By continuing to use this website you are giving consent to cookies being used. The detection and localization of coating defects such as chipping at either the center or the edge of the tablet may be caused by different phenomena, such as twinning of tablets during film coating or insufficient flexibility of the coating film and thus allowing systematic adjustment of the defect-causing process parameters . Tablet Discolouration may be solved by minor processing remedies, such as increasing processing temperatures, reducing spray rates, or increasing pan speed to reduce dwell times in the spray zone can reduce over-wetting and thus prevent interaction between tablet core ingredients (such as that between iron salts and ascorbic acid). This includes improper cleaning of the surface of contaminants, as well as inadequate surface profile. Film-coated products seem to exhibit more than their fair share of defects. Tablet scuffi­ng has, at various times, been associated with the use of coating formulations based on polyvinyl alcohol (PVA). Quality by design approach was explored to optimize the tablet coating process using Opadry®, an optimized one step film coating system. © 2021 Pharmapproach Limited. Interference is simply the addition of the fields of the various waves involved. Eur J Pharm Biopharm, 71 (2009), pp. Magnetically assisted impaction coating, electrostatic dry coating in solventless coatings, aqueous film coating and Supercell coating technology are also available recent technique of coating. Rowley, on the other hand, confi­rmed that the main issue is related to the level of titanium dioxide used. Optimizing spray gun setup so that there is no mis-spraying, that all spray guns are spraying at the same rate, and that each is providing the same area of coverage over the tablet bed surface. Dip coating is ideal for coating both sides of a flat substrate simultaneously, and can be used to create gradient coatings by varying withdrawal speed. film coating defect, since it is aesthetically unpleasing, exposes active to environmental factors and gives the impression of sub–standard product (Figure 6). common defects 30 6. There are two types of adhesion failure: intercoat adhesionfailure and substrate adhesion failure. For example, interaction of ingredients in the core, often in the presence of moisture derived from the coating process, can create dark spots that remain visible through the coating. Figure 1. Increasing the number of spray guns to expand the spray zone and give better surface coverage. Infilling of Logos. coating defects on a soft and friable multivitamin tablet. Reduction in the levels of titanium dioxide used in the coating formulations (as suggested by Ogasawara et al.) It can be caused by surface contamination, condensation on the substrate, applying two different coating products that are incompatible or by exceeding the overcoating time. Notify me of follow-up comments by email. Coatings applied with poor surface preparation will peel, and in some c… terms of site, rate, and time [2–5]. Capillary Flow. in film coating is the consistency of tablet hardness. Here are the six most common causes of conformal coating defects we see, along with recommendations for how to avoid them: 1. While both cohesive and adhesive failure are implicated here (both phenomena being linked to internal stress), appropriate solutions typically involve addressing the initial cracking problem by increasing the mechanical strength of the coating. In the case in which foamy material tends to build up within the logo, it is interesting to note that the addition of conventional antifoam agents does not decrease the incidence of this defect. Film coating is also applicable to mask taste and improve patient compliance. Toward a greater understanding of the scuffi­ng defect observed on Fi­lm-coated tablets. In the case of modifi­ed-release dosage forms, coating process conditions can influence the degree to which phase separation can occur with a resulting impact on the size of pores created within the fi­lm structure (and hence drug release) when ethylcellulose is used as primary insoluble polymer and hydroxypropyl cellulose as the water-soluble pore former. Usually, however, a portion of the coating will remain in the compression mix. Course Outline . This may be as a result of partially spray-dried material gradually building up within the logo or, the buildup of dried foamy material within the logo. For coating formulations prepared from powdered premixes made by a third party vendor, the issue of ineffective pigment dispersion must be dealt with by those vendors. For example, if a capsule-shaped tablet is required, changing from the more traditional design to one in which there is a small degree of curvature on the edges of the tablets can reduce the area of contact between tablets and greatly minimize the risk of twinning. Using