“…Coulomb attraction holds oppositely charged ions together in solution in the ion-pair complex [ 56 ]. Some antibiotics have been analyzed using spectrophotometric methods including amoxicillin [ 40 ], azithromycin [ 41 , 57 ], tetracycline, doxycycline [ 58 ], and cefixime trihydrate [ 59 ]. They have also been used to analyze gentamicin sulfate [ 60 ], cefadroxil, ceftazidime, cefazolin sodium, cefoperazone sodium, cefaclor, cephaprin sodium, cefotaxime sodium, and cefuroxime sodium [ 61 ].…”