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techceuticals-blog · 4 years ago

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Solid Dose Pharmaceutical Training

Contact Info!

Address: 2917 E 79th St Cleveland Ohio 44104 Phone Number: (216) 658-8038 Website URL: http://techceuticals.com

At Solid Dose Experts Techceuticals we help tablet and capsule manufacturing and packaging companies improve and perform to the best of their ability. We have been in business since 1989 providing training, troubleshooting, and equipment to the Pharmaceutical, Nutraceutical, and Dietary supplement industries. We provide our clients with technical tips, articles, and training programs include tablet and capsule formulation assistance, operator training, public training seminars, and hands-on training sessions for the Solid Dose Manufacturing, tablet compression, encapsulation, and film coating. We can also provide GAP analysis, cGMP training and customized programs for small hands-on groups or a complete manufacturing process presentation for the entire company. Since the beginning, Techceuticals has actively assisted many “startup” companies and we have installed new & used machinery, trained employees on the Set-up, Operation and Cleaning of the equipment used in Processing, Manufacturing and Packaging. We also provide troubleshooting assistance for all of our clients. Our mission is to provide total customer satisfaction through innovation and continuous improvement of business processes and product quality. We continuously strive to provide clear training, technical support and assistance for equipment selection, operation, and troubleshooting. We always want all of our customers to feel free to call or email their questions. We are proud to make a difference by being part of the solution. You can visit our website and fill out a contact form for us to reach you or you can call, mail or email us to schedule an appointment. We are open Monday through Friday and will be more than happy to go into further detail about all of the services and equipment that we can offer your company. Contact us today!

ADDITIONAL DETAILS G Maps : https://goo.gl/Cn3snm Hours: Hours:Mon-Fri 8:30am-5:30pm Payment Method : Cash , Cheque , MasterCard , Visa

#Health #Medicine #Lab #Capsule

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techceuticals-blog · 8 years ago

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The Manufacturing Process — Part 6

Common Tablet Defects — Making tablets batch after batch without an occasional defect would be unusual. Some products start up with problems and end with them. Tablet to tablet weight variations create tablet defects. Consistent tablet weight is essential to making a good tablet. Without good and consistent weight control, solving other defects will be difficult (if not impossible) because of how a tablet press operates. Some of the most common tablet defects are:

Weight variation Friability variation Picking and Sticking Capping Laminating Chipping Mottled Double Pressing Often problems with compression can be associated with many root causes. One very common issue is machine start up. The tablet press is cold. the steel is cleaned and bare metal can allow granules to stick to these metal surfaces. The reason a lubricant is in the product is to prevent granules from sticking. Many companies are very accustomed to a double start up.

The first one distributes powders which begin to stick, especially to the punches and to the die table. The operator will often remove the stuck granules and then at second start up no sticking occurs because the working surfaces are now protected by the lubricant.

Weight, Friability

Tablet weight is the key to controlling hardness and friability. Controlling tablet weights within a tight range will contribute to better tablet hardness and friability.

Many variables can influence weight fluctuations. The key weight control factors are product uniformity in particle size & density, proper tablet press set-up, and control of flow rates into the die cavity.

However, the importance of weight control cannot be over emphasized. Weights must be uniform in order to trouble shoot most other tablet defects. Friability testing is done by tumbling tablets to see how well they will withstand the tumbling action which replicates typical handling situations. This test is done to make certain that the tablet does not fracture of break apart. Too much friability means that the tablet chips or fractures break away from the rest of the tablet.

Picking and Sticking

Picking & Sticking occurs when granules stick to the punch faces during compression. Sometimes the punch face design and debossing can be modified to eliminate the problem. Other times granules are not dried properly. They become case hardened during the drying process, which means that the granules are wet on the inside.

During compression these granules break open and the wet product sticks to the punch faces. If this occurs, the drying process must be improved. To overcome sticking on the press, increase hardness by making the tablet thinner and increase dwell time to make the wet granules adhere to other granules rather than the punch face.

Also, if a blend is incomplete this could mean that the lubricant in the formula is not protecting the granule from sticking to the punch cup surface. If all else fails polish the punch cup surface.

Capping and Laminating

Capping is often referred to as air entrapment. During compression, air is evacuated from between the granules to allow the granules to lock to one another. If the “air” does not escape during the compression process the top of the tablet (the tablet cap) wants to come off. The tooling (punches & dies) are designed to allow air to escape during compression along the upper punch tip and die wall. This is why capping occurs on the top “cap” of the tablet.

Capping is not just air entrapment. During compression air evacuation pushes the very fine dry granules out with the air. It is these dry & light particles that do not want to lock together, resulting in tablet “caps” wanting to come off the tablet.

Lamination is when the tablet splits apart anywhere except at the upper cap. Lamination is often blamed on over compressing. Too much compression force flattens out the granules and they no longer lock together.

