Planta Med 2006; 72 - P_345
DOI: 10.1055/s-2006-950145

Quality caracterisation of propolis tinctures by pharmacopoeial parameters and wax content

J Cvek 1, S Zubčic 1, D Vitali 2, I Vedrina-Dragojevic 2, S Tomic 1, M Medic-Šaric 2
  • 1Agency for medicinal products and medical devices, Ksaverska cesta 4, 10000 Zagreb, Croatia
  • 2Faculty of Pharmacy and Biochemistry, University of Zagreb, A. Kovačica 1, 10000 Zagreb, Croatia

The increasing use of propolis preparations nowdays requires setting of clear criteria for their quality control. For that purpose, ten tinctures of propolis samples from different Croatian regions were subjected to analysis of general pharmacopoeial parameters wich are fundamental for the creation of quality specification. These are relative density (determined using instrument Mettler Toledo DE40 Density Meter), dry residue of extract (determined according to Ph. Eur. 5.0 method), and content of ethanol and its possible impurities – methanol and isopropanol (developed and validated gas chromatography method for their simultaneous analysis was applied). Additionally, by the method of Woisky and Salatino we determined the content of waxes as the main inactive constituents in order to determine the level of their migration from crude propolis samples to the prepared tinctures (extraction solvent: 80% V/V ethanol; drug – preparation ratio=1:10) [1]. Relative density values increased along with the increase of dry residue of extract (e.g. the lowest values were determined in propolis tincture from South Dalmatian Islands: d20 =0.8688, RSD(n=2)=0.42% and dry residue=4.40% w/w, RSD(n=2)=0.80% while the highest values were obtained for propolis tincture from central Croatia: d20 =0.8841, RSD(n=2)=0.01% and dry residue=7.62% w/w, RSD(n=2)=0.28%). Investigated validation parameters for GC method satisfied the acceptance criteria (correlation coefficient more than 0.999; precision: RSD(n=21)=0.60%; average recovery(n=21): 99.08%; DL=0.001% for methanol and 0.002% for isopropanol; QL=0.003% for methanol and 0.006% for isopropanol). Ethanol content was in range from 73.98 to 77.74% V/V (RSD(n=3)=0.06–2.43%) which is in accordance with USP 29 requirement for alcohol content in herbal extracts (90–110% of declared amount). Contents of methanol and isopropanol were below detection limits. Presence of waxes was not observed in propolis tinctures indicating the suitability of applied extraction method.

Reference: 1. Woiski, R.G., Salatino, A. (1998), J. Apic. Res. 37:99–105.