![]() ![]() Sugar-coating solution consists of 70% syrup and other coloring pigments. ColoringĬoloring phase is a significant step in sugar-coating process, which gives the tablet improved appearance and stability. Smoothing is performed many times (about 10 cycles), until tablets are suitable for the next (coloring) phase. In some cases, however, syrup also comprises acacia, gelatin, pigments, starch, or opacifier. Smoothing syrup generally consists of 60%–70% sugar solid. Smoothing process is applied in order to smooth out subcoated rough surfaces and to increase tablet bulk to desired size. ![]() Suspension process is suitable for automatic methods. After that, sucrose solution is applied followed by drying. During the suspension process, a suspension of fillers in gum solution is applied. Finally, drying air is applied in order to evaporate the water. In lamination process, the subcoat mixture consists of sucrose and binder solution such as acacia or gelatin, which is applied over the tablet surface followed by powder containing materials such as calcium carbonate, titanium dioxide, calcium sulfate, and talc. Generally, lamination process and suspension process methods are used for subcoating. In this process, there is a significant increase in tablet weight. Subcoating is performed to round the tablets edges. The amount of sealing coat material depends on tablet porosity and batch size hence, optimizing the quantity of sealing coating applied is very important to ensure tablet cores are sealed effectively. ![]() However, this has largely been replaced by zein CAP and PVAP due to polymerization problems. Shellac was previously used as a sealant. Sealing coat consists of Shellac, cellulose acetate phthalate (CAP), polyvinylacetate phthalate (PVAP), hyroxylpropyl cellulose, hyroxypropyl methylcellulose (HPMC), and Zein (a corn protein derivative). Hence, it offers good stability of product and can also strengthen the tablet core. SealingĪ seal coat is applied over the tablet core to protect against water penetration into the tablet from the sucrose coatings to follow. The process of sugar coating involves various steps, i.e., sealing, subcoating, smoothing, coloring, and polishing. Unlike film coating, sugar coating is a more laborious multistep process, leading to final tablet weight increases of up to 30%–50%, significantly increasing tablet size. Ĭolorants (dyes, iron oxides, titanium dioxide).įillers (calcium carbonate, titanium dioxide, talc).īinders (acacia, gelatin, cellulose derivatives).Coating materials can be categorized as follows: Various classes of pharmaceutical coating materials used in tablet coating depending on the phase of coating are reached. There are three main processes for tablet coating: sugar coating, film coating, and enteric coating. ![]()
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