Lamination can also occur when groups of fine and light particles do not lock together. These groups of fine and light particles simply will not compress well. Reducing thickness and increasing dwell time will give these particles more of a chance.

Dwell time can be increased by adding pre-compression or slowing the machine speed down. Machining a taper into the die will help eliminate capping and lamination.

Chipping

Many tablets are sensitive to chipping after compression. First make certain that the punch tip edges are not damaged. Some punch tip designs are more sensitive to damage from handling than others. Once confirmed that the chips are not being created by damaged punches then make certain that the “take off blade” is set correctly for proper ejection off the machine. If the blade is too high it will allow the tablet to wedge under the blade causing chipping. If the tablet is friable the tablet can become chipped as the tablet travels off the press, down the tablet chute, through the tablet metal detector, tablet deduster and finally into the collection bin.

Transferring finished tablets must be done carefully. Many times investigations into chipped tablets discover poor handling and transfer of tablet bins from compression to storage and then onto the packaging floor. Packaging machinery can also cause chipping.

Double Impressions

Double Impressions will happen on a tablet press when the punches are allowed to twist or jump. Round punch tips want to twist naturally due to the rotation of the press. Double impressions usually occur on the bottom of the tablet from the lower punches. It usually means that the lower punch retainers are loose and the punches are jumping during compression.

Make certain the lower punch retainers are clean and not worn. They do need to be replaced often. When a machine starts up it is cold. As it warms up, lower punch retainers can become loose and may need to be tightened to prevent double impressions. Therefore, it is important to check them often at start-up.

Also, many newer machines now use punch seals. As seals become worn they will allow the punches to bounce or twist during compression.

-Michael Tousey, Techceuticals

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techceuticals-blog · 8 years ago

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The Manufacturing Process — Part 5

Encapsulation — Commonly referred to as a capsule filler, the encapsulation machine has the ability to fill many different products. Powders, granulations, liquids, tablets and capsules can be filled into a two piece capsule.

Encapsulation machinery technology varies a great deal from one manufacturing to the next. Not all machines can fill a wide variety of products; most are designed to handle free flowing powders much like powders that are prepared for a tablet press.

The capsule filler must first position all of the incoming capsules into an upright position (rectification), separate the cap from the body (top from bottom), attain the proper fill volume (capsule weight), and then the product filled body is rejoined with the cap and ejected from the machine. Some capsule filling machines have the ability to compress or tamp the powder for proper filling volume and weigh control.

Encapsulators can be defined as 1) Hand operated 2) Semi Automatic 3) Automatic. The Hand Operated capsule filler requires the operator to organize the capsules in the correct position, separate the cap from the body, and fill & close the caps (basically the hand filler is a holder for the capsule body).

There are exceptions and some hand operated fillers assist the operator with separation and closing functions. The Semi automatic machine requires the operator to move rings (capsule holder rings) from the rectifier to the filling and closing stations allowing for production up to 25,000 capsule per hour.

Automatic machines with speeds up to 90,000 per hour can be divided into two categories: Continuous and Intermittent operation.

The intermittent motion machine is divided into segments. Each segment indexes from each machine function; rectify, fill, tamp, close and eject.

The automatic machine is a continuous operation somewhat comparable to a rotary tablet press in that the rotation is continuous and does not start and stop.

Capsule Care

Gelatin capsules that are old and improperly stored can dry out and become brittle; they have a rather high defect rate when compared, say, to finished tablets. Even with all the quality check points many capsules are unusable by the time they reach the production floor. Just ask any process operator and they will tell you about the impact that defective capsules have on production rates. Even on the semi-automatic model 8 machinery defective capsules can slow production rates significantly. Common Capsule defects include: Dented, cracked, split, over size caps, and empty capsules after the filling cycle.

Printing Technology

The principle of operation in printing is the successful transfer of the image from a surface to the object. In the case of tablets the transfer is made from the ink pot to the gravure (or design roll) roll, to the rubber roll to the tablet.

All offset printing, regardless of equipment manufacturer, is accomplished in this manner. Gravure rolls should be inspected for defects before they are used on the production floor. As an example, using a jeweler’s glass to inspect the ink retaining screens is recommended before the roll is placed in use. Rolls received with incomplete or missing screens will not be able to hold ink in the impression cavities and the image cannot be transferred to the rubber roll. If this occurs, you will have unknowingly introduced defectively printed tablets into the batch.

Most equipment manufacturers recommend using a 50-50 mix of n-butanol and isopropyl alcohol as both an ink thinning and cleaning agent. All ink manufacturers supply recommended specific gravity ranges for their inks.

Controlling the ink viscosity is critical throughout the entire batch.

-Michael Tousey, Techceuticals

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techceuticals-blog · 8 years ago

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The Manufacturing Process — Part 4

Tablet Compression �� While an experienced operator can take a marginal granulation and make a good quality tablet, an inexperienced operator (not fully understanding tablet press operation) will be unable to produce a quality tablet.

