A method for over-molding a tubular filter element 16, at least at one end 16b thereof, with a thermoplastic end cap 12. The over-molding method can be used to manufacture easily and cost-effectively a filter cartridge, of good durability, from an unprecedented range of polymeric materials and components. The thermoplastic over-molding method does not require pre-lamination of said end 16b, and can be performed at temperatures and pressures that do not result in undesirable morphological changes in the tubular filtration medium. Exemplary filter cartridges made through the over-molding method comprise a tubular filtration medium interposed between thermoplastic end caps, the thermoplastic material of the end caps infiltrating the tubular filtration medium, thereby creating mechanical interlock zones at the ends thereof.