Abstract
The thermal behavior of the δ form of chloramphenicol palmitate was examined by differential scanning calorimetry. The previous prediction that by very rapid quenching the melted chloramphenicol palmitate would crystallize to the δ form was realized on cooling at 80°/min using helium as a purge gas in the Perkin-Elmer DSC 1B. The heat of crystallization from the melt to the δ form (-2.8±0.2 kcal/mole) and the heat of transition from the δ form to the sub-α form (-2.7±0.2 kcal/mole) coincided with the predicted values (-2.9±0.5 and -2.2±0.7 kcal/mole), respectively. The area under the broad exothermal peak (P2) corresponding to the change from the sub-α form to the α form could not be determined directly in this experiment and was calculated from the equation (1).
