Protein kinase C (PKC) inhibitors are under investigation as potential anti-arthritic drugs. Attempts to resolve a lead compound into its respective enantiomers were made using normal chiral phase methodologies, e.g., Chiralcel OD, OG, OJ using isopropanol-hexane mixtures. Although good retention was achieved on some chiral columns, no separation was seen.Silica-based cellulose tris-3,5-dimethylphenylcarbamate, Chiralcel OD, has been used previously to successfully resolve various drugs by reversed-phase HPLC using aqueous buffer-acetonitrile eluting systems.This work investigates the direct chiral resolution of a range of PKC inhibitor racemates by reversed-phase chiral HPLC on Chiralcel OD using acetonitrile-phosphate buffer mixtures. The effect on the separation was studied with variables such as acetonitrile concentration, flow-rate, buffer pH and column temperature.The effect on chromatography at sub-ambient temperature is discussed and examples are given where enhancement on resolution was achieved. In some cases baseline separation was obtained allowing determination of enantiomeric excess down to 0.1% level.Although an increase in band broadening was observed as the temperature was reduced it did not reach an unacceptable level, even at 0°C.