Tablets coating

Perform Installation Qualification. Verify equipment identification, required documents, utilities, component materials, drawings, and manuals. 

Perform general operational controls verification testing. Verify coating pan motor, supply blower, exhaust motor, and spray system. 

Operate system throughout the range of operating design specifications or range of intended use. Verify switches and push-buttons, rotator direction, motor variable speed, supply temperature, differential pressure, and pan air flow. 

Verify that all safety devices are operating as specified in the manual. 

Verify that recommended lubricants are used during machine operation. 

---

Pharmaceutical tablets coated with lactose often develop a brown discoloration. The factors that primarily affect the... 

Vinyl acetate [108-05-4] (VAc), CH2=CHOOCCH2, the ethenyl ester of acetic acid, is primarily use for the manufacture of poly(vinyl acetate) [9003-20-7] (PVAc) and vinyl acetate copolymers. Poly(vinyl acetate) homo- and copolymers are found as components in coatings, paints and sealants, binders (adhesives, nonwovens, constmction products, and carpet-backing), and miscellaneous uses such as chewing gum and tablet coatings. AppHcations have grown over the years in a number of areas (1 4). 

Other apphcations for VP/VA copolymers are uses as water-soluble or remoistenable hot melt adhesives (140), pharmaceutical tablet coatings, binders, and controUed-release substrates. 

The copolymers are insoluble in water unless they are neutralized to some extent with base. They are soluble, however, in various ratios of alcohol and water, suggesting appHcations where deUvery from hydroalcohoHc solutions (149) but subsequent insolubiUty in water is desired, such as in low volatile organic compound (VOC) hair-fixative formulations or tablet coatings. Unneutralized, their Ts are higher than expected, indicating interchain hydrogen bonding (150). 

Properties of lakes that enhance their usefiilness iaclude their opacity, their abiUty to be iacorporated iato products ia the dry state, their relative iasolubihty, and their superior stabiUty toward heat and light. Such properties have made possible the more effective and more efficient preparation of candy and tablet coatings, and often eliminate the need to remove moisture from dry products before coloring them. Lakes have also made possible the coloring of certain products that, because of their nature, method of preparation, or method of storage, caimot be colored with ordinary color additives. 

Delivery systems that respond to changes in pH have been known to the pharmaceutical industry for more than a century. The pH-sensitive enteric coating is probably the oldest controUed-release technology. Unna introduced an enteric tablet coating based on keratin in 1884 (108). Enteric coatings are used primarily to protect the gastric mucosa from local irritation or to ensure that tablets do not dissolve until they reach the intestine. 

Plumb AP, Rowe RC, York P, Doherty C. The effect of experimental design in the modelling of a tablet coating formulation using artificial neural networks. Eur J Pharm Sci 2002 16 281-8. 

Bod choice of core geometry Fig. 21 Tablet-coating geometry. 

In a four-part article, Porter [130] provided a comprehensive review of tablet coating technology, with emphasis on contemporary practice. More specifically, a recent review [131] discusses characterization techniques for the aqueous film coating process and provides a useful influence matrix between process variables and final product attributes. 

Figure 8 The release of trimazosin versus time for a tablet coated with either a dense or an asymmetrical membrane. (From Ref. 20.)...

SM Herbig, JR Cardinal, RW Korsmeyer, KL Smith. Asymmetric-membrane tablet coatings for osmotic drug delivery. J Controlled Release 35 127-136, 1995. 

Recently, a new class of excipients based on ethylene oxide-vinyl alcohol copolymers (see Figure 17.12) has been developed (PEO-g-PVA). The combination of PVA and PEO should result in an excellent instant-release tablet coating. One way to... 

In some instances there is a possibility that the efficacy of these preparations may be compromised by conditions associated with the digestive tract. Most function at pH values approaching neutrality. They would thus display activity possibly in saliva and particularly in the small intestine. However, the acidic conditions of the stomach (where the pH can be below 1.5) may denature some of these enzymes. Furthermore, the ingested enzymes would also be exposed to endogenous proteolytic activities associated with the stomach and small intestine. Some of these difficulties, however, may be at least partially overcome by formulating the product as a tablet coated with an acid-resistant film to protect the enzyme as it passes through the stomach. 

