Tablet Coating

xajitawu's version from 2015-04-28 12:17


Question Answer
purposeprotect drug from the environment; mask unpleasant taste/odor; easier swallowing; improve product identity; minimize cross contamination; improve appearance; reduce incompatibilities; reduce abrasion; modify drug release
For sugar coating, what is primarily used?sucrose
What are the 6 main steps of sugar coating?sealing; subcoating; smoothing; color coating; polishing; printing
what is purpose of sealing:protect from water
what do you see as sealing?alchoholic solutions (10-30% solids) of resins such as shellac, zein, and cellulose acetate phthalate
What step in sugar coating resuts in a 50-100% increase in weight?subcoating
Subcoating step:solution of gelatin, acacia, and sucrose is applied to the sealed tab cores; followed by a dusting powder application which reduces stickiness and allows buildup; subcoat is fromed from alternative layers of gum (solution) and powder
what does the dusting powder contain:calcium carbonate, titanium dioxide, talc, sucrose and powdered acacia
what is the solution for smoothing?60-70% sugar solids and 1-5% titanium dioxide (as an opacifier) is applied
what is the most critical step in sugar coating?color coating
water soluble dye is dissolved in _____syrups; up to 60 applications may be needed
Pigmentsif it is opaque or combined with an opacifier, that desired color can develop faster, resulting in thinner coats
Pigments that are used are either ___ or ___inorganic pigments (titanium dioxide, iron oxides) or certified lakes
when polishing, what do you use?waxes (beeswax, carnauba wax, candelia wax or hard paraffin)
when do you add printing?before or after polishing
how is film coating typically applied?spraying the coating liquid onto a moving mass of product
advantages of film coatingminimal weight increase; much shorter processing time; increased process efficiency/output, increased flexibility in formulations, improved resistance to chipping
what kind of liquids are used in film coating?water-based coating liquids; polymer, plasticizer, colorant, vehicle
what polymer is preferred in film coating?cellulose ethers
what are typical plasticizers used in film coating?glycerin, propylene glycol, polyethylene glycols, citrate esters, phthalate esters
what kind of colorants are used in film coating?water soluble dyes or lakes (al lakes)
typical concentrations of materials used in film coating?5-20% coating solids; 60-70% of total solids is polymer; 6-7% plasticizer; 20-30% pigment
what is delayed release (enteric coating)?coating remains intact in the stomach but it dissolves and contents are released once the dosage form reaches the intestine
repeat-action in enteric coatingan additional amount of drug is applied over enteric coat; it is released in the stomach and the remainder in the intestine
most enteric coatings are ____?weak acids; undissociated in the stomach, but readily ionize when the pH is above 5 in the intestine (soluble)
what are some polymers used in enteric coating?cellulose acetate phthalate, polyvinyl acetate phthalate, carboxymethyl ethylcellulose, acrylic copolymers
what materials are used in sustained-release coating?mixtures of waxes w/ fa, f alcohols, monoglycerides; shellac and zein; ethylcellulose (membrane around tab); acrylic polymers
what is being coated to obtain a sustained-release effect?dried granules; drug loaded beads (nonpareils); drug crystals; drug/ion exhange complexes; tablets
what is a variation to sustained release coating?osmotic pump; the osmotic pressure created by the influx of water across the semipermeable membrane pumps the drug through the orifice
sugar coating procedure:coating fluid is ladled onto a bed of tabs in rotating coating pan; tabs are stirred by hand; then dried by blowing air; pan fitted w/ exhaust to allow moisture and dust to be removed; polishing step is performed in cloth lined pan
film coating procedure:coating liquid is sprayed in the form of finely atomized droplets over moving tab mass in pan; droplet formation-impingement-wetting/spreading-adhesion
fluidized-bed coating equipmentapplication of modified release coating; drug layering on nonpareils; spheronization of powder particles