Determination of buprenorphine in raw material and pharmaceutical products using ion-pair formation

A simple and sensitive extractive spectrophotometric method has been described for the determination of buprenorphine either in raw material or in pharmaceutical formulations. The developed method is based on the formation of a colored ion-pair complex (1 : 1 drug/dye) of buprenorphine and bromocresol green (BCG) in buffer pH 3 and extracting in chloroform. The extracted complex shows absorbance maxima at 415 nm. Beer's law is obeyed in the concentration range of 1.32-100.81 μg mL−1 . The proposed method has been applied successfully for the determination of drug in commercial sublingual tablets and injectable dosage form. No significant interference was observed from the excipients commonly used as pharmaceutical aids with the assay procedure

Effects of angiotensin II on expression of α3, αv and 3 integrin proteins in B16-F10 melanoma cells

Introduction: Several reports indicated the role of angiotensin II antagonists in suppression of different tumvors. Some of the recent studies point to the increasing effect of angiotensin II on expression of important factors regarding to the tumor growth. Also the role of integrins in growth and metastasis of tumoral cells is very important but the role of angiotensin II in the expression of integrins is not clear yet. Materials and Methods: Melanoma tumors were induced in C57 mice using S.C. injections of B16-F10 cells. Losartan was I.P. injected to C57 mice. Also B16-F10 cells were cultured and incubated with angiotensin II with or without losartan for two hours and the expression of α3, αv and 3 integrins were studied using western blotting.Results: Our results indicate the suppressing role of losartan on tumor growth (day17, P=0.013; day18: P=0.0015). In addition angiotensin II increased significantly the expression of studied integrins in B16-F10 cultured cells (integrin αV: P=0.049; Integrin α3: P= 0.016; integrin β3: P= 0.037), and losartan completely abolished this effect. Conclusion: The role of angiotensin II in tumor growth may be because of reasons including its role in elevating the expression levels of α3, αv and 3 integrins. In animal model of melanoma, losartan suppressed the tumor growth through AT1 receptors inhibition. The present study indicates the importance of the drugs such as losartan besides the standard therapeutic approach for tumor