Pfizer's patent on sildenafil citrate expired in Brazil in 2010. Alkaline salts, such as sodium bicarbonate, potassium bicarbonate, or potassium citrate, will increase pH. The recommended formulation includes sodium chloride, sodium citrate, potassium chloride, and glucose. Other commercially used salts include tricholine citrate and choline bicarbonate. Common counterions include chloride, bromide, sulfate, phosphate, nitrate, acetate, oxalate, citrate, and tartrate. Some drugs also can increase urine pH, including acetazolamide, potassium citrate, and sodium bicarbonate. Excess ammonium ferric citrate and potassium ferricyanide are then washed away. Both used sodium citrate as an anticoagulant. The process uses two chemicals&colon; ferric ammonium citrate and potassium ferricyanide. Other carboxylate salts form complexes; e.g., citrate and tartrate. The best known is a process using ammonium ferric citrate and potassium ferricyanide. Gallium salts like gallium citrate and gallium nitrate may be used. It is an aqueous alkaline mixture of CuSO and sodium citrate. Disodium citrate and trisodium citrate are also known. This can be avoided by using an alternative anticoagulant like sodium citrate or heparin.