Formulation 2008, 2, 258-274. 3) www.ethypharm.com/typo3conf/ext/in_docs/dl.php?id=26 accessed on February 14, 2011.