Excipients for Pellet Production
Writer： admin Time：2021-07-06 17:22 Browse：℃
The excipients for pellet production include blocker, adhesive, plasticizer, porogen and so on. Traditional Chinese medical extract can be used as adhesive. Some pellets nucleus are blank but are coated with drugs on their surface. And most types of pellets need film coating so as to control the dissolution rate by adjusting the film thickness or pellet weight and to further realize the goal of sustained- or control-release of pellets.
1. Blank pellet
It refers to the nucleus which are rolled from sucrose powder or sugar powder with certain granularity, starch and proper adhesive. There are multiple suppliers for it.
2. Wax and insoluble framework material
Wax includes beeswax, castor wax, hydrogenated vegetable oil, stearic acid, carnauba wax, glycerol mono (di, tri) stearic acid wax and octadecanol and framework material includes ethyl cellulose (EC), PVC, polypropylene (PP), polysiloxane and so on. Scientists studied on the pellets with beeswax, starch and dextrin as framework material and found that type and concentration of wax and starch can influence release of drugs.
3. Melting adhesive
It is mainly used for melting granulation and includes wax, polyethylene glycol (PEG), stearic acid, glyceryl monostearate and so on.
4. Film coating material
1) Enteric coating material
Shellae, cellulose acetate phthalate (CAP) and acrylic resin (Eudragit) are all enteric coating materials. CAP dissolves when pH value is above 6. Eudragit is widely applied and it can be typed as E, L, S, RL, RS, E30D and L30D. E-type dissolves when the medium’s pH value is less than 1. And L-type and S-type can dissolve when the medium’s pH value is above 6 and 7 respectively. E30D dissolves neither in acid nor in alkali and permeates. L30D dissolves in intestinal juice with pH value above 6. Eudragit I, II and III in China are equivalent to Eudragit L30D, L and S. Erythromycin enteric pellets coated with Eudragit II and III has pretty good effect.
2) Water-soluble material
Including polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), methylcellulose (MC), hydroxypropyl methylcellulose (HPMC) and so on.
3) Water-insoluble material
Including ethyl cellulose (EC), cellulose acetate, cellulose acetate propionate and so on.
4) Aqueous dispersion film coating material
What are commonly used are aqueous dispersion of acrylic resin, ethyl cellulose pseudolatex, cellulose acetate phthalate (CAP) latex, aqueous dispersion of poly phenylenedicarboxylic acid vinyl acetate (PVAP), aqueous dispersion of hydroxypropyl methylcellulose acetate succinate (HPMCAS) and so on. For example, it is founded that aqueous dispersion can delay release of ibuprofen.
5. Plasticzer
1) Water-soluble plasticizer
Including propylene glycol, glycerol, polyethylene glycol (PEG) and so on.
2) Water-insoluble plasticizer
Including glycerol triacetate, acetylmonoglyceride, phthalate, castor oil and so on.
6. Porogen
It mainly includes hydrophilic liquid carrier (glycerol, PEG200), electrolyte (NaCl, KCl, Na2SO4), sugars (lactose, fructose, sucrose, mannose), surface active agent (polysorbate 80, sodium dodecyl sulfate), polymers (PEG, PVP), microcrystalline cellulose, some hydrogels (HPMC (3 or 5CPS), CMC, tragacanth gum), foaming agent (carbonate, bicarbonate).
