Response surface methodology (RSM) was used to optimize the formulation of a nanoemulsion for central delivery following parenteral administration. A mixture of medium-chain triglyceride (MCT) and safflower seed oil (SSO) was determined as a sole phase from the emulsification properties. Similarly, a natural surfactant (lecithin) and non-ionic surfactant (Tween 80) (ratio 1:2) were used in the formulation. A central composite design (CCD) with three-factor at five-levels was used to optimize the processing method of high energy ultrasonicator. Effects of pre-sonication ultrasonic intensity (A), sonication time (B), and temperature (C) were studied on the preparation of nanoemulsion loaded with valproic acid. Influence of the aforementioned specifically the effects of the ultrasonic processing parameters on droplet size and polydispersity index were investigated. From the analysis, it was found that the interaction between ultrasonic intensity and sonication time was the most influential factor on the droplet size of nanoemulsion formulated. Ultrasonic intensity (A) significantly affects the polydispersity index value. With this optimization method, a favorable droplet size of a nanoemulsion with reasonable polydispersity index was able to be formulated within a short sonication time. A valproic acid loaded nanoemulsion can be obtained with 60% power intensity for 15 min at 60 °C. Droplet size of 43.21±0.11 nm with polydispersity index of 0.211 were produced. The drug content was then increased to 1.5%. Stability study of nanoemulsion containing 1.5% of valproic acid had a good stability as there are no significant changes in physicochemical aspects such as droplet size and polydispersity index. With the characteristisation study of pH, viscosity, transmission electron microscope (TEM) and stability assessment study the formulated nanoemulsion has the potential to penetrate blood-brain barrier in the treatment of epilepsy.
Response surface methodology (RSM) was utilized to investigate the influence of the main emulsion composition; mixture of palm and medium-chain triglyceride (MCT) oil (6%–12% w/w), lecithin (1%–3% w/w), and Cremophor EL (0.5%–1.5% w/w) as well as the preparation method; addition rate (2–20 mL/min), on the physicochemical properties of palm-based nanoemulsions. The response variables were the three main emulsion properties; particle size, zeta potential and polydispersity index. Optimization of the four independent variables was carried out to obtain an optimum level palm-based nanoemulsion with desirable characteristics. The response surface analysis showed that the variation in the three responses could be depicted as a quadratic function of the main composition of the emulsion and the preparation method. The experimental data could be fitted sufficiently well into a second-order polynomial model. The optimized formulation was stable for six months at 4 °C.
6 December 2012 in International Journal of Neuroscience
Ischemic heart disease and stroke are the two leading causes of death worldwide. Antiplatelet therapy plays the most significant role in the management of these cardiovascular and cerebrovascular occlusive events to prevent recurrent ischemic attack. Clopidogrel, an antiplatelet drug, is widely prescribed either alone or in combination with aspirin as dual antiplatelet therapy for the prevention of vascular occlusive events. The antiplatelet response to clopidogrel varies widely. Hyporesponders and nonresponders are likely to have adverse cardiovascular events during follow-up. Some drugs, such as proton pump inhibitors (omeprazole), calcium channel blockers, selective serotonin reuptake inhibitors (nefazadone), coumarin derivatives (phenprocoumon), benzodiazepines, sulfonylurea, erythromycin, and itraconazole, decrease the antiplatelet effect of clopidogrel when administered concomitantly. Decreased response to clopidogrel is common among Asians due to genetic polymorphisms associated with clopidogrel resistance, and it is nearly 70% in some of the Asian communities. It is necessary to study Asian populations, because there are a large number of Asians throughout the world due to increased migration. Current guidelines do not make genetic testing or platelet response testing mandatory prior to clopidogrel prescription. Therefore, it is important for clinicians treating Asian patients to keep in mind the interindividual variability in response to clopidogrel when prescribing the drug.
25 February 2009 in Dementia and Geriatric Cognitive Disorders
Background/Aims: In view of the differing sensitivity and specificity of the Mini-Mental State Examination (MMSE) in the non-English-speaking populations, we conducted the first validation study of the Malay version (M-MMSE) in Malaysia among 300 subjects (from the community and outpatient clinics). Methods: Three versions were used: M-MMSE-7 (serial 7), M-MMSE-3 (serial 3) and M-MMSE-S (spell ‘dunia’ backwards). Dementia was assessed using the criteria of the Diagnostic and Statistical Manual of Mental Disorders IV. The optimal cutoff scores were obtained from the receiver operating characteristics curves. Results: Seventy-three patients (24.3%) had dementia and 227 (75.7%) were controls. Three hundred patients completed the M-MMSE-7, 160 the M-MMSE-3 and 145 the M-MMSE-S. All 3 versions were valid and reliable in the diagnosis of dementia. The optimal cutoff scores varied with each version and gender. In the control group, significant gender differences were observed in the patients with the lowest educational status. Increasing educational levels significantly improved the M-MMSE performance in both genders. Conclusion: All 3 versions of the M-MMSE are valid and reliable as a screening tool for dementia in the Malaysian population, but at different cutoff scores. In those with the lowest educational background, gender-adjusted cutoff scores should be applied.
1 December 2013 in Colloids and Surfaces B: Biointerfaces
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