Fast dissolving tablet- review : Fast dissolving tablet- review K.Senthil Kumar M.Pharm
QIS COLLEGE OF PHARMACY,ONGOLE .A.P INTRODUCTION : INTRODUCTION Definitions of RDT:
“A Solid dosage form containing medicinal substances, which disintegrates
rapidly usually within a matter of seconds, when placed upon the tongue”.
According to European pharmacopoeia:
“A tablet that is to be placed in the mouth where it disperses rapidly before
swallowing”. Terminologies for fDT : Terminologies for fDT Rapid Dissolving tablets are also known as
Melt in Mouth tablets
Mouth dissolving tablets (MDT)
Fast disintegrating tablets (FDT)
Orally disintegrating tablets
Rapid disintegrating tablets (RDT)
Oro dispersible tablets (ODT)
Quick dissolving tablets. REQUIREMENTS OF RDT : REQUIREMENTS OF RDT Taste of the Medicament
Size of tablet MECHANICAL STRENGTH : MECHANICAL STRENGTH In order to allow FDTs to disintegrate in the oral cavity, they are made of
either very porous and soft-molded matrices or compressed into tablets
with very low compression force, which makes the tablets friable and/or brittle,
difficult to handle, and often requiring specialized peel-off blister packing that
may add to the cost. HYGROSCOPICITY : HYGROSCOPICITY 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. PALATABILTY : PALATABILTY As most drugs are unpalatable, orally disintegrating drug delivery systems usually
contain the medicament in a taste-masked form.
Delivery systems disintegrate or dissolve in patient’s oral cavity, thus releasing the
active ingredients which come in contact with the taste buds; hence, taste-masking
of the drugs becomes critical to patient compliance. SIZE OF TABLET : SIZE OF TABLET The degree of ease when 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 TASTE MASKING : TASTE MASKING Many drugs are bitter in taste. A tablet of bitter drug dissolving/ disintegration
in mouth will seriously affect patient compliance and acceptance for the dosage
form.So effective taste masking of the bitter drugs must be done so that the
taste of the drug is not felt in the oral cavity. SALIENT FEATURES RDT : SALIENT FEATURES RDT No risk of choking.
Requires no water intake.
Overcomes unacceptable taste of the Drugs.
Quick disintegration and dissolution of the dosage form.
Facilitates faster onset of therapeutic action.
Improved bioavailability can be achieved.
Avoids First Pass Metabolism due to pregastric absorption.
Ideal dosage form for Peadiatric and geriatric patients.
Ease of administration for patients who are mentally ill, disabled and unco-operative. MECHANISMS OF DRUG RELEASE : MECHANISMS OF DRUG RELEASE The drug releases from the FDT due to the action of super disintegrants
Croscarmellose sodium, and
Sodium Starch glycollate
Amberlite IPR 88
Smecta MECHANISAM OF SUPERDISINTEGRANT : MECHANISAM OF SUPERDISINTEGRANT Due to deformation
Due to disintegrating particle /repulsive force
Capillary action and porosity ( wicking )
Chemical reaction ( acid base reaction) Wicking action : Wicking action a. Water is pulled by disintegrant and reduces the physical bonding force between
b. Particles swell and breakup the matrix form within the tablet. DEFORMATION & REPULSION : DEFORMATION & REPULSION a. DEFORMATION b. REPULSION
a. Particles swell to precompression size and breakup matrix
b. Water is drawn into pores and particles repel each other because of
resulting electrical force. CONVENTIONAL TECHNIQUES FOR FDT : CONVENTIONAL TECHNIQUES FOR FDT Tablet moulding
Freeze drying (or) Lyophilization
Use of sugar based excipients Tablet molding : : 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. SUBLIMATION : SUBLIMATION Spray-drying : Spray-drying Spray drying can produce highly porous and fine powders that dissolve rapidly.
The formulations are incorporated by hydrolyzed and non hydrolyzed gelatins as
supporting agents, mannitol as Bulking agent, sodium starch glycolate or
crosscarmellose sodium as disintegrating and an acidic material (e.g. citric acid)
and / or alkali material (e.g. I sodium bicarbonate) to enhance disintegration and
Tablet compressed from the spray dried powder disintegrated within 20 seconds
when immersed in an aqueous medium Mass-extrusion : Mass-extrusion This technology involves softening the active blend using the solvent mixture of
water soluble polyethylene glycol, using methanol and expulsion of softened mass
through the extruder or syringe to get a cylinder of the product into even segments
using heated blade to form tablets.
