en مقاله کامل Full Length/Original Article A sensitive high performance liquid chromathography (HPLC) analytical procedure was developed for the quantitive determination of trimethoprim (TM* and sulphamethoxazole (SM) in commercial dosage forms. C18 analytical column (stainless steel, 25 cm * 4.6 mm i.d.) was packed with 5-*m particles of the reversed phase material and used for assays. Mobile phase containing 0.025 M sodium phosphate as aqueous phase and acetonitrile with 0.4% triethylamine as organic phase. The drugs were quantified at flow-rate of 1.2 ml/min, with ultraviolet detection at 260 nm. The minimum detectable quantities in assays were 100 ng/ml for SM and 75 ng/ml for TM. The method is well suited to routine application and adequate sensitivity with precision. Trimethoprim, Sulphamethoxazole, Co-trimoxazole, HPLC 75 78 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-393&slc_lang=en&sid=1 Abbas Rezaee عباس رضایی rezaee@netl1cs.modares.ac.ir Yes Qorban Behzadian Nejad قربان بهزادیان نژاد No Abbas Kebriaeezadeh عباس کبریایی زاده No