Understanding the machine operation and being able to identify the difference between a machine issue and a granulation issue is important. Operators should be qualified, tested and certified in the operation of a tablet press.

While tablet presses are used for many applications, the basis of formula development is the same for each application. The final granulation to be compressed must have three basic characteristics, all of which are critical: Flow, Compress and Eject.

A tablet press can be fully automated to the point that it can be operated in a lights out operation. This puts all the emphasis on the cleaning and proper set up of the machine. This is also true of a non automated machine. The emphasis is on cleaning and proper setup.

With few exceptions, rotary tablet presses operate the same basic way. Many machines have very advanced features that may provide better compression and weight control at high speed.

However, understanding the basics of compression is the key to understanding all tablet presses. The tablet press is the report card on all previous unit operations; the tablet press is only half responsible for the final tablet quality, the formula and powder preparation operation is the other half. A good press cannot improve a bad formula.

Tablet Weight Control

Having consistent flow of a granulation provides the needed avenues to control tablet weights. Consistent tablet weight will result in repeatable tablet hardness. Tablet hardness is a function of tablet thickness and tablet weight.

A given volume of granulation compressed to a specific thickness will result in a given hardness. Though excipients play a large roll in the dissolution rate of a tablet, so does tablet hardness.

A tablet press and tools will not improve a granulation. If used correctly though, the press and tools can be used to maximize the granulation and maintain a consistently hard tablet with acceptable disintegration & dissolution rates.

The three most important variables of making a good tablet are; weight control, weight control and weight control.

Tablet Coating

Once a good tablet is made, we often need to add a coating. The coating can serve many purposes; it makes the tablet stronger and tougher, improves taste, adds color, and makes the tablet easy to handle and package. The coating can be a thick sugar based coating or a very thin film. Most pharmaceutical tablets are coated with a thin film coating. This coating is sprayed as a solution (a mixture of solids in a liquid).

For many years the liquid was a solvent such as alcohol or some other quick drying solvent. The use of solvents can present problems in handling, operator safety, solvent recovery and the odor of the tablet can smell like the solvent, which is not a desirable attribute.

In general, many manufacturers have moved to a water based solution instead of using a solvent. This presents a challenge in applying and quickly removing this water based solution so it does not disrupt the integrity of the tablet.

Tablet film coating equipment has evolved to enhance this drying capability. Essentially a tablet coating system is much like a fancy clothes dryer. The water based solution is sprayed in a very fine mist so as to dry almost immediately as it reaches the tablets. As the water dries it leaves the solids as a thin film on each tablet.

The coating system continuously supplies hot air, at the same time pulling air through small holes in the coating drum. The drum is commonly referred to as the coating pan, with small holes called perforations. This process can take as little a 30 minutes or it can take several hours.

Tablets must be tough enough to tumble while the solution is added. The solution is distributed from tablet to tablet during the tumbling and drying process. The spraying, distribution and drying all takes place at the same time.

Coating Equipment

Tablet coating equipment combines several technologies and is commonly referred to as a coating system. This system consists of the coating pan, spraying system, air handling unit, dust collector and controls. The coating pan is really a drum within a cabinet, allowing for control of air flow, air temperature and controlled solution application.

The spraying system consists of spraying guns, a solution pump, tank & mixer and air lines. The solution is pumped into the guns and the air combines with the solution for atomization into a very fine mist.

The air handling unit (AHU) is basically a way of heating and filtering the air. Dehumidification and/or humidification maybe be needed depending on your location and application requirements.

The Dust Collector collects the dust during the preheat and tumbling cycles and the Controls connect all of the components creating a complete coating system.

The Coating Process

Tablets are loaded into the coating pan, creating a bed of tablets. There must be enough tablets to attain good mixing, but not too many or the tablets will spill when the door is opened. Consistent batch sizes are important to attain consistent results. The tablet bed is tumbled slowly, as the warm air is introduced; the dust collector pulls the dust off the tablets and into a collection bin.

When the tablet bed temperature reaches the proper temperature the spraying can begin. Once tablets have an initial base coating the spray rate can be increased. The controls are monitored by the operator or computer, recording data frequently. Tablet defects can occur if the temperature, spray rate and air volume are allowed to fluctuate.

-Michael Tousey, Techceuticals

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techceuticals-blog · 8 years ago

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The Manufacturing Process — Part 3

Dry Granulating — Dry granulating, also called Slugging, Chilsonating or Roller compaction, involves the pressing of mixed powders into an object to be reground into a precise powder. This action increases particle density, improves powder flow and captures fines.