such equipment, a better separation of tablet and coating fragments was achieved. Common Defects A paint defect is in many cases due to a number of causes. Mechanical deficiencies in the tablet cores (tablets are not robust enough to withstand film coating process). In both cases, the remedies are relatively simple and include: This is one of the most troublesome defects caused by mechanical stress, primarily because it cannot be easily resolved by minor adjustment of the coating process. Mishandling of tablets during loading/ emptying of coating pans. 7. Tablets momentarily stick together, often just after they pass through the spray zone, and then break apart leaving defects in the surface of the... Read More. Problems of this nature may be alleviated by, To continue reading, click on the page buttons below…, Your email address will not be published. Rowley, F. A. Generally, unless it is deliberately intended (as in the case of modified release dosage forms), the application of a film coating to pharmaceutical dosage forms should not have any influence on drug release and bioavailability. Thus, any rework procedure must be suitably validated so as to ensure that recompressed tablets perform within the specifications of the original product. This problem can be eliminated by simply addressing over-wetting conditions (reducing spray rates, increasing processing temperatures, or both). Tablet breaking force (or tensile strength) must be maximized, while minimizing tablet friability. Although many film-coating problems tend to be visual or cosmetic defects that may not negatively impact product efficacy, their existence detracts from the perception of overall product quality and may affect consumer/patient confidence. The delivery of a sprayed coating solution onto a variable range of tablet surface hardness will net poor results at best. In-filling of Logos/Break Lines. In this guide, we introduce the concept behind slot-die coating as a deposition technique and explain the theory that underpins the movement of solution within a slot-die coater. Entrapment of gases or vapor in or under the film due to overheating either during spraying or at the end of the coating. Using high solids film-coatings systems (such as Aquarius Preferred HSP) that facilitates the use of lower processing temperatures, Adjusting core formulation to improve dissolution behaviour and offset sensitivity to processing conditions. Other coatin… In addition to unsuitable punch design, core surface erosion can be facilitated by over-wetting (which causes the tablet surface to soften and hence become less resistant to attritional effects), presence of centrally placed logo, insufficient film strength (to provide resistance to edge damage) and too high pan speed. Regular Access to Part 1 + Part 2: 650 € 520 € On purchasing the course, you'll get: Recording of Part 1; Recording of Part 2; Exclusive Preview . Introduction Spin coating is a procedure used to apply uniform thin films to flat substrates. Film coating is a thin polymer layer applied on to a solid dosage form. When edge wear occurs, the coating process conditions, the tablet core and the coating for-mulation can all be considered in the effort to eliminate the problem. The spraying air pressure affected the film-core interface and the occurrence of coating defects. This problem is caused when agglomerates of lubricants such as stearic acid and polyethylene glycol melt under the influence of the coating process conditions used. Once the foam/material has accumulated to a level approaching the outer contour of the tablet surface, normal attrition can occur, allowing the structure to be covered with a continuous film. The overall coating process, coating methods and operating variables, solution handling, drying, and web transport must be optimized for a thin coating to produce defect-free film at low cost. Excessive tablet-to-tablet colour variability may be attributed to; This is the term for two tablets that stuck together, usually after becoming aligned along flat surfaces. Also, implementation of a proactive approach that acknowledges such problems focuses on problem avoidance during product and process development and provides the most effective means of dealing with a subject that for so long has plagued the production of ­film-coated dosage forms. This ultimately determines how the wet films are produced. Contaminants can include water-soluble salts, dust from abrasive blasting of the substrate surface, as well as environmental dirt and dust that was not properly cleaned off the surface. Coatings and Inks formulators / developers with a need to solve & prevent film coating defects faster by better applying science behind film defects. Zeitler, L.F. GladdenIn-vitro tomography and non-destructive imaging at depth of pharmaceutical solid dosage forms. FILM COATING PROCESSES ALBERTO ALISEDA