The most common ionizers used in film transport systems are static bars and ionized air blowers. Studies indicate that the density of this kind of defect decreases with increasing coating weight,(4) suggesting that such a defect can be masked by a thick coating. Adhesive Oozing / Bleeding Blistering Setting appropriate drying temp is a key to get raid of Blisters. Appearance is similar to that of an orange. Inappropriate drying (inlet air) temperature. Picking is primarily an over wetting issue and it occurs when the uid delivery rate exceeds the drying capacity of the process. Enter the email address you signed up with and we'll email you a reset link. The attritional effects in the typical film-coating process cannot be overemphasized. Selection of different tablet core design/ surface profile. This could be that the flash off zone before heat curing is inadequate or the oven profile is incorrect. It is a coating defect in which the film either cracks across the crown of the tablet (cracking) or splits around the edges of the tablet (Splitting). Orange peel often occurs when a binder fails to flow uniformly across an object's surface. Effect of temperature on the adhesion, elasticity, and strength of the film. Decrease the spray rate and use optimum drying conditions. Pin holing is one of the most common surface issues especially in sprayed application. Cracking of applied film coating can be microscopic or macroscopic in nature. In general following methods are used Gravure Gravure with Myer Bar Kiss Coating Floating Knife Comma Coating Or Reverse Roll coating. So much so that when vinyl films and overlaminates are rolled up on a roll, the films can pick the impression of backside of the release liner. Tablet Coating techniques: Concepts and recent trends. Pan loading with insufficient amount of core tablets. Scuffing is appeared when tablets are more sliding rather than trembling. During drying, the film may shrink and pull away from the sharp corners of an intagliation or bisect, resulting in a bridging of the surface. Because tablet edges are often exposed most to these attritional effects, fracture at this point is not uncommon and results in parts of the tablet surface being chipped and dented. A coating formulator wants to develop a adhesive that loses its foam as soon as application has finished and film formation proceeds. It is a coating defect where part of film of tablets momentarily stick together or stick to the pan, often just after they pass through the spray zone, and then sticked area being detached from the tablet surface. Polymeric film coating, in the formal sense, is a process that has been extensively used in pharmaceutical companies for over half a century. Adhesive coated during extremely hot weather or cool damp weather, which causes the adhesive film to dry faster on top than on the bottom. Get the Information Regarding Medicines and Diseases, Operation and Cleaning of Fluidized Bed Dryer, Ten Tips to Prevent an Accidental Overdose. Application of higher rate of the coating solution. Another approach being most often used to prevent crawling is lowering the surface tension of the liquid adhesive by adding wetting agent. Pan fill with sufficient amount of core tablets. The problem is commonly seen with nutraceutical products. It can also be introduced during the application process.
Under static conditions, the contact angle Q of a liquid drop placed on a given substrate determines whether wetting is good or poor. They may be electrically operated, passive, or may use radioactive materials as the ion generation source. (2012). document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); (adsbygoogle = window.adsbygoogle || []).push({}); Copyright 2022 Pharmapproach Limited. 2. Wetting becomes more critical when the surface energy of the substrate is low and/or when the surface tension of the liquid Adhesive is high. Despite the viscosity being high the foam bubbles might be able to move to the surface of the film where they can break. An orange peel effect is generally caused by the Adhesive viscosity that's too high. Recoat , (avoiding temperature/humidity extremes) . Corona treatment helps to a great extent in improving the wettability of the substrate. The problem may also be a consequence of spraying coating liquids with excessively high viscosities such that effective atomization is difficult to achieve. Especially this problem has happened with the presence of inappropriate logo. A wide variety of coating defects occur and the same are discussed. It is defect whereby pits occur in the surface of a tablet core without any visible disruption of the film coating. Tablet picking results when two adjacent tablets stick together and subsequently break apart (as a result of the constant motion within the coating equipment) leaving defects in the surface of the coating where pieces of coating have been removed. Application of higher rate of the coating solution. This article will focus on identifying the most common defects in film coating process, along with typical causes and possible solutions. Reducing pan speed throughout the coating process (or at least until sufficient coating has been applied so that the tablets receive some protection from the applied coating). During the coating, process tablets pass from many stages during those stages tablet face many problems so for avoiding these problems we use few techniques to solve this type of coating problem, in this article we do a detailed discussion on the tablet coating problems and remedies for their solution. Examples of suspension (Chemistry, Food & Pharmaceuticals), Difference between Drug Design and Drug Development, Tablet Compression Machine: Types, Functional Parts, List of tablet coating defects and remedies, 7. A small , dome like bulge in the coated film or a small recess in a coating film. Edinburgh: Churchill Livingstone. Insufficient film strength to provide resistance to edge damage.