The Dry Granulating method is used over other technologies for one or more of the follow reasons:

Granulate materials which are sensitive to heat and/or moisture Produce a uniform particle size range Improve flow properties Control dust Control bulk density Produce uniform blends Control particle hardness Improve wetting or dispersion rates Powders can be compacted using a tablet press; this is called Slugging. Once slugging is completed or powders are compacted on a Chilsonator or Roller Compactor, they are milled. It is best to Mill densified powders using a low shear mill for best results. Using a high shear mill may over-mill or result in an over production of fine particles.

Milling

Milling equipment is used to Improve flow, reduce segregation, enhance drying, and limit wide particle size distribution

Milling machinery used in the preparation of tablet & capsule formulations can be categorized as to their mechanical energy; Low, Medium or High energy mills will impart a force on the powders called shear force. Therefore, milling machinery is defined by Low, Medium and High shear applications.

Some milling machines allow for changes in the type of mechanical action used to reduce the powder to the proper final particle size range. Mills can be used to de-lump powders without actual particle size reduction.

Often different mills are used within different unit operations throughout the complete manufacturing process: At weigh-up for de-lumping, before blending for proper particle size distribution, after wet granulating to enhance drying, and after dry granulating to prepare powders for final blending and tablet compression.

Mill Application

Generally we want to be as gentle with powders as possible. Some powders have high moisture content and they may be subject to compaction within the mill; others are very hard and friable and are subject to producing “fines”. Fines are powders that are very small and “dusty”, which will pass through a 200 mesh screen.

Fine dusty particles impede the flow, do not compress well and can become air born. The air born dust can be witnessed on filters, walls, cabinets and machine components. Besides affecting yields, the dust will combine with oil and grease on the tablet press causing the punches to become tight, requiring more frequent cleaning cycles.

Common milling equipment: Low Shear Mills; Oscillators and Comils. Medium Shear Mills; Quick Sieves and Hammer Mills. High Shear Mills; Pulverizes and Hammer Mills.

Many companies do not have designated milling rooms which requires moving single mills from location to location. In this event, you must always check motor rotation before operating any milling equipment.

Powder Flow and Blending

There are at least ten (10) different variables that can contribute to the success or failure of powder flow on a tablet press. In addition to the well studied particle size, shape and distribution. There are also particle surface texture, cohesivity, surface coating, particle interaction, static electricity, recovery from compaction and wear/attrition while in the holding container.

These other non-traditional measurements, studied and appreciated, shed significant light on flow issues heretofore not fully understood: Particle size, Size distribution, Shape, Surface texture, Cohesivity, Surface coating, Particle interaction, Electro-static charge, Compaction recovery, andWear/attrition characteristics.

Most powders, without the aide of granulation and flow agents, simply cannot flow at speeds required for high speed tabletting. All powders have the capacity to form bridges, create rat holes and stick to contact surfaces. To some extent, most powder mixes exhibit some degree of each problem situation above. The issue becomes critical when any or all of the situations begin to affect unwanted change in powder flow. Bottom line: Recognize that a “good” final blend is often viewed as such because it has good content uniformity and potency, not by its ability to flow.

However, good flow is imperative to attaining a good tablet. Understanding powder characteristics will contribute to accurate blending practices.

Final Blend

The final blend represents the result of the formulating, granulating and lubrication effort. The reason we test blends is to optimize blend time, demonstrate lack of segregation after blending is completed, and confirm that specified blend conditions produce acceptable uniformity during validation.

An individual powder or finished blend may flow very well under one set of circumstance and not flow well at all under another. Notice that under Powder Flow we see attributes of the powder itself while under Powder Process we see what may happen under different processing circumstances.

The message here is for management to be aware of these potential issues on the production floor.

Uniform Blending

Materials go from an unmixed state to a state of relative homogeneous consistency. Achieving a homogeneous blend is accomplished through a combination of time and mechanical energy. Given enough time, components will pass from an unblended state to a relatively homogeneous blend and back to an unblended state.

Blend studies determine the optimum endpoint. All blends have a unique pathway to their optimum state of uniformity. Because under blending and over blending fall on either side of the optimization curve, the symptoms are somewhat similar; and include Content Uniformity problems, Weight and Hardness variation.

The most common blenders used for final blending are the V blender, the double cone blender and the tote blender. All use low shear tumble blending as the most effective way to achieve good mixing with a variety of powders and granules.

-Michael Tousey, Techceuticals

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techceuticals-blog · 8 years ago

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The Manufacturing Process — Part 2

The Formula — We have determined that a formula contains many ingredients other than just the active ingredient. The ingredients within the formula in addition to the active are called excipients.

Excipients are needed to make a good quality tablet at the required tablet press speed. They help the flow, compressibility and the ability of the tablet to eject from the tablet press without falling apart. Excipients also enhance the hardness, disintegration, appearance, color, taste, and the overall performance of the tablet.

As stated previously, a formula that is designed on a slow speed tablet press may not work on a high speed press. Even the best tablet press with all the best design features may not be able to compress a formula at any speed. Each formula has a limit to how fast it can be compressed. In order to increase the speed, the formula must be changed.

