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Experimental and mathematical studies on the drug release properties of aspirin loaded chitosan nanoparticles.
Shi, Y, Wan, A, Shi, Y, Zhang, Y, Chen, Y
BioMed research international. 2014;:613619
Abstract
The study of drug release dynamic is aiming at understanding the process that drugs release in human body and its dynamic characteristics. It is of great significance since these characteristics are closely related to the dose, dosage form, and effect of the drugs. The Noyes-Whitney function is used to represent how the solid material is dissolved into solution, and it is well used in study of drug dynamic. In this research, aspirin (acetylsalicylic acid (ASA)) has been encapsulated with different grades of chitosan (CS) varying in molecular weight (Mw) for the purpose of controlled release. The encapsulation was accomplished by ionic gelation technology based on assembly of positively charged chitosan and negatively charged sodium tripolyphosphate (TPP). The encapsulation efficiency, loading capacity, and drug release behavior of aspirin loaded chitosan nanoparticles (CS-NPs) were studied. It was found that the concentration of TPP and Aspirin, molecular weights of chitosan have important effect on the drug release patterns from chitosan nanoparticles. The results for simulation studies show that the Noyes-Whitney equation can be successfully used to interpret the drug release characteristics reflected by our experimental data.
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Aspirin for primary prevention of cardiovascular events: meta-analysis of randomized controlled trials and subgroup analysis by sex and diabetes status.
Xie, M, Shan, Z, Zhang, Y, Chen, S, Yang, W, Bao, W, Rong, Y, Yu, X, Hu, FB, Liu, L
PloS one. 2014;(10):e90286
Abstract
OBJECTIVE To evaluate the benefits and harms of aspirin for the primary prevention of CVD and determine whether the effects vary by sex and diabetes status. METHODS We searched Medline, Embase, and Cochrane databases for randomized controlled trials comparing the effects of aspirin with placebo or control in people with no pre-existing CVD. Two investigators independently extracted data and assessed the study quality. Analyses were performed using Stata version 12. RESULTS Fourteen trials (107,686 participants) were eligible. Aspirin was associated with reductions in major cardiovascular events (risk ratio, 0.90; 95% confidence interval, 0.85-0.95), myocardial infarction (0.86; 0.75-0.93), ischemic stroke (0.86; 0.75-0.98) and all-cause mortality (0.94; 0.89-0.99). There were also increases in hemorrhagic stroke (1.34; 1.01-1.79) and major bleeding (1.55; 1.35-1.78) with aspirin. The number needed to treat to prevent 1 major cardiovascular event over a mean follow-up of 6.8 years was 284. By comparison, the numbers needed to harm to cause 1 major bleeding is 299. In subgroup analyses, pooled results demonstrated a reduction in myocardial infarction among men (0.71; 0.59-0.85) and ischemic stroke among women (0.77; 0.63-0.93). Aspirin use was associated with a reduction (0.65; 0.51-0.82) in myocardial infarction among diabetic men. In meta-regression analyses, the results suggested that aspirin therapy might be associated with a decrease in stroke among diabetic women and a decrease in MI among diabetic men and risk reductions achieved with low doses (75 mg/day) were as large as those obtained with higher doses (650 mg/day). CONCLUSIONS The use of low-dose aspirin was beneficial for primary prevention of CVD and the decision regarding an aspirin regimen should be made on an individual patient basis. The effects of aspirin therapy varied by sex and diabetes status. A clear benefit of aspirin in the primary prevention of CVD in people with diabetes needs more trials.
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Effects of Quyu Xiaoban capsules on clinical outcomes and platelet activation and aggregation in patients with unstable angina pectoris.
