The role of the renin-angiotensin system (RAS) in the development of various malignancies has recently been extensively examined and, since it has been shown to significantly influence many aspect of cancer initiation and progression, the idea of RAS-targeted anticancer therapy has arisen. This article reviews the mechanisms underlying RAS-induced physiological and pathological responses related to cancer biology, including tumor growth, cell proliferation, apoptosis, angiogenesis, inflammation, and protein degradation, emphasizing the associated cellular transduction schemes activated by main RAS effectors. Also the dual nature of RAS-dependent effects, resulting from its complex physiology has been commented. Finally, based on the available data from clinical trials and experimental studies, the possibilities of the introduction of RAS-modulating drugs into standard clinical practice in oncology have been discussed with the focus on both, positive and negative effects associated with the administration of various classes of pharmaceuticals to cancer patients.

Context: The compatibility studies of moexipril hydrochloride (MOXL), imidapril hydrochloride (IMD), enalapril maleate, (ENA) and lisinopril (LIS) in solid state with magnesium stearate and glyceryl behenate were performed. Objective: The aim of this study was to detect any possible drug–excipient interactions in order to optimize technological process conditions by the selection of the most adequate lubricant. Materials and methods: Reversed-phase high-performance liquid chromatography was employed for studying drug–excipient binary mixtures in 1:1 ratio and pure drugs under forced ageing test conditions: temperature 318K (45°C) and relative humidity range of 50.9%–75.4%. The method had been revalidated prior to use. The degradation rate constants for the binary mixtures and pure substances were calculated. Results: The experimental results evidenced that moexipril and enalapril degradation accorded with autocatalytic-second-order kinetics, imidapril degradation followed first-order reaction mechanism, and LIS followed reversible first-order reaction mechanism. A degradation pathway for each substance was proposed to account for the observed decomposition products. It was determined that moexipril stability decreased threefold in the presence of magnesium stearate indicating an incompatibility − (4.15 ± 0.12) 10⁻³ compared to (1.43 ± 0.32) 10⁻⁶ for moexipril in pure. No interaction between magnesium stearate and the remaining studied compounds was observed. The stability studies of MOXL–glyceryl behenate binary mixture revealed no interaction. Conclusion: Magnesium stearate and increased relative humidity induce MOXL instability, while glyceryl behenate is an optimal lubricant, and therefore, it is recommended for moexipril-containing solid formulations. However, for the formulations containing moexipril and magnesium stearate, it is suggested to minimize the humidity level during storage.

High global expenditure on out-of-label-date drugs, along with safety concerns associated with the accumulation of degradation impurities, justify the need for stability profiling. In this article, a comprehensive study on the solid-state stability of ramipril (RAM) was performed via isothermal methods under stress conditions. A validated stability-indicating HPLC protocol was used. The effects of various factors on the rate of RAM degradation were investigated, including: temperature, relative air humidity (RH), excipients (talc, starch, methylcellulose and hydroxypropyl methylcellulose), mode of tablet storage, and immediate packaging. The degradation impurities were also identified by HPLC–MS. It was found that RAM was unstable, and temperature accelerated its degradation. RAM was also vulnerable to RH changes, suggesting that it must be protected from moisture. The reaction followed first-order kinetics. The studied excipients stabilized RAM as a pure substance. The tableting process deteriorated its stability, explaining the need for appropriate immediate packaging. RAM in the form of tablets must be stored in blisters, and it cannot be crushed into two halves. The degradation impurities were ramiprilat and the diketopiperazine derivative.