TABLETS Coating Pharmacy school Chen Jian Why coat tablets? Tablet properties Protect the medicinal agent ■Smooth surface ■Mask the taste ■Physical shape Provide esthetics or distinction Mechanical strength Provide special release characteristics Coated tablets Sugar-coated tablets ■Sugar Coated Tablets 1.Waterproofing and sealing 2.Subcoating Film Coated Tablets 3.Smoothing and final rounding 4.Finishing and coloring Enteric coated tablets 5.Polishing 1
1 TABLETS Pharmacy school Chen Jian Coating Why coat tablets? Protect the medicinal agent Mask the taste Provide esthetics or distinction Provide special release characteristics Tablet properties Smooth surface Physical shape Mechanical strength Coated tablets Sugar Coated Tablets Film Coated Tablets Enteric coated tablets Sugar-coated tablets 1. Waterproofing and sealing 2. Subcoating 3. Smoothing and final rounding 4. Finishing and coloring 5. Polishing
Film-coating tablets Ingredients of Film-forming solutions Film-coating places a thin skin-tight Film-forming polymer coating of a plastic-like material over the ■Plasticizer compressed tablet. Colorant and opacifier ■Solvents Antiadherent Film-forming solutions polymer Plasticizer ·HPMC ·PEG ■HPC ■Glycerin ■Propylene glycol ■Acrylate acid resin ■Castor oil ■PVP ■Phthalate ■others others Solvents Enteric coated tablets ■Ethanol This formulation is preferred when, ■Isopropanol The API irritates gastric mucosa Drugs that produce nausea and vomiting. Acetone API is sensitive to low pH Water When it's necessary to release the drug undiluted. 2
2 Film-coating tablets Film-coating places a thin skin-tight coating of a plastic-like material over the compressed tablet. Ingredients of Film-forming solutions Film-forming polymer Plasticizer Colorant and opacifier Solvents Antiadherent Film-forming solutions polymer HPMC HPC Acrylate acid resin PVP others Plasticizer PEG Glycerin Propylene glycol Castor oil Phthalate others Solvents Ethanol Isopropanol Acetone Water Enteric coated tablets This formulation is preferred when, The API irritates gastric mucosa Drugs that produce nausea and vomiting. API is sensitive to low pH When it’s necessary to release the drug undiluted
Enteric coated tablets Aqueous polymeric dispersions Materials used for enteric coating: ■Nontoxic ·CAP PVAP ■High polymer content .Shellac ■Low viscosity 。Acrylate acid resin ·HPMCP Productive 。others Aqueous polymeric dispersions Mechanism of film formation ■Latexes ■Pseudolatexes 8888 ↑↑ Micronized polymeric powder 文xX】 XOXOOOOO R 年 Aqueous polymeric dispersions Aqueous polymeric dispersions ■Polymer Brand Polymer component ■Plasticizer Eudragit Acrylate acid resin Pigment Aquacoat EC ■Antiadherent Surelease EC ■… Sureteric PVAP 3
3 Enteric coated tablets Materials used for enteric coating: CAP PVAP Shellac Acrylate acid resin HPMCP others Aqueous polymeric dispersions Nontoxic High polymer content Low viscosity Productive Aqueous polymeric dispersions Latexes Pseudolatexes Micronized polymeric powder Mechanism of film formation Aqueous polymeric dispersions Polymer Plasticizer Pigment Antiadherent …… Aqueous polymeric dispersions Sureteric PVAP Surelease EC Aquacoat EC Eudragit Acrylate acid resin Brand Polymer component
Coating methods Film defects ■Pan coating ■Sticking and picking ■Roughness Fluidized bed coating .Bridging and filling ■Roll coating ■Blistering ■Compression coating Color variation ■Cracking 4
4 Coating methods Pan coating Fluidized bed coating Roll coating Compression coating Film defects Sticking and picking Roughness Bridging and filling Blistering Color variation Cracking