Validation of an analytical method for the quantification of human fibrinogen in pharmaceutical products by size-exclusion liquid chromatography (SEC-HPLC).

Fibrinogen plays a vital role in normal homeostasis by promoting platelet aggregation, clot formation and fibrinolysis. It is quantified in finished pharmaceutical products using different methods described in pharmacopoeia, but these are inaccurate, difficult to validate and do not allow for identification of aggregates or protein products of the same formulation. The aim of this study was to develop and validate a method for quantification of the content of fibrinogen and other proteins present in pharmaceutical formulations by comparing it with current pharmacopeial methods. Fibrinogen was quantified in two commercial products and compared to a pharmacopeial method using a validated method for size-exclusion high-pressure liquid chromatography (SEC-HPLC). The fibrinogen level was in accordance with both products' specifications. The SEC-HPLC method showed that the percentage of fibrinogen was 94.88 for one product and 50.68 for the other, and detected high molecular weight aggregates in the second product. The SEC-HPLC method that we developed is an improvement to the current pharmacopeial method, because it allows for quantification of fibrinogen and determination of product purity. This is important because greater purity can reduce potential adverse effects of pharmaceutical products in patients.

Sexual Dimorphism in the Regulation of Estrogen, Progesterone, and Androgen Receptors by Sex Steroids in the Rat Airway Smooth Muscle Cells.

The role of sex hormones in lung is known. The three main sex steroid receptors, estrogen, progesterone, and androgen, have not been sufficiently studied in airway smooth muscle cells (ASMC), and the sex hormone regulation on these receptors is unknown. We examined the presence and regulation of sex hormone receptors in female and male rat ASMC by Western blotting and flow cytometry. Gonadectomized rats were treated with 17ß-estradiol, progesterone, 17ß-estradiol + progesterone, or testosterone. ASMC were enzymatically isolated from tracheas and bronchi. The experiments were performed with double staining flow cytometry (anti-α-actin smooth muscle and antibodies to each hormone receptor). ERα, ERß, tPR, and AR were detected in females or males. ERα was upregulated by E2 and T and downregulated by P4 in females; in males, ERα was downregulated by P4, E + P, and T. ERß was downregulated by each treatment in females, and only by E + P and T in males. tPR was downregulated by P4, E + P, and T in females. No hormonal regulation was observed in male receptors. AR was downregulated in males treated with E + P and T. We have shown the occurrence of sex hormone receptors in ASMC and their regulation by the sex hormones in female and male rats.