Cracking in conformal coating is where a smooth surface fractures into sections with the cracks in the coating leaving the area below exposed to potential contaminants. It is surface defect resulting in the film being rough and nonglossy. Peeling refers to the formation of uneven or rough irregularities on the surface of a coating film applied on a core tablet surface. Improper flash or recoat time between coats. Dear Members , I have made an attempt to highlight the issue's related to coating defects in general. Coating droplets are over-dried before contacting tablet surface, increasing tablet surface roughness and filling the logo. A lot of hustle can be prevented by using available knowledge that is simple and easy. If first coats of enamel are allowed to become too dry, solvent in the paint droplets of following coats will be absorbed into the first coat before proper flow is achieved. Permeability to moisture 4.
These charges often cause attraction of Dirt , Dust , fibre and hair on to the web material and defects in coating uniformity resulting in quality problems and customer dissatisfaction. Dirt Pickup: Accumulation of dirt, dust particles , fiber and hair , on the adhesive film; may be a major problem. Academia.edu no longer supports Internet Explorer. What are tablet coating defects and remedies? Causes and Remedies of Scuffing of Film-coated Tablets. Spraying coating formulations once the required inlet temperature has been reached instead of prewarming the tablets (a process that usually involves some tablet motion without any coating being applied). Your email address will not be published. Required fields are marked *. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. In other words, pitting is the deformation of the core of the tablet without any visible signs of disruption of the film coating. Adhesive Coating is a simple process There are various methods available for the same. In some cases the substrate must be modified in such a way that the surface energy of the substrate is raised, i.e. [Rodger Talbert] Paint Technology Handbook(b-ok.org), Coating materials for electronic applications: polymers, processes, reliability, testing, COATING INSPECTOR PROGRAM Level 2 Student Manual Jan 2014, Coating Inspector Program Level 1 Student Manual, DETERMINATION OF THE VARIOUS DEFECTS ATTRIBUTED TO THE MANUFACTURE, SURFACE PREPARATION AND APPLICATION OF TEXTURED PAINTS, Interactions and penetration of polymers and nanolatexes into wood: An overview, PAINTING INSPECTION GRADE 3/2 (ATC88) TWI Ltd, Training and Examination Services WORLD CENTRE FOR MATERIALS JOINING TECHNOLOGY, File ID 86440 Filename Thesis SOURCE (OR PART OF THE FOLLOWING SOURCE): Type Dissertation Title Coating strategies for the protection of outdoor bronze art and ornamentation Author L, A review on self-cleaning and multifunctional materials, Robust hybrid elastomer/metal-oxide superhydrophobic surfaces, Coating Inspector Program Level 2 Student Manual, Designation: D3276 151151 Standard Guide for Painting Inspectors (Metal Substrates) 1, E99154 b863 489a 8ad5 cb1e5c0c6780 150331011256 conversion gate, A E.48, [THE GRAPHIC STANDARDS GUIDE TO ARCHITECTURAL FINISHES], Architectural Specification Issued For Construction, Study of Separation of Pigments in Paints for Development of Multicolor Paint, .Current Opinion in Colloid & Interface Science 6 2001 383401 Capillary forces and structuring in layers of colloid particles, 9076Emulsions Foams and Suspensions - Fundamentals and Applications, Observation and Modelling of Fluid Transport into Porous Paper Coating Structures, A review on aqueous film coating technology, The conservation of panel paintings and related objects, Wallpaper 1x1 A Textbook for Craftsmen and Those who wish to Be, Jasa P A S A N G Wallpaper Tangerang - 081338236055, Manufacturing Technology for Aerospace Structural Materials This Page is Intentionally Left Blank Manufacturing Technology for Aerospace Structural Materials, European Coatings Tech Files Coatings Formulation 2 nd Revised Edition, Manufacturing Technology for Aerospace Structural Materials - F.C.
However addition of around 0.5 to 1.0 % of Defoam / Anti Foam is generally followed . the substrate is changed from hydrophobic to hydrophilic. Precipitation of coating polymer due to use of a poor solvent or high coating temperature.
