Tim Freeman Series On Powder Characterization For Pharmaceutical Operations

‘Powder characterization for pharmaceutical operations' is a series of six guest editorials contributed by Tim Freeman, Director of Operations at Freeman Technology, specialists in the measurement and understanding of powder behavior. Starting with ‘Powder characterization for formulators', each item will examine in turn powder characterization for the pharmaceutical industry from the point of view of different professions or functions. As well as formulators these will include quality control teams, equipment manufacturers, and process designers and engineers.

Pharmaceutical Online is pleased to present a new series of guest columns on powder characterization written by Tim Freeman, director of operations at Freeman Technology. In each installment, Freeman tackles a different topic and how it can impact your organization. Following are his columns that have already been published and are now available in Pharmaceutical Online's archives:

Powder Characterization Techniques For Wet Granulation Applications
Wet granulation is a routine unit operation within the pharmaceutical industry, and a common precursor to tableting. It is typically carried out as a batch process, with endpoint detection an important issue. Here, dynamic powder rheometry offers proven benefit. By providing sensitive detection of the transition from wet mass to granulate, using a property that is independent of scale, this powerful analytical technique accelerates scale-up and over the longer term improves manufacture.

Powder Characterization Techniques For Tableting Applications
Simple to administer, tablets are a feature of every day life. Tablet production has a history dating back more than a century, but retains its ability to frustrate. The drive towards faster production speeds, increasingly potent actives and the adoption of complex tablet structures present modern day tablet manufacturers with significant challenges. Understanding how to manipulate the properties of the blend towards better processing performance and high quality of final product is essential.

Powder Characterization Techniques For Dry Powder Inhaler Applications
At the very heart of dry powder inhaler technology lies a demanding powder engineering challenge. Particles in the sub-5 micron range - the ideal for deposition in the lung - tend to be cohesive, making them difficult to handle and disperse. Achieving efficient dispersion of the active to a respirable size is a primary goal of formulators. However, addressing manufacturing issues at an early stage is also beneficial.

Powder Characterization For Selecting Material Of Construction
For powder processors material of construction or surface finish choice is an important element of design, critical to achieving the fundamental compatibility between powders and process that underpins successful long term performance. A range of metals and polymers is available to cope with the specific demands of the pharmaceutical industry but choosing between them requires a considered cost benefit analysis. Unfortunately, while cost is relatively easy to establish, benefit may be much harder to quantify.

Powder Characterization For Process Designers And Engineers
For process designers specifying new plant, the goal is to engineer equipment that will process and handle powders consistently and efficiently, as defined by the design brief. In contrast, engineers working as part of the manufacturing team rarely have the option of changing out equipment, but strive to achieve acceptable operation using the existing plant. While these goals are somewhat different the two groups share a need for detailed process understanding, knowledge of the interplay between powder properties and process equipment and how, in combination, they deliver product with the intended properties and quality.

Powder Characterization For Formulators
Accelerating product development through formulation into successful manufacture and on to the market place, is an important goal for the pharmaceutical industry. Optimizing the formulation process, and more efficient production are strong themes as revenues come under intense pressure. For formulators the principal focus is developing a product that delivers desirable clinical performance, but manufacturing demands are increasingly influential.

Powder Characterization For QC
While adopting Quality by Design opens the way to increased operational flexibility and efficiency, its achievement requires the pharmaceutical industry to extend its knowledge base, especially in key areas such as powder processing. Within the industry, manufacturing success is usually assured by adhering to detailed procedures, having a formulation that works, rigorously testing in-process material, and perhaps most crucially, drawing on operating expertise developed over the years, tricks that ease the processing of difficult batches. Such expertise is hard won, and valuable, but tends to be very limited in its applicability. One cost-effective way of accessing the information required for QbD is to unlock the knowledge inherent in experience, using modern powder characterization techniques.

Powder Characterization For Equipment Manufacturers
Equipment manufacturers share with process engineers the task of specifying plant for optimal performance. For processes involving powders this is a challenge, with fundamental compatibility between plant and material being the key to success. Designing or modifying equipment to suit the characteristics of a powder provides a firm basis for reliable and successful operation, building quality into the manufacturing process, in accordance with the concept of QbD. Here and in a subsequent editorial we examine ways of using universal powder testers such as the FT4 from Freeman Technology to achieve these goals.

Powder Characterization Techniques For Capsule Filling
Capsules are widely used to provide metered doses for oral and pulmonary drug delivery. For oral administration, fill weights are typically in the range 50 to 500 mg but for dry powder inhalers, dose size is far smaller, principally within the range 0.5 to 15 mg. These smaller volumes, in combination with the fine particle size of inhaler formulations, are particularly challenging. Capsule filling success relies on characterizing powders in a way that allows for a correlation between measured properties and the powder's behavior in the dosing equipment. Research has shown that bulk, shear, and dynamic powder properties all influence capsule filling performance, so powder testers with all three methodologies are uniquely applicable.

Reviewing The Traditional Powder Testing Toolkit
Flowability – the ease with which a powder flows – is arguably the most important characteristic of powder behavior. For pharmaceutical manufacturers, engineering the right flow properties has always been the key to many processes, one important example being the successful production of quality tablets at the required rate. Today though, the increasing emphasis on more efficient manufacture and continuous processing intensifies the need for reliable, relevant, and precise flowability measurement. This changing climate makes it timely to review traditional flowability test methods, examining both their value and limitations.

About Tim Freeman
Tim Freeman, Director of Operations at Freeman Technology, has created a series of articles relating to the Quality by Design initiative implemented by the company. Tim Freeman has a degree in Mechatronics from the University of Sussex in the UK and has worked for Freeman Technology since the mid 1990s. Since Freeman Technology's launch of the FT4 Powder Rheometer, he has been responsible for application and method development and works closely with customers in the pharmaceutical and powder processing industries.

About Freeman Technology
Freeman Technology was founded in 1988 by Reg Freeman. The company is a specialist company that has pioneered the measurement and understanding of powders and their flow properties. Effective powder processing underpins almost all pharmaceutical manufacture.