Topic outline

  • Introduction

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    A medicine is commonly defined as a substance or preparation that can treat or prevent disease. Historically, most medicines were made from natural products. Advances in the last two centuries have led to the introduction of man-made chemical medicines, biologics and gene therapies. In addition, new technologies, such as tissue engineering , which uses living cells to repair tissues or organs, and nanomedicine , which uses tiny ‘nano’ particles in a variety of healthcare settings, have increased the options available.

    These training materials provide short descriptions of the different types of medicine, how they work and how they are developed.

  • Semi-synthetic Chemical Medicines

    As discussed in the introduction, natural substances, which may be extracted from plants, bacteria or animal cells, can have medicinal properties, but may not make ideal medicines. Semi-synthetic medicines are produced by the chemical modification of naturally occurring substances to overcome some of their limitations. This method of production distinguishes semi-synthetic medicines from fully or totally synthetic medicines (man-made chemical medicines created entirely in the laboratory, see the section on chemical medicines) and fully natural compounds, such as the herbal remedy St John’s wort (Hypericum perforatum) (used without any additional chemical modification). Semi-synthetic medicines may therefore be regarded as intermediates between natural and synthetic substances.