The dried cylinder can also be used to coat granules of bitter tasting drugs and
thereby masking their bitter taste. Direct compression: : 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. 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 PATENTED TECHNOLOGIES : PATENTED TECHNOLOGIES Zydis Technology
Flash Dose Technology (Ceform Technology)
Flash Tab Technology
Nanocrystal Technolog ZYDIS TECHNOLOGY: : 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. DUROSOLV TECHNOLOGY : DUROSOLV TECHNOLOGY The tablets made by this technology consist of a drug, fillers and a
Tablets are prepared by using conventional tableting equipment and have
good rigidity. These can be packed into conventional packaging system
like blisters. OROSOLV TECHNOLOGY: : OROSOLV 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. DRUGS TO BE PROMISING INCORPORATED : DRUGS TO BE PROMISING INCORPORATED Analgesics and Anti-inflammatory Agents
Anti-neoplastic Agents and Immunosuppressants
Cardiac Inotropic Agents
Histamine H,-Receptor Antagonists etc… PREFORMULATION STUDIES : PREFORMULATION STUDIES Compatability studies = FTIR / DSC
Angle of repose Ө = tan -1 (h/r)
Determination of Bulk density = W / VO
Tapped density = W / Vf
Hauser’s Ratio= Tapped density/Bulk density
compressibility index : CI = 100 (VO – Vf )/ Vo
Moisture content Marketed rdt TABLET : Marketed rdt TABLET WEIGHT VARIATION TEST : WEIGHT VARIATION TEST I.P. procedure for uniformity of weight was followed, twenty tablets
were taken and their weight was determined individually and collectively
on a digital weighing balance. The average weight of one tablet was determined
from the collective weight.
The weight variation test would be a satisfactory method of determining the drug
content uniformity FRIABILITY TEST : FRIABILITY TEST The pharmacopoeial limit of friability test for a tablet is not more than 1% using
Tablet friability apparatus, carried out at 25 rpm for 4 min (100 rotations).
This test is again not applicable for lyophilized and flash dose tablets,but is
always recommended for tablets prepared by direct compression and moulding
techniques to ensure that they have enough mechanical strength to withstand the
abrasion during shipping and shelf life. Wetting time & water absorption ratio : Wetting time & water absorption ratio An wetting time and water absorption ratio reported the use of a piece of double folded
tissue paper placed in a petridish containing 6 ml of water. One tablet was placed on this
paper and the time for complete wetting of tablet was noted as wetting time.The wetted
tablet was then weighed and the water absorption ratio, R, was determined according to
R = 100 (Wa−Wb) /Wb Wb and Wa are the weights of tablet before and after water absorption Hardness test : Hardness test The tablet tensile strength is the force required to break a tablet by compressing it
in the radial direction and is measured using a tablet hardness tester. MOISTURE UPTAKE TEST : MOISTURE UPTAKE TEST The test can be carried out by keeping ten tablets along with calcium chloride in
a desiccator maintained at 37 °C for 24 hrs to ensure complete drying of the
The tablets are then weighed and exposed to 75% RH, at room temperature for 2
weeks. The required humidity can be achieved by keeping saturated sodium
chloride solution in the dessicator for 24 hrs.
The tablets are reweighed and the percentage increase in weight is recorded. If the moisture uptake tendency of a product is high, it requires special dehumidified area for manufacturing and packing. MEASUREMENT TABLET POROSITY : MEASUREMENT TABLET POROSITY The mercury penetration porosimeter can be used to measure the tablet
porosity which is a relative assessment of the degree of water penetration in
the formulation, responsible for its fast disintegration. IN-VITRO DISPERSION TIME : IN-VITRO DISPERSION TIME The test is performed by placing two tablets in 100 ml water and stirring it gently,
till the tablets get completely disintegrated.
The formulation is considered to form a smooth dispersion if the complete
dispersion passes through a sieve screen with a nominal mesh aperture of 710 μm
without leaving any residue on the mesh. IN-VITRO DISINTEGRATION TEST : IN-VITRO DISINTEGRATION TEST This test are carried out by using any one of the following method
Tablet disintegration apparatus
Modified dissolution apparatus(as per J.Pharm)
Disintegration Test on Shaking Water Bath
Disintegration Test with Rotary Shaft Method
Disintegration Test using Texture Analyzer
Disintegration Test using ElectroForce Modified dissolution apparatus : Modified dissolution apparatus DISINTEGRATION WITH test analyzer : DISINTEGRATION WITH test analyzer DISINTEGRATION WITH ROTARY SHAFT METHOD : DISINTEGRATION WITH ROTARY SHAFT METHOD IN VITRO DISSOLUTION STUDY : IN VITRO DISSOLUTION STUDY The dissolution method for oral disintegrating tablets is the same as
that of conventional tablets.
USP 2 paddle apparatus is most suitable and common choice for dissolution test of oral disintegrating tablets, where the paddle speed is 50 rpm is used.
The USP 1 (basket) apparatus may have certain application for such tablets
but is used less,frequently due to specific physical properties of tablets.
Specifically tablet fragments or disintegrating tablet masses become trapped on the inside top of the basket spindle where little or no effective stirring occurs, yielding irreproducible results in dissolution profiles. Conclusion : Conclusion Rapidly disintegrating tablets (FDTs) have better patient acceptance
and compliance and may offer improved biopharmaceutical properties,
improved efficacy, and better safety compared with conventional
oral dosage forms.
Prescription FDT products initially were developed to overcome the difficulty
in swallowing conventional tablets with water among pediatric, geriatric, and
psychiatric patients with dysphagia.
Future possibilities for improvements in FDTs and drug delivery are bright,
but the technology is still relatively new.