Liu, YF, Yu, HM, Zhang, C, Yang, RX, Yan, FF, Liu, Y, Zhang, Y, Zhao, YX
Journal of alternative and complementary medicine (New York, N.Y.). 2007;(5):571-6
Abstract
OBJECTIVES To investigate the effects of the Traditional Chinese Medicine (TCM) Quyu Xiaoban capsules (QYXB) on clinical outcomes and platelet activation and aggregation in patients with unstable angina pectoris (UAP) and phlegm and blood stasis syndrome. DESIGN Ninety (90) UAP patients were randomly divided into two groups: the control group received a loading dose of 300 mg aspirin and a maintenance dose of 100 mg of aspirin plus baseline therapy for 4 weeks, and the trial group received the same doses of aspirin and baseline therapy plus QYXB for 4 weeks. The severity of anginal attacks, alterations of TCM symptoms and signs, and electrocardiographic (ECG) changes were observed in all patients before and after treatment. Plasma platelet aggregation (PAG) rate and P-selectin level were measured in all patients at baseline and at the end of the fourth week. RESULTS After treatment for 4 weeks, both group of patients showed improvement in the severity of angina pectoris and TCM symptoms and signs, and there was a significant difference of the total effective rate in clinical improvement between the two groups, whereas no difference of the total effective rate in ECG improvement between the two groups was found. Compared with the baseline level, PAG rate in both groups decreased significantly at the end of the fourth week (63.74 +/- 11.18% versus 55.69 +/- 10.40 % in the control group, and 63.83 +/- 12.70% versus 50.04 +/- 8.91% in the trial group). Similar changes of P-selectin levels were observed in both groups (9.40 +/- 1.25 ng/mL versus 8.90 +/- 1.34 ng/mL in the control group and 9.56 +/- 1.16 ng/mL versus 7.80 +/- 0.98 ng/mL in the trial group). However, both PAG rate and P-selectin level decreased to a greater extent in the trial group than in the control group after treatment, and the difference between treatment was significant (both p<0.05). Nevertheless, these biochemical changes were too small to explain fully the beneficial clinical outcomes achieved by QYXB capsules. CONCLUSIONS On the background of baseline and aspirin therapy, QYXB capsules significantly attenuated anginal attacks and improved TCM symptoms and signs in patients with UAP, and the exact mechanisms underlying these therapeutic effects remain to be explored.
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Effects of Quyu xiaoban capsules on clinical outcomes and platelet activation and aggregation in patients with unstable angina pectoris.
Liu, YF, Yu, HM, Zhang, C, Yang, RX, Yan, FF, Liu, Y, Zhang, Y, Zhao, YX
Journal of alternative and complementary medicine (New York, N.Y.). 2007;(3):369-74
Abstract
OBJECTIVES To investigate the effects of the Traditional Chinese Medicine (TCM) Quyu Xiaoban capsules (QYXB) on clinical outcomes and platelet activation and aggregation in patients with unstable angina pectoris (UAP) and phlegm and blood stasis syndrome. DESIGN Ninety patients with UAP were randomly divided into two groups: a control group that received a loading dose of 300 mg aspirin and a maintenance dose of 100 mg of aspirin plus baseline therapy for 4 weeks, and a trial group that received the same doses of aspirin and baseline therapy plus QYXB for 4 weeks. The severity of anginal attacks, alterations of TCM symptoms and signs, and electrocardiographic (ECG) changes were assessed in all patients before and after treatment. The plasma platelet aggregation (PAG) rate and P-selectin level were measured in all patients at baseline and at the end of the fourth week of treatment. RESULTS After treatment for 4 weeks, both group of patients showed improvement in the severity of angina pectoris and TCM symptoms and signs, but there was a significant difference in the two groups' rates of clinical improvement, whereas the rate of ECG improvement of the two groups showed no difference. As compared with the baseline value, the PAG rate in both groups decreased significantly at the end of the fourth week (63.74 +/- 11.18% vs. 55.69 +/- 10.40% in the control group, and 63.83 +/- 12.70% vs. 50.04 +/- 8.91% in the trial group). Similar changes in P-selectin levels were observed in the two groups (9.40 +/- 1.25 ng/mL vs. 8.90 +/- 1.34 ng/mL in the control group, and 9.56 +/- 1.16 ng/mL vs. 7.80 +/- 0.98 ng/mL in the trial group). However, both the PAG rate and P-selectin level decreased to a greater extent in the trial group than in the control group after treatment, and the difference between the two groups was significant (both p < 0.05). Nevertheless, these biochemical changes were too small to fully explain the beneficial clinical outcomes achieved with QYXB capsules. CONCLUSIONS In comparison with both the respective baseline values and with aspirin therapy, QYXB capsules significantly attenuated anginal attacks and improved TCM symptoms and signs in patients with UAP. The exact mechanisms underlying these therapeutic effects remain to be explored.