An Alternate Crystal Form of Gabapentin: A Cocrystal with Oxalic Acid

A cocrystal of gabapentin and oxalic acid has been prepared employing a strategy based on a hydrogen-bonded synthon described by the graph set notation R42(8). High throughput techniques and solvent drop grinding were used along with traditional crystallization methods, including crystallization in aqueous solutions at various pH. A number of new solid forms have been detected. The cocrystal of gabapentin and oxalic acid was fully characterized including single crystal structure analysis, which revealed the R42(8) synthon.