Long-term stability of gentamicin sulfate-ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) solution for catheter locks

Abstract

A lock solution composed of gentamicin sulfate (5 mg/mL) and ethylenediaminetetraacetic acid disodium salt (EDTA-Na₂, 30 mg/mL) could fully eradicate in vivo bacterial biofilms in totally implantable venous access ports (TIVAP). In this study, fabrication, conditioning and sterilization processes of antimicrobial lock solution (ALS) were detailed and completed by a stability study. Stability of ALS was conducted for 12 months in vial (25 °C ± 2 °C, 60% ± 5% relative humidity (RH), and at 40 °C ± 2 °C, RH 75% ± 5%) and for 24 h and 72 h in TIVAP (40 °C ± 2 °C, RH 75% ± 5%). A stability indicating HPLC assay with UV detection for simultaneous quantification of gentamicin sulfate and EDTA-Na₂ was developed. ALS was assayed by ion-pairing high performance liquid chromatography (HPLC) needing gentamicin derivatization, EDTA-Na₂ metallocomplexation of samples and gradient mobile phase. HPLC methods to separate four gentamicin components and EDTA-Na₂ were validated. Efficiency of sterility procedure and conditioning of ALS was confirmed by bacterial endotoxins and sterility tests. Physicochemical stability of ALS was determined by visual inspection, osmolality, pH, and sub-visible particle counting. Results confirmed that the stability of ALS in vials was maintained for 12 months and 24 h and 72 h in TIVAP.

Keywords: Gentamicin-EDTA-Na2 loaded antimicrobial lock solution; Pharmaceutical compounding; Stability indicating HPLC assay method; Totally implantable venous access ports.

Fig. 1

(A) A typical chromatogram of gentamicin standard solution (USP) (216 µg/mL) after OPA derivatization. (B) A typical chromatogram of sisomicin after OPA derivatization (4.65 mg/mL). (C) A typical chromatogram of ALS after OPA derivatization (gentamicin 217 µg/mL). (D) Analysis of ALS (gentamicin 217 µg/mL) under oxidative conditions (3% H₂O₂, 80 °C for 3 h) after OPA derivatization.

Fig. 2

(A) A typical chromatogram of EDTA-Na₂ (USP) (1.3 mg/mL) after CuSO₄ complexation. (B) A typical chromatogram of nitrilotriacetic acid (43 µg/mL) after CuSO₄ complexation. (C) A typical chromatogram of ALS (EDTA-Na₂: 1.3 mg/mL) after CuSO₄ complexation. (D) Analysis of ALS (EDTA-Na₂: 1.3 mg/mL) under stress oxidative conditions (3% H₂O₂, 80 °C for 3 h) after CuSO₄ complexation.

Fig. 3

(A) A typical calibration curve of the cumulative peak area (C1, C1a, C2a, C2) of gentamicin sulfate (Panpharma^®) (a) and four components (b, c, d and e) ranged from 87 to 260 µg/mL. (B) A typical EDTA-Na₂ calibration curve ranged from 0.52 to 1.56 mg/mL.

Fig. 4

Linear relationship between water loss through TIVAP and time of storage at 40 °C ± 2 °C, RH 75% ± 5%.