Solid-state Characterization of Excipients

Drug formulations usually contain excipients whose function is to positively influence the solubility or stability of the drug product. The physical and chemical characterization of the solid-state properties of drugs and excipients is fundamental for planning new formulations and developing new strategies for the treatment of diseases. Solid-state characterization is key to understanding the physical properties of pharmaceutical solid materials and ensuring optimal physical form. These physical properties can have an impact on the bulk properties, drug formulation performance, processability, stability and appearance of the material. Among the wide variety of solid structures of excipients (polycrystals, hydrates, solvates and amorphous materials), characterization of the solid-state is used to identify those materials that guarantee the bioavailability and safety of the product. At BOC Sciences, different complementary analytical methods are often used to characterize the respective solid forms of excipients.

Figure 1. Challenges of solid state properties studies. (Bhusnure, O. G. 2016)

Our Capabilities

Particle Characterization

The purpose of formulation development is to design a product and its manufacturing process to consistently deliver the desired quality target product profile. This involves the key quality attributes of the excipient, which are often determined by assessing the degree of variation in a particular property, such as particle size, shape and size distribution, that affects the quality and performance of the drug product. Particle properties of excipients are closely related to flowability, content uniformity, bioavailability, dissolution and absorption behavior, which are key parameters for the pharmaceutical industry. Our scientists are experienced in the use of various instruments including Static Image, Dynamic Light Scattering, Raman Mapping, Scanning Electron Microscopy (SEM) and Dynamic Image Analysis (DIA) to measure the particle size and distribution of different excipients.

Polymorphism Characterization

Polycrystalline is defined as the ability of a material to form different crystal structures, and polycrystalline materials are almost always organic substances. Different polycrystalline forms of the same excipient can exhibit different properties such as bioavailability, melting point, stability, solubility, and hygroscopicity. Therefore, understanding the relationship between the solid-state properties of an excipient and the possible polymorphism is a useful strategy to optimize the development of excipients.

Figure 2. Levels of Solid State Properties. (Maheshwari, R.; et al. 2018）

Crystalline Behavior Research

In general, excipients interact with the water contained therein leading to the formation of crystalline excipients. The crystallinity of excipients in pharmaceuticals is associated with changes in particle morphology of the active pharmaceutical ingredient (API), reduction in powder density, and improvement in dispersibility. We have introduced Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD) and Raman Spectroscopy for the comprehensive identification and analysis of different crystalline excipients, and our services include:

• Distinguishing between amorphous and crystalline excipients
• Detection and quantification of crystalline content in excipients
• Quantitative and qualitative analysis of the crystalline chemical components present in the excipients

Morphological Analysis

Properties such as flowability and compressibility associated with the overall level of solid forms are strongly influenced by variations in particle level characteristics such as particle size, size distribution and morphology. Therefore, understanding the morphological characteristics of solid excipients used in pharmaceutical formulations is important to verify the quality of the raw material and to identify variations in the production line. BOC Sciences has introduced a variety of characterization instruments and analytical tools to characterize the morphology of excipients and the multidimensional visualization of their distribution in tablets

Features of Solid-state Characterization Services

• Our solid state characterization team provides a range of services to support the development of pharmaceutical products during formulation or process development, and quality control
• We offer customized excipient solid-state characterization services to determine particle shape, size distribution, etc. enabling you to understand physicochemical properties for successful formulation development
• Our crystal morphology capabilities include powder X-ray diffraction (XRPD) for confirmation of polycrystalline forms
• Spectroscopic structure characterization is achieved through the application of BOC Sciences' well-established spectroscopic instrumentation including infrared spectroscopy (FTIR), UV/Visible, Nuclear Magnetic Resonance (NMR) and Raman spectroscopy