Hirani et al Tropical Journal of Pharmaceutical Research, April 2009; 8 (2): 161-172 © Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria. All rights reserved . Available online at http://www.tjpr.org Review Article Orally Disintegrating Tablets: A Review Jaysukh J Hirani 1* , Dhaval A Rathod 1, Kantilal R Vadalia 2 1Smt. R.D.Gardi B. Pharmacy College, Rajkot-360110, 2Shri H.N.Shukla College of Pharmacy, Rajkot, Gujarat, India. Abstract Drug delivery systems are becoming increasingly sophisticated as pharmaceutical scientists acquire a better understanding of the physicochemical and biochemical parameters pertinent to their performance. Over the past three decades, orally disintegrating tablets (ODTs) have gained considerable attention as a preferred alternative to conventional tablets and capsules due to better patient compliance. ODTs are solid dosage forms containing medicinal substances which disintegrate rapidly, usually in a matter of seconds, when placed on the tongue. Products of ODT technologies entered the market in the 1980s, have grown steadily in demand, and their product pipelines are rapidly expanding. New ODT technologies address many pharmaceutical and patient needs, ranging from enhanced life-cycle management to convenient dosing for paediatric, geriatric, and psychiatric patients with dysphagia. This has encouraged both academia and industry to generate new orally disintegrating formulations and technological approaches in this field. The aim of this article is to review the development of ODTs, challenges in formulation, new ODT technologies and evaluation methodologies, suitability of drug candidates, and future prospects. Keywords : Orally disintegrating tablet, Improved bioavailability, Texture analyser, Nanomelt TM Received: 30 June 2008 Revised accepted: 02 November 2008 *Corresponding author: Email: [email protected]; Tel: + 91 9925062150, +91 (0)281 2488613; Fax no: +91 (0)281 2488614 Trop J Pharm Res, April 2009; 8 (2): 161 Hirani et al Introduction Recent market studies indicate that more than half of the patient population prefers ODTs to 10 For the past one decade, there has been an other dosage forms and most consumers enhanced demand for more patient-friendly would ask their doctors for ODTs (70%), and compliant dosage forms. As a result, the purchase ODTs (70%), or prefer ODTs to 11 demand for developing new technologies has regular tablets or liquids (>80%) . 1 been increasing annually . Since the development cost of a new drug molecule is The US Food and Drug Administration Center very high, efforts are now being made by for Drug Evaluation and Research (CDER) pharmaceutical companies to focus on the defines, in the ‘Orange Book’, an ODT as “a development of new drug dosage forms for solid dosage form containing medicinal existing drugs with improved safety and substances, which disintegrates rapidly, efficacy together with reduced dosing usually within a matter of seconds, when 12 frequency, and the production of more cost- placed upon the tongue” . The significance of effective dosage forms. these dosage forms is highlighted by the adoption of the term, “Orodispersible Tablet”, For most therapeutic agents used to produce by the European Pharmacopoeia which systemic effects, the oral route still represents describes it as a tablet that can be placed in the preferred way of administration, owing to oral cavity where it disperses rapidly before 13 its several advantages and high patient swallowing . compliance compared to many other routes 2. Tablets and hard gelatin capsules constitute a ODT products have been developed for major portion of drug delivery systems that are numerous indications ranging from migraines currently available. However, many patient (for which rapid onset of action is important) to groups such as the elderly, children, and mental illness (for which patient compliance is important for treating chronic indications such patients who are mentally retarded, 14 uncooperative, nauseated, or on reduced as depression and schizophrenia) . liquid-intake/diets have difficulties swallowing these dosage forms. Those who are traveling Descriptions of Orally Disintegra- or have little access to water are similarly ting Dosage Forms 3-5 affected . ODTs are distinguished from conventional To fulfill these medical needs, pharmaceutical sublingual tablets, buccal tablets, and technologists have developed a novel oral lozenges, which require more than a minute to dosage form known as Orally Disintegrating dissolve in oral cavity. In the literature, ODTs Tablets (ODTs) which disintegrate rapidly in also are called orodisperse, mouth-dissolving, saliva, usually in a matter of seconds, without quick-dissolve, fast-melt, and freeze-dried the need to take it water. Drug dissolution and wafers. absorption as well as onset of clinical effect and drug bioavailability may be significantly A freeze-dried wafer is a quick-dissolving, greater than those observed from thin matrix that contains a medicinal agent 6-8 conventional dosage forms . that does not need water for swallowing. This fragile dosage form requires unit-dose Although chewable tablets have been on the packaging to ensure physical stability. The market for some time, they are not the same wafer disintegrates instantaneously in the oral as the new ODTs. Patients for whom chewing cavity and releases drug, which dissolves or is difficult or painful can use these new tablets disperses in the saliva. The saliva is easily. ODTs can be used easily in children swallowed and the drug is absorbed across who have lost their primary teeth but do not the gastrointestinal tract (GIT) 15 . 9 have full use of their permanent teeth . Trop J Pharm Res, April 2009; 8 (2): 162 Hirani et al - An orally disintegrating tablet (ODT) is a • is cost-effective. solid dosage form that contains medicinal substances and disintegrates rapidly (within The Need for Development of ODTS seconds) without water when placed on the tongue. The drug is released, dissolved, or The need for non-invasive delivery systems dispersed in the saliva, and then swallowed 13 persists due to patients’ poor acceptance of, and absorbed across the GIT . and compliance with, existing delivery regimes, limited market size for drug A quick-dissolving tablet (also known as a companies and drug uses, coupled with high fast-dissolving, fast-dissolving multiparticulate, cost of disease management. rapid-dissolving, mouth-dissolving, fast- melting, or orodispersing tablets) is an oral Patient factors 17-20 tablet that does not require water for swallowing. The tablet dissolves within 60 Orally disintegrating dosage forms are seconds when placed in the mouth. The active particularly suitable for patients, who for one ingredients are absorbed through mucous reason or the other, find it inconvenient to membranes in the mouth and GIT and enter swallow traditional tablets and capsules with the blood stream. A fraction of pregastric drug an 8-oz glass of water. These include the absorption may bypass the digestive system following: and metabolism by the stomach acids and enzymes. In general, the tablets are physically • Pediatric and geriatric patients who have robust and can be packaged in multidose 16 difficulty in swallowing or chewing solid containers . dosage forms • Patients who are unwilling to take solid Ideal properties of ODTs preparation due to fear of choking • Very elderly patients who may not be The performance of ODTs depends on the able to swallow a daily dose of technology used during their manufacture. antidepressant. The necessary property of such tablets is the • An eight-year old with allergies who ability to disintegrate rapidly and disperse or desires a more convenient dosage form dissolve in saliva, thereby obviating the need than antihistamine syrup for water. Various technologies have been • A middle-aged woman undergoing developed that enable ODT to perform this radiation therapy for breast cancer may unique function. An ideal ODT should meet be too nauseous to swallow her H - the following criteria: 2 blocker • A schizophrenic patient in an institutional • does not require water for oral setting who may try to hide a administration yet disintegrates and conventional tablet under his or her dissolves in oral cavity within a few tongue to avoid their daily dose of an seconds atypical antipsychotic • has sufficient strength to withstand the • A patient with persistent nausea, who rigors of the manufacturing process and may be journey, or has little or no access post-manufacturing handling to water • allow high drug loading • has a pleasant mouth feel Effectiveness factor • is insensitive to environmental conditions such as humidity and Increased bioavailability and faster onset of temperature action are a major claim of these formulations. • is adaptable and amenable to existing Dispersion in saliva in oral cavity causes pre- processing and packaging machineries gastric absorption from some formulations in Trop J Pharm Res, April 2009; 8 (2): 163 Hirani et al those cases where drug dissolves quickly. Challenges in Formulating ODTS Buccal, pharyngeal and gastric regions are all 21 areas of absorption for many drugs . Any pre- Palatability 11,25 gastric absorption avoids first pass metabolism and can be a great advantage in As most drugs are unpalatable, orally drugs that undergo a great deal of hepatic disintegrating drug delivery systems usually metabolism. Furthermore, safety profiles may contain the medicament in a taste-masked