Devender M. Sharma*1, Satish B. Kosalge1, Swati N. Lade1
Hi – Tech college of pharmacy, Chandrapur (M.S.)


Tablets are unit solid dosage form of medicament which largely used to compare other dosage form of medicaments. In tablet manufacturing, wet granulation and dry granulation methods largely used as compare to MADG process. In wet granulation and dry granulation methods various steps has been carried out like dispensing and shifting, dry mixing, granulation, pre-drying, shifting, premixing, lubrication and compression. But in MADG process, escape various steps like slugging, pre- drying, shifting, and drying. Hereby in MADG process save energy, cost of product and time also. The main object of review is hereby moisture activated dry granulation process very beneficial in case of water insoluble drug and water poorly soluble drug other than granulation method like wet granulation. Another objective of review how moisture activated dry granulation process carried out and given various advantages over the other granulation method. In water insoluble drug case MADG process largely used and very useful method for pharmaceutical industries.

Reference Id: PHARMATUTOR-ART-2552

Tablet is a unit solid dosage form containing active ingredient with or without suitable excipients. These are most widely used dosage form. The main objective of the design and manufacture of the compressed tablet is to deliver orally correct amount of drug in the proper form over proper time and at desired location, so as to have suitable chemical integrity protected at the point of its action. (Aniket et al., 2011)The physical design, manufacturing process, and complete chemical makeup of the tablet can have a profound effect on the efficiency of the drug being administered. (Aniruddha et al., 2001) Poorly water soluble drugs are associated with slow drug absorption leading eventually to inadequate and variable bioavailability and nearly 40% of the new chemical entities currently being discovered are poorly water-soluble drugs. (B.Venkateswara et al., 2014) Based upon their permeability characteristics, the Biopharmaceutics classification system (BCS) classifies such drugs in two major classes, i.e., Class II and IV. The BCS class II drugs are poorly water-soluble entities with high permeability. Most formulation strategies for such drugs are targeted at enhancing their fine dispersion at absorption level. (Devender et al., 2017) Ibuprofen being poorly water-soluble drug known to demonstrate dissolution or solubility limited absorption. The bioavailability of the drug is low, yet its rate of absorption is quite inconsistent and delayed with time. Based upon its aqueous solubility and various dissolution parameters, the drug bioavailability can unambiguously be regarded as limited solely to dissolution. (Devender et al., 2017)

Tablet Manufacturing Process
Tablet manufacturing process can be broadly classified as granulation and direct compression. Granulation process may be defined as the size enlargement process in which fine or coarse particles is converted into physically stronger and larger agglomerates having good flow properties, better compression characteristics and uniformity and a process for collecting particles together by creating bonds between them. It is the most widely used technique in the pharmaceutical industry for the preparation of materials for tabletting. (Sharma et al., 2007)

Granulation may be either wet granulation or dry granulation i.e., by using binder solution or, by using dry binder. Pharmaceutical granules typically have a size range between 0.2 to 4.0 mm, depending on their subsequent use. Most of formulation in tablet manufacturing is by wet granulation process. (Devender et al., 2017)

Granulation is the process in which primary powder particles are made to adhere to form larger, multi particle aggregates called granules. After granulation process the granules may either be packed (when used as a dosage form - powder), or they may be mixed with other excipients prior to tablet compaction or capsule filling. (Chen et al., 1990) Granulation is used mainly to improve flow and compressibility of powders so as to prevent segregation of the blend components to improve content uniformity, and eliminate excessive amounts of fines. Particle size of the granulate is mainly affected by the quantity and feeding rate. (Christensen et al., 2009).