Department of Mechanical Engineering, University of Washington, Seattle, WA, USA ALFRED BERCHIELLI Pharmaceutical Development, Pfizer Global Research & Development, Groton, CT, USA PANKAJ DOSHI Chemical Engineering and Process Division, National Chemical Laboratory, Pune, India JUAN C. LASHERAS Jacobs School of Engineering, … Many common problems with film-coated products and processes are … To achieve good painting work, applicators and site supervisors should understand the causes and preventive measures of common defects that occur at different stages of works. Coating Deterioration Kenneth B. Tator, KTA-Tator, Inc. PAINTS AND COATINGS of all types are widely used to provide color and pleasing aes-thetics, and to prevent deterioration of the underlying substrate when exposed to various environments. Improving tablet core robustness, either by addressing the core formulation or examining the tabletting process (slowing down press speeds to increase dwell time, increasing compaction forces, and possible use of precompression). In some cases, several defects may occur simultaneously and hinder the determination of the causes and redemption works. Tablet Coating With Its Defects - Free download as Powerpoint Presentation (.ppt / .pptx), PDF File (.pdf), Text File (.txt) or view presentation slides online. 2-22. Causes and Remedies of Blistering: Causes: Remedies: 1. In a similar vein, migration/ bleeding of ingredients from the tablet core, through the coating can also be a factor. Finally, poor dispersion of pigment ingredients within the coating formulation can also be a source of tablet discolouration; in which case, this must be dealt with at the time of preparation of the coating suspension to make sure pigments are effectively dispersed into the final coating suspension. Enter your email address to subscribe to this blog and receive notifications of new posts by email. Recovery of film-coated tablets thus typically involves milling of the tablets to produce “granules” that can be introduced (at a predetermined level) into other batches of compression mix (of the same product). Information about tablet coating and its defects This topic is also addressed in NSTM Chapter 631, Section 6. Definition: Cratering happens when a defect on the film’s coating results in craters appearing on the tablet which in turn results in the exposure of the tablet’s surface. In this type of defect, tablets break apart during loading of coating pans, during the coating process, or during unloading of coating pan. Rosoff, M. and Sheen, P. (1983). Description An adhesion failure appears as a paint that is flaking off because it failed to stick to either the substrate or a prior coating (if there was one). Coated tablet dissolution problem can be solved by. This defect is commonly seen with nutraceutical products and may be expressed in many ways. Tablet-to-tablet colour variability corresponds to inter-tablet variation of coating. Intercoat adhesion failure(Dmitry Guzhanin / The general buildup of prematurely dried material can be corrected by optimizing the atomization process to give a more uniform distribution of droplet sizes. Ogasawara, Y., Steffenino, R. and Cunningham, C. Scuf­fing measurement methodology and improved fi­lm coating systems. J.A. Unlike with sugar-coated tablets, film-coated tablets cannot be readily recovered (should a batch be rejected) by simply washing off the coating. Article Download PDF CrossRef View Record in Scopus Google Scholar. This is followed by a discussion of some of the applicatio… Normally, dried material that is deposited on the tablet surfaces would breakdown as tablets slide over each other but because the intagliation form a protected area, this will not occur for material that resides in the logo. By continuing to use this website you are giving consent to cookies being used. All Rights Reserved . & THIN FILM COATINGS Low Defect Wafer Level Optical Solutions. However, the addition of alcohol, the use of spray nozzles capable of finer atomization, optimizing the mixing process either by setting mixer height correctly, choosing mixer blade of correct size (about 30% of tank diameter), choosing optimal mixer speed and incorporation powder into water as fast as possible to avoid excessive viscosity build-up before all powder has been wetted out have been found to be effective. For example, for an immediate-release product, ibuprofen tablets (because of the relatively low melting point of this active substance) are well known to exhibit dissolution problems when exposed to high processing temperatures. Optimizing pan loading to make sure the tablets are tumbling effectively, with no intermittent stalling of the tablet bed, and to ensure that a consistent gun-to-bed distance is maintained. Excessive attritional conditions used during application of the applied coating. As more coating is applied to tablet surfaces, the