We monitor thermochemical events and weight loss as a function of temperature to achieve insight into solid form characteristics, mechanisms of polymorphic transformations and solid state degradation pathways. To analyze these properties of bulk and formulated solid products, we use modern differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA).
DSC, Modulated DSC
Differential scanning calorimetry is one of the most widely used thermal analysis techniques for the characterization of pharmaceutical solids. We measure thermal events such as melting, recrystallization, decomposition and glass transitions. In addition, we can perform quantitative mixture analysis (i.e., determination of polymorph mixtures). Modulated DSC offers expanded capabilities by allowing for the measurement of heat capacities and the characterization of reversible and nonreversible thermal transitions.
Melting point determination is an important aspect of polymorph analysis in terms of stability. We provide melting point determination per the various methods outlined in the USP.
Thermogravimetric Analysis and Thermogravimetric/Infrared Analysis
We conduct thermogravimetric analysis to measure the thermally induced weight loss of a sample as a function of temperature. In conjunction with DSC and hot-stage optical microscopy, TGA provides an excellent approach to the determination of thermal properties of the pharmaceutical material. Extending the TGA technique to thermogravimetric/infrared analysis (TG/IR) provides the ability to not only measure thermally induced weight loss, but also to chemically identify the volatile component during each weight loss step. As a volatile component evolves from the sample in the TG furnace, it is swept into a gas-phase IR cell for spectroscopic analysis and potential chemical identification. TG/IR is an ideal technique for solvate and hydrate analysis.
Hot-Stage Optical Microscopy
Hot-stage optical microscopy is a technique we use in conjunction with differential scanning microscopy, thermal gravimetric or thermal gravimetric/infrared to characterize the thermal properties of your pharmaceutical solid. We provide analysis with two different hot-stages that allow for controlled temperature experiments from -196 to 600 °C. We can also capture video or digital images of visual thermal events such as melting, recrystallization or volatilization.
We perform isothermal microcalorimetry to study a wide variety of physical and chemical processes. It can be used to evaluate excipient compatibility, amorphous content, degradation rate, relative stability of polymorphs and any other process associated with a change in enthalpy. Our instrumentation includes specialized accessories that allow control of the relative humidity and oxygen content of the sample environment.
We use solution calorimetry to measure the heat of a solution of a solute as it dissolves in a solvent. This measurement can be used for detection and quantification of polymorphs and amorphous material, determination of the relative stability of polymorphs and for monitoring dissolution processes. Our instrumentation includes both semi-adiabatic and isothermal solution calorimeters.