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The term biopharmaceutics was introduced in the 1960s by Levy [1]. The word originates from the combination of bio‐ from the Greek meaning relating to living organisms or tissue and pharmaceutics defined as the science of pharmaceutical formulations; in this case the living organism is the person (or animal being treated). In modern parlance, the term biopharmaceutics encompasses the science associated with the physical/chemical properties of the drug product (including all components therein) and the interactions of this product with parameters linked to the route of administration that affect the rate and extent of drug uptake or presence at the site for local action. It combines knowledge of materials science; physiology; anatomy and physical sciences.

In more simple terms it is everything that controls the availability of the drug: that is how the drug exits the dosage form and travels to the systemic circulation (for systemically acting drugs) or to the local site of action for locally acting agents. It provides a link between the formulation and the clinical performance of a drug; a mechanistic understanding of biopharmaceutics ensures that the formulation is optimised in terms of exposure. This is shown schematically in Figure 1.1 where biopharmaceutics is focussed on absorption.

Figure 1.1 Schematic of the fate of drugs once administered orally; biopharmaceutics relates to the absorption aspect of this image.

The term biopharmaceutics can cause confusion; particularly with the advent of biopharmaceutical drug products. There is evidence in confusion in terminology back in the 1970s where efforts were made to standardise the terminology used [2]; these efforts defined biopharmaceutics in several ways according to the experts at the time of publication. The most widely used definition is, ‘The study of the influence of formulation on the therapeutic activity of a drug product. Alternatively, it may be defined as a study of the relationship of the physical and chemical properties of the drug and its dosage form to the biological effects observed following the administration of the drug in its various dosage forms’ [3].

An analysis of new drug approvals in 2019 (US, EU and Japan) showed that oral products represented the majority of approvals (50%) with tablets and capsules as the dominant oral dosage forms [4]. Thus biopharmaceutics has tended to focus on oral more than alternative routes of administration.

Historically biopharmaceutics was part of clinical pharmacology and pharmaceutical chemistry, only becoming its own scientific discipline in the 1970s. In scientific terms, the MeSH definition (MeSH [Medical Subject Headings] is the United States National Library of Medicine controlled vocabulary thesaurus used for indexing articles for PubMed) of biopharmaceutics (introduced in 1970) is, ‘The study of the physical and chemical properties of a drug and its dosage form as related to the onset, duration and intensity of its action’. The MeSH term ‘biopharmaceutics’ being introduced in the 1970s provides an insight into the history of the topic; the scientific discipline existed long before but was previously listed in scientific data based under a bigger heading of pharmacology as:

Figure 1.2 Frequency of biopharmaceutics as a MESH terms in publications versus time.

Source: Data from Pubmed.gov, November 2020.

 Chemistry, Pharmaceutical (1966–1969)

 Drug Compounding (1966–1969)

 Drugs (1966–1969)

 Pharmacology (1966–1969)

A search in PubMed of ‘Biopharmaceutics’ [Mesh] conducted in November 2020 resulted in 2725 retrieved documents with a peak in the early 1970s as the science of biopharmaceutics developed. There has also been a general trend of increased use of the term biopharmaceutics since the year 2000. This is shown in Figure 1.2.

There have been a number of key events in the history of biopharmaceutics and these are highlighted in Figure 1.3.