The naproxen-PEG esteri cation reaction was performed using 1g of (S)-(+)-naproxen (4.84 mmol). This was dissolved in 8mL of dimethyl formamide. This was mixed with an equal amount of polyethylene glycol (4.84 mmol). This solution was then treated with N,N'-Dicyclohexylcarbodiimide (9.68 mmol) and 4-Dimethylaminopyridine (2 mmol). Yield: 64.75%. For further extraction the mixture was dried over anhydrous magnesium sulfate and concentrated with a rotary evaporator.