Increase solids content of coating liquid, Improve mechanical strength of core by increasing compaction force, changing tablet shape, modifying core formulation or changing process by which core is produced (e.g. Pharmaceutics: The science of dosage form design. Lachman, L., & Liebermann, H. A. In other words, it is the fading or dulling of a coated tablet color after a prolonged period of storage at a high temperature. Scrape or sand substrate to remove wrinkled coating. It is a coating defect where whitish specks or haziness in the film appear. Use optimized suspension preparation to avoid aeration. Logo In-filling /Break Lines In-filling, IV Bolus vs IV Infusion of Parenteral Drug Product, Difference between Bioavailability and Bioequivalence. Entrapment of gases in or underneath the film due to overheating either during spraying or at the end of the coating run.
Degree of coating cure. Peeling refers to the formation of uneven or rough irregularities on the surface of a coating film applied on a core tablet surface. This causes obvious quality problems in printing, coating and laminating and cleanliness problems with food, medical and pharmaceutical packaging films.
Reduction of the surface tension is required to avoid fish-eyes. Use high molecular weight of plasticizer. Meltingordissolutionoflubricantontabletsurfaceormeltingofcore ingredientduetohighcoretemperature. PEOPLE ALSO READ:SOP for Operation and Cleaning of Vibrosifter. It is a coating defect where the coating becomes dull immediately or after prolonged storage at high temperatures. The coating solution penetrates the surface of the tablet, often at the crown where the surface is more porous, causing localized disintegration of the core and disruption of the coating. Inadequate distribution of the coating suspension.
50-58. Mottle typically occurs when metallic flake pigment is used in a coating. It is a coating defect where the film becomes detached from the substrate forming a blister. Very high spray rate with low temperature. Ltd. Allen, L. V. (2013). Pan loading with insufficient amount of core tablets.
The use of air ionizers is the most common, cost effective method of controlling static charges on the film web. It is a coating defect where pits appear on the surface of a tablet core without any visible disruption of the film coating. 3. It a defect where tablets break apart during pan loading or while tumbling in the pan or during the coating process, or during unloading of the coating pan. Use coating formulation with increased hiding power. Low the viscosity of the coating solution. Chipping/ Edge Erosion: a common tablet coating defect, 11. Decrease in viscosity of coating suspension. Too little air pressure, wide fan patterns or spraying at excessive nozzle distances causes droplets to become too dry during their travel time to the work surface and they remain as formed by gun nozzle. Mainly, tablet coating is to be done for masking unpleasant taste and odor, protection, identification, improvement of patient compliance, and delivering to the targeted part of GIT. Higher internal stresses in the film than the tensile strength of the film. Use lower molecular weight polymeric blends or polymers.
Static charges are generated on the surface of the film as it unwinds from the roll and as it contacts and separates from surfaces such as idler rolls, nip rolls and printing or coating rolls. Incorporation of surfactants in the formulation will help you to improve the coating appearance. Causes and remedies of Core Erosion/ Surface Erosion. This condition relates to inadequate spreading of coating solution before drying thereby causing a bumpy or orange peel effects on the coating. Causes and Remedies of Cracking/Splitting. In other words, it is a haziness or appearance of white specks in the film coated tablet.
Charges exist in two polarities: positive and negative. Avoid the use of sorbitol with HPMC (Hydroxy Propyl Methyl Cellulose), HPC (Hydroxy Propyl Cellulose), Cellulose ethers, and Methyl Cellulose. Low molecular plasticized coating system. Peeling: Loss of bond due to poor adhesion. First, foam bubbles can be stabilized by additives having a surfactant (soap) structure. Unequal distribution of coating suspension. A defect which involves variation in colour of the film. It is a coating defect where the coating becomes dull immediately or after prolonged storage at high temperatures. The use of surfactants in adhesive formulation will avoid pinholes to appear on the dry paint film.
