Excipient classes

Erode, G. L. in Vaginal Microbicide Formulations Workshop, Rencher, W. R (Ed), Lippincott-Raven (Philadelphia, PA), Chemical/physical principles in microbiocide formulations with emphasis on hydrophobe modified cationic polysaccharides-a new excipient class, 1998, Chap. 5, pp. 38-50. 

Residual solvents are divided into three classes. Class 1 solvents are those known to cause toxic effects and should be avoided in the production of active substances and excipients. Class 2 solvents present less severe toxicity than class 1, and class 3 solvents have such low toxic potential that exposure limits are not necessary. Table 12 presents the general characteristics of the solvents included in each class, and Table 13 lists the solvents and their concentration limit in pharmaceutical products. 

Any previous demonstration of carcinogenic potential in the relevant excipient class... 

Provide the reason for the presence of each ingredient in the formula. Why was a particular ingredient (e.g., povidone) used from an excipient class (e.g., binder) Performance Supply Cost Indicate whether a particular grade or manufacturer is required for an ingredient and the reasons. Justify the level or range of each ingredient, especially the binder, disintegrant, and lubricant. 

Incompatibilities have also been observed in solid dosage forms. A typical tablet contain binders, disin-tegrants, lubricants and fillers. Compatibility screening for a new drug should consider two or more excipients from each class. Serajuddin et al. have developed a drug-excipient compatibility screening model to predict interactions of drug substances with excipients [49],... 

A relatively new class of co-processed excipients now exists. These excipients are essentially a preblend of two or more excipients that are commonly used in conjunction with each other. 

Absorbents are another class of excipient material used in feed additive premixes. They are used when the drug substance is a liquid or is readily soluble in water, oil, or some other solvent. The liquid is sprayed onto the absorbent in a mixer as the mixer is running. Examples of absorbents are vermiculite, Fullers earth, corn cob fractions, and clay. 

Recently, a new class of excipients based on ethylene oxide-vinyl alcohol copolymers (see Figure 17.12) has been developed (PEO-g-PVA). The combination of PVA and PEO should result in an excellent instant-release tablet coating. One way to... 

The Committee for Proprietary Medicinal Products [8] applied the BCS, with certain requirements, to dispense with bioequivalency tests if the active pharmaceutical ingredient is class I and the in vitro dissolution of the finished dosage form is fast [9], An active substance is considered highly soluble if the amount contained in the HDS of an IR product is dissolved in 250 ml of each of three buffers within the range of pH 1-8 at 37°C (e.g., pH 1.0, 4.6, and 6.8). There should be linear and complete absorption, which indicates HP to reduce the possibility of an IR dosage form influencing the bioavailability [8], The similarity of the dissolution profiles of the test and reference products is demonstrated in each of three buffers within the range of pH 1-8 at 37°C (e.g., pH 1.0,4.6, and 6.8). If there is rapid dissolution of the product, where at least 85% of the active substance is dissolved within 15 min, no further comparison of the test and reference is required. Further requirements include that excipients be well established and have no interaction with the pharmacokinetics of the active substance and that the method of manufacture of finished product... 

The results for matrices containing as excipient are shown in Table 2 and Figs 1 and 2. Table 2 shows that only at the lowest matrix loading (30% (w/w)) could equation (2) be fitted to release data. It may further be seen that at this loading level release exponents n always yield values which exceed the value of 0.5. In one class a release exponent of 0.79 is obtained. 

Sherwood BE, Becker JW. A new class of high functionality excipients silicified microcrystalline cellulose. Pharm Tech 1998 22(10) 78—88. 

The long-term stability of an oral liquid formulation can also be affected by a number of unexpected reasons. Contamination by solvents used during the tank cleaning or even in the manufacture of excipients or API can be a source of instability of an oral solution. Uncontrolled levels of Class I, II, or III solvents could lead to the rejection of a batch or an excipient vendor. Class III solvents have a permitted daily exposure of 50 mg or less per day. (See the International Conferences on Harmonization, Impurities Guidelines for Residual Solvents. Q3C, Federal Register 1997 62(247) 67377 and also http //www.fda.gov/cvm/Guidance/guidelOO.PDF). 

Enteric coatings are a commonly used class of excipients for delaying the release of drug from dosage forms until the dosage forms reach the small intestine. Enteric coatings are useful for protection of drugs that are labile to acidic environment in... 

EXCIPIENTS USED TO ENHANCE DISSOLUTION OF BIOPHARMACEUTICAL CLASSIFICATION SYSTEM CLASS II AND IV DRUGS... 

---