The source text says only that phenytoin is among the medicines that can make hormonal contraceptives (HCs) work less well. It gives no link between phenytoin and Mucopolysaccharide Polysulphate + Salicylic Acid, so there is no interaction between these two medicines to describe from this text.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.