Increase spray rate and/or reduce processing temperatures. Ionizers emit vast quantities of both negative and positive charged gas molecules called air ions. Avoid the use of sorbitol with HPMC (Hydroxy Propyl Methyl Cellulose), HPC (Hydroxy Propyl Cellulose), Cellulose ethers, and Methyl Cellulose. It is possible to minimise conformal coating cracking effects by Lowering the initial cure temperature Allowing an initial drying time at room temperature before exposure to elevated temperature Reducing the coating thickness to avoid CTE mismatch issues Select a coating with a wider temperature range performance. Loading and unloading tablets from the coating pan. Orange Peel is Uneven , rough irregularities in the surface of a coated film. It is a coating defect where tablets stick together especially when two tablets stick together. The plasticizers that make films soft, also make them very impressionable. However, poor operator techniques, or too much adhesive coating thickness , will also produce a rough finish. Where there is a primer and top coat of adhesive, peeling may involve some or all coats. Especially during Gravure or Kiss roller coating , air can be brought into the adhesive . Precipitation of coating polymer due to use of a poor solvent or high coating temperature. Peeling from undercoat or substrate Delamination in adhesive coating is where the coating lifts from the surface , leaving the area below exposed. 3. It is a coating defect where tablet surfaces erode as tablets tumble during the coating process. Commonly flat surfaces along the edgesofcapsule-shaped tablets. Uneven coatings and "wicking" of adhesive are often the result of static charges. Thus the sudden drying of the top layer , and entrapment of solvent in the layer below is avoided. Especially this problem has happened with the presence of inappropriate logo. Addalcoholorusespraynozzlecapableof fineratomization.
Reduce coating solids to facilitated equal coating distribution. It occurs when the internal stress (that develops within the film as it dries) exceeds the tensile strength of the film. Increase the hardness of the film by increasing the molecular weight of the coating polymer. So, read this article about tablet coating defects and remedies to identify and solve your coating problems. Use a coating formula that provides enough protection from moisture. Use coating with proper mechanical strength. This defect can be so severe that the monogram or bisect is completely obscured. Fish-eyes can be caused by oily spots or silicone particles and/or by air-borne droplets that are deposited on the coated surface. In addition, appropriate design of tablet punches (especially with respect to the logo) may help to alleviate the problem, whereas adjustment of process conditions may also prove beneficial. Increasing compaction forces to reduce tablet friability.
Coating over contaminated surface (e.g., dirt or wax). In your post, your discuss 18 tablet coating defects and their remedies, it is most resourceful that i ever seen in online. Elongated shapes or caplet shaped tablets. Extreme shop floor temperature.
Trapped solvents can also show up as blisters. Unmodified plastics, for example, are a group of materials having low surface energy. SOP for Calibration of Shimadzu HPLC (Prominence i LC 2030), Column Cleaning, Regeneration and Storage of Silica Based Columns, USP 2021 (United State Pharmacopeia 44 - NF 39), Method Validation in Pharmaceutical Analysis A Guide to Best Practice, Dexamethasone: First Drug in Corona Virus. Adhesive droplets dry before they can flow out and level smoothly together. Because of the catastrophic nature of film cracking, the most effective approaches involve designing tablet core formulations that minimize or eliminate the risk of significant expansion behaviour occurring and creating film-coating formulations that are flexible enough to withstand any tablet core expansion that might occur. The strong electrostatic fields associated with these charges attract dust particles, fibers, bugs and hair resulting in surface contamination. Also, I liked your pictures. Discuss some common tablet coating problems and solutions. Reducetheamountofhygroscopicexcipient such asdisintegrant. High degree of attrition related to the coating process. Use coating with proper mechanical strength. Solutions to bridging involve improving film adhesion and/or reducing stress within the film, and usually require some reformation of either the tablet core or the film coating solution. As a result of such detachment, the film is able to shorten and thus partially relieve the stress within the film. After being flattened in temper rolling, these areas reflect light differently, appearing as either dark or bright spots depending on the lighting condition. This can be achieved thanks to surface modifying agents such as surfactants. Compatibility between the coating and the surface adhered to due to surface energies mismatch 3. To high processing temperaturelow molecular weight of Plasticiser.
