Comparison of Italic cytoxicity of generic paclitaxel and irinotecan formulations with their reference formulations on seven human intrahepatic cholangiocarcinoma cell lines

Background: Several chemotherapies have now been introduced for the treatment of cholangiocarcinoma (CCA).  Although it has previously been reported that two new chemotherapeutic agents, paclitaxel and irinotecan, showed strong cytotoxic effect to human CCA cell lines the treatment cost currently using reference formulations of these two drugs are very expensive.  To date, the generic drugs for both paclitaxel and irinotecan are now commercially available in Thailand with relatively low price compared to reference formulations.  However, the study demonstrating the efficacy of the innovator and generic formulation of these two agents has never been reported.Objective: To determine and compare the cytotoxic activity of generic paclitaxel and irinotecan formulations with the reference formulations on seven human intrahepatic CCA cell lines.Design: In vitro studySetting: Faculty of Medicine, Khon Kaen UniversityMaterial and Method: Cytotoxic activitiy of chemotherapeutic agent on CCA cellines was determined by sulforhodamine B (SRB) assay.  The IC50 value expressed as the concentration of drug that caused a 50% growth inhibition comparing with no drug treated control.  The cytotoxic activity of the generic formulation was compared to the reference formulation using Student’s unpaired t-test.Results: Paclitaxel exhibited strong potency towards most CCA cell lines with IC50 values ranging from 0.001-1.40 mM whereas irinotecan showed IC50 values ranging varied from 0.02 to 69 mM. KKU-M055 was the most sensitive cell line to paclitaxel and KKU-OCA17 showed the highest sensitivity to irinotecan whereas KKU-M156 was the least sensitive cell line to both drugs. IC50 values of the generic product (IntaxelÒ, Dabur, India) and reference product (TaxolÒ, Bristol-Myers Squibb, USA) formulations were not significantly different (P \> 0.05).  Similary, the cytotoxicity of the generic formulation of irinotecan (IrinotelÒ, Dabur, India) was not statistically significant different from the reference formulation (CamptoÒ, Aventis Pharma, UK).Conclusion: The cytotoxic activity of paclitaxel towards six CCA cell lines was more potent than irinotecan except for KKU-OCA17.  No different in the IC50 values of the generic and reference formulations of paclitaxel and irinotecan against seven CCA lines suggest that the in vitro efficacy of generic and reference formulations of these two drugs are very similar.  

Determination of Growth Inhibitory Effect of Gemcitabine on Human Intrahepatic Cholangiocarcinoma Cell lines and Comparison of its Inhibition Between the Generic and Reference Formulation

Background and Objective: Gemcitabine is one of the most popular drug-of-choices that is currently used for the treatment of cholangiocarcinoma (CCA).\  However, the study revealing the inhibitory effect of this agent in the series of CCA cell lines established from Thai patients has not been reported. We aim to determine and compare the growth inhibitory effect of generic gemcitabine formulation with the reference formulation on CCA cell lines.Methods: Seven CCA cell lines established in Srinagarind Hospital, Khon Kaen University were used. A cell growth inhibition by gemcitabine was determined by sulforhodamine B.\  The IC50 value was expressed as the concentration of drug that caused a 50% growth inhibition comparing with untreated control.\  The IC50 values of those two formulations were compared using independent t-test.Results: Growths of KKU-M055, KKU-OCA17 and KKU-M139 CCA cell lines were highly inhibited by gemcitabine (IC50 = 13.35-16.0 M) whereas KKU-M214 was moderately inhibited by this drug (IC50 = 36.7 M). These least inhibited growths were found on KKU-100, KKU-M156 and KKU-M213 (IC50 = 406-4629 M).\  The generic (Gramagen) and the reference product (Gemza) formulations were not significantly different in their inhibitory effects on the all seven CCA cell lines.\ Conclusions: Although the inhibitory effect of gemcitabine was varied towards seven CCA cell lines, there was no difference in the IC50 values of the generic and reference formulations. Our findings indicate that the in vitro efficacy of these two formulations is similar.\ Keywords: growth inhibitory effect, gemcitabine, cholangiocarcinoma, generic formulation

Comparison of Antigen Retrieval Techniques in Immunohistochemistry

Objective: The study aimed to find the best antigen retrieval buffer and heat source for the immunohistochemical staining of various kinds of antibodies in our laboratory.Materials and methods: We designed the method to evaluate the efficacy of three different retrieval solutions including 10mM Tris-HCl + 1mM EDTA, pH 9, 0.05%citraconic anhydride solution pH 7.4 and 10 mM citrate buffer pH 6, and 3 heat source pretreatment methods (Microwave, pressure cooker and water bath treatment)to retrieve twenty-one immunoreactivity in formalin-fixed, paraffin-embedded sections.Results: We found that, modified retrieval solution, 10mM Tris-HCl + 1mM EDTA buffer, pH 9 is the most efficient for a large variety of antibodies and not depending on heat sources. On the other hand, 0.05% citraconic anhydride solution and 10mM citrate buffer are moderate and poor retrieval solutions, respectively. Moreover, these two solutions are heat source-dependent.Conclusion: These results demonstrate that 10mM Tris-HCl + 1mM EDTA, pH 9 and heat-pretreatment is useful for the immunohistochemistry of many antigens in aldehyde-fixed, paraffin-embedded tissues. Keywords: antigen retrieval, immunohistochemistry, citraconic anhydride, formaldehyde