A 26-week repeated-dose toxicity study of allisartan isoproxil in Sprague-Dawley rats

Alleviation of renal injury in rabbits by allisartan

The objective of this study was to determine the relationship between renal injury and inflammatory response induced by high-fat diet in rabbits and the interventional effect of allisartan. Fifteen 6-week-old healthy male rabbits were randomly divided into three groups: normal control (NC) group, high-lipid diet (HLD) group, high-lipid diet and allisartan (HLD+ALST) group. After allisartan treatment for 12 weeks, changes in total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), serum creatinine (Scr) and blood urea nitrogen (BUN) were measured enzymatically in the three groups. The left side of the kidney tissue was kept for paraffin section, and HE staining, periodic acid-Schiff (PAS) staining and Masson staining were used to observe the renal pathologic changes. TC, TG, LDL-C, Scr and BUN levels were all higher and HDL-C levels were lower in the HLD group compared with the NC group. Compared with the HLD group, Scr and BUN levels were significantly decreased in the HLD+ALST group. The results of HE staining showed that allisartan improved the changes of renal tissue morphology in rabbits on high-fat diet, reduced glomerular mesangial cell proliferation and improved glomerulosclerosis; PAS staining showed that glomerular glycogen deposition was reduced and glomerular red staining was significantly lighter; Masson staining showed that renal tubular blue-stained collagen fibers were reduced. In conclusion, hyperlipidemia can lead to aberrant expression of multiple cellular proteins and kidney tissue morphological damage in rabbits. On the other hand, allisartan attenuated renal injury and the mechanism may be related to the downregulation of the inflammatory response.

Alleviation of renal injury in rabbits by allisartan

The objective of this study was to determine the relationship between renal injury and inflammatory response induced by high-fat diet in rabbits and the interventional effect of allisartan. Fifteen 6-week-old healthy male rabbits were randomly divided into three groups: normal control (NC) group, high-lipid diet (HLD) group, high-lipid diet and allisartan (HLD+ALST) group. After allisartan treatment for 12 weeks, changes in total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), serum creatinine (Scr) and blood urea nitrogen (BUN) were measured enzymatically in the three groups. The left side of the kidney tissue was kept for paraffin section, and HE staining, periodic acid-Schiff (PAS) staining and Masson staining were used to observe the renal pathologic changes. TC, TG, LDL-C, Scr and BUN levels were all higher and HDL-C levels were lower in the HLD group compared with the NC group. Compared with the HLD group, Scr and BUN levels were significantly decreased in the HLD+ALST group. The results of HE staining showed that allisartan improved the changes of renal tissue morphology in rabbits on high-fat diet, reduced glomerular mesangial cell proliferation and improved glomerulosclerosis; PAS staining showed that glomerular glycogen deposition was reduced and glomerular red staining was significantly lighter; Masson staining showed that renal tubular blue-stained collagen fibers were reduced. In conclusion, hyperlipidemia can lead to aberrant expression of multiple cellular proteins and kidney tissue morphological damage in rabbits. On the other hand, allisartan attenuated renal injury and the mechanism may be related to the downregulation of the inflammatory response.

Effect of allisartan on blood pressure and left ventricular hypertrophy through Kv1.5 channels in hypertensive rats

BACKGROUND

The objective of the present work was to study the anti-hypertensive effect of allisartan on blood pressure (BP) and in facilitating left ventricular remodeling through voltage-gated potassium channels (Kv) 1.5 channels.

METHODS

A total of 30 SD rats were randomly divided into sham operation group, hypertension control group, and allisartan treatment group. Hypertension was induced by renal artery stenosis. The animals of treatment group were administered with allisartan once a day at a dose of 30 mg/kg body weight through an oral gavage for 4 weeks. The heart function of animals post 4 weeks of treatment was evaluated by echocardiography, and the degree of ventricular hypertrophy and cardiomyocyte hypertrophy were evaluated by histomorphology. The expression of Kv1.5 is detected by real-time quantitative polymerase chain reaction while Western blotting was used to detect the protein expression.

RESULTS

Four weeks after renal artery stenosis, a significant difference was observed in the whole heart ratio, left heart ratio, and cardiomyocyte area between allisartan treatment group and the hypertension control group (P< .01). A significant decrease in BP of allisartan treatment group compared to hypertension control group (P< .01) was observed. The expression of Kv1.5 mRNA was increased significantly (P< .01) in allisartan treatment group compared to hypertension control group. Western blot analysis also confirmed the increased expression of Kv1.5 channel.

