We studied the mid-IR emission in a sample of 149 local active galactic nuclei (AGN) with Spitzer/IRS observations. We measured the flux for the 11.3microns PAH feature to study the star formation (SFR) and explore if this molecule can be used as an SFR tracer. This study systematically investigates the potential correlations between AGN activity and the PAH 11.3microns signature. We detected the 11.3microns PAH feature in the spectra of 73% of our sample and calculated the SFR. The derived SFR exhibited a positive correlation with X-ray luminosity, indicating a link between the gas in kiloparsec and parsec regions. We studied the connection between the SFR and AGN parameters, and found that, to employ this molecule as an SFR indicator in AGN, specific corrections are necessary.