Comparative study of particle size distribution analysis by laser diffraction between dry and wet dispersion methods and scanning electron microscopy

• Autor(a) principal: Sequeira, Sara Tomás
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/38119
• topic: API; particle engineering; PSD; laser diffraction (wet and dry dispersion); SEM; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

An Active pharmaceutical Ingredient (API) may assume several different physical forms such as dry powders, wet dispersions and semi-solid dispersions. Depending on the route of administration, the size of API particles may be considered a critical attribute, since this property may affect a variety of product characteristics, such as reactivity, stability, efficacy, texture, fluidity, viscosity, density among others. Fine API particles below ten micrometers in size, are required for pharmaceutical formulations administered by the pulmonary and ophthalmic routes. To achieve the desired particle size, several particle-engineering techniques may be employed. In this thesis, a variety of products (API’s & excipients) essentially intended for use in inhalation and ophthalmic formulations were characterized regarding particle size before and after being processed by particle engineering techniques. In order to evaluate the particle size distribution of the studied products, two laser diffraction techniques and an electron microscopy technique were used. The laser diffraction techniques used are based on the same theoretical principles however the mathematical algorithm used for data conversion and the particulate dispersion medium are different. For analysis by wet dispersion, the equipment used was Malvern Mastersizer Hydro 2000 S and Mastersizer 3000 Hydro MV. For the analysis by dry dispersion, the equipment used was Sympatec (comprising the units Helos, Rodos / M and Aspiros). Further characterization regarding particle size and morphology was carried out in a Phenom ProX Generation 5 microscope, a scanning electron microscope (SEM). During the course of this work, whenever possible, the above mentioned techniques were used and a comparison between them was done. Since these two laser diffraction techniques use different mathematical models for generating PSD data, it is expected that the PSD values reported are not exactly coincident. This means that every PS request should be always reported to a validated method.