Erratum to: Novel hyaluronic acid–methotrexate conjugate suppresses joint inflammation in the rat knee: efficacy and safety evaluation in two rat arthritis models. Issue 1 (December 2016) - Tamura, Tatsuya; Higuchi, Yoshinobu; Kitamura, Hidetomo; Murao, Naoaki; Saitoh, Ryoichi; Morikawa, Tadashi; Sato, Haruhiko