Treatment regimen
Patients were divided into 2 equal groups: intranasal 0.9% sodium chloride (group A) and intranasal 2% DTPA in borate buffer, pH 8 (group B). The pharmaceutical preparations of the described treatment were prepared by (blinded for review). These preparations were filled into identical opaque nasal spray bottles delivering a volume of 0.1 mL. The prescribed treatment bottle was administered to the participants 3 times daily for 1 month. The sodium chloride group was used to eliminate the variations between the treated and non-treated groups. Improvement in the olfactory function was demonstrated. In addition, participants’ nasal secretions were collected before treatment and 1 month later. The concentrations of calcium cations of the collected nasal secretions were determined using an ion-selective electrode.