It depends on their hydrophobicity degree (in addition to other parameters such as molecular weight, charges, 3D conformatiom..). It can be estimated by determining the partition coefficient (log P).
Indeed, highly hydrophobic drugs are deeply burried within the phospholipid chains so they cannot cross the plasma membrane. In the other hand, hydrophobic compounds that have moderate and low degree of lipophilicity diffuse more or less easily the phospholipid bilayers.