DENSITY

Density (tapped density, bulk density, true density) is one of the most important parameters used to characterise many solids, especially lightweight powders. It is significant in terms of e.g., fluidisation characteristics and predicting powder compaction / packing, and is also of relevance in the field of injection moulding. In the pharmaceutical industry, density can impact the tableting and handling properties of most drug products, and some studies have shown that density can have an impact on dissolution and final dose form compressability.

Agenda1 can determine the density of your materials via the Erweka Tapped Volumeter (USP standard tests - bulk and tapped density) or via Helium Pycnometry (true density).

PARTICLE SIZE

Particle size is an important parameter in many industries. For instance, in the ceramics sector, the size of the particles suspended in the slip determines the final product quality, and in the paint industry, incorrect particle size can result in poor colour strength or hue, and defects in opacity, transparency or gloss are often due to poor particle size distribution as this article demonstrates. Particle size is also of particular significance in the pharmaceutical industry, as it impacts all aspects of final product performance including: flow behaviour, blending efficiency, wetting, drying times, dissolution performance, bioavailability and chemical / physical stability.

SPECIFIC SURFACE AREA

Specific surface area is often a determining factor in e.g., bioavailability, dissolution rate, catalyst activity, electrostatic properties of powders, light scattering, opacity, sintering properties, glazing, moisture retention, and shelf-life. This importance is seen in many industries.

For instance, particulate surface area is the single most important property of a colloid (see this article), and an understanding of the impact of surface area is crucial to the effective use of particulate catalysts. Consistency of surface area from batch to batch is of particular signficance, as this DOE Case Study demonstrates. Additionally, the surface area of particles can be a crucial factor in determining their potency and toxicity. Thus, in the pharmaceutical industry specific surface area is as important as particle size.

POROSITY

Understanding the porosity of a particulate product (e.g., catalysts, sorbents, active pharmaceutical ingredients, drug delivery substrates) can help optimise the properties and performance of that product. In its simplest form, a porous material is one which presents a vastly increased surface area; thus the questions "how active is my catalyst" and "how efficiently will this drug work" derive their answers from the question "how porous is my material?"

Agenda1 carries out porosimetry and specific surface area measurements using nitrogen physisorption (BET analysis, adsorption / desorption isotherms).

POLYMORPH DETERMINATION

Polymorphism is the ability of a solid material to exist with more than one crystal structure. Different polymorphs of the same material can have significantly different properties of e.g., dissolution performance, physical and chemical stability, bioavailability, equilibrium morphology (and hence particle size / flow / packing characteristics). Polymorphism can potentially be found in any crystalline material, and is of particular relevance to industrires such as pharmaceuticals, agrochemicals, pigments and dyestuffs.

Understanding the polymorphic form and behaviour of your material is crucial for toxicity, patent, stability, product performance and regulatory purposes.

CRYSTALLINITY DETERMINATION

An amorphous solid is one in which there is not long-range order in the arrangement of the atoms or molecules. That is, it has no crystal structure. A crystalline solid is one in which there is long-range atomic order. Most classes of solid materials can be found or prepared in an amorphous form.

The degree of crystallinity / amorphicity demonstrated by a solid has a significant impact on the properties and performance characteristics of that solid, such as long term storage stability, bioavailability, mechanical properties, powder cohesion, dissolution rate, surface activity, and regulatory acceptability. The metastable nature of many amorphous materials can provide a valuable opportunity in terms of enhancing performance (e.g., solubility and bioavailability) but the inherent instability of such materials means they are often seen as problematic from a manufacturing / regulatory point of view. Contamination of a crystalline material with variable amounts of amorphous content, for example, may lead to regulatory refusal. Thus understanding the nature of your material and being able to quantify the amount of each phase present is of crucial importance. Agenda1 can help you gain such an understanding.

PARTICLE SHAPE

Particle shape (morphology / habit) can directly influence product performance and its measurement can lead to improved process and product understanding as This Article demonstrates. However, unlike particle size, shape is not routinely measured or controlled.

One example is in the toner industry, where the control of particle shape distribution offers improved powder flowability, improved transfer ratio from the photoconductor to the paper and improved image quality (see Article Here). In the pharmaceutical industry, morphology can affect properties such as powder density, cohesion, packing properties and flowability, all of which have major impact on a company's ability to reliably and reproducibly formulate drug particles into finished products (see Article Here).

MOLECULAR STRUCTURE

A thorough understanding of molecular structure can provide an understanding of the fundamental processes impacting the behavior of the molecule. Where biosimilar molecules are concerned, correct structural elucidation is vitally important in its own right, as well as for regulatory or IP reasons. Agenda1 can facilitate molecular structure elucidation.