Nirmatrelvir methyl tert-butyl ether solvate
The structure of nirmatrelvir MTBE solvate, C23H32F3N5O4·C5H12O, at 150 K has monoclinic (P21) symmetry. The asymmetric unit contains one nirmatrelvir molecule and one methyl tert-butyl ether solvent molecule. The extended structure consists of N—H⋯O hydrogen bonds that create [010] chains. Crystals of the title compound were grown from various methyl tert-butyl ether–methanol solvent mixtures, with crystal […]
Crystal Structure of Ritonavir Form IV
The crystal structure of Ritonavir Form IV is reported. The structure was determined by electron diffraction, and the molecular conformation and hydrogen bonding show similarities to those of Forms I and III. Form II is shown to be the most thermodynamically stable of the four known polymorphs. Polymorphism means a solid material can form different […]
Sustaining Member of Microscopy Society of America
Chemical Microscopy is now a Sustaining Member of the Microscopy Society of America (MSA) and is being recognized in the controlled-circulation trade magazine Microscopy Today, Volume 33, Number 4, July 2025. About the Microscopy Society of America The Microscopy Society of America (MSA) is a non-profit organization dedicated to enabling the discoveries that positively impact […]
Resonant Acoustic Mixing: Enhancing Low-Dose Blend Uniformity
Our paper investigates sample preparation techniques to improve the uniformity of low-dose pharmaceutical blends mixed using resonant acoustic mixing (RAM) technology. The study focuses on a challenging active pharmaceutical ingredient, caffeine, and its blending with lactose monohydrate, for which achieving acceptable homogeneity has been difficult. Researchers explored practical strategies like pre-processing with RAM, sieving, and […]
Upcoming Demonstration of Micromanipulator
Chemical Microscopy LLC will host a hands-on demonstration of the Micro Support Axis Pro benchtop micromanipulator on Wednesday, September 25, 2024, at 10:30 AM at the Purdue Research Park in West Lafayette, Indiana. The Axis Pro system consists of a zoom microscope, motorized XYZ stage, and two motorized arms. All motion is controlled through an […]
Is a lack of respect for microscopy holding back the microspectroscopy field?
On December 26, 2023, our founder, Dale Purcell, and Brooke Kammrath, published an opinion piece in Techniques and Tools. Be sure to check it out!
Ritonavir Form III
Ritonavir Form III: Lightning strikes twice at the same time, 137 miles apart Abstract Polymorph screening is a crucial step in the characterization and development of pharmaceuticals. The 1998 recall of ritonavir upon the unexpected appearance of the more stable Form II polymorph remains a notorious case of disappearing polymorphs as the presence of Form […]
Salts and Polymorph Screens for Bedaquiline
Summary Bedaquiline is used to treat multi-resistant tuberculosis in adults. The fumarate salt is commercially available and used in the product Sirturo. To provide open access to bedaquiline molecule once the patent on the chemical substance expires, new salts were screened. The current studies focus on the attempted isolation of the acetate, benzoate, benzenesulfonate, hydrobromide, […]
Maleate salts of bedaquiline
Summary Bedaquiline is one of two important new drugs for the treatment of drug-resistant tuberculosis (TB). It is marketed in the US as its fumarate salt, but only a few salts of bedaquiline have been structurally described so far. We present here five crystal structures of bedaquilinium maleate. Dale K. Purcell, Ph.D. of Chemical Microscopy […]
Crystal structures of salts of bedaquiline
Bedaquiline is one of two important new drugs for the treatment of drug-resistant tuberculosis (TB). This paper discusses the crystalline structure of three salts of bedaquiline. Dale K. Purcell, Ph.D. of Chemical Microscopy LLC performed the spectroscopic analyses as reported.