Merck

Corrosion inhibitors from expired drugs.

International journal of pharmaceutics (2012-05-09)
Nicolae Vaszilcsin, Valentin Ordodi, Alexandra Borza
ABSTRACT

This paper presents a method of expired or unused drugs valorization as corrosion inhibitors for metals in various media. Cyclic voltammograms were drawn on platinum in order to assess the stability of pharmaceutically active substances from drugs at the metal-corrosive environment interface. Tafel slope method was used to determine corrosion rates of steel in the absence and presence of inhibitors. Expired Carbamazepine and Paracetamol tablets were used to obtain corrosion inhibitors. For the former, the corrosion inhibition of carbon steel in 0.1 mol L(-1) sulfuric acid solution was about 90%, whereas for the latter, the corrosion inhibition efficiency of the same material in the 0.25 mol L(-1) acetic acid-0.25 mol L(-1) sodium acetate buffer solution was about 85%.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Sodium acetate trihydrate, meets USP testing specifications
Sigma-Aldrich
Sodium acetate trihydrate, BioXtra, ≥99.0%
Sigma-Aldrich
Sodium acetate trihydrate, BioUltra, ≥99.5% (NT)
Sigma-Aldrich
Sodium acetate trihydrate, Vetec, reagent grade, 99%
Sigma-Aldrich
Sodium acetate trihydrate, ReagentPlus®, ≥99.0%
Sigma-Aldrich
Sodium acetate trihydrate, puriss., meets analytical specification of Ph. Eur., BP, USP, FCC, E262, 99.0-101.0% (calc. to the dried substance), ≤0.00002% Al
Sigma-Aldrich
Sodium acetate trihydrate, ACS reagent, ≥99%
Sigma-Aldrich
Sodium acetate, 99.995% trace metals basis
Supelco
Sodium acetate solution, NMR reference standard, 50 mM in D2O (99.9 atom % D), water 1 %, NMR tube size 3 mm × 8 in.
Sigma-Aldrich
Sodium acetate, anhydrous, BioUltra, for luminescence, for molecular biology, ≥99.0% (NT)
Sigma-Aldrich
Sodium acetate solution, BioUltra, for molecular biology, ~3 M in H2O
Sigma-Aldrich
Sodium acetate, Vetec, reagent grade, 98%
Sigma-Aldrich
Sodium acetate, anhydrous, for molecular biology, ≥99%
Sigma-Aldrich
Sodium acetate, meets USP testing specifications, anhydrous
Sigma-Aldrich
Sodium acetate, powder, BioReagent, suitable for electrophoresis, suitable for cell culture, suitable for insect cell culture, ≥99%
Sigma-Aldrich
Sodium acetate, BioXtra, ≥99.0%
Sigma-Aldrich
Sodium acetate, anhydrous, ReagentPlus®, ≥99.0%
Sigma-Aldrich
Sodium acetate, puriss. p.a., ACS reagent, reag. Ph. Eur., anhydrous
Sigma-Aldrich
Sodium acetate, ACS reagent, ≥99.0%