Protein crystallography has become a mainstream analytical method in assisting the pharmaceutical chemistry field. Specific work on proteases which are instrumental in lead compound discovery have blossomed over the passed two decades as the need for Co-crystallization of target proteins with small molecules is seeing a drastic increase now that their uses in drug design have become fully apparent. Work on phosphorous cleaving and donating enzymes (Kinases and phosphatases) has also become an area of current interest as potential cancer therapy by affecting the energy yield in a cancer cell through interruption of ATP generation. “The use of protein crystallography is highly influential in structure-guided drug design as researchers can help determine the absolute stereochemistry of a compound and alter it if necessary to favour the necessary binding conformation”3.
Co-crystals have come up in pharmaceutical chemistry as an important and controversial topic. Although there is disagreement on the definition of what is classified as a co-crystal, their importance in pharmaceutical chemistry and X-ray crystallography is noted. Co-crystals are believed to be a crystalline structure of at least two components composed of atoms, molecules or ions. These components form a single unique crystalline structure and have proven to be quite beneficial in vitro as a medicinal delivery system.
Several advances on the design, growth and characterization of co-crystals have increased exponentially over the past several decades. It has only been in the past several years however, that reference to pharmaceutical chemistry has begun to flourish as the discovery that co-crystals actually alter their physicochemical properties without out any effect on bioactivity via structural compromise. Although discovered over 100 years ago, co-crystal chemistry is a relatively newly researched and developed field in the broader spectrum of pharmaceutical chemistry. The use X-ray crystallography is a necessary tool when dealing with co-crystals, as it is essential to successfully isolate and identify these products instead of a concurrent product composed of perhaps a mixed ionic or salt complex.
With regards to absolute structure determination and co-crystal chemistry, Alshahateet et. al4 researched the plausibility of creating an optically pure form of the non-steroidal anti-inflammatory drug (NSAID) Ibuprofen in a co-crystal form for the exact reasons aforementioned. The co-crystal structure does not affect bioactivity but at the same time can alter physicochemical properties in vitro, a property very much desired in the field of pharmaceutical chemistry.
The S-enantiomer of ibuprofen is the API (active pharmaceutical ingredient) “which was examined with a co-crystal composed of 2-aminopyrimidine and its ability for the two to form a co-crystal was characterized by a single X-ray crystallography. It...