Use coating formulation which is less tacky. Effect of temperature on the adhesion, elasticity, and strength of the film. Tablet coating is the application of a coating composition in a moving bed of tablets with the concurrent use of heated air to facilitate the evaporating of the solvent [1] and with the intention of conferring benefits and properties to the dosage form over the uncoated variety. Entrapment of gases or vapor in or under the film due to overheating either during spraying or at the end of the coating. However, the use of wetting agents can worsen key properties of the system, like hardness, recoat ability and foam sensitivity. Be aware that the use of defoamer, being an approach that cannot always be prevented, increases the risk of cratering , as well as reduction in Peel adhesion values. Entrapment of gases or vapor in or under the film due to overheating either during spraying or at the end of the coating. Common Tablet Defects:Causes and Remedies, Advantages and Disadvantages of Pharmaceutical Emulsions, Problems Encountered During Trituration and Possible Solutions, Mechanisms Involved in the Mixing of Pharmaceutical Powders, Mixing of Pharmaceutical Powders in Small-Scale Operations, 9 Reasons Why Customers Choose Your Competitors Products Over Yours, Common Medical Abbreviations and Their Meaning, Understanding the Various Types of Hepatitis Virus, Six Reasons for the Importance of Primary Care for the Elderly, National Agency for Food & Drugs Admin & Control, Journal of Pharmaceutical Development and Industrial Pharmacy, Coated product performance and functionality, Processing efficiencies and manufacturing costs, Optimizing spray rate and/or drying air temperatures and volumes to achieve better atomization of the coating liquid and improve drying, Thinning of coating solution with additional solvent to reduce viscosity and thus improve atomization. You can download the paper by clicking the button above. It is a coating defect where whitish specks or haziness in the film appear. Exposure of the Adhesive film to high temperature , humidity or moisture shortly after adhesive is coated , especially if there was inadequate exhaust. These occurrences become especially evident in converting operations such as sheeting, bag making and die-cutting where the film is no longer under the control of the mechanical structure of the web and its transport system. Excessive foaming of the coating solution. use granulation process instead of direct compaction). Please feel free and leave your comments regarding tablet coating defects and remedies.
Under static conditions, the contact angle Q of a liquid drop placed on a given substrate determines whether wetting is good or poor. They may be electrically operated, passive, or may use radioactive materials as the ion generation source. (2012). document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); (adsbygoogle = window.adsbygoogle || []).push({}); Copyright 2022 Pharmapproach Limited. 2. Wetting becomes more critical when the surface energy of the substrate is low and/or when the surface tension of the liquid Adhesive is high. Despite the viscosity being high the foam bubbles might be able to move to the surface of the film where they can break. An orange peel effect is generally caused by the Adhesive viscosity that's too high. Recoat , (avoiding temperature/humidity extremes) . Corona treatment helps to a great extent in improving the wettability of the substrate. The problem may also be a consequence of spraying coating liquids with excessively high viscosities such that effective atomization is difficult to achieve. Especially this problem has happened with the presence of inappropriate logo. A wide variety of coating defects occur and the same are discussed. It is defect whereby pits occur in the surface of a tablet core without any visible disruption of the film coating. Tablet picking results when two adjacent tablets stick together and subsequently break apart (as a result of the constant motion within the coating equipment) leaving defects in the surface of the coating where pieces of coating have been removed. Application of higher rate of the coating solution. This article will focus on identifying the most common defects in film coating process, along with typical causes and possible solutions. Reducing pan speed throughout the coating process (or at least until sufficient coating has been applied so that the tablets receive some protection from the applied coating). During the coating, process tablets pass from many stages during those stages tablet face many problems so for avoiding these problems we use few techniques to solve this type of coating problem, in this article we do a detailed discussion on the tablet coating problems and remedies for their solution. Examples of suspension (Chemistry, Food & Pharmaceuticals), Difference between Drug Design and Drug Development, Tablet Compression Machine: Types, Functional Parts, List of tablet coating defects and remedies, 7. A small , dome like bulge in the coated film or a small recess in a coating film. Edinburgh: Churchill Livingstone. Insufficient film strength to provide resistance to edge damage.
Cracking in conformal coating is where a smooth surface fractures into sections with the cracks in the coating leaving the area below exposed to potential contaminants. It is surface defect resulting in the film being rough and nonglossy. Peeling refers to the formation of uneven or rough irregularities on the surface of a coating film applied on a core tablet surface. Improper flash or recoat time between coats. Dear Members , I have made an attempt to highlight the issue's related to coating defects in general. Coating droplets are over-dried before contacting tablet surface, increasing tablet surface roughness and filling the logo. A lot of hustle can be prevented by using available knowledge that is simple and easy. If first coats of enamel are allowed to become too dry, solvent in the paint droplets of following coats will be absorbed into the first coat before proper flow is achieved. Permeability to moisture 4.
