Identification of cisplatin and transplatin in pure solution of diamminedichloroplatinum (II) with UV-vis spectroscopy

Author(s): Valeria Galemba

Mentor(s): Giordano Paniconi, Chemistry

Abstract

Platinum-based anticancer drugs are widely used in cancer therapy. The five main platinum-based anticancer drugs are cisplatin, carboplatin, oxaliplatin, nedaplatin, and lobaplatin. Cisplatin is applied to treat a variety of types of cancers such as testicular, ovarian, etc. The relationship cisplatin and DNA linkage is well documented, and it is responsible for DNA cross-linking. As a result of DNA cross linkage is inhibition of DNA replication. This study hypothesizes that cisplatin will have a different absorption wavelength than transplatin. To test the hypothesis, UV-vis spectroscopy is used to identify the wavelengths of both isomers of diamminedichloroplatinum(II). This method of identification is low cost and highly effective due to its mechanism; therefore, it is an efficient way to distinguish cisplatin in the pure solution and a mixture with complex biological substances, such as blood and urine. The results of this study suggest that cisplatin is identified in cases of DNA presence by using UV-vis spectroscopy. These results cannot determine if cisplatin can be identified in a pure solution. On this basis, UV-vis spectroscopy can be used to observe changes in the wavelength of cisplatin due to the concentration of DNA. These changes cannot be observed with transplatin due to its inability to inhibit DNA replication.

Video Transcript

Hello, my name is Valeria Galemba and my project is Identification of cisplatin and transplatin in pure solution of diamminedichloroplatinum(II) with UV-vis spectroscopy. I worked with diamminedichloroplatinum because it’s a mixture of cisplatin and transplatin, which are two isomers of this pure solution. Cisplatin is used as an anti-cancer drug and widely available in cancer treatment. The mechanism involves cross linkages with DNA that result in inhibition of DNA replication. Transplatin has different mechanism that is not as efficient as cisplatin but it is more toxic than cisplatin. We used UV-vis spectroscopy because it is an efficient way to identify the chemicals based on their absorbance. When we got the data, we looked for the absorbance and wavelength  of each chemical. Unfortunately, we did not have a chance to work with a pure solution and identify the percentage of each isomer in the diamminedichloroplatinum(II). We looked at articles that involved DNA as cisplatin because we expected to see a change in wavelength and absorption. Absorption is directly affected by the concentration therefore at a higher concentration of the solution or the solvent or the solute the absorption is going to be higher. 

 The first to graph belongs to the authors of the “The interactions of cisplatin and DNA studied by atomic force microscopy” article and in this graph we can see that based on the absorption both of the experiments have a similar pathway and similar wavelengths but in some of the variables are time and absorption. 

So at a smaller absorption aka smaller concentration of the solution the wavelength we will still have the same peaks but it will be at a lower stage. If the absorption is initially higher then cisplatin will increase overtime due to the concentration. We can see that change from b-e. It is increasing the wavelength due to decreased concentration.  The other article we looked at was “The spectrophotometric determination of cisplatin in urine, using o-phenylenediamine as derivatizing agent”. In this study we looked over cisplatin interactions with other drugs and contamination of cisplatin and how it will affect their peaks. In the first case, it was cisplatin with the solvent o-phenylenediamine. We can see these two peaks that are very distinctive and it only shows that it is cisplatin and there is no way that it can be mixed with the other drug unlike the curve b and c. Where we can see that the o-phenylenediamine solution within dimethylformamide forms a singular curve which is similar to urine blank. In conclusion, cisplatin can be detected in a mixture with  a DNA-containing sample by using UV-vis spectroscopy. We saw it by looking at the data and comparing the absorption level with and wavelength which are indirectly proportional to each other. It is still unknown if the percentage of each isomer in a pure solution because we didn’t work with a pure solution of diamminedichloroplatinum. We rather work with a solution with DNA. Further examination is required to distinguish and pinpoint their differences that structurally and functionally mark them. 

And here are all the citations for article and picture. Thank you so much for your time.

3 replies on “Identification of cisplatin and transplatin in pure solution of diamminedichloroplatinum (II) with UV-vis spectroscopy”

Interesting topic, Valeria, well-presented. Why is it important, clinically, or in research, to be able to find Cisplatin instead of Transplatin, in solution?

It is important clinically to identify cisplatin in a mixture because it possesses an effective anti cancer mechanism. Transplatin is less effective and more toxic to the body. Thank you for your question!

Hi Valeria, this is a great presentation! I was wondering that for the absorption/concentration, which would be optimal in terms of the amount of concentration, low or high? Also, what would be the benefits of a lower concentration vs. a higher concentration of Cisplatin?

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