Let \(R\) be a regular local ring containing a field of characteristic zero, \(K\) its field of fractions and \((V, \Phi)\) a quadratic space over \(R\). \textit{I. Panin} proved that if \((V, \Phi) \otimes_RK\) is isotropic over \(K\), then \((V, \Phi)\) is isotropic over \(R\) [Invent. Math. 176, No. 2, 397--403 (2009; Zbl 1173.11025)]. Using the same argument of the above result, the author extends the Wedderburn theorem to a large class of regular local rings. Theorem. Let \(R\) be a regular local ring containing a field of characteristic zero and \(A\) an Azumaya \(R\)-algebra. If \(A \otimes_RK \cong M_n(D)\), a matrix ring of order \(n\) where \(D\) is a central division algebra over \(K\), then \(A \cong M_n(\Delta)\), where \(\Delta\) is a maximal (unramified) \(R\)-order of \(D\). In other words, every class of the Brauer group of \(R\) is represented by an Azumaya algebra \(\Delta\) such that \(\Delta \otimes_RK\) is a division \(K\)-algebra. It is also pointed out that the above theorem has been generalized to arbitrary semi-local regular rings by \textit{B. Antieau} and \textit{B. Williams} [Doc. Math., J. DMV 20, 333--355 (2015; Zbl 1349.14068)].