Why Granulate?

To improve powder flow. To improve compressibility. To reduce fines. To control the tendency of powders to segregate. To control density. To capture and fuse small quantities of active material. The average tablet press speed in the pharmaceutical industry produces 3,000 tpm (tablets per minute) or 50 tablets per second. Tablet press speeds can exceed 10,000 tpm or 166 tps.

Granule Formation in the Wet Granulating Process

Most of the early research in granulating took place in pans and drums and some of the theory and knowledge gained using that equipment is not directly applicable in all technologies. There are however at least three theories which have been accepted by academics as applicable. These three mechanisms are:

Nucleation Transition in the funicular and capillary stage Ball growth. In nucleation, the formation starts with loose agglomerates or single particles which are wetted by the binding solution and form small granules by pendular bridging. Continued addition of binding solution and tumbling action consolidates and strengthens the granules through the funicular stage and into the capillary stage. In this transition stage the granules continue to grow by one of two mechanisms: single particle addition and multiple granule formation. Theoretically, at the end of the transition stage there are a large number of small granules with a fairly wide size distribution.

Wet Granulating Process Steps

In the pre-mix step the powders to be granulated are added and mixed prior to the introduction of the binder. In the wet massing step the binder is added to the mixture and the components are massed to a predetermined end point.

In the drying step the wet mass is dried to a predetermined end point, commonly measured with a test called the “LOD” or loss on drying test. The finished granulation is then milled to reduce the size of any caked material into a standardized particle size distribution. This distribution is usually measured using a series of screens lined up top to bottom from largest screen to a pan to collect the dust.

In the final blend, the lubricant is added to the granulation producing the final blend. Granulation is actually caused by a complex interaction of several variables and knowledge of each is necessary to control the granule formation process. If we establish which variables are critical to granule formation, we will have the basis to control granule growth for a reproducible process.

How Granules are Tested

There are four standardized tests which are commonly performed on either milled or finished granules:

LOD- water content Bulk Density, mg/ml Particle Size Distribution Angle of Repose, flow gradient Two of the four tests, Loss on Drying (LOD) and Particle Size Distribution, are commonly performed by operators on the production floor. In some cases, the operator only performs the LOD and the other three tests are performed in the laboratory. The practice varies depending on the situation.

-Michael Tousey, Techceuticals

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techceuticals-blog · 8 years ago

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The Manufacturing Process — Part 1

The Manufacturing Process was created for companies and individuals to gain a complete understanding of the basic requirements needed to make tablets and capsules. The objective is that the reader will gain a quick, yet comprehensive understanding of solid dosage operations used in the manufacturing process.

The focus will be a step by step explanation of each unit dose operation, common equipment, and practical knowledge of each operation. The main topics are Formulation, Blending, Milling, Granulation, Drying, Final Blending, Tabletting, Tablet Press Tooling, Coating, and Encapsulation. Common tablet & capsule defects and problem solving are also part of the objective.

Designed for new & experienced employee training, the expectation is that having this information will create a common denominator; thus producing an opportunity for better communication between manufacturing groups. The company will no longer hear that the problem is the fault of another department. The reader should be able to understand each unit of operation. They should understand how machines work and the usage of each piece of equipment and why one technology is preferred over another.

Specialized training — In-Plant and Public Seminars

Techceuticals has developed a complete series of training programs. These programs can be presented for everyone involved in the manufacturing process. Operators, Leads, Managers, R&D, Engineering, Maintenance, Quality Assurance, and packaging personnel will all be able to gain knowledge and a better communication method between departments.

Each of the programs can be tailored to meet the specific needs of the customers facility and application. All training courses and seminars can include testing modules.

Unit Dose Operations

Every separate manufacturing step is called a “Unit Operation”. Weighing, Blending and Tabletting are individual unit operations. A “Batch” of powder or granulation is processed in each unit operation. The objective is Batch to Batch Reproductibility in each Unit Operation. Unit Operations are determined by what manufacturing steps are needed to combine the active ingredient with other needed ingredients to make a quality finished product.

The three most common Unit Operation pathways are Direct Compression, Wet Granulating, and Dry Granulating. Which pathway is used depends on what is needed to do to make a tablet out of the active ingredient.

Powders must Flow; making a tablet or a capsule requires the powders to be somewhat fluid. Good flow can be compared to granulated sugar. Bad flow can be compared to powdered sugar. Products must flow freely to achieve proper dosage. Tablet presses and encapsulation machinery do not actually weigh the individual dosage amount, they fill by volume.

Powders must Compress; Particles must lock together. Overly wet particles will cause Sticking. Overly dry particles will cause Lamination. Fine particles escape during compression.

Time under pressure is Dwell time. Tablet Press speed relates to compressibility and time under pressure. Tablets and capsules must also eject from the die after being compressed.