stresses that develop within the coating as it dries overcome the forces of attachment of the... Read More. Related Keywords: film coating defects slideshare, defects in film coating, film coating defects pdf, tablet coating defects colorcon, defects in film coating, tablet coating process, sugar coating and film coating, defects in film coating, logo bridging in tablet coating, tablet defects with pictures, tablet coating slideshare, Your email address will not be published. This section describes coating defects and failures commonly encountered aboard Navy ships, particularly on metal surfaces. Use mild drying conditions. Depending on the fracture characteristics of the tablets, and to some extent the adhesion of the coating to the tablet surface, the milling process may cause the coating to flake off so that it can be removed from the tablet core material by sieving. CRATERING • It is defect of film coating whereby volcanic-like craters appears exposing the tablet surface • Reason: 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. This website uses cookies. Higher rate of application of coating solution. Visit our. Formulating robust tablets is critical to minimizing defects that arise during film-coating application. Pigmented, fully-formulated film coating systems, containing either hypromellose (HPMC) or polyvinyl alcohol (PVA) as the base polymers, were used in the study. While there are certain coating process changes that can be made to obviate this problem, including increasing pan speed to reduce the dwell time in the spray zone (thus reducing over-wetting), improving the drying conditions (such as increasing process air temperatures or volumes and/or decreasing spray rates) or expanding the spray zone (either by increasing gun-to-bed difference, pattern air pressure or the number of spray guns) to minimize the risk of localized over-wetting, proactively dealing with the issue during product development provides a more effective solution. Article Download PDF View Record in Scopus Google Scholar. It is a coating defect where the film becomes detached from the substrate forming a blister. Visit our. Although this defect does not interrupt the film coat, it does diminish the pharmaceutical elegance of the dosage form. For example, designing coating formulations (such as high solids coating formulations) that can minimize moisture penetration into the tablet core during application of the coating can effectively reduce or eliminate the problem. Although variation in the amount of coating applied on each tablet within the batch will, on a weight basis, always exist, the challenge is to ensure that enough coating is applied to prevent visible differences in amount of coating applied or even affecting fi­nal product functionality. Coatings also extend shelf-life, mask bitter tastes and off-putting odors, and add flavor and color. We also offer practical tips and outline the considerations that are needed to ensure high coating uniformity when working with slot-die coating. For example, fi­lm coatings based on poly (vinyl) alcohol as well as delayed-release coating based on acrylic polymers are well known for their increased tackiness behaviours. Using binders that deform plastically, such as hydroxpropylcellulose (HPC), can be very beneficial, as shown below. Thus, when these kinds of polymers are required, the use of anti-adhesive agents (such as lecithin, talc, glyceryl monostearate, magnesium stearate) in the coating formulation can be quite effective in reducing their tackiness. Keywords: substrate; centrifugal force; spin coating; thin film; photolithography; acceleration 1. can be quite effective; however, this approach will also reduce the opacity of the coating formulation, necessitating the use of higher levels of applied coating to achieve complete tablet core coverage. Adjusting coating formulation to allow reduction in coating process temperatures. One approach that can be very effective deals with core design. In fact, logo definition is a key CQA because it allows the manufacturer, pharmacist, and end-consumer to recognize the brand. Logo Bridging. Effect of temperature on the adhesion, elasticity, and strength of the film. Required fields are marked *. Selecting a film coating formulation with increased hiding power (lighter colours tend to exhibit better “hiding power” than darker ones). This may be alleviated by using hybrid polymeric film coatings based on combinations of Hydroxypropyl methylcellulose (HPMC) and copovidone. Lieberman, H., Lachman, L. and Schwartz, J. This is another mechanical defect that occurs as tablets tumble during the coating process. Notify me of follow-up comments by email. A practical guide for ensuring a defect-free coating and drying process. Reducing coating solids to facilitate more even coating distribution.

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