Multi station rotary presses Prof. R. Shanthini 22 Oct 2012 Source: http://vivekkivani.blogspot.com/

Although tablet compressing machinery has undergone numerous mechanical modifications over the years, the compaction of materials between a pair of moving punches within a stationary die has remained unchanged The principle modification from earlier equipment has been an increase in production rate which is regulated by Number of tooling sets Number of compression stations Rotational speed of the press Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University

Special adaptations of tablet machines allow for the compression of layered tablets and coated tablets A device that chills the compression components to allow for the compression of low-melting point substances such as waxes i.e. suppositories Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University

Compression The ultimate test of a tablet formulation and granulation process is whether the granulation can be compressed on a high-speed tablet press. During compression, the tablet press performs the following functions: Filling of empty die cavity with granulation. Precompression of granulation (optional). Compression of granules. Ejection of the tablet from the die cavity and take-off of compressed tablet. Prof. R. Shanthini 22 Oct 2012

When evaluating the compression characteristics of a particular formulation, prolonged trial runs at press speeds equal to that to be used in normal production should be tried. Only then are potential problems such as sticking to the punch surface, tablet hardness, capping, and weight variation detected. High-speed tablet compression depends on the ability of the press to interact with granulation. Prof. R. Shanthini 22 Oct 2012

Following are the parameters to be considered while choosing speed of press. Granulation feed rate. Delivery system should not change the particle size distribution. System should not cause segregation of coarse and fine particles, nor it should induce static charges. Prof. R. Shanthini 22 Oct 2012

For high-speed machines, induced die feed systems is necessary. The die feed system must be able to fill the die cavities adequately in the short period of time that the die is passing under the feed frame. The smaller the tablet , the more difficult it is to get a uniform fill a high press speeds. For high-speed machines, induced die feed systems is necessary. These are available with a variety of feed paddles and with variable speed capabilities. So that optimum feed for every granulation can be obtained. Prof. R. Shanthini 22 Oct 2012

After the die cavities are filled ,the excess is removed by the feed frame to the center of the die table. Compression of the granulation usually occurs as a single event as the heads of the punches pass over the lower and under the upper pressure rollers. This cause the punches to the penetrate the die to a preset depth, compacting the granulation to the thickness of the gap set between the punches. Prof. R. Shanthini 22 Oct 2012

The rapidity and dwell time in between this press event occurs is determined by the speed at which the press is rotating and by the size of compression rollers. Larger the compressions roller, the more gradually compression force is applied and released. Prof. R. Shanthini 22 Oct 2012

The final event is ejection of compressed tablets from die cavity. Slowing down the press speed or using larger compression rollers can often reduce capping in a formulation. The final event is ejection of compressed tablets from die cavity. During compression, the granulation is compacted to form tablet, bonds within compressible material must be formed which results in sticking. Prof. R. Shanthini 22 Oct 2012

High level of lubricant or over blending can result in a soft tablet, decrease in wettability of the powder and an extension of the dissolution time. Binding to die walls can also be overcome by designing the die to be 0.001 to 0.005 inch wider at the upper portion than at the center in order to relieve pressure during ejection. Prof. R. Shanthini 22 Oct 2012

DIFFERENT PUNCHES & DIES Prof. R. Shanthini 22 Oct 2012

Tableting methods (already seen) Dry methods Direct compression Dry granulation Wet methods Wet granulation Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University

1. Milling and mixing of drugs and excipients WET GRANULATION DRY GRANULATION DIRECT COMPRESSION 1. Milling and mixing of drugs and excipients 2. Preparation of binder solution 2. Compression into slugs or roll compaction 2. Compression of tablet 3. Wet massing by addition of binder solution or granulating solvent 3. Milling and screening of slugs and compacted powder   4. Screening of wet mass 4. Mixing with lubricant and disintegrant 5. Drying of the wet granules 5. Compression of tablet 6. Screening of dry granules 7. Blending with lubricant and disintegrant to produce “running powder” 8. Compression of tablet Prof. R. Shanthini 22 Oct 2012

Direct compression Tablets are compressed directly from powder blends of the active ingredient and suitable excipients No pretreatment of the powder blends by wet or dry granulation procedures is necessary Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University

Advantages Economy Machine: fewer manufacturing steps and pieces of equipment Labor: reduce labor costs Less process validation Lower consumption of power Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University

Advantages (contd.) Elimination of granulation process Heat (wet granulation) Moisture (wet granulation) High pressure (dry granulation) Processing without the need for moisture and heat which is inherent in most wet granulation procedures Avoidance of high compaction pressures involves in producing tablets by slugging or roll compaction Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University

Advantages (contd.) Elimination of variabilities in wet granulation processing Viscosity of the granulating solution (depend on its temperature), How long it has been prepared, Rate of binder addition and kneading can affect the properties of the granules formed The granulating solution, the type and length of mixing and the method and rate of wet and dry screening can change the density and particle size of the granules, which can have a major effect on fill weight and compaction qualities Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University

Advantages (contd.) Type and rate of drying can lead to unblending as soluble active ingredients migrate to the surfaces of the drying granules Less unit processes incorporated in production means less chances of batch-to-batch variation are compounded Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University

Direct compression fillers Common materials that have been modified in the chemical manufacturing process to improve fluidity and compressibility Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University

Soluble fillers Spray dried lactose (good flowability; less compressibility) Fast-Flo lactose (much more compressible and highly fluid) Tabletose: aggromerate form of lactose (More compressible than spray dried but less compressible than Fast Flo lactose) Di-Pac: cocrystallization of 97% sucrose and 3% modified dextrin Sorbitol Maltodextrin (Highly compressible; completely soluble ) And more…. Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University

Insoluble fillers Starch 1500: intact starch grains and ruptured starch grains that have been partially hydrolyzed and subsequently agglomerated Era-Tab: spray-dried rice starch (good fluidity; compressibility depends on moisture) Avicel: microcrystalline cellulose (the most important tablet excipient developed in modern times; most compressible) Dicalcium phosphate (Emcompress or DiTab) Prof. R. Shanthini 22 Oct 2012 Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of Pharmaceutical Sciences, Khon Kaen University