The existence of an optimal quadrature formula of the form \(\int^{b}_{a}f| x| dx\approx \sum^{n}_{k=1}\sum^{\nu_ k-1}_{\lambda =0}a_{k\lambda}f^{(\lambda)}(xk)\) with preassigned multiplicities \((\nu_ k)_ 1^ n\) in the classes \(LW_ q^ r:=\{f\in C^{(r-1)}:f^{(r-1)}\)- abs. cont., \(\| Lf\|_ q\leq 1\}\) for \(1\) is proved and its characterization is given.