The determination of the concentrations of metamizol sodium in inflamed joints of pigs after intravenous and iontophoretic application

Concentrations of the NSAID metamizol sodium (MmNa) in the synovial fluid and hyaline cartilage of inflamed knee and elbow joints of pigs after i.v. application and iontophoresis (IPh) were investigated. The research was conducted on 14 male pigs divided equally into two experimental groups and exposed to artificial inflammation of knees and elbows prior to the application of MmNa. The first group (A) was administered 2.5 g (twice the maximum therapeutic dose) MmNa intravenously, whilst the second group (B) was exposed to the same dose, but applied by IPh into contralateral knee and elbow joints. Four hours after the application of MmNa biopsies of the affected knee and elbow joints were performed. The average concentration of MmNa in the synovial fluid of inflamed joints in group A was 9.81±1.96μg/g, while in group B was 170.66±2.07 μg/g, being 17 times higher. The average concentration of MmNa in the hyaline cartilage was 2.29±1.16μg/g following i.v. administration and 98.36±21.58μg/g after IPh, i.e. approximatelly 43 times higher. This led to the conclusion that IPh of MmNa, resulting in incomparably higher concentrations in inflamed joints without any adverse systemic effects, has an advantage over i.v. application