A REVIEW ON NEW INNOVATIONS AND TECHNOLOGIES IN THE FORMULATION OF ORALLY DISINTEGRATING TABLETS

ABOUT AUTHORS:
YASWANTH ALLAMNENI^1*, NAVYA ALLAMNENI², R AMARNATH¹, T RAMASWAMY CHOWDARY¹, V SATYANARAYANA¹, K VENKATESWARA RAO^1
1Research and Development Department, Natco Pharma Limited, Kothur, Mahaboobnagar, Andhra Pradesh – 509228.
²Department of Pharmaceutical Technology, Narasaraopeta Institute of Pharmaceutical Sciences, Narasaraopeta, Guntur,
Andhra Pradesh, India.
*yaswanthallamneni@gmail.com

ABSTRACT
The main aim of this article was to review the development of ODTs, challenges in formulation, new ODT technologies and evaluation methodologies, suitability of drug candidates, and future prospects.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. Orally disintegrating tablets are also called as orodispersible, quick disintegrating, mouth dissolving, fast disintegrating, rapid dissolving tablets, porous tablets, and rapimelts.Orally disintegrating systems have carved a niche amongst the oral drug delivery systems due to the highest component of compliance they enjoy in patients especially the geriatrics and pediatrics. However, of all the above terms, USP approved these dosage forms as ODTs.  These tablets are distinguished from conventional sublingual tablets, lozenges, and buccal tablets which require more than a minute to dissolve in the mouth. According to the recently issued draft guidance for Industry of orally disintegrating tablets, FDA specifically recommends that, in addition to the original definition for an ODT, ODTs be considered solid oral preparations that disintegrate rapidly in the oral cavity, with an in vitro disintegration time of approximately 30 sec or less according to the united states pharmacopoeia (USP) disintegration method or alternative. ODTs release drug in the mouth for absorption through local oromucosal tissues and through pregastric (e.g., oral cavity, pharynx, and oesophagus), gastric (i.e., stomach) and post gastric (e.g. .small and large intestines) segments of the gastrointestinal tract.

REFERENCE ID: PHARMATUTOR-ART-1285

IMPORTANT IN THIS ARTICLE:

* MECHANISM OF TABLET DISINTEGRATION

* TECHNOLOGIES FOR THE PREPARATION OF ODT’s

INTRODUCTION
ODTs are solid dosage forms containing medicinal substances which disintegrate rapidly, usually in a matter of seconds, when placed on the tongue. Many pharmaceutical dosages are administered in the form of pills, granules, powders, and liquids. Generally, a pill design is for swallowing intact or chewing to deliver a precise dosage of medication to patients. The pills, which include tablets and capsules, are able to retain their shapes under Moderate pressure. However, some patients, particularly pediatric and geriatric patients, have difficulty swallowing or chewing solid dosage forms. Many pediatric and geriatric patients are unwilling to take these solid preparations due to a fear of choking. In order to assist these patients, several fast-dissolving drug delivery systems have been developed.
Fast-dissolving drug delivery in recent years, a variety of improved methods for delivering drugs has been developed with the aim of improving performance, convenience and compliance. ODTs disintegrate and or dissolve rapidly in the saliva without the need for water. Some tablets are designed to dissolve in saliva remarkably fast, within a few seconds, and are true fast-dissolving tablets. Others contain agents to enhance the rate of tablet disintegration in the oral cavity, and are more appropriately termed fast-disintegrating tablets, as they may take up to a minute to completely disintegrate. When put on tongue, this tablet disintegrates instantaneously, releasing the drug, which dissolves or disperses in the saliva. Some drugs are absorbed from the mouth, pharynx and oesophagus as the saliva passes down into the stomach. In such cases, bioavailability of drug is significantly greater than those observed from conventional tablet dosage form. The advantage of orally disintegrating dosage Forms are increasingly being recognized in both industry and academia.
ODTs, as a novel dosage form, have several characteristics to distinguish them from the more traditional dosage forms. Taste-masking is of critical importance in the formulation of an acceptable ODT. Traditional tablet formulations generally do not address the issue of taste masking, because it is assumed that the dosage form will not dissolve until passing the oral cavity. Many oral suspensions, syrups, and chewable tablets simply contain flavors, sugars and other sweeteners to overwhelm or complement the bitter taste of the drug Current methods of taste masking in fast dissolving/disintegrating tablets include sweeteners and flavors; however, these are not a sufficient means for taste-masking many bitter drugs. Most of the FDDT technologies incorporate unique forms of taste masking as well. The primary methods of taste-masking include adsorption onto or complexation with carriers and spray coating of drug particles.
Products of ODT technologies entered the market in the 1980’s, have grown steadily in demand, and their product pipelines are rapidly expanding. The first ODT form of a drug to get approval from the US (FDA) was a Zydis ODT of Claritin (Loratadine) in December 1996. It was followed by a Zydis ODT formulation of Klonopin (Clonazepam) in December 1997, and a Zydis ODT formulation of Maxalt (Rizatriptan) in June 1998. Catalent Pharma Solutions in the U.K., Cima Labsin the U.S. and Takeda Pharmaceutical Company in Japan led the development of ODTs. Recent market studies indicate that most of the patient population prefers ODTs to other dosage forms and would ask their doctors for ODTs (70%), purchase ODTs (70%), or prefer ODTs to regular tablets or liquids (>80%). 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. List of marketed ODT products were shown in Table 1.

