Overview on Functionality Added Co-processed Excipients for Orodispersible Tablets

Orally disintegrating tablets are an emerging trend in novel drug delivery system and have received ever increasing demand during the last few decades. Orally disintegrating tablets ODTs are the dosage form which will disintegrate in mouth within seconds without need of water. This type of property in dosage form can be attained by addition of different varieties of excipients. But the number of fillers/binders/disintegrant which can be used for ODT formulations is limited because these bulk excipients have to fulfill special requirements, such as being soluble in water, pleasant taste, mouth feel, sweetness, and rapid dispersibility. 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.

New combinations of existing excipients are an interesting option for improving excipient functionality now a day. In excipients mannitol is used as diluents but now a day’s modified mannitol is available which give extensive flow, compression and rapid dispersibility to the tablet e.g. like Orocel, Mannogem EZ, and Pearlitol SD 200. The current review article is prepared to have a look over the recent development in excipient technology and the approaches involved in development of such excipients. It emphasizes on the different examples of functionality added materials also called as multifunctional co processed excipients available in market such as Ludiflash, Pharmburst, and F- MELT.

Introduction

Orally disintegrating tablets (ODTs) have been referred to as fast melt tablets, orodispersible tablets, fast disintegrating dosage forms among others and these terms are often used interchangeably. In 1998, ODTs were classed as a new dosage form by the United States Food and Drug Administration (US FDA) Center of Drug Evaluation and Research (CDER) and defined as: “solid dosage form containing medicinal substances which disintegrates rapidly, usually within a matter of seconds, when placed upon the tongue.”

A guidance document for the industry published by the FDA in 2008 further describes an ODT as a dosage form that can be administered with or without water¹ and disintegrates within 30 sec. based on the United States Pharmacopoeia disintegration test method or alternative. While arbitrary, the criteria of 30 sec. disintegration time as well as a tablet weight of not more than 500mg are intended to differentiate ODTs from chewable and conventional compressed tablets².

Disintegrants are agents added to tablet and some encapsulated formulations to promote the breakup of the tablet and capsule “slugs’ into smaller fragments in an aqueous environment there by increasing the available surface area and promoting a more rapid release of the drug substance. They promote moisture penetration and dispersion of the tablet matrix. Oral route of drug administration is perhaps the most appealing route for the delivery of drugs. Of the various dosage forms administered orally, the tablet is one of the most preferred dosage form because of its ease of manufacturing, convenience in administration, accurate dosing, stability compared with oral liquids and because it is more tamper proof than capsules. The gastrointestinal tract provides sufficient fluid to facilitate disintegration of the dosage form and dissolution of the drug. The large surface area of gastric mucosa favors the drug absorption. Therefore, the oral route has continued to be the most appealing route for drug delivery despite the advancements made in the new drug delivery systems. Rapidly disintegrating tablets have received much attention in recent years, as they are preferred by pediatric and geriatric patients.

Moreover, the drug dissolution is facilitated by the tablets’ quick disintegration. The simplest way to achieve quick disintegration is to use a superdisintegrant in concert with suitable diluents. Superdisintegrants such as croscarmellose sodium, crospovidone, and sodium starch glycolate are frequently used in tablet formulations to improve the rate and extent of tablet disintegration and thereby increase the rate of drug dissolution. Oral tablet administration to patients is a significant problem and has become the object of public attention. The problem can be resolved by the creation of rapidly dispersing or dissolving oral forms, which do not require water to aid swallowing. Among the various methods to design an ODT dosage form, the use of co-processed, functional excipients customized for ODT development is an attractive option to achieve optimal product design with good manufacturing performance.

These co-processed excipients are predominantly based on polyols (mannitol, xylitol, sorbitol, etc.) or carbohydrates, in combination with disintegrants and in some instances, with binders, silicon dioxide and inorganic materials. The combination is designed to physically modify their properties in a manner not achievable by simple physical mixing and without significant chemical change. On the whole, these co-processed excipients claim to have improved physico-mechanical properties (e.g. pleasant mouthfeel, low hygroscopicity, better flow and compactibility) to support processing particularly by direct compression on conventional tablet presses to manufacture harder and less friable ODTs without compromising disintegration times².

The International Pharmaceutical Excipients Council (IPEC) defines excipient as “Substances, other than the API in finished dosage form, which have been appropriately evaluated for safety and are included in a drug delivery system to either aid the processing or to aid  manufacture, protect, support, enhance stability, bioavailability or patient acceptability, assist in product identification, or enhance any other attributes of the overall safety and effectiveness of the drug delivery system during storage or use.”

Table 1: Marketed co-processed excipients for Orodispersible Tablets³

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Sanjay S. Patel, Siddhi V. Shah. Overview on Functionality Added Co-processed Excipients for Orodispersible Tablets. Asian Journal of Pharmaceutical Research 2022; 12(4):323-4. doi: 10.52711/2231-5691.2022.00052