Valganciclovir

A novel liquid chromatography with quadrupole time-of-flight-tandem mass spectroscopy method for ultra-trace level identification and quantification of the genotoxic impurity 2,6-diamino-5-nitropyrimidin-4(3H)-one in valganciclovir hydrochloride

In the present study, the main objective is to develop an analytical method for ultra-trace level measurement of 2,6-diamino-5-nitropyrimidin-4(3H)-one (DMNP) in valganciclovir hydrochloride (VAL) using liquid chromatography-quadrupole time-of-flight-tandem mass spectroscopy (LC-QTOF-MS/MS). In the early stages of guanine synthesis, DMNP is formed, and guanine is known to be the key starting material for the synthesis of VAL. Taking into consideration DMNP potential genotoxicity, this analytical method has been developed. This method is time saving and suitable for confirming the masses of parent and fragment ions by MS and MS/MS further fragmentation. An isocratic program and Acquity UPLC HSS cyano column (100 × 2.1 mm × 1.8 μm) were used to achieve optimal separation between VAL and the DMNP impurity. A 0.1% ammonia solution in Milli-Q water was used as mobile phase A, and methanol was used as mobile phase B in the ratio 90:10 v/v in isocratic mode. In accordance with the International Conference on Harmonization's requirements, the developed method was validated. The detection and quantification levels were found to be 0.028 and 0.083 ppm respectively. The DMNP impurity is linear from 0.083 to 1.245 ppm levels with correlation coefficient (R2 ) of 0.9960. The recoveries were found to be 97.0-107.9%.

Valganciclovir: recent progress

In 2001 valganciclovir was approved by the FDA for treatment of HIV associated retinitis and in 2003 for prevention of post transplant CMV. This review provides an update on the status of its use and areas of controversy: How long should prophylaxis be given?; What is the appropriate dose for prophylaxis?; Can it be used in children, and at what dose?; Can it be used to treat CMV disease? The question of optimal dosing will probably not be settled as the sample size for controlled trials would be prohibitive. Other trials clearly show that extended therapy provides added benefit, the drug is safe and an appropriate dose has been identified in children and oral therapy of CMV disease is effective.

A cost too high to bear? Prophylaxis versus preemptive therapy to prevent post-transplantation cytomegalovirus

Both prophylaxis and preemptive therapy are used to prevent the development of cytomegalovirus (CMV) disease after transplantation. Preemptive therapy exposes the least number of patients to costly and potentially toxic drugs. Prophylaxis is less labor intensive and requires less expensive monitoring. While the overall cost of the two modalities is similar, current literature suggests that prophylaxis has an advantage in avoiding secondary effects of CMV. Randomized comparative trials are imperative.