Excipients in tablets and capsules

Although excipients are the non-active ingredients, they are indispensable for the successful production of acceptable solid dosage forms. The important roles played by excipients in tablets and capsules, freeze-dried, and spray-dried powders, as well as powder aerosol formulations, were discussed. Some recent applications of excipients in controlled, release formulations for biologicals were also highlighted. Finally, incompatibility problems attributable to excipients were considered with an emphasis on the indirect role of excipients through moisture distribution. 

The lack of digestive enzyme lactase in many Hispanics, especially Mexican-Americans and African-Americans, causes lactose intolerance, with nausea, diarrhea and occasionally vomiting. It is understandable that lactose is no longer preferred as a filler (non-active excipient) in tablets and capsules. 

Toxicology Essentially nontoxic Uses Sweetener for pharmaceuticals diluent, excipient in tablets and capsules Features May be compressed directly into selfbinding tablets Regulatory NF compliance Manuf./Distrib. AMRESCO http //www.amresco-inc.com, Adept Sol ns. Ashland http //www.ashchem.com, Avebe Am. http //www.avebe.com] Barrington http //WWW. barringtonchem. com CarboMer http //www.carbomer.com, Cerestar USA Corn Prods. 

Uses Viscosity modifier, stiffienng agent, coemulsifier and emulsion stabilizer used in topical cream formulations used with other excipients in tablets and capsules. Properties Wh. solid charac. odor insol. in water m.p. 46-51 C flash pt. > 100 C Toxicology LD50 (oral, rat) > 20 g/kg TSCA listed Environmental Readily biodeg. 

Excipients. Along with active material contained in tablets and capsules, a variety of so-called inert ingredients are present, for example, starch, magnesium aluminum silicate, methylcellulose, carboxy-methylcellulose, lactose, kaolin, talc, calcium sulfate, and magnesium stearate. Tablets may also have a... 

For tablets and capsules, excipients are needed both for the facilitation of the tableting and capsule-filling process (e.g., glidants) and for the formulation (e.g., disintegrants). Except for diluents, which may be present in large quantity, the level of excipient use is usually limited to only a few percent and some lubricants will be required at <1%. Details of the types, uses, and mechanisms of action of various excipients for tablet and capsule production have been discussed at length in other articles in this encyclopedia. The types and functions of excipients for tablet production are summarized in Table 1. Although binders. 

Some fungal polysaccharides have been proposed as excipients for the pharmaceutical industry. Scleroglucan was used in tablets and capsules, proving to be suitable... 

Ensuring homogeneous mixing of the components (APIs and excipients) of a pharmaceutical preparation is a crucial prerequisite for obtaining proper solid dosages (tablets and capsules). Pharmaceutical manufacturers invest much time, labor and material resources in this process. Blending is intended to ensure uniform distribution of all components in the end products,so that each dose wiU contain the correct amount of the active ingredient. 

Excipients are sub-divided into various functional classifications, depending on the role that they are intended to play in the resultant formulation, for example, fillers, disintegrants, binders, lubricants and glidants. An added complexity is the fact that certain excipients can have different functional roles in different formulation types. Thus, lactose is widely used as a filler or diluent in solid oral dosage forms, for example, tablets and capsules [2] and as a carrier for inhalation products [3]. 

We include certain excipients in a formulation specifically because they interact with the physiological fluids and the bodily functions in a certain way. For example, as discussed above, we include disintegrants in immediate release tablet and capsule formulations, because we know that when they encounter the aqueous environment of the stomach, they will cause the tablet or capsule to disintegrate and thereby aid dissolution of the API. Another example is the general case of hydrophilic colloid matrices used as prolonged release drug delivery systems. We know that when these materials contact the aqueous environment of the GIT they swell and create a diffusion barrier that slows the rate of dissolution of the dissolved drug. 

Although they are often categorized as inert, preformulation studies can determine the inhuence of excipients on stability, bioavailability, and processability. Excipients are categorized into groups according to their main function, although some may be multifunctional, and examples of common excipients used in the manufacture of tablets and capsule are detailed in Table 3. 

Extraction OF Tablets and Capsules Elaborate solvent fractionation schemes are not usually necessary for solid dosage preparations. Most drugs are soluble in methanol and most of the excipients are not therefore the preparation of a simple methanol extract is all that is required. However, if the methanol extract is too concentrated, the spot on the TLC plate will be overloaded and the resultant chromatogram will be useless. Any subsequent ultraviolet spectrophotometric examination of the extract may give specfra which are not on scale. This cannot always be avoided, but the following guide-lines have been found useful. 

Excipients that aid powder flow in tablet or capsule manufacture. Materials such as colloidal silica improve flow from hopper to die and aid packdown in the die or capsule shell. Accuracy and consistency of fill and associated dose is thereby improved. 

In reality, no single excipient would satisfy all the criteria therefore, a compromise of the different requirements has to be made. For example, although widely used in pharmaceutical tablet and capsule formulations as a diluent, lactose may not be suitable for patients who lack the intestinal enzyme lactase to break down the sugar, thus leading to the gastrointestinal tract symptoms such as cramps and diarrhea. The role of excipients varies substantially depending on the individual dosage form. 

Health care, medical, and pharmaceutical applications In controlled-release products as tablet and capsule binders, tablet and capsule excipients, wound healing materials, and blood volume expanders and for constipation and diarrhea treatment... 

Mixing or blending is a critical process in the manufacture of dosage forms, especially in the production of tablets and capsules.The tablets or capsules prepared from the blend of poor mixing with active ingredients and excipients may fail the quality control test for content uniformity of the dosage forms. The acceptance limit according to the USP is based on the calculation of an individual assay of 10 tablets with a relative standard deviation equal to or less than 6%. Failure to meet the criteria results in rejection of the production lot. 

In conclusion, 1 would just like to state that it has long been the feeling of some critics that the effect which excipients might exert on the quantitative analysis of tablets and capsules by nonaqueous titrimetry is probably so great as to limit its usefulness to the assay of the basic materials alone, or at best, to those manufacturers where the control laboratory might be able to exert its influence in the formulation. From our experiences and in our opinion, such a situation is far from actual fact. We believe that nonaqueous titrimetry will be utilized more and more by control laboratories and official compendia once they fully realize that careful choice of solvent systems can greatly minimize and even eliminate the possibility of interference by excipients. 

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