CONCLUSION

The results showed that allisartan lowers BP and improves left ventricular remodeling through increased expression of Kv1.5 mRNA.

Pharmacokinetics and Safety of a Single Dose and Multiple Doses of Allisartan Isoproxil, an Angiotensin II Receptor Blocker, in Healthy Chinese People

Allisartan isoproxil (AI) is a blocker of the angiotensin II type 1 receptor. We evaluated the safety and pharmacokinetics of single- and multiple-dose AI in healthy Chinese individuals. Participants were assigned to receive AI or placebo. Plasma concentration of EXP3174 (carboxylic acid derivative) was measured using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were determined by noncompartmental methods. Twelve subjects were enrolled, and the ratio of men to women was 5:1. Main pharmacokinetic parameters of EXP3174 after single and multiple doses of AI were a mean maximum concentration in plasma (C_max ) of 2242 ± 1037 ng/mL and median time to reach C_max (T_max ) of 3.5 hours (2.5-8 hours). The median T_max, at steady state was 4.0 hours (1.5-8 hours). The mean C_max at steady state (C_{max, SS} ) was 2047 ± 1050 ng/mL. In terms of EXP3174, there was no significant difference in the C_{max, SS} , area under the curve from time zero to 24 hours of quantifiable concentration at steady state (AUC_{0-24 SS} ), and AUC_0-72 after multiple doses of AI. Serious adverse events did not occur. These data suggest that AI is safe and well tolerated in healthy Chinese individuals at a single dose of 480 or 480 mg once daily for 7 days.

Allisartan isoproxil reduces mortality of stroke-prone rats and protects against cerebrovascular, cardiac, and aortic damage

Stroke is a common cause of death and disability. Allisartan isoproxil (ALL) is a new angiotensin II receptor blocker and a new antihypertensive drug discovered and developed in China. In the present study we investigated the therapeutic effects of ALL in stroke-prone renovascular hypertensive rats (RHR-SP) and the underlying mechanisms. The model rats were generated via two-kidney two-clip (2K2C) surgery, which led to 100% of hypertension, 100% of cerebrovascular damage as well as 100% of mortality 1 year after the surgery. Administration of ALL (30 mg · kg-1 · d-1 in diet, for 55 weeks) significantly decreased stroke-related death and prolonged lifespan in RHR-SP, but the survival ALL-treated RHR-SP remained of hypertension and cardiovascular hypertrophy compared with sham-operated normal controls. In addition to cardiac, and aortic protection, ALL treatment for 10 or 12 weeks significantly reduced cerebrovascular damage incidence and scoring, along with a steady reduction of blood pressure (BP) in RHR-SP. Meanwhile, it significantly decreased serum aldosterone and malondialdehyde levels and cerebral NAD(P)H oxidase expressions in RHR-SP. We conducted 24 h continuous BP recording in conscious freely moving RHR-SP, and found that a single intragastric administration of ALL produced a long hypotensive effect lasting for at least 12 h on systolic BP. Taken together, our results in RHR-SP demonstrate that ALL can be used for stroke prevention via BP reduction and organ protection, with the molecular mechanisms related to inhibition of angiotensin-aldosterone system and oxidative stress. This study also provides a valuable scoring for evaluation of cerebrovascular damage and drug efficacy.

Spray-dried nanocrystals for a highly hydrophobic drug: Increased drug loading, enhanced redispersity, and improved oral bioavailability

For a highly hydrophobic and drug, it is difficult to formulate and solidify its nanocrystals with high drug loading and good redispersity. In this study, Allisartan Isoproxil was used as a model drug, and SDS was tested in combination with sugar alcohols to improve the drug loading and redispersity for its spray-dried nanocrystals, simultaneously. These spray-dried nanocrystals had high drug loading of 61.7% and good redispersity, which was mainly attributed to the addition of SDS. In addition, the nanocrystals were characterized by scanning electron microscopy, differential scanning calorimetry, X-ray power diffraction analysis, Fourier transform infrared spectroscopy and Raman spectroscopy. The results showed that Allisartan Isoproxil was unchanged in chemical structure, but was partially amorphous. Regarding the in vitro dissolution, the optimism formulation shown an increased dissolution compared with the bulk drug and aggregated nanocrystals. Importantly, the optimum formulation increased the oral bioavailability of crude ALS-3 for 4.73 times. In conclusion, we developed a method to solidify aqueous nanocrystals with increased drug loading, good redispersity and improved bioavailability for high hydrophobic drugs.