Table 1: List of ODT Products Available in the Market

SIGNIFICANCE OF ORALLY DISINTEGRATING TABLETS

Ø  Convenience of administration and accurate dose as compared to liquids. No need of water to swallow the dosage form, which is highly convenient feature for patients who are travelling and do not have immediate access to water.
Ø  Ease of administration to patients who refuse to swallow a tablet, such as pediatric, geriatric, mentally ill, disabled and uncooperative patients.
Ø  Some drugs are absorbed from the mouth, pharynx and oesophagus as the saliva passes down into the stomach; in such cases bioavailability of drugs is increased.
Ø  Good mouth feel property of ODTs helps to change the psychology of medication as “bitter pill” particularly in pediatric patients.
Ø  Ability to provide advantages of liquid medication in the form of solid preparation.
Ø  Rapid dissolution of drug and absorption, which may produce rapid onset of action.
Ø  Insensitive to environmental conditions such as humidity and temperature.

CHALLENGES IN THE FORMULATON OF ORALLY DISNTEGRATING TABLETS
a. Palatability
It is a formidable challenge for formulation scientists to mask the taste of bitter tasting drugs selected for Oral disintegrating tablets. As most drugs are unpalatable, orally disintegrating drug delivery systems usually contain the medicament in a taste-masked form. Hence, taste-masking of the drugs becomes critical to patient compliance.

b. Mechanical strength
In order to allow ODTs to disintegrate in the oral cavity, they are made of either very porous or soft molded matrices or compressed into tablets with very low compression force, which makes the tablets friable or brittle, and difficult to handle. Only few technologies can produce tablets that are sufficiently hard and durable to allow them to be packaged in multidose bottles.

c. Hygroscopicity / Moisture sensitivity
Several orally disintegrating dosage forms are hygroscopic and cannot maintain physical integrity under normal conditions of temperature and humidity. Hence, they need protection from humidity which calls for specialized product packaging.

d. Dose /Amount of drug
The application of technologies used for ODTs is limited by the amount of drug that can be incorporated into each unit dose. Molecules requiring high doses present mainly three challenges to the development of fast dissolve dosage forms; a) taste masking of the active ingredient, b) mouth feel or grittiness and c) tablet size. These challenges are not unrelated because most drugs will require taste masking, the amount of taste masking materials used in different dosage forms will depend on the drugs degree of bitterness relative to its dose, which will in turn affect the final tablet size.

e. Aqueous solubility
Water-soluble drugs pose various formulation challenges because they form eutectic mixtures, which result in freezing-point depression and the formation of a glassy solid that may collapse upon drying because of loss of supporting structure during the sublimation process. Such collapse sometimes can be prevented by using various matrix forming excipients such as mannitol than can induce crystallinity and hence, impart rigidity to the amorphous composite.

f. Size of tablet
The degree of ease in taking a tablet depends on its size. It has been reported that the easiest size of tablet to swallow is 7-8 mm while the easiest size to handle was one larger than 8 mm. Therefore, the tablet size that is both easy to take and easy to handle is difficult to achieve.

g. The Drug Property
Many drug properties could potentially affect the performance of fast dissolving tablets. For example, the solubility, crystal morphology, particle size and bulk density of a drug can affect the final tablet characteristics, such as tablet strength and disintegration.

h. Mouth feel
The ODT should not disintegrate into larger particles in the oral cavity. The particles generated after disintegration of the ODT should be as small as possible. ODT should leave minimal or no residue in mouth after oral administration. Moreover addition of flavors and cooling agents like menthol improve the mouth feel.

i. Sensitivity to environmental conditions
ODT’s generally should exhibit low sensitivity to environment conditions such as humidity and temperature as most of the materials used in an ODT are meant to dissolve with minimum quantity of water.

