title: Arsenic species in solutions for parenteral nutrition.
abstract: BACKGROUND
  In spite of its high toxicity, arsenic is a common contaminant in pharmaceuticals. This is stated by pharmacopoeias' monographs where it is not generically included with other heavy metals, but has its own specifications. Arsenic should not exceed 0.1 mg/L in most pharmaceutical products for IV administration. This limit, however, was established without taking into consideration the specific arsenic species which contribute to this amount. In this work, the presence of arsenite and arsenate species in solutions of amino acids, salts, vitamins, and lipids commercialized for IV administration was investigated.
  
  
  METHODS
  The measurements were done by hydride generation atomic absorption spectrometry.
  
  
  RESULTS
  The results showed that all commercial formulations contain both arsenic species in some level; however, the total arsenic content exceeded the allowed limit in only a few samples. Calcium gluconate, sodium bicarbonate, heparin, and vitamin solutions were the most contaminated, presenting total arsenic concentration ranging from 62 to 249 microg/L. The most important finding, however, was the different ratios As(V)/As(III) among the formulations. Whereas practically only As(V) was found in ampoules containing water for injection and salt solutions (NaCl, KC1, phosphates), As(III) predominated in solutions of vitamins, gluconate, and glucose. As these are reducing substances, we investigated the possibility of their reaction with As(V) and its conversion into As(III). The heating of As(V) in the presence of gluconate, glucose, ascorbic acid, methionine, isoleucine, sodium chloride, and pure water, in autoclave for 15 minutes, showed that, whereas no As(III) was found in pure water and sodium chloride solution, approximately 50% of As(V) was converted into As(III) in the remainder of the solutions.
  
  
  CONCLUSIONS
  The results showed that As(V), the main species in these formulations, may be converted into As(III), depending on the presence of reducing substances among the formulation constituents.
authors.affiliation: Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, Brazil. ndenise@smail.ufsm.br
authors.forename: Denise
authors.initials: D
authors.lastname: Bohrer
authors.forename: Paulo Cícero
authors.initials: PC
authors.lastname: do Nascimento
authors.forename: Emilene
authors.initials: E
authors.lastname: Becker
authors.forename: Leandro Machado
authors.initials: LM
authors.lastname: de Carvalho
authors.forename: Morgana
authors.initials: M
authors.lastname: Dessuy
mesh_terms: D001151:Arsenic / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D001152:Arsenicals / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D004340:Drug Contamination; D005526:Food, Formulated / Q000032:analysis*; D005942:Gluconates / Q000032:analysis; D005947:Glucose / Q000032:analysis; D006801:Humans; D006859:Hydrogen / Q000737:chemistry; D010084:Oxidation-Reduction; D010288:Parenteral Nutrition; D012996:Solutions; D013054:Spectrophotometry, Atomic / Q000379:methods*; D014815:Vitamins / Q000032:analysis
chemical_list: D001152:Arsenicals; D005942:Gluconates; D012996:Solutions; D014815:Vitamins; D006859:Hydrogen; D005947:Glucose; D001151:Arsenic; C030691:gluconic acid