Excipient Classification

Avdeef, A., Bendels, S., Tsinman, O., Tsinman, K., Kansy, M. Solubility-excipient classification gradient maps. Pharm. Res. 2007, 24, 530-545. 

The pore structure of a solid can contribute to the disintegration, dissolution, adsorption, and diffusion of a drug material [26,27]. Because of this, porosity and pore size distribution measurements have been used extensively to study tablets [28-30], granules [31,32], and excipients [33]. The following classification system of pore sizes has been developed based on the average pore radii [6] ... 

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]. 

The advantage of supervised classification is that it avoids a wavelength selection step or the interpretation of PCA loading. It also rapidly extracts several chemical components. These methods provide accurate results provided the sample spectra are similar to the reference spectra. In our case the powder agglomeration was heterogeneous and the layers had a high content of excipient, making it possible to apply supervised classification. 

Apte SP, Ugwu SO. A review and classification of emerging excipients in parenteral medications. Pharm Tech 2003 27 46. 

Use of Nonactive Pharmaceutical Excipients in Oral Drug Formulations Biopharmaceutical Classification System Considerations... 

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

Table 3 The Effect of Hydrophilic Excipients on the Dissolution Rates of Griseofulvin (a Biophannaceutical Classification System Class II Drug)...

Table 4 The Dissolution and Release of Biopharmaceutical Classification System Class II and IV Drugs Are Enhanced by Hydrophilic Excipients...

CLASSIFICATION OF PHARMACEUTICAL EXCIPIENTS IN SOLID DOSAGE FORMS... 

TABLE 16 Classification of Hygroscopicity and Example Pharmaceutical Excipients... 

Bulk powder characteristics are important in understanding the handling properties of an excipient or a granulated product. A classification system to evaluate the flow properties of powders has been introduced by Carr.P A flowable powder is defined as free-flowing and tends to flow steadily and consistently, whereas a floodable powder exhibits an unstable, discontinuous, and gushing type of flow. A number of studies have investigated the bulk powder properties of starch " and granulations made with starch. The starch materials were found to exhibit poor to borderline flow properties. 

How can we give a valid classification for a treatment that is doctor-dependent We should also compare products of the same type only, and yet the quality of the preparations and excipients is highly variable and impossible to control. 

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