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MECHANISM OF TABLET DISINTEGRATION
The mechanism by which the tablets are broken into small pieces and then produce a homogeneous suspension is based on:                 

-  Capillary action/ water wicking
-  By swelling
-  Air expansion /heat of wetting
-  Due to disintegrating particle/particle repulsive forces
-  Due to deformation
-  Due to release of gases
-  By enzymatic reaction

INGREDIENTS TO BE USED FOR ORALLY DISNTEGRATING TABLETS
Important ingredients that are used in the formulation of ODTs should allow quick release of the drug, resulting in faster dissolution. This includes both the actives and the excipients. Excipients balance the properties of the actives in FDDTs. This demands a thorough understanding of the chemistry of these excipients to prevent interaction with the actives. Determining the cost of these ingredients is another issue that needs to be addressed by formulators. The role of excipients is important in the formulation of fast-melting tablets. These inactive food-grade ingredients, when incorporated in the formulation, impart the desired organoleptic properties and product efficacy. Excipients are general and can be used for a broad range of actives, except some actives that require masking agents.
Binders keep the composition of these fast-melting tablets together during the compression stage. The right selection of a binder or combination of binders is essential to maintain the integrity and stability of the tablet. The temperature of the excipient should be preferably around 30–35C for faster melting properties. Further, its incorporation imparts smooth texture and disintegration characteristics to the system. Binders can either be liquid, semi solid, solid or mixtures of varying molecular weights such as polyethylene glycol. The choice of a binder is critical in a fast- dissolving formulation for achieving the desired sensory and melting characteristics, and for the faster release of active ingredients. Commonly available fats such as cocoa butter and hydrogenated vegetable oils can also be used.

ROLE OF SUPER-DISINTEGRANTS IN ODT FORMULATIONS
Superdisintegrant plays the major role in oral disintegrating tablet. The disintegration efficiency is based on the force-equivalent concept (the combined measurement of swelling force development and amount of water absorption). Superdisintegrants are generally used at a low level in the solid dosage form, typically 1 – 10 % by weight relative to the total weight of the dosage unit. Common disintegrants used are Croscarmellose sodium (Vivasol, Ac-Di-Sol), Crospovidone (Polyplasdone), Carmellose (NS-300), Carmellose calcium (ECG-505), Sodium starch glycolate (SSG) etc. Recently few ion exchange resins (e.g. Indion 414) are found to have superdisintegrant property and are widely used in pharmaceutical industry. List of super disintegrants used for the formulation of orally disintegrating tablets with their mechanism of action were given in Table 2.

Table 2: List of Superdisintegrants for the Formulation of ODT’s

TASTE MASKING OF ODT
The biological definition of taste (gustation) is a chemical reaction derived from sensory responses from the four main taste perceptions: salt, sour, bitter, and sweet. Most of the drugs have unpalatable taste in which taste masking plays critical role in formulating ODTs. As popularity in ODTs has grown, so has the demand for expertise in taste masking.Maximum patient acceptability with ODT is seen if they provide pleasant taste and mouth feel. To provide this property in tablets various sweeteners and flavours are employed. Usually sugar-based excipients are used as they are highly water soluble and dissolve quickly in saliva. Mannitol is most widely used excipient in formulating ODT. Aspartame and citric acid are most commonly used along with various flavorants such as mint flavour, orange flavour, strawberry flavour, peppermint flavour to produce pleasant taste and mouth feel.

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TECHNOLOGIES FOR THE PREPARATION OF ODT’s
The orally disintegrating property of the tablet is attributable to a quick ingress of water into the tablet matrix resulting in its rapid disintegration. Hence, the basic approaches to developing fast dissolving tablets include maximizing the porous structure of the tablet matrix, incorporating the appropriate disintegrating agent, and using highly water-soluble excipients in the formulation.