Three Principle Methods of Developing Powders for Tablet Making

Tablets made by blending the dry powdered ingredients together, and then compressing into tablets is called “A Directly Compressible Formula”. We are saying that the characteristics of these powders will blend together with the other ingredients and stay mixed. This combination of ingredients will flow, compress and eject from the tablet press. Furthermore, the tablet will have good hardness, friability, and will dissolve quickly.

If powders will not make a good tablet because they do not compress, don’t flow well, are too fluffy or separate after blending, the particles need to be combined and attached using a pharmaceutical glue called a binder. When the binder is put into water or a solvent solution and is sprayed or metered into the powders this process is called “The Wet Granulation Process”. The solids within the liquid solution form bonds between particles which are maintained even after the liquid is dried and milled. There are many different types of binders that can be used.

All powders have a variety of characteristics; some may only require a very small amount of binder and some may require large amounts of binder. Many powders require some level of intense mixing while adding a liquid binder, actually comparable to kneading dough when making bread. Once the powder and binding solution are kneaded they are then milled for drying. The bonds that hold the particles together can withstand the milling process forming a uniform size “granule”. If we accomplish these “unit operation” steps correctly (pre-blending, binder addition, milling, drying and final blending) the result is a compressible powder called a granulation.

A granulation is the formation of small agglomerates called “granules”. Each granule will contain a proper mix of the ingredients of the formula. We can control the final density of the granules by the amount of liquid binding solution and the mechanical energy created by the type of machine used. The machines used to blend powders and add liquid are called “granulators”.

Some granulators have the ability to dry the excess moisture. Many granulators do not have the ability to dry the wet massed granulation; therefore the wet granulation must be moved to the next unit operation which is called Drying.

There are many types of Dryers that we will discuss later. When powders are sensitive to liquids, heat, or both, we must blend the powders with a pre- granulated “dry binder”. If the blended powders will not work with the addition of the dry binder and liquid, or heat cannot be used, then we must “Dry Granulate”. The Dry Granulation method uses mechanical force to densify and compact powders together which forms dry granules. This compaction can be done on a tablet press using “slugging tooling”. Slugging tooling or slugging punches & dies are a method to dry compact powders into granules.

The other method is to use a machine called a Roller Compactor or Chilsonator. This is basically the same kind of machine used to make the charcoal briquettes for our outside grill. The slugged or roller compacted powders are then milled, final blended and compressed on a tablet press.

Of these three principle methods, the “Wet Granulation” method is the most common. It is also the most demanding and requires many unit operations. In The Tablet & Capsule Process, we will discuss each of the principle methods and discover the unit operations required for each method. We will define each processing step and the common equipment types used in each unit operation.

The final goal is to make a quality tablet with the following attributes:

Good Weight Control Good Thickness Control Good Hardness Control Good Ejection No Capping No Lamination No Sticking Good Friability Good Disintegration Good Dissolution -Michael Tousey, Techceuticals

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techceuticals-blog · 8 years ago

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How Tablet Quality Affects Coating Success

High-quality coating begins with high-quality tablets, and no coating can achieve peak adherence unless all the tablets in a batch are uniform. When the substrate is prepared properly, tablet coating quality is predictable. A film coating won’t hide tablet quality problems and will, in fact, likely magnify quality variations, even when they aren’t extreme. This article discusses how variations in tablets — even when in the acceptable range — can affect film coating.

Tablet coating, it’s been said, is more art than science. In some cases, that might be true, but it’s still worth knowing certain facts — science if you will about this challenging and dynamic process if you want to succeed more regularly. Knowing the facts makes it a science. Not knowing them and trying to solve problems makes it an art.

There are many coating types and application methods. This article focuses on the most common method, film coating, where a mist of solution (suspension) coalesces and adheres as a thin film on the surface of tablets. When done right, it’s a very predictable and reliable scientific process.

Why Coat?

Film coatings offer several benefits. A primary one is protection against erosion, chipping, and breakage. With a film coating, tablets are stronger and tougher, so they can withstand the routine buffeting of transport and packaging. Coatings also extend shelf-life, mask bitter tastes and off-putting odors, and add flavor and color.

Functional coatings go even further. They can deliver active ingredients to accelerate the therapeutic effect, control the release of the active ingredient, and provide a barrier against moisture. Functional coatings that are pH-dependent, known as enteric coatings, allow tablets to pass through the highly acidic environment of the stomach unaltered and then disintegrate in the near-neutral intestines.

A capped tablet. This reject should never enter the coating drum. Different surface, different hardness

To minimize the art and maximize the science of film coating, reduce the variables. One of the biggest variables is tablet hardness, specifically the surface hardness. No batch of tablets is more difficult to coat than the one with a wide range of hardnesses, because the coating will not interact with each tablet the same way.

