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Context: Ethylcellulose is commonly dissolved in a solvent or formed into an aqueous dispersion and sprayed onto various dosage forms to form a barrier membrane to provide controlled release in pharmaceutical formulations. Due to the variety of solvents utilized in the pharmaceutical industry and the importance solvent can play on film formation and film strength it is critical to understand how solvent can influence these parameters., Objective: To systematically study a variety of solvent blends and how these solvent blends influence ethylcellulose film formation, physical and mechanical film properties and solution properties such as clarity and viscosity., Materials and Methods: Using high throughput capabilities and evaporation rate modeling, thirty-one different solvent blends composed of ethanol, isopropanol, acetone, methanol, and/or water were formulated, analyzed for viscosity and clarity, and narrowed down to four solvent blends. Brookfield viscosity, film casting, mechanical film testing and water permeation were also completed., Results and Discussion: High throughput analysis identified isopropanol/water, ethanol, ethanol/water and methanol/acetone/water as solvent blends with unique clarity and viscosity values. Evaporation rate modeling further rank ordered these candidates from excellent to poor interaction with ethylcellulose. Isopropanol/water was identified as the most suitable solvent blend for ethylcellulose due to azeotrope formation during evaporation, which resulted in a solvent-rich phase allowing the ethylcellulose polymer chains to remain maximally extended during film formation. Consequently, the highest clarity and most ductile films were formed., Conclusion: Employing high throughput capabilities paired with evaporation rate modeling allowed strong predictions between solvent interaction with ethylcellulose and mechanical film properties.

This three-part review has been developed following the evaluation of literature where ethylcellulose, methylcellulose, or hypromellose was used to make microcapsules. Parts 1 and 2 of the review are published in separate papers. Part 1 covers the various materials used to formulate microcapsules, and Part 2 covers the various techniques used to make microcapsules. In the current paper, Part 3 covers the end-use applications for which microcapsules are used. Examples of applications to be covered include modified release, improved efficacy and safety, multiparticulate compression, improved processability and stability, and taste- and odor-masking. It is hoped that formulators can use Part 3 to understand the various end-use applications of microcapsules made from these encapsulating polymers. SciFinder was utilized to perform the literature search. SciFinder leverages literature databases, such as Chemical Abstracts Service Registry and Medline. A total of 379 references were identified during the review. The need for a three-part review reflects the extensive amount of literature identified concerning these three encapsulating polymers.

This review highlights references where ethylcellulose, methylcellulose and hypromellose were used to make microcapsules. The review has been divided into three parts. This first part discusses various materials used to formulate microcapsules, such as the three encapsulating polymers as well as protective colloids, plasticizers and surfactants. The second part covers the various techniques used to make microcapsules, such as temperature-induced phase separation, emulsion solvent evaporation, solvent evaporation, film coating, and others. The third part covers the various applications for which microcapsules are used, such as modified release, improved efficacy and safety, taste- and odor-masking, and others. It is hoped that formulators can use Part 1 as a guide to the literature documenting formulation of microcapsules made from these encapsulating polymers. SciFinder was utilized to identify the pertinent literature. SciFinder leverages literature databases, such as Chemical Abstracts Service Registry and Medline. A total of 379 references were identified during the review. The need for a three-part review reflects the extensive amount of literature identified concerning these three encapsulating polymers.

This three-part review has been developed following the evaluation of literature where ethylcellulose, methylcellulose or hypromellose was used to make microcapsules. Parts 1 and 3 of the review are published as separate papers. Part 1 covers the various materials used to formulate microcapsules, and Part 3 covers the various end-use applications for microcapsules. In the current paper, Part 2 covers the techniques used to make microcapsules. Examples of techniques to be covered include temperature-induced phase separation, emulsion solvent evaporation, solvent evaporation, film coating, nonsolvent addition and spray drying. It is hoped that formulators can use Part 2 to understand how to formulate microcapsules using these encapsulating polymers. SciFinder was utilized to perform the literature search. SciFinder leverages literature databases, such as Chemical Abstracts Service Registry and Medline. A total of 379 references were identified during the review. The need for a three-part review reflects the extensive amount of literature identified concerning these three encapsulating polymers.