1. Conventional Technologies
a. Freeze Drying
Freeze drying a process in which water is sublimated from the product after freezing. Lyophilization is a pharmaceutical technology which allows drying of heat sensitive drugs and biological at low temperature under conditions that allow removal of water by sublimation. Lyophilization results in preparations, which are highly porous, with a very high specific surface area, which dissolve rapidly and show improved absorption and bioavailability.

b.Tablet Molding
Molded tablets are prepared by using water soluble ingredients so that the tablets dissolve completely and rapidly. The powder blend is moistened with a hydro-alcoholic solvent and is molded into tablets under pressure lower than that used in Conventional tablet compression. The solvent is then removed by air-drying.

c. Melt Granulation
Melt granulation technique is a process by which pharmaceutical powders are efficiently agglomerated by a meltable binder. The advantage of this technique compared to a conventional granulation is that no water or organic solvents is needed. Because there is no drying step, the process is less time consuming and uses less energy than wet granulation.

d. Sublimation
Even though the conventional tablets contain highly water-soluble ingredients, they often fail to disintegrate rapidly because of low porosity. To improve the porosity, solid ingredients that volatilize readily (e.g. urea, ammoniumcarbonate, ammonium bicarbonate, hexamethelene tetramine, camphoretc.) are added to the other tablet ingredients and the mixture iscompressed into tablets. The volatile materials are then removed viasublimation, which generates porous structures thus enabling rapid disintegration.

e. Phase Transition Process
It is concluded that a combination of low and high melting point sugar alcohols, as well as a phase transition in the manufacturing process, are important for making ODTs without any special apparatus. ODT’s were produced by compressing powder containing erythritol (melting point: 122 °C) and xylitol (melting point: 93 95 °C), and then heating at about 93 °C for 15 min. After heating, the median pore size of the tablets was increased and tablet hardness was also increased. The increase of tablet hardness with heating and storage did not depend on the crystal state of the lower melting point sugar alcohol.

f. Three Dimensional Printing (3DP)
Three-dimensional printing (3DP) is a rapid prototyping (RP) technology. Prototyping involves constructing specific layers that uses powder processing and liquid binding materials. A novel fast dissolving drug delivery device (DDD) with loose powders in it was fabricated using the three dimensional printing (3DP) process. Based on computer-aided design models, the DDD containing the drug acetaminophen were prepared automatically by 3DP system. It was found that rapidly disintegrating oral tablets with proper hardness can be prepared using TAG. The rapid disintegration of the TAG tablets seemed due to the rapid water penetration into the tablet resulting from the large pore size and large overall pore volume.

g. Spray Drying
Spray drying can produce highly porous and fine powders that dissolve rapidly. Allen et al., have used spray-drying for the production of ODTs. The formulationscontained hydrolyzed and unhydrolyzed gelatin as a supporting agent for the matrix,mannitol as a bulking agent and sodium starch glycolate or croscarmellose as adisintegrant. Disintegration and dissolution were further enhanced by adding an acid (e.g.,citric acid) or an alkali (e.g., sodium bicarbonate). The suspension of above excipients wasspray-dried to yield a porous powder which was compressed into tablets. Tabletsmanufactured by this method disintegrated in less than 20 seconds in an aqueous medium.

h. Mass extrusion
This technology involves softening of the active blend using the solvent mixture of water-soluble polyethylene glycol and methanol and subsequent expulsion of soft mass through extruder or syringe to get a cylinder of the product which can be separated into even segments using heating blade to form tablets. The dried cylinder can also be used to coat granules of bitter tasting drugs and thereby masking their bitter taste.

i. Cotton Candy Process /Sugar-floss systems
The cotton candy process is so named as it utilizes a unique spinning mechanism to produce a crystalline structure or a matrix known as floss, which mimic cotton candy.
The manufacturing process can be divided into four steps as detailed below.

. Floss Blend
. Floss Processing
. Floss Chopping and Conditioning
. Blending and Compression

j. Direct compression
Easiest way to manufacture tablets is direct compression. Low manufacturing cost, conventional equipments and limited number of processing steps led this technique to be a preferable one. However disintegration and dissolution of directly compressed tablets depend on single or combined effect of disintegrant, water soluble excipients and effervescing agents. Disintegrate efficacy is strongly affected by tablet size and hardness. Large and hard tablets have disintegration time more than that usually required. As consequences, products with optimal disintegration properties often have medium to small size and /or high friability and low hardness. Breakage of tablet edges during handling and tablet rupture during the opening of blister alveolus, all result from insufficient physical resistance.

Disintegrants have major role in the disintegration and dissolution process of ODTs made by direct compression. To ensure a high disintegration rate, choice of suitable type and an optimal amount of disintegrant is important. Other formulation components such as water soluble excipients or effervescent agents can further enhance dissolution or disintegration properties. But main drawback of using effervescent excipients is their highly hygroscopic nature.