Even when all the tablets are within the specified “acceptable range,” some will have a softer surface that erodes more easily. The tablets with harder surfaces may not allow the coating to adhere as well, which could lead to defects such as peeling. Identifying the variation in tablet surface hardness is difficult, however, because there is no instrument to measure it. (Traditional hardness testers actually quantify breaking strength, which tells us little to nothing about surface hardness.) In fact, we should say surface hardnesses, because the hardness of the top, bottom, and sides of a single tablet differ.

We know tablet surface hardnesses are different because of how tablets are compressed and ejected. When a tablet is formed, the top is softer because air pushed upward gets trapped within the upper cup of the tooling; fines migrate to the vent area (gap) between the die wall and the upper punch tip. Because of the hardness differences, a coating may not adhere equally to all areas.

The erosion visible beneath the coating occurred during the preheatcycle, which should have been stopped. Understand the substrate

As discussed above, the top cap of a tablet is often softer than the lower cap because of how it’s made. In addition, because the top bears a logo or other debossing, it’s more prone to erosion than the tablet’s bottom cap.

As for the side (side band) of the tablet, the larger it is, the greater the friction and heat when the tablet is ejected from the die. To minimize friction, most tablets include lubricants, also known as mold-release agents. The lubricant creates a glossy surface on the tablet and it tends to get glossier as tablet hardness increases. Hard, glossy surfaces are not ideal for film coating. Incidentally, the larger the side band, the more difficult it is to apply an even coating all the way around the tablet.

The tablet edges, formed by the land area of the punch tip, also warrant comment. They don’t accept coatings as well as other areas. In fact, after finishing a batch, it’s common to find tablets that aren’t coated along the edge. Plus, that’s where the granulation can extrude into the gap between the punch tips and die wall. Known as flash, wing, or crown, this excess material varies in size and shape according to the condition of the punches and dies, how they’ve been installed, the clearances, and their wear properties. To prevent the flash from causing defects, remove it using a deduster or during the preheat cycle before spraying begins.

The tablet’s constituents also affect the coating. Ideally, when a coating suspension is sprayed on tablets, the carrier (usually water, but sometimes a solvent) dries rapidly, leaving the solid portion to lock together into a “shell.” But if some portion of the tablet’s surface resists coating impingement, variability increases. In terms of absorption properties, some ingredients are like cotton t-shirts and others like raincoats. Because particles of each type can reach the A capped tablet. This reject should never enter the coating drum. Sometimes the heat of the coating process will cause acceptable tablets to cap. The erosion visible beneath the coating occurred during the preheat cycle, which should have been stopped. Tablets with a soft surface are nearly impossible to coat without creating defects. surface, the coating attaches to some particles but forms bridges over others. By and large, these little bridges hold up well, but when they don’t, it’s often because the particle is too large. Check-screening the granulation before it reaches the press will help prevent the problem, which usually shows up as a white spot on the coated tablet.

Magnesium stearate — the most common tablet lubricant — is the most likely to cause this defect because it’s not water-soluble like most other ingredients. If a lump of magnesium stearate is compressed on the surface of the tablet, the coating defect looks like a pimple. Again, proper screening can reduce the number of these defects.

The amount of coating applied to tablets is measured in percentage weight gain, which typically ranges between 1 and 3 percent. Clear protective coatings skew toward the lower end of that range, while functional coatings and color coatings are on the upper end. The coating suspension itself is usually about 15 percent solids, but can range as high as 35 percent. Most coatings are prepared by combining a ready-to-mix powder formulation and water, which creates a suspension. The suspension must be well mixed and free of lumps and foam so that it sprays uniformly. It’s the polymers in the coating that bridge over any absorption-resistant particles on the tablet surface, while plasticizers enable the coating to withstand expansion and contraction to prevent cracking. Ultimately, successful coating depends on the strength of the tablet and how well its particles and the coating lock onto one another. Any soft or friable tablet particles will result in defects and possibly a batch failure. In fact, poor tablet surfaces are a leading cause of failures.

Time to coat

Most tablets are coated in batches but the number of continuous coaters is growing. Actually, most of these systems operate semi-continuously, coating batch after batch without stopping. I have yet to see a manufacturing operation in which tablets flow directly from the press to the coater, and there’s a good reason for that: Tablets are hot when they leave the press from the friction of compression and ejection. (Typically, the faster the press, the hotter the tablet.) Also, depending on the ingredients, tablets usually gain hardness over the first 24 to 48 hours. If you were to coat the tablets before they cooled and hardened, the coating would probably fail. In most cases — and there are exceptions — you get the best results if you let the tablets rest 24 hours before you coat them.

