Introduction: Human Serum Albumin (HSA) is a major component of plasma proteins, responsible in various physiological functions and plays an important role in stabilizing the osmotic pressure in the system. Albumin is a water-soluble polypeptide with a molecular mass of about 68,000daltons. Biochemical studies have been performed to verify conformationals modifications influenced by pH of the solution after freeze-dried, it was discovered that proteins could be precipitated by varying the pH. The HSA lyophilized kit is produced using the 20% HAS (Grifols) as row material, which contains polymer residues and aluminum beyond the albumin, these components can make possible to activate the coagulation factor. Technetium-99m labeled human serum albumin (99mTc-HSA) has been use in nuclear medicine for almost 30years, for cardiac function tests or evaluates the gastrointestinal protein loss. It is use as an agent to determinate alterations in the lymphatic circulation, diagnostic of primary and secondary lymph edema.

Objective: The aim of this study is to evaluate the influence of pH in the stability of the freeze-dried human serum albumin (HAS), due the acquisition of different manufactures of row material, studying and verifying an insolvable aggregate formed after dissolution in difference pH.

Material: The production is carried in SuperModulyo or IMA (Edwards), lyophilizators under vacuum and low temperature. Each lyophilized vial contains: 10.0 mg of HAS and 0.04 mg SnCl2.H2O at pH equal of row material 20% HAS; pH = 7.0. Before Millipore 0.22μm filtration, the final solution must be centrifuged at 1,000rpm/5minutes for disaggregation of polymers or other components. The pre-treated solution is fractionated (1mL in each vial) followed lyophilization. The freeze-dried HAS been submitted to quality control: dissolution, pH; radiochemical purity, sterility and stability.

Results:The dissolution test was studied at pH 5.0 up to 7.0. The quality control was carried out in three consecutive batches. The radiochemical quality control was evaluated in TLC-SG (Al) chromatography system in 85% methanol, during 4 hours and the stability up to 6 months.

Conclusion: This study was part of the continuous improvement in routine production. The differences mass and pH of row material sometimes affect the end product, making difficult its dissolution and stability. The pH and the centrifugation step before lyopillization make it possible to continue the routine production after the re-validation process. The quality control tests were according the pharmacopeia values. All the analyzed batches, showed an acceptable pH value (pH 7.0) and a radiochemical purity >95%. The shelf life of the lyophilized kit was more than 6 months when it is stored under 2 - 8ºC.