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2. Patented Technologies
a. Zydis Technology
A Zydis tablet is produced by lyophilizing or freeze-drying the drug in a matrix usually consisting of gelatin. The product is very lightweight and fragile, and must be dispensed in a special blister pack. Patients should be advised not to push the tablets through the foil film, but instead peel the film back to release the tablet. The Zydis product is made to dissolve on the tongue in 2 to 3 seconds

b. Orasolv Technology
In this system active medicament is taste masked. It also contains effervescent disintegrating agent. Tablets are made by direct compression technique at low compression force in order to minimize oral dissolution time. 

c. Durasolv technology
The tablets made by this technology consist of a drug, fillers and a lubricant. Tablets are prepared by using conventional tableting equipment and have good rigidity. These can be packed into conventional packaging system like blisters.

d. Wow Tab Technology
It is patented by yamanouchi Wow means “without water”. Wow tab is an intra buccally soluble, compressed tablets consisting of granules made with saccharides of low and high mouldability. When low- and high-moldable saccharides are used alone tablets obtained do not have desired properties of rapid disintegration and hardness, so combinations are used. It is used to obtain a tablet of adequate hardness and fast dissolution rate. The wow tab formulation is stable to environment due to its significant hardness than zydis and Orasolv. Wow tab product is suitable for both conventional bottle and blister package.

e. Oraquick
This technology is patented by K.V Pharmaceuticals. It utilizes taste masking microsphere technology called as micromask, which provides superior mouth feel, significant mechanical strength, and quick disintegration/dissolution of product. (Bandari S et al., 2008) This process involves preparation of micro particles in the form of matrix that protects drug, which can be compressed with sufficient mechanical strength. Low heat of production in this process makes it appropriate for heat-sensitive drugs.

f. NanoCrystal technology
Elan’s proprietary NanoCrystal technology (NanomeltTM) can improve compound activity and final product characteristics. Decreasing particle size increases the surface area, which leads to an increase in dissolution rate. This can be accomplished predictably and efficiently using NanoCrystal technology. NanoCrystal particles are small particles of drug substance, typically less than 1000 nm in diameter, which are produced by milling the drug substance using a proprietary wet milling technique.

g. Pharmaburst technology
SPI Pharma, New castle, patents this technology.The Pharmaburst ODT uses a proprietary disintegrant (Pharmaburst) that is based on mannitol blended with conventional tableting aids. It utilizes the coprocessed excipients to develop ODT, which dissolves within 30-40 s. This technology involves dry blending of drug, flavour, and lubricant followed by compression into tablets.

h. FlashTab   
Ethypharm, Saint Cloud, France has patented the Flashtab technology. This technology includes granulation of excipients by wet or dry granulation method and followed by compressing into tablets. (Chang et al., 2000). This technology relays on the use of super disintegrants. Flashtab is a combination of wet and dry granulation before compression. Micro particles of taste-masked API are blended with conventional tableting aids and disintegrants such as pvp or crospovidone (cross-linked PVP), cross-linked sodium carboxymethyl cellulose and swelling agents such as starches or microcrystalline cellulose. Disintegration times are typically less than 1 min.

i. Frosta technology
Akina patents this technology. The frosta technology is based on the compression of highly plastic granules at low pressure to prepare fast melting tablets. The highly plastic granules are composed of three components: a plastic material, (Maltrin QD M580 and MaltrinM180 are maltodextrin and corn syrup solids) a water-penetrationenhancer (Mannogem EZ Spray) and a wet binder (sucrose, polyvinylpyrrolidone and hydroxypropyl methylcellulose). Each of the three componentsplays an essential role in obtaining tablets with higher strengthand faster disintegration time.

j. Advantol™ 200
Advantol™ 200 is a directly compressible excipient system offering "Soft-Melt" functionality and specially formulated for nutraceutical applications. SPI Pharma’s Advantol platform uses proprietary co-processing technology. Advantol requires no special manufacturing equipment or tooling. Advantol formulations utilize a standard rotary tablet press with standard tooling under normal tableting temperature and humidity conditions to make robust “soft-melt” tablets.

k. Advatab
AdvaTab tablets disintegrate rapidly in less than 30 seconds. These tablets are prepared using polymer-coated drug particles that are uniformly dispersed in an ultra-fine, low-water content, rapidly disintegrating matrix with superior organoleptic properties. AdvaTab tablets are compressed using a proprietary, patented, external lubrication system in which the lubricant is applied only to the tablet surface, resulting in robust tablets that are hard and less friable and can be packaged in bottles or blister.        