Granulation method can be broadly classified into two types: (Devender et al., 2017)
A) Wet granulation
B) Dry granulation
C) Direct compression

Wet granulation
A. Steps involved in the wet granulation
a. Mixing of the drugs and excipients
b. Preparation of binder solution
c. Mixing of binder solution with powder mixture to form wet mass.
d. Coarse screening of wet mass using a suitable sieve (6-12 # mesh)
e. Drying of moist granules.
f. Screening of dry granules through a suitable sieve (14-20 # mesh)
g. Mixing of screened granules with disintegrates, glidant, and lubricant.

B. Special wet granulation techniques
a. High shear mixture granulation
b. Fluid bed granulation
c. Extrusion-spheronization
d. Spray drying Dry granulation

The process mainly involves a series of operations such as weighing, mixing, granulation, screening the damp mass, drying, dry screening, lubrication and finally compression. However, as all of these operations are time bound, problem of reproducing uniform granulation from one lot to the next, is the greatest disadvantage of this method. (Devender et al., 2017) The active ingredients, diluents and disintegrants are mixed and blended well. Twin-shell blender or Ribbon blender may be employed for large scale blending. The blended material is then shifted through a screen of suitable mesh to remove or break the lumps. The solution of binding agent is added to the powder with stirring till the mass attains the consistency of damp snow or brown sugar. A Sigma blade mixer or Twin-shell blender may be used in pharmaceutical industry for this purpose. The damp mass is then force through a six or eight mesh screen. A manual screen is used for small batches but for larger quantities one of several comminuting mills suitable for wet screening can be used. A Fitzpatrick comminuting mill is the equipment of choice. The granular material thus obtained is dried on trays in a hot air oven or in a fluid bed dryer. (Deepak et al., 2017) Oven drying may take about 12hours or longer. During drying the particles may agglomerate and form lumps and therefore a dry screening operation is usually required after drying. (Himanshu et al., 2010) An oscillating granulator is often suited for the purpose. This is followed by the addition of lubricant as a fine powder (usually 100 # mesh). Excessive amount of fines or the fine powders should be avoided however10-20% fines facilitate the preparation of tablets of uniform weight. (Dong et al., 2008)

Tablet granulation can also be prepared rapidly by utilizing the air suspension coating technique. In this method, particles of active drug or inert material are suspended in the vertical column and the solution of granulating material is sprayed. The particle size gradually increase and the granules are obtained. (Devender et al., 2017)
When a soluble die is incorporated in the granulating agent, wet granulation method can produce uniformly tablets. Wet granulation is best suited to tablet making for potent drugs given in the minute doses. Wet granulation technique is receiving great significance, because direct compression method is not most suitable technique for many active substances that are in high dosages or in fine powder form. (Nidhi et al., 2014)

Granulation is one of the most common unit operation employed to improve the flow and compressibility of particulate material by size enlargement and densification. Granulation can be divided into wet and dry method. (Nidhi et al., 2014) Wet granulation method is more often chosen over dry granulation because of dust elimination, single pot processing and obtaining predictable granulation end point determination. Example of wet granulation method include fluid bed, high shear, pelletization techniques such as extrusion-spheronization, spray drying, rotary processing and so forth. In wet granulation, a liquid is use to agglomerate powder particles with constant agitation into a coherent mass which is subsequently dried and sized for subsequent processing. Despite their advantages, wet granulation method is not suitable for thermo-labile and moisture sensitive materials or materials that are highly cohesive. (Puckhraj et al., 2012)

Most drug actives do not possess adequate flow properties and compressibility to produce a final dosage form of desired physical and mechanical properties. (Ranpise et al., 2013) These properties include content uniformity, low friability, strong enough for subsequent handling and processing such as coating and packaging and good dissolution profiles to achieve the requisite bioavailability. (Hong-Liang et al., 2008) Hence, other material or excipients are often added to the powdered active to improve the tablet ability of the overall blend. Depending on the nature of the actives, excipients such as MCC pH 101, MCC pH 102, spray dried lactose and starch 1500 can be added to provide a balance of plasticity and brittle fracture needed to bring about successful bonding within a tablet. (Ismat et al., 2009)



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