Does Ospen work after the expiry date?

The drug Ospen contains phenoxymethylpenicillin - an antibiotic belonging to natural penicillins, which has a bactericidal effect by inhibiting the synthesis of the bacterial cell wall. In order for the antibiotic to work effectively, it must reach the right concentration in the body, and the limit at what concentration it will kill or inhibit the growth of bacteria, and at what concentration it will not, can be very thin. After the expiration date of the drug, the manufacturer does not guarantee that the product has full therapeutic potency (i.e. retains the indicated dose) and is safe. Of course, the process of decomposition of the antibiotic will take place gradually, so this does not mean that immediately after the expiration date, the drug completely loses its properties, but even small differences in the concentration of the antibiotic given may affect its effectiveness in a given infection, and the use of too low a therapeutic dose generates a risk of developing antibiotic resistance (you can read more about it here: https://www.gdziepolek.pl/blog/antybiotyki-czy-przestana-dzialac). Compounds formed by the decomposition of penicillins may vary m.in depending on the storage conditions of the drug. Available studies indicate the breakdown of penicillins mainly into penicillic acid, which has sensitizing potential. Of course, in order to accurately determine the rate and products of decomposition of the drug Ospen after the expiration date, it would be necessary to perform appropriate studies - without this we can only guess and theorize. In addition, I attach a leaflet of the drug and an article that may be helpful: https://www.gdziepolek.pl/produkty/58158/ospen-1500-tabletki-powlekane/ulotka https://www.gdziepolek.pl/artykuly/fakty-i-mity-o-antybiotykach