The nature and composition of the formulations will be different for each stage of development but the formulation chosen for full-scale clinical trials must, as far as possible, be the same as the product that is intended for marketing. Preformulation studies at various stages of development. in vitro screening using chemical, physicochemical or biological assays, pre-clinical in vitro laboratory safety tests, in vivo efficacy and safety studies in relevant animal species, first-in-human studies to determine the optimum drug to progress into clinical development, initial volunteer/patient studies and full-scale clinical trials ( Figures 1.1 and 1.2). To minimise attrition it is essential, therefore, to understand the physicochemical characteristics of compounds or biological entities that are candidates for development into final products.Īt various stages during the development of a new medical product the candidate drug must be formulated into a dosage form that is appropriate for the intended study e.g. Finally, reference is made to the characterisation of powders and particulate systems by measuring their fundamental and derived properties.ĭiscovering and developing new medicines is a long, complex and expensive process and the failure rate is high during the process. Assessing the stability of active ingredients and excipients, both in isolation and in combination, is covered using stress testing, including the effect of pH, temperature, humidity, light and oxidizing agents. Moisture uptake and sorption the classification of hygroscopicity and evaluation of polymorphism and crystallinity is outlined together with methodology, such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and powder X-ray diffraction. The chapter covers the measurement of solubility and dissolution rate, molecular dissociation, p K a, diffusion, partition and permeability and how these can be included in a biopharmaceutical classification system. Preformulation studies are also performed to predict the stability of the formulation during manufacture, transport and storage and thus determine the shelf life of the marketed product. Data acquired from such preformulation studies forms an important basis for understanding the potential pharmacokinetics of a drug in humans and animals and the opportunities and limitations for process change as the product is scaled up in manufacture. 1-41ĭrug Discovery CHAPTER 1 Preformulation StudiesĮ-mail: various stages during development, it is essential to understand the physicochemical characteristics of compounds or biological entities that can affect their development into final products. Jones, CHAPTER 1:Preformulation Studies, in Pharmaceutical Formulation: The Science and Technology of Dosage Forms, 2018, pp.
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