Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs43094-020-00120-3/MediaObjects/43094_2020_120_Fig1_HTML.png)
Physicochemical properties of chondroitin sulfate (CS) and glucosamine sulfate potassium chloride (GlcN) samples provided by suppliers (S1 and S2) and obtained from the pharmacy. Comparative analyses of pH values for CS (a) and GlcN (b) samples. Comparative analyses of apparent density values for CS (c) and GlcN (d) samples. Values are expressed as mean ± standard deviation and analyzed by one-way ANOVA followed by Tukey’s post-test. *p < 0.05 between S1 and S2; ap < 0.05 in relation to S1; bp < 0.05 when compared to S2. S1, supplier 1; S2, supplier 2; Ph (S1), pharmacy analyses from supplier 1 samples; Ph (S2), pharmacy analyses from supplier 2 samples