These charges often cause attraction of Dirt , Dust , fibre and hair on to the web material and defects in coating uniformity resulting in quality problems and customer dissatisfaction. Dirt Pickup: Accumulation of dirt, dust particles , fiber and hair , on the adhesive film; may be a major problem. Academia.edu no longer supports Internet Explorer. What are tablet coating defects and remedies? Causes and Remedies of Scuffing of Film-coated Tablets. Spraying coating formulations once the required inlet temperature has been reached instead of prewarming the tablets (a process that usually involves some tablet motion without any coating being applied). Your email address will not be published. Required fields are marked *. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. In other words, pitting is the deformation of the core of the tablet without any visible signs of disruption of the film coating. Adhesive Coating is a simple process There are various methods available for the same. In some cases the substrate must be modified in such a way that the surface energy of the substrate is raised, i.e. [Rodger Talbert] Paint Technology Handbook(b-ok.org), Coating materials for electronic applications: polymers, processes, reliability, testing, COATING INSPECTOR PROGRAM Level 2 Student Manual Jan 2014, Coating Inspector Program Level 1 Student Manual, DETERMINATION OF THE VARIOUS DEFECTS ATTRIBUTED TO THE MANUFACTURE, SURFACE PREPARATION AND APPLICATION OF TEXTURED PAINTS, Interactions and penetration of polymers and nanolatexes into wood: An overview, PAINTING INSPECTION GRADE 3/2 (ATC88) TWI Ltd, Training and Examination Services WORLD CENTRE FOR MATERIALS JOINING TECHNOLOGY, File ID 86440 Filename Thesis SOURCE (OR PART OF THE FOLLOWING SOURCE): Type Dissertation Title Coating strategies for the protection of outdoor bronze art and ornamentation Author L, A review on self-cleaning and multifunctional materials, Robust hybrid elastomer/metal-oxide superhydrophobic surfaces, Coating Inspector Program Level 2 Student Manual, Designation: D3276 151151 Standard Guide for Painting Inspectors (Metal Substrates) 1, E99154 b863 489a 8ad5 cb1e5c0c6780 150331011256 conversion gate, A E.48, [THE GRAPHIC STANDARDS GUIDE TO ARCHITECTURAL FINISHES], Architectural Specification Issued For Construction, Study of Separation of Pigments in Paints for Development of Multicolor Paint, .Current Opinion in Colloid & Interface Science 6 2001 383401 Capillary forces and structuring in layers of colloid particles, 9076Emulsions Foams and Suspensions - Fundamentals and Applications, Observation and Modelling of Fluid Transport into Porous Paper Coating Structures, A review on aqueous film coating technology, The conservation of panel paintings and related objects, Wallpaper 1x1 A Textbook for Craftsmen and Those who wish to Be, Jasa P A S A N G Wallpaper Tangerang - 081338236055, Manufacturing Technology for Aerospace Structural Materials This Page is Intentionally Left Blank Manufacturing Technology for Aerospace Structural Materials, European Coatings Tech Files Coatings Formulation 2 nd Revised Edition, Manufacturing Technology for Aerospace Structural Materials - F.C.
However addition of around 0.5 to 1.0 % of Defoam / Anti Foam is generally followed . the substrate is changed from hydrophobic to hydrophilic. Precipitation of coating polymer due to use of a poor solvent or high coating temperature.
Increase solids content of coating liquid, Improve mechanical strength of core by increasing compaction force, changing tablet shape, modifying core formulation or changing process by which core is produced (e.g. Pharmaceutics: The science of dosage form design. Lachman, L., & Liebermann, H. A. In other words, it is the fading or dulling of a coated tablet color after a prolonged period of storage at a high temperature. Scrape or sand substrate to remove wrinkled coating. It is a coating defect where whitish specks or haziness in the film appear. Use optimized suspension preparation to avoid aeration. Logo In-filling /Break Lines In-filling, IV Bolus vs IV Infusion of Parenteral Drug Product, Difference between Bioavailability and Bioequivalence. Entrapment of gases in or underneath the film due to overheating either during spraying or at the end of the coating run.
Degree of coating cure. Peeling refers to the formation of uneven or rough irregularities on the surface of a coating film applied on a core tablet surface. This causes obvious quality problems in printing, coating and laminating and cleanliness problems with food, medical and pharmaceutical packaging films.
Reduction of the surface tension is required to avoid fish-eyes. Use high molecular weight of plasticizer. Meltingordissolutionoflubricantontabletsurfaceormeltingofcore ingredientduetohighcoretemperature. PEOPLE ALSO READ:SOP for Operation and Cleaning of Vibrosifter. It is a coating defect where the coating becomes dull immediately or after prolonged storage at high temperatures. The coating solution penetrates the surface of the tablet, often at the crown where the surface is more porous, causing localized disintegration of the core and disruption of the coating. Inadequate distribution of the coating suspension.
