Volume 4, Issue 2, September – October 2010; Article 015 ISSN 0976 – 044X International Journal of Pharmaceutical Sciences Review and Research Page 87 Available online at www.globalresearchonline.net FAST DISSOLVING TABLETS: PREPARATION, CHARACTERIZATION AND EVALUATION: AN OVERVIEW Md.Nehal Siddiqui * , Garima Garg, Pramod Kumar Sharma Department of Pharmaceutical Technology, Meerut Institute of Engineering and Technology, Baghpat Bypass,Delhi Roorkee Highway, Meerut-250005, U.P. ABSTRACT Oral route is the most preferred route for administration of various drugs because it is regarded as safest, most convenient and economical route. Recently researcher developed the fast dissolving tablet (FDT) with improved patient compliance and convenience. FDTs are solid dosage forms which dissolve rapidly in saliva without chewing and additional water. FDTs overcome the disadvantages of conventional dosage form especially dysphagia (difficulty in swallowing) in pediatric and geriatric patients. This review includes ideal properties, characteristics, challenges in formulation, suitability of drug candidates, various technologies developed for FDT, patented technologies, evaluation methods and various marketed products. Keywords: Fast dissolving tablet, Oral route, Excipients, Oral dissolving tablet. INTRODUCTION The conventional dosage forms (tablet and capsule) have wide acceptance up to 50-60% of total dosage forms.Tablet is still most popular conventional dosage forms existing today because of ease of self administration ,compact in nature, easy to manufacture and it can be deliver in accurate dose. One important drawback of solid dosage forms is the difficulty in swallowing (dysphagia) or chewing in some patients particularly pediatric and geriatric patients. The problem of swallowing is common phenomenon in geriatric patient due to fear of choking, hand tremors, dysphasia and in young individuals due to underdeveloped muscular and nervous systems and in schizophrenic patients which leads to poor patient compliance 1 . Difficulties in swallowing of tablet and capsule are also occur when water is not available, in diarrhea, coughing during the common cold, allergic condition and bronchial infection 2 . Approximately one-third of the population (mainly pediatric and geriatric) has swallowing difficulties, resulting in poor compliance with oral tablet drug therapy which leads to reduced overall therapy effectiveness. For these reason, tablets that can rapidly dissolve or disintegrate in the oral cavity have attracted a great deal of attention 2 . 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 upon the tongue.” Fast dissolving tablets are also known as mouth-dissolving tablets, melt-in mouth tablets, Orodispersible tablets, rapimelts, porous tablets, quick dissolving tablet. Fast dissolving tablets dissolve or disintegrate in the oral cavity without the need of water. Most fast dissolving tablets must include substances to mask the bitter taste of the active ingredient. This masked active ingredient is then swallowed by the patient's saliva along with the soluble and insoluble excipients 3,4 . It has been concluded that faster the dissolution, faster the absorption (only the unionized form of drug) and onset of action. Some drugs are absorbed from the oral cavity, pharynx and esophagus as the saliva passes down into the stomach. Thus the bioavailability of drug is significantly more than those observed from conventional tablets dosage form 5 . The time for disintegration of fast disintegrating tablets is generally considered to be less than one minute 6-9 . The fast dissolving solid dosage form turns into a soft paste or liquid form for easy swallowing, and thus it is free of risk of choking 10,11 . In recent years, a variety of improved methods for delivering drugs have been developed with the aim of improving bioavailability, convenience and patient compliance. Some tablets are designed to dissolve in saliva within a few seconds, and so called true fast-dissolving tablets. Fast dissolving technology offers following advantages 11-16 ,  Improved compliance/added convenience  No water needed  No chewing needed  Better taste  Improved stability  Suitable for controlled as well as fast release actives  Allows high drug loading.  Ability to provide advantages of liquid medication in the form of solid preparation.  Adaptable and amenable to existing processing and packaging machinery  Cost- effective.