HPLC analysis was carried out on a LC-20A Prominence HPLC (Shimadzu, Duisburg, Germany) equipped with a system controller CBM-20A, a solvent delivery unit LC-20 AT (double plunger), an on-line degassing unit DGU-20A, an auto-sampler SIL-20AC, a photo diode array detector SPD-M20A. As stationary phase, a ZORBAX Eclipse Plus (Agilent, Santa Clara, CA, USA) C18 column (4.6 x 100 mm; 3.5 μm) was used. Quantification of drugs was performed with a stepwise gradient using acetonitrile and water with 0.05% TFA. Initially the HPLC methods were developed for individual drugs. After that, the series of standard solutions of different known concentrations were measured to obtain the standard curve followed by the drug quantification at their respective lambda max. For all the HPLC data, please refer to Figure S8-S28.