Cyclosporin A (CyA) is a cornerstone immunosuppressant for the prophylaxis against
allograft rejection after organ transplantation. The most widely prescribed CyA formulation
is Neoral soft gelatine capsules (Novartis Pharmaceuticals, Basel, Switzerland). After
Novartis patent expiration, several generic formulations have been developed. In this
paper, a simple and reliable HPLC method was developed and validated for the evaluation
of four CyA degradation products (ID-005-95, CyH, IsoCyH and IsoCyA) and two related
compounds (CyB and CyG) aimed for the quality control of Neoral capsules and its generic
formulations. In a second step, the validated method was then compared to the USP
assay method for capsules, where some of the mentioned impurities were not adequately
resolved from the CyA peak. Isocratic elution at a flow rate of 1.0mLmin(-1) was employed
on a Lichrospher RP-18 (4mmx250mm; 5microm) analytical column maintained at 75 degrees
C with a tetrahydrofuran:phosphoric acid (0.05M) (44:56, v/v) as mobile phase. The
chromatograms were recorded using a Hewlett Packard 1100 chromatographic system. The
UV detection wavelength was performed at 220nm and 10microL of sample was injected.
The developed method was validated in terms of selectivity, linearity, precision,
accuracy, limit of detection and limit of quantitation. The validate method was successfully
applied to commercial capsules, Neoral and generic versions. Therefore, the proposed
method is suitable for the simultaneous determination of CyA as well as its major
impurities.