Avoid introducing air when you prepare coatings. This suspension is too foamy. For the best results, coatings must be applied in a controlled environment, and the tablets must be heated — between 42° and 46°C usually — and dedusted before spraying begins by rotating them in the coating drum. Every coating system has an air-handling unit to supply conditioned air and to extract dust and moisture. If the tablets and/or the coating environment are too cool, over-wetting can occur, which will soften the tablet surfaces and thereby promote erosion. When the environment is too hot, the coating dries too rapidly and doesn’t have time to adhere to the tablet surface.

The construction of coating pans, also called drums, has changed significantly over the years to control drying rates. Spray guns have also been upgraded to prevent “beards” from forming on the nozzle. In practice, the guns spray a mist in the direction of the airflow so it’s pulled toward and through the tablet bed. The objective is to expose the tablets to frequent and light misting so the coating dries quickly but not too quickly. Gun-to-bed distance is also important. Too close and the tablets will be overly wet; too far, and the coating dries before it contacts the tablets. The drum’s speed, the rate of airflow, and the shape of the tablets also affect how the coating process performs.

Michael D. Tousey is president of Techceuticals, 2917 East 79th Street, Cleveland, OH 44104. Tel. 216 658 8038. Website: www.techceuticals.com.Thecompanyspecializesin training people tooperate and maintain tablet presses and othersolid dosage equipment. It alsotroubleshoots solid dosage processes and equipment.

Techceuticals offers Solid Dose Training courses, as well as Solid Dose Operations eTraining. Check out the eTraining trailer relating to coating.

Originally published by Tablets & Capsules

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techceuticals-blog · 8 years ago

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Ten Tips on Troubleshooting Tabletting

When things go wrong in the compression department, they can go wrong very quickly. Identifying the root cause can be difficult unless certain things have been done upfront.

1. Inspect the working length of each set of tooling and maintain very close tolerances. New tooling varies by as much as 0.002 inch (0.05 millimeter), and any greater variation may cause or exacerbate weight, thickness, hardness, and friability problems. Match the working lengths o f the upper and lower punches to balance the compression forces. For example, along upper should be matched with a short lower.

2. Inspect dies for wear rings, and note that dies wear at different rates than the punches. Install dies so they all face the same direction and they wear at the same rate. Then turn them all over to double their life expectancy.

3. Set punch penetration as high in the die as possible. That allows air to release more quickly during compression, which improves hardness and reduces the chance of sticking.

4. Replace lubricant on the press after cleaning, which strips lubricant from the die table and tooling. Think of the lubricant as a mold-release agent, kind of like butter or cooking spray in a fry pan. If you for get to add it, the food will stick. Thus, season the press and tooling by rubbing the lubricant over the die table and punch cups before introducing the powder. Any excess lubricant will be eliminated in the first few revolutions of the press and be used up in tablets that you normally rejected anyway.

5. Replace the scraper blade as needed. It must scrape filled dies evenly, as weight control becomes impossible when the scraper is worn.

6. Know when the product was blended. With few exceptions, freshly blended powders cannot be tabletted because they’re too “fluid.” Let the powder settle for several hours. On the other hand, don’t let the powder get “stale” by settling too much. Sometimes, even 5 days is too long. Most, but not all, powder blends have a window when they are best tabletted. Start tracking press performance and blend age for each of your formulas to discover the optimal range. Often, the window ranges from 1 to 4 days.

7. Lubricate the punches properly to prevent most black specks from appearing in your tablets. Many modern presses lubricate automatically as they operate. Yet some batches are dustier than others, and that may not suffice. Some operator scan hear when the press is running harder from handling drier, finer powders. Monitor the punches and adjust the frequency of punch lubrication for each batch. Don’t change the timing. Instead, activate or override the lubricant cycle based on the amount of fine dust you encounter.

8. Check weight control accuracy first when you encounter problems or defects (hardness, thickness, friability,capping, laminating, splitting,or sticking). Also, stop taking average weights and begin taking many samples to observe the actual variation.Slightly reducing weight (fill volume) reduces tablet hardness and vice versa. The greater the variation in tablet weights, the greater the likelihood of one or more of these defects.

9. Reduce press speed to improve tablet weight, hardness, capping, lamination, friability, and sticking. If there is no change, then powder compressibility is in question, not the press. After all, if you cannot make great tablets at slow speed, why try to make them at higher speed? You risk compromising the entire batch.

10. Understand how to use pre-compression. Usually, it is best to start with low-force pre-compression and gradually increase it as you study tablet quality. Too many operators tend to over-compress at pre-compression,which can cause capping, lamination, sticking, and picking.In our business, no batch is ever identical to another, so eliminate variation wherever you can, be it in raw materials, punch working length,setup, cleaning, or lubrication.

Michael D. Tousey is director and owner of Techceuticals,365 Red Cedar St., Unit 202, Bluffton, SC 29910.Tel. 843 815 7441, fax 843815 7443. Website: www.techceuticals.com. The company specializes in trouble shooting the manufacture and packaging of tablets and capsules and offers free instruction at its website.

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