Using Microemulsion as Carrier for Drug Transdermal Delivery: The Effect of Surfactants and Cosurfactants.

BACKGROUND: The purpose of this study was to evaluate the effect of types of surfactants and cosurfactants on physicochemical properties and permeability of sumatriptan-loaded microemulsions through rat skin. METHODS: Different types of surfactants and cosurfactants were used to prepare drug-loaded microemulsions. The physicochemical characters and permeability parameters of these formulations were measured. RESULTS: The experimental microemulsions with varying components had small droplet size ranging from 24.6 nm to 2568.8 nm, low viscosity ranging from 7.49 to 43.34 cps and significant permeation enhancement ratio ranging from 23.0 to 98.6 when compared to the control group. CONCLUSION: The composition and proportion of surfactants and cosurfactants were key factors for the physiochemical properties of drug-loaded microemulsions. The cumulative transdermal amount of the microemulsion containing mixture surfactant of Laureth-3/Laureth-23 was higher than that of the microemulsion with a mixture of Tween 80/Span 20. In the selected cosurfactant, diethylene glycol monoethyl ether (DEGMEE) showed highest permeation enhancement. Thermodynamic stability tests revealed that the experimental microemulsion was a stable enough formulation to be considered as a suitable carrier for sumatriptan.

Nanocarriers enhance the transdermal bioavailability of resveratrol: In-vitro and in-vivo study.

The aim of this study was to develop and assess the potential of nanostructured emulsion carriers for resveratrol topical application. Different compositions of resveratrol-loaded nanostructured emulsions were prepared using different types and amounts of surfactants and oily phases (isopropyl myristate and caproyl 90). The produced nanostructured emulsions were within the nanosized range 23.4-422.2nm with low viscosity range 2.15-17.53cps. The transdermal amount and deposition amount in the skin after 24 applications of resveratrol-loaded nanostructured emulsion were significantly increased about 896.2-fