an improved process for preparing an aromatic polyanhydride is disclosed . the aromatic polyanhydride is prepared by reacting an aromatic dicarboxylic acid with an anhydride to form an anhydride prepolymer , isolating and purifying the prepolymer , and subjecting the prepolymer to melt polycondensation conditions . the improvement specifically relates to the purification of the acid so it is essentially free of impurities before it is reacted with the anhydride . the polymers prepared from the improved process have higher molecular weights than the molecular weights achieved from the prior art processes , and exhibit outstanding thermal stability and mechanical properties . this combination of properties allows the aromatic polyanhydrides to be melt processed to prepare numerous devices . in addition , these aromatic polyanhydrides are bioabsorbable , and this attribute in combination with its ability for melt processing makes the polyanhydrides particularly well - suited for the preparation of implantable surgical devices such as wound closure devices which are designed to absorb in the body when exposed to moist bodily tissue .