Dimethyl sulfoxide (dmso)

Cellulose acetate (molecular weight 30,000 g/mol, 39.8 wt% acetyl) and cetylpyridinium bromide (CPBr, 99%) were provided by Spectrum Chemical Co. (USA). Attapulgite (ATP, 99%), dimethyl sulfoxide (DMSO, 99%) and potassium dichromate (K₂Cr₂O₇, 99%) were purchased from were bought from Alpha Chemika (India). Sodium chloride (NaCl, > 98%) and ethanol (C₂H₅OH, 99%) were provided by El Nasr Pharmaceutical Chemicals Company (Egypt).

FP, salmeterol xinafoate (SAL) and diethylene glycol were obtained from Sigma (Pool, UK). L-lysine and 2,5-furyl dichloride were purchased from Acros Organics (Geel, Belgium). Ethyl acetate, trifluoroacetic acid (TFA), dimethyl sulfoxide (DMSO), acetone, and acetonitrile were obtained from Alpha Chemika (Mumbai, India). Glycerin was obtained from Labchem (Zelienople, PA, USA). Additionally, potassium hydroxide (KOH) pellets were obtained from Riedel-de Haën (Seelze, Germany), while methyl alcohol, diethyl ether, and HPLC-grade water were purchased from Tedia High Purity Solvents (Fairfield, CT, USA).

All chemicals and regents used for this study were analytical grade and used without further purification. 1,10-phenanthroline monohydrate (BDH chemical Ltd., Poole, England), copper (II) acetate monohydrate [Cu(CO₂CH₃)₂·H₂O], triethylamine, NaHCO₃, NaOH, and Mueller-Hinton agar were purchased from Loba Chemie PVT Ltd., Addis Ababa. Metformin hydrogen chloride (Met.HCl) and ciprofloxacin hydrogen chloride (Cip.HCl) were obtained from Cadila Pharmaceuticals PLC, Ethiopia. Methanol, ethanol, HCl, DMSO, ethyl acetate and dichloromethane (DCM) were purchased from Alpha Chemika, Addis Ababa, Ethiopia. Thin Layer Chromatography (MERCK Silica gel 60 F254) together with UV Cabinet (UV-Vis lamp at 254 and 365 nm) were used to monitor the progress of the chemical reactions. The melting points of the complexes were determined using capillary tubes (Thiele tube). UV-Vis spectrophotometer (SM-1600 Spectrophotometer), FTIR (Perkin-Elmer BX spectrometer, Shimadzu Corporation, Japan), TGA/DTC (DTG-60H SHIMADZU thermal analyzer) and High resolution mass spectra (Waters-LCT-Premier mass spectrometer) were used to characterize the synthesized metal complexes.