CONCLUSIONS
The ODTs have potential advantages over conventional dosage forms, with their improved patient compliance; convenience, bioavailability and rapid onset of action had drawn the attention of many manufactures over a decade. The introduction of fast dissolving dosage forms has solved some of the problems encountered in administration of drugs to the pediatric and elderly patient, which constitutes a large proportion of the world's population. Hence, patient demand and the availability of various technologies have increased the market share of Fast dissolving tablets, which in turn prolongs the patent life of a drug. Keeping in view of the advantages of the delivery system, rapidly disintegrating dosage forms have been successfully commercialized, and because of increased patient demand, these dosage forms are expected to become more popular. Thus ODT may be developed for most of the available drugs in near future.

EVALUATION OF ODT’s
Crushing strength and friability can be assessed as stated in pharmacopoeias. Butsome tests are of special concern and theseinclude the following.

a. Wetting time
Wetting time of dosage form is related to thecontact angle. It needs to be assessed to givean insight into the disintegration properties ofthe tablets; a lower wetting time implies a quicker disintegration of the tablet. For this purpose, a tablet is placed on a piece of tissue paper folded twice and kept in a small Petri dish (ID = 6.5 cm) containing 6 ml of water, and the time for complete wetting is measured.

b. Disintegration Time
The time for disintegration of ODTs is generally less than one minute and actual disintegration time that patient can experience ranges from 5-30 seconds. The standard procedure of performing disintegration test for these dosage forms has several limitations and they are not suitable for the measurement of very short disintegration times. The method needs to be modified for ODTs as disintegration is required without water; thus the test should mimic disintegration in salivary contents. A modified dissolution apparatus is applied to an ODT with a disintegration time that is too fast to distinguish differences between tablets when the compendial method is used. A basket sinker containing the tablets is placed just below the water surface in a container with 900 mL of water at 37 0C, and a paddle rotating at 100 rpm is used. The disintegration time is determined when the tablet has completely disintegrated and passed through the screen of the sinker.

c. Moisture uptake studies
Moisture uptake studies for ODT should be conducted to have an insight into the stability of the formulation, as several excipients used are hygroscopic. Ten tablets from each formulation are kept in a desiccator over calcium chloride at 370C for 24 h. The tablets are then weighed and exposed to 75% RH at room temperature for two weeks. The required humidity (75% RH) is achieved by keeping saturated sodium chloride solution at the bottom of the desiccator for three days. One tablet as control (without superdisintegrant) is kept to assess the moisture uptake due to other excipients. Tablets are weighed and the percentage increase in weight is recorded.

ACKNOWLEDGEMENT
Authors wish to give thanks to Natco Pharma Ltd., Hyderabad for constant support and given literature to carry out this review. We also acknowledge the help provided by our colleagues in completion of the review.

REFERENCES
1.    Adel M, Semreen M K, Qato M K. 2005. Fast dissolving dosage forms – technique. Pharm Tech. 2005; 25:  68-75.
2.    Allen L V wang B. Method of making a rapidly dissolving tablet. US patent, 1986; 43: 123-131.
3.    Dangagi P M, Sreenivas S A, Mastiholimath V S. Orodispersible tablets: New fangled drug delivery system a review. Ind. J Pharm. Edu. Res. 39:4.
4.    Indurwade N H, Rajyaguru T H, Nakhat P D. Novel approach – Fast dissolving tablets, Indian Drugs. 2001; 39: 405-409.
5.    Kaushik D. Mouth dissolving tablets: A review. Ind Drugs. 2004; 41: 187-193.
6.    Kuchekar B S, Badhan A C. Design of fast dissolving tablets. Ind J. Pharm Edu. 2001; 35:150.
7.    Slowson M, Slowson S. What to do when patients cannot swallow their medications. Pharm. Times. 1985; 51: 90-96.  
8.    Seager, H. Drug-deliver Products and the Zydis Fast-dissolving Dosage Form. J. Pharm. and Pharmacol. 1998; 50: 375-382.
9.    Mizumoto T, Allen A, Loyd V. Methods for producing a rapidly dissolving dosage form. US patent 1996; 5: 576.
10.    Reddy L H, Ghosh B, Rajneesh T. Fast dissolving drug delivery system a review of the literature. Ind J. of Pharm Sci. 2002; 64: 331-336.

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