The invention relates to novel tetracyclic pyrroloquinolone derivatives of the formula or : 1wherein all variables are as herein defined, pharmaceutical compositions containing the compounds and their use for the treatment of sexual dysfunction. The green strength shortcomings are to be overcome as quickly as possible to prevent stress cracks by the fact that the hardener added to the polyurethane shortens the working life to 5 to 60 seconds. The multi-bit samples from each channel are re-sampled by a regenerated sample clock to determine the logic values of the signal at precise times.