50-58. Mottle typically occurs when metallic flake pigment is used in a coating. It is a coating defect where the film becomes detached from the substrate forming a blister. Very high spray rate with low temperature. Ltd. Allen, L. V. (2013). Pan loading with insufficient amount of core tablets.
The use of air ionizers is the most common, cost effective method of controlling static charges on the film web. It is a coating defect where pits appear on the surface of a tablet core without any visible disruption of the film coating. 3. It a defect where tablets break apart during pan loading or while tumbling in the pan or during the coating process, or during unloading of the coating pan. Use coating formulation with increased hiding power. Low the viscosity of the coating solution. Chipping/ Edge Erosion: a common tablet coating defect, 11. Decrease in viscosity of coating suspension. Too little air pressure, wide fan patterns or spraying at excessive nozzle distances causes droplets to become too dry during their travel time to the work surface and they remain as formed by gun nozzle. Mainly, tablet coating is to be done for masking unpleasant taste and odor, protection, identification, improvement of patient compliance, and delivering to the targeted part of GIT. Higher internal stresses in the film than the tensile strength of the film. Use lower molecular weight polymeric blends or polymers.
Static charges are generated on the surface of the film as it unwinds from the roll and as it contacts and separates from surfaces such as idler rolls, nip rolls and printing or coating rolls. Incorporation of surfactants in the formulation will help you to improve the coating appearance. Causes and remedies of Core Erosion/ Surface Erosion. This condition relates to inadequate spreading of coating solution before drying thereby causing a bumpy or orange peel effects on the coating. Causes and Remedies of Cracking/Splitting. In other words, it is a haziness or appearance of white specks in the film coated tablet.
Charges exist in two polarities: positive and negative. Avoid the use of sorbitol with HPMC (Hydroxy Propyl Methyl Cellulose), HPC (Hydroxy Propyl Cellulose), Cellulose ethers, and Methyl Cellulose. Low molecular plasticized coating system. Peeling: Loss of bond due to poor adhesion. First, foam bubbles can be stabilized by additives having a surfactant (soap) structure. Unequal distribution of coating suspension. A defect which involves variation in colour of the film. It is a coating defect where the coating becomes dull immediately or after prolonged storage at high temperatures. The use of surfactants in adhesive formulation will avoid pinholes to appear on the dry paint film.
Increase spray rate and/or reduce processing temperatures. Ionizers emit vast quantities of both negative and positive charged gas molecules called air ions. Avoid the use of sorbitol with HPMC (Hydroxy Propyl Methyl Cellulose), HPC (Hydroxy Propyl Cellulose), Cellulose ethers, and Methyl Cellulose. It is possible to minimise conformal coating cracking effects by Lowering the initial cure temperature Allowing an initial drying time at room temperature before exposure to elevated temperature Reducing the coating thickness to avoid CTE mismatch issues Select a coating with a wider temperature range performance. Loading and unloading tablets from the coating pan. Orange Peel is Uneven , rough irregularities in the surface of a coated film. It is a coating defect where tablets stick together especially when two tablets stick together. The plasticizers that make films soft, also make them very impressionable. However, poor operator techniques, or too much adhesive coating thickness , will also produce a rough finish. Where there is a primer and top coat of adhesive, peeling may involve some or all coats. Especially during Gravure or Kiss roller coating , air can be brought into the adhesive . Precipitation of coating polymer due to use of a poor solvent or high coating temperature. Peeling from undercoat or substrate Delamination in adhesive coating is where the coating lifts from the surface , leaving the area below exposed. 3. It is a coating defect where tablet surfaces erode as tablets tumble during the coating process. Commonly flat surfaces along the edgesofcapsule-shaped tablets. Uneven coatings and "wicking" of adhesive are often the result of static charges. Thus the sudden drying of the top layer , and entrapment of solvent in the layer below is avoided. Especially this problem has happened with the presence of inappropriate logo. Addalcoholorusespraynozzlecapableof fineratomization.
