Manufacturing Process
285 ml of acetic acid was added to a 1000 ml Erlenmeyer flask containing Teflon-coated magnetic stirring bar. Stirring the acetic acid, slowly 15 ml of concentrated sulfuric acid was added; weighing out 15.0 g of hematoporphyrin hydrochloride (preferably obtained from Roussel Corporation, Paris, France); adding to the acid solution; the reaction acetic mixture was stirred for 1 h. To the reaction acetic mixture 3 L of 5% sodium acetate was added.
The 5% sodium acetate solution now contains a dark red precipitate which is preferably allowed to stand for 1 h with occasional stirring; the dark red precipitate is then again filtered, preferably using the above-identified filter mechanism; the filter cake from the filtering process is then washed with glass-distilled water until the filtrate is at pH of 5.5-6.0 (1500-2500 ml of wash water may be required); and the filter cake is then preferably allowed to dry in air at room temperature. The air-dried precipitate is ground, using for instance, a mortar and pestle until a fine powder is obtained. The powder may then be transferred to a 250 ml round bottom flask. The flask is then attached to a rotating evaporator and rotation under vacuum is maintained at room temperature for preferably 24 h and hemoporphyrin acetate was obtained.
Acetylated hematoporphyrin (1 part by weight) is dissolved in 0.1 N sodium hydroxide (50 parts by volume) and stirred for 1 h at room temperature. After the stir period the solution is adjusted to pH 9.4 to 9.6 with 1 N hydrochloric acid. It is filtered through a 5 μm filter and then concentrated to (12.5 parts) of its original volume in an ultrafilter with 10,000 molecular weight cut off membranes. The solution is then purified via diafiltration maintaining constant volume with 120 volumes of water and keeping the pH at 9.4 to 9.6 with 0.1 N sodium hydroxide. This is also done at room temperature. After the purification, the solution is removed from the ultrafilter, diluted to 3/8 (18.8 parts) of its original volume and pH adjusted to 7.5 to 7.7 with 1 N hydrochloric acid. The solution is then stored at 4°C for 14 to 21 days. Afterstorage, the solution is pH adjusted to 9.4 to 9.6 with 0.1 N sodium hydroxide and concentrated to 1/4 (12.5 parts) of its original volume. The solution is then repurified as above. The solution is diluted to 3/8 (18.8 parts) of its original volume and pH adjusted to 7.5 to 7.7 with 1 N hydrochloric acid. The solution is then analyzed and, if necessary, it is adjusted to between 13 to 18 mg/ml by the addition of water. The solution is then filtered through a 0.22 μm filter into bottles for storage at 1°C to 4°C to await further processing.
