The common excipients of oral solid dosage forms

Solid preparations are currently the most widely circulated and most used dosage forms in the market, and they usually consist of two main substances and excipients. Excipients, also known as excipients, refer to the general term for all additional materials in solid preparations except the main drug. According to the different properties and functions of the excipients, the excipients of solid preparations are often divided into: fillers, binders, disintegrants, lubricants, release regulators, and sometimes coloring agents and flavoring agents can also be added according to the requirements of the preparation to improve Or adjust the appearance and taste of the formulation.
The excipients of solid preparations should meet the requirements for medicinal use, and have the following characteristics: ①It should have high chemical stability and not have any physical and chemical reactions with the main drug; ②It should not affect the therapeutic effect and content determination of the main drug; ③No harm to the human body Harmful, five poisons, no adverse reactions.
1. Filler (thinner)
Due to the low dose of the main drug, the dose of some drugs is sometimes only a few milligrams or less, which is not conducive to tablet forming or clinical administration. Therefore, when the main drug content is less than 50mg, a certain dose of filler, also known as diluent, needs to be added.
An ideal filler should be physiologically and chemically inert and not affect the bioavailability of the active ingredient of the drug. Commonly used fillers mainly include: ① Starch, including wheat starch, corn starch, and potato starch, among which corn starch is the most commonly used; stable in nature, low in hygroscopicity, but poor in compressibility; ② Lactose, excellent in properties and compressible , good fluidity; ③ sucrose, has strong hygroscopicity; ④ pregelatinized starch, also known as compressible starch, has good compressibility, fluidity and self-lubricity; ⑤ microcrystalline cellulose, referred to as MCC , has strong binding ability and good compressibility; known as “dry binder”; ⑥Mannitol, compared with the above fillers, is slightly more expensive, and is often used in chewable tablets, which also has a delicate taste; ⑦Inorganic salts, mainly including calcium sulfate, calcium phosphate, calcium carbonate, etc., with relatively stable physical and chemical properties.
2. Wetting agent and adhesive
Wetting agents and binders are excipients added during the granulation step. The wetting agent itself is not viscous, but a liquid that induces the viscosity of the material by wetting the material. Commonly used wetting agents mainly include distilled water and ethanol, among which distilled water is the first choice.
Adhesives refer to the auxiliary materials that rely on their own viscosity to endow non-viscous or insufficiently viscous materials with suitable viscosity. Commonly used adhesives mainly include: ① Starch slurry, which is one of the most commonly used adhesives, is cheap , and has good performance, and the commonly used concentration is 8%-15%; ②Methylcellulose, referred to as MC, has good water solubility; ③Hydroxypropylcellulose, referred to as HPC, can be used as a powder direct tableting binder; ④Hydroxypropylmethylcellulose, referred to as HPMC, the material is soluble in cold water; ⑤Carboxymethylcellulose sodium, referred to as CMC-Na, suitable for drugs with poor compressibility; ⑥Ethylcellulose, referred to as EC , the material is insoluble in water, but soluble in ethanol; ⑦Povidone, referred to as PVP, the material is extremely hygroscopic, soluble in water and ethanol; ⑧In addition, there are polyethylene glycol (referred to as PEG), Materials such as gelatin.
3. Disintegrant
Disintegrants refer to excipients that promote the rapid breakdown of tablets into fine particles in gastrointestinal fluids. Except for oral tablets with special requirements such as sustained-release tablets, controlled-release tablets, and chewable tablets, disintegrants generally need to be added. Commonly used disintegrants are: ① dry starch, suitable for insoluble or slightly soluble drugs; ② carboxymethyl starch sodium, referred to as CMS-Na, this material is a high-efficiency disintegrant; ③ low-substituted hydroxypropyl cellulose, referred to as L -HPC, which can swell rapidly after absorbing water; ④Cross-linked methyl cellulose sodium, referred to as CCMC-Na; the material swells first in water and then dissolves, and is insoluble in ethanol; The disadvantage is that it has strong hygroscopicity and is commonly used in the granulation of effervescent tablets or chewable tablets; ⑥Effervescent disintegrants mainly include a mixture of sodium bicarbonate and citric acid, and citric acid, fumaric acid, and sodium carbonate can also be used , Potassium Carbonate and Potassium Bicarbonate etc.
4. Lubricant
Lubricants can be broadly divided into three categories, including glidants, anti-sticking agents, and lubricants in a narrow sense. ① Glidant: its main function is to reduce the friction between particles, improve the fluidity of powder, and help reduce the difference in tablet weight; ② anti-sticking agent: its main function is to prevent sticking during tablet compression, In order to ensure the smooth operation of tablet compression, it can also improve the appearance of tablets; ③ chivalrous lubricant: reduce the friction between the material and the mold wall, so as to ensure the smooth operation of tablet compression and pushing. Commonly used lubricants (in a broad sense) include talc powder, magnesium stearate (MS), micronized silica gel, polyethylene glycols, sodium lauryl sulfate, hydrogenated vegetable oil, etc.
5. Release modulator
Release regulators in oral tablets are suitable for controlling the speed and degree of drug release in oral sustained-release preparations, so as to ensure that the drug is delivered to the patient site at a certain speed and maintains a certain concentration in tissues or body fluids, thereby Obtain expected therapeutic effect and reduce toxic and side effects. Commonly used release regulators are mainly divided into matrix type, film-coated slow-release polymer and thickener.
(1) Matrix-type release modulator
①Hydrophilic gel skeleton material: it swells when exposed to water to form a gel barrier to control drug release, commonly used are methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, povidone, carbomer, alginic acid Salt, chitosan, etc.
② Insoluble skeleton material: Insoluble skeleton material refers to a high molecular polymer that is insoluble in water or has minimal water solubility. Commonly used mainly are ethyl cellulose, polyethylene, five-toxic polyethylene, polymethacrylic acid, ethylene-vinyl acetate copolymer, silicone rubber, etc.
③ Bioerodible framework materials: Commonly used bioerodible framework materials mainly include animal fat, hydrogenated vegetable oil, beeswax, stearyl alcohol, carnauba wax, glyceryl monostearate, etc. It can delay the dissolution and release process of water-soluble drugs.
(2) Coated release modifier
① Insoluble polymer materials: common insoluble skeleton materials such as EC.
②Enteric polymer materials: common enteric polymer materials mainly include acrylic resin, L-type and S-type, hydroxypropylmethylcellulose acetate succinate (HPMCAS), cellulose acetate phthalate (CAP ), hydroxypropylmethylcellulose phthalate (HPMCP), etc. It utilizes the dissolution characteristics of the above materials in intestinal juice, and dissolves in specific parts to play a role.
6. Other accessories
In addition to the above commonly used excipients, other excipients are sometimes added in order to better meet the needs of drug administration, improve drug recognition or improve compliance. For example, coloring, flavoring and sweetening agents.
①Coloring agent: The main purpose of adding this material is to improve the appearance of the tablet and make it easier to identify and distinguish. Commonly used pigments should meet the pharmaceutical specifications, and the amount added should generally not exceed 0.05%.
②Aromatics and sweeteners: The main purpose of aromatics and sweeteners is to improve the taste of medicines, such as chewable tablets and orally disintegrating tablets. Commonly used fragrances mainly include essences, various aromatic oils, etc.; commonly used sweeteners mainly include sucrose, aspartame, etc.