Asacol Mesalamine tablet coated 2.4-4.8 g Distal ileum... 

The effects of organosilane type on the VB1 release are large and show that for tablets coated twice and dried at 60 °C, the samples coated with bis(trimethoxysilyl)hexane (TSH), bis(triethoxysilyl)octane (TSO), bis (trimethoxysilylpropyl)amine (TSPA) and bis[3-(trimethoxysilyl)propyl]-ethylenediamine (enTMOS) give slower release than the other samples including uncoated mesoporous silica used for a comparison (Figure 2.16). 

It is worth noting that a monotropic polymorphic system offers the potential of annealing the substance to achieve the preferred form of the thermodynamically stable phase. The use of the most stable form is ordinarily preferred to avoid the inexorable tendency of a metastable system to move toward the thermodynamic form. This is especially important especially if someone elects to use a metastable phase of an excipient as part of a tablet coating, since physical changes in the properties of the coating can take place after it has been made. Use of the most stable form avoids any solid-solid transition that could... 

Figure 7.4 Collection of commercial Raman probes designed for different installations (a) laboratory scale probe with interchangeable immersion or noncontact optics, shown with immersion option (b) probe shown in (a) installed in laboratory fermentation reactor (c) production scale immersion probe (d) probe shown in (c) installed in a glass reactor (e) gas phase probe with flow through cell (f) probe shown in (e) installed in process piping (g) wide area illumination (WAI) noncontact probe after completion of a pharmaceutical tablet coating operation. Adapted, with permission. Copyright 2004 Kaiser Optical Systems, Inc.

Fluorescence from pharmaceutical capsule shells and tablet coatings has hindered measurement of their composition by Raman spectroscopy. By switching from the conventional backscattering mode to a transmission mode, Matousek et al. demonstrated that fluorescence could be eliminated in many instances [8]. Backscattering- and transmission-mode Raman spectra of several samples are shown in Figure 7.5. Each spectrum was acquired in 10s with 80mW 830-mn laser power. Matousek et al. also speculate that signal acquisition times could be relatively easily shortened to well below 0.1 s when the transmission mode is combined with optimized optics [8]. 

The thickness of pharmaceutical tablet coatings was predicted using target factor analysis (TFA) applied to Raman spectra collected with a 532-mn laser, where the samples were photobleached in a controlled manner before spectra were acquired. The authors acknowledge numerous issues that limit the direct applicability of this approach to process control. These include potential damage or alteration of the samples from photobleaching, laser wavelength selection, and data acquisition time. However, most of the issues raised relate to the hardware selected for a particular implementation and do not diminish the demonstration [286]. 

S. Romero-Torres, J.D. Perez-Ramos, K.R. Morris and E.R. Grant, Raman spectroscopic measurement of tablet-to-tablet coating variability, J. Pharm. Biomed. Anal., 38, 270-274 (2005). 

Figure 8.9 (a) Single wavelength NIR chemical image at 2070nm showing tablet coating differences between... 

Examples of terahertz spectroscopy as a PAT tool in the pharmaceutical industry include monitoring of polymorphism, tablet coatings, and crystallinity, even at the stage of product development to aid in process design. ... 

The traditional tablet coating is a sugar coat applied in stages. First the tablet surface is sealed... 

Tablets, coated 500 mg with buffers (ofc) Extra Strength Adprin-B (Pfeiffer), Extra Strength Bayer Plus Caplets (Sterling Health), Ascriptin Extra Strength (Aventis), Cama Arthritis Pain Reliever (Sandoz), Arthritis Pain Formula (Whitehall)... 

Lubricants are used in tablet preparation and include magnesium stearate, stearic acid and polyethylene glycol. They only comprise at most 1-2% of the tablet bulk so that their potential to interfere is slight, particularly since their chromophores are weak. The fatty acid lubricants can often be observed if analysis of a tablet extract is carried out by GC-FID. Tablet coatings are often based on modified sugar polymers such as hydroxypropylmethylcellulose. These coatings are used at about 3% of the tablet bulk, are water soluble and do not absorb UV light. 

---