The hydrophilic gel with 2% erythromycin according to the TMF always gives us clubbers. Is there no other method to prepare this gel?

The reason is apparently at the quality Klucel (HPC) but you get a better result if you use the small mixer "Aerolatte". Under turning the mixer, sprinkle the hydroxypropylcellulose in the antiseptic solution in which erythromycin is dissolved. You will have quite a few bubbles but cover the gel and keep that 1 night in the fridge. For small quantities, Aerolatte is a handy one. One finds this in many things of kitchen supplies.