from 40 to 500 pc.

Fig. \[figure:age\_sep\] shows the dependence between $\log t$ and $\log S$ for star clusters in five studied galaxies in the used ranges of separation. Coefficients of the equation $$\log t {\rm [yr]} = \alpha \log S {\rm [pc]}+\beta
\label{equation:ts_gen}$$ for cluster samples in the galaxies are given in Table \[table:coeff\].

Note that three of five studied galaxies (NGC 628, NGC 3184, and NGC 6946) have a regular symmetrical morphology. NGC 5585 has rather the Large Magellanic Cloud type. NGC 3726 has a distorted asymmetric disc. In addition, it is the most distant galaxy of the sample and, therefore, we were unable to identify a sufficient number of close SC-H[ii]{}R pairs with $S<80$ pc in it (Fig. \[figure:age\_sep\]).

The most reliable results are those obtained for NGC 628 and NGC 6946. On the one hand, these galaxies have a symmetrical regular structure, on the other hand, they provide us with a large statistical material for analysis – more than 500 SC-H[ii]{}R pairs.

The graphs in Fig. \[figure:age\_sep\] and the coefficients given in Table \[table:coeff\] show closely resembling slopes for cluster samples in three galaxies (NGC 628, NGC 3184, and NGC 6946) with a regular structure. The 