Reduce coating solids to facilitated equal coating distribution. It occurs when the internal stress (that develops within the film as it dries) exceeds the tensile strength of the film. Increase the hardness of the film by increasing the molecular weight of the coating polymer. So, read this article about tablet coating defects and remedies to identify and solve your coating problems. Use a coating formula that provides enough protection from moisture. Use coating with proper mechanical strength. This defect can be so severe that the monogram or bisect is completely obscured. Fish-eyes can be caused by oily spots or silicone particles and/or by air-borne droplets that are deposited on the coated surface. In addition, appropriate design of tablet punches (especially with respect to the logo) may help to alleviate the problem, whereas adjustment of process conditions may also prove beneficial. Increasing compaction forces to reduce tablet friability.
Coating over contaminated surface (e.g., dirt or wax). In your post, your discuss 18 tablet coating defects and their remedies, it is most resourceful that i ever seen in online. Elongated shapes or caplet shaped tablets. Extreme shop floor temperature.
Trapped solvents can also show up as blisters. Unmodified plastics, for example, are a group of materials having low surface energy. SOP for Calibration of Shimadzu HPLC (Prominence i LC 2030), Column Cleaning, Regeneration and Storage of Silica Based Columns, USP 2021 (United State Pharmacopeia 44 - NF 39), Method Validation in Pharmaceutical Analysis A Guide to Best Practice, Dexamethasone: First Drug in Corona Virus. Adhesive droplets dry before they can flow out and level smoothly together. Because of the catastrophic nature of film cracking, the most effective approaches involve designing tablet core formulations that minimize or eliminate the risk of significant expansion behaviour occurring and creating film-coating formulations that are flexible enough to withstand any tablet core expansion that might occur. The strong electrostatic fields associated with these charges attract dust particles, fibers, bugs and hair resulting in surface contamination. Also, I liked your pictures. Discuss some common tablet coating problems and solutions. Reducetheamountofhygroscopicexcipient such asdisintegrant. High degree of attrition related to the coating process. Use coating with proper mechanical strength. Solutions to bridging involve improving film adhesion and/or reducing stress within the film, and usually require some reformation of either the tablet core or the film coating solution. As a result of such detachment, the film is able to shorten and thus partially relieve the stress within the film. After being flattened in temper rolling, these areas reflect light differently, appearing as either dark or bright spots depending on the lighting condition. This can be achieved thanks to surface modifying agents such as surfactants. Compatibility between the coating and the surface adhered to due to surface energies mismatch 3. To high processing temperaturelow molecular weight of Plasticiser.
Use coating formulation which is less tacky. Effect of temperature on the adhesion, elasticity, and strength of the film. Tablet coating is the application of a coating composition in a moving bed of tablets with the concurrent use of heated air to facilitate the evaporating of the solvent [1] and with the intention of conferring benefits and properties to the dosage form over the uncoated variety. Entrapment of gases or vapor in or under the film due to overheating either during spraying or at the end of the coating. However, the use of wetting agents can worsen key properties of the system, like hardness, recoat ability and foam sensitivity. Be aware that the use of defoamer, being an approach that cannot always be prevented, increases the risk of cratering , as well as reduction in Peel adhesion values. Entrapment of gases or vapor in or under the film due to overheating either during spraying or at the end of the coating. Common Tablet Defects:Causes and Remedies, Advantages and Disadvantages of Pharmaceutical Emulsions, Problems Encountered During Trituration and Possible Solutions, Mechanisms Involved in the Mixing of Pharmaceutical Powders, Mixing of Pharmaceutical Powders in Small-Scale Operations, 9 Reasons Why Customers Choose Your Competitors Products Over Yours, Common Medical Abbreviations and Their Meaning, Understanding the Various Types of Hepatitis Virus, Six Reasons for the Importance of Primary Care for the Elderly, National Agency for Food & Drugs Admin & Control, Journal of Pharmaceutical Development and Industrial Pharmacy, Coated product performance and functionality, Processing efficiencies and manufacturing costs, Optimizing spray rate and/or drying air temperatures and volumes to achieve better atomization of the coating liquid and improve drying, Thinning of coating solution with additional solvent to reduce viscosity and thus improve atomization. You can download the paper by clicking the button above. It is a coating defect where whitish specks or haziness in the film appear. Exposure of the Adhesive film to high temperature , humidity or moisture shortly after adhesive is coated , especially if there was inadequate exhaust. These occurrences become especially evident in converting operations such as sheeting, bag making and die-cutting where the film is no longer under the control of the mechanical structure of the web and its transport system. Excessive foaming of the coating solution. use granulation process instead of direct compaction). Please feel free and leave your comments regarding tablet coating defects and remedies.