[Hydrogen potential of antibiotic solutions subjected to environmental conditions: a preliminary trial]

This experimental study was performed to assess the hydrogen potential (pH) of the antimicrobials ceftriaxone sodium, vancomycin hydrochloride, metronidazole, penicillin G potassium, and amikacin sulphate, following reconstitution, diluted with NaCl 0.9% (SF) and glucose solution 5% (GS), at eight different time intervals and under the normal daily conditions of lighting and temperature within the hospital unit (no air conditioning). The objective of this study was to verify the changes in the acid-base behavior of the solutions, which indicate chemical instability and can be associated with complications during intravenous therapy. Of the 186 analyzed pH values, there were no variations greater than 1.0 and no physical alterations visible to the naked eye. All solutions had a pH less than 7, and there were no significant differences for clinical practice regarding the diluent. The mean pH values after dilution with SF and GS for vancomycin hydrochloride, metronidazole, and amikacin sulphate are a risk factor for the development of intravenous complications due to their extreme acidity.