Development and Validation of Stability-Indicating RP-UPLC Method for the Determination of Methdilazine in Bulk Drug and in Pharmaceutical Dosage Form

Table 1

Summary of solvent optimization.

Solvent A	Solvent B	Observations/remarks
5 mM ammonium acetate	Methanol	Very broad peak with peak splitting
5 mM ammonium acetate	Acetonitrile	Peak eluted too early
Dibasic potassium phosphate (pH 3.0 with 10% H3PO4)	Methanol	Very broad peak with peak splitting
Dibasic potassium phosphate (pH 3.0 with 10% H3PO4)	Acetonitrile	Less theoretical plates and peak fronting
Monobasic potassium phosphate (pH 3.0 with 10% H3PO4)	Methanol	Broad peak and less theoretical plates
Potassium dihydrogen orthophosphate and 1-pentane sulphonic acid (pH 4.0) at 60% ratio	Acetonitrile at 40% ratio	Good peak shape with theoretical plates above 2000