Biopharmaceutics basics

The Library/Educational Resources Section of the American Association of Colleges of Pharmacy maintains the AACP Basic Resources for Pharmaceutical Education [53]. The reader is referred to this list of books, periodicals, bibliographies, guides, handbooks, dictionaries, directories, and web sites important to pharmacy. The list contains specific sections for the pharmaceutical sciences, including pharmaceutics, biopharmaceutics and pharmacokinetics, cosmetics and industrial pharmacy. 

Fortunately, protein concentration methods are relatively simple (low-tech) and inexpensive. The simplest assays require only a spectrophotometer calibrated for wavelength and absorbance accuracy, basic laboratory supplies, and good pipetting techniques. Protein concentration assays are quite sensitive, especially given the typical detection limits required for most biopharmaceuticals. 

Methods development starts with a relatively high number of techniques to characterize and test samples. The number of protocols is often reduced once the critical parameters and the methods that identify them have been defined. The analyst must evaluate the initial techniques with respect to their purposes. If the goal is to generate research data, the practicality of the method and its limitations are not of primary concern if the goal is to use the technique as part of a test procedure, it has to be evaluated in terms of its potential to meet full validation. Critical procedures (e.g., release testing) that cannot be validated will bring a project to an expensive halt. For these reasons, this chapter provides basic principles as well as limitations of capillary electrophoresis (CE) as applied to the analysis of real biopharmaceutical molecules. 

The initial formulation for most drugs is to allow basic in vivo toxicology, pharmacology and biopharmaceutical assessments to be conducted. Aqueous solutions for injection are optimum for this application since the entire dose is administered at a single time point and the problem of bioavailability does not arise. It is important that these formulations are considered carefully, particularly for drugs that are poorly water soluble, because potentially useful compounds may be rejected inadvertently. These early formulations are also crucial because they set an in vivo benchmark for the drug s future performance. 

Water represents one of the most important raw materials used in biopharmaceutical manufacture. It is used as a basic ingredient of fermentation media, and in the manufacture of buffers used throughout product extraction and purification. It represents the solvent in which biopharmaceutical products sold in liquid form are dissolved, and in which freeze-dried biopharmaceuticals will be reconstituted immediately prior to use. It is also used for ancillary processes, such as the cleaning of equipment, piping and product-holding tanks. It is additionally used to clean/rinse the vials into which the final product is filled. 

The main external review body in the biopharmaceutical and pharmaceutical industries is the Food and Drug Administration (FDA), but at some later stage it may be necessary to prepare a monograph for the quality control of a new product and this would be achieved by interacting with officials from the United States Pharmacopeia (USP) in order to have a section published in the pharmacopoeia. The purpose of this chapter, therefore, is to introduce both of these organizations and provide an understanding of their basic functions. 

To understand the mechanism of action of permeation enhancers, the routes by which drugs are absorbed first need to be considered. Chapter 9 reviews the basic biopharmaceutics of buccal and sublingual drug delivery, so only a very brief discussion of this in the context of permeation enhancement will be given below. 

Chapter 9 Basic Biopharmaceutics of Buccal and Sublingual Absorptions.175... 

Dayneka, N., Garg, V., and Jusko, W., Comparison of four basic models of indirect pharmacodynamic response, Journal of Pharmacokinetics and Biopharmaceutics, Vol. 21, No. 4, 1993, pp. 457-478. 

Biopharmaceutics, pharmacokinetics, and pharmacodynamics are the most important parts of pharmaceutical sciences because they bridge the gap between the basic sciences and the clinical application of drugs. The modeling approaches in all three disciplines attempt to ... 

The basic principles of toxicology are applicable across product classes. It is the specific attributes of the product that have the greatest influence on the successful practice of biopharmaceutical toxicology (see Table 3.2). This focus on product attributes has defined the case-by-case approach. Table 3.3 provides a further definition of the case-by-case approach (see Table 3.3). 

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