An exemplary embodiment of this invention relates to a method of inspection of a filled hard capsule sealed with a solvent sealing agent, including a process for determining the quality of the seal. The process may include: supplying a filled hard capsule sealed with a solvent sealing agent; supplying a microwave resonator wherein a measuring field having a resonance curve is generated; directing the capsule through the measuring field; measuring characteristics related to the modification of the resonance curve produced by the presence of the capsule in the measuring field, in comparison with a reference resonance curve corresponding to an empty state of the resonator; and using the measured characteristics to determine a value associated with the quality of the seal. Other exemplary embodiments of this invention relates to a method for sorting capsules on the basis of the result of the inspection method and to an associated equipment able to carry out such methods.