Orally Disintegrating Tablets

Products, Technologies, and Development Issues
Oct 02, 2005
Volume 29, Issue 10

Over the past three decades, orally disintegrating tablets (ODTs) have gained much attention as a preferred alternative to conventional oral dosage forms such as tablets and capsules. An ODT is a solid dosage form that disintegrates and dissolves in the mouth (either on or beneath the tongue or in the buccal cavity) without water within 60 seconds or less. The US Food and Drug Administration Center for Drug Evaluation and Research (CDER) defines in the Orange Book an ODT as "A solid dosage form containing medicinal substances, which disintegrates rapidly, usually within a matter of seconds, when placed upon the tongue" (1). The European Pharmacopoeia however defines a similar term, orodisperse, as a tablet that can be placed in the mouth where it disperses rapidly before swallowing (2).

Descriptions of orally disintegrating dosage forms.
These tablets are distinguished from conventional sublingual tablets, lozenges, and buccal tablets which require more than a minute to dissolve in the mouth. In the literature, ODTs also are called orally disintegrating, orodisperse, mouth-dissolving, quick-dissolve, fast-melt, and rapid-disintegrating tablets and freeze-dried wafers (see sidebar, "Descriptions of orally disintegrating dosage forms") (3–5).

ODTs release drug in the mouth for absorption through local oromucosal tissues and through pregastric (e.g., oral cavity, pharynx, and esophagus), gastric (i.e., stomach), and postgastric (e.g., small and large intestines) segments of the gastrointestinal tract (GIT). In this article, the term conventional oral dosage forms refers to tablets and capsules that must be swallowed with water for dissolution, release, and absorption of the drug in the stomach and GIT distal sites.

Recent market studies indicate that more than half of the patient population prefers ODTs to other dosage forms (6) and most consumers would ask their doctors for ODTs (70%), purchase ODTs (70%), or prefer ODTs to regular tablets or liquids (>80%) (7). These responses may, in part, be attributed to known ODT advantages such as ease of administration, ease of swallowing, pleasant taste, and the availability of several flavors (8). ODTs also offer clinical advantages such as improved safety and, in some cases, improved efficacy and other broader indications. In addition, several business needs are driving ODT technology development and the commercialization of new products such as the need for expanded product lines, improved life-cycle management, extended patent life, and marketing advantages.

Table I: Summary of orally disintegrating tablet products on the US market (3, 5).
At present, ODTs are the only quick-dissolving dosage form recognized by FDA and listed in Approved Drug Products with Therapeutic Equivalence Evaluations (also called the Orange Book) (3, 9). Table I lists several ODT products that are marketed in the United States. ODT products have been developed for numerous indications ranging from migraines (for which a rapid onset of action is important) to mental illness (for which patient compliance is important for treating chronic indications such as depression and schizophrenia) (3).

This article compares various ODT products and technologies and highlights their manufacturing processes, development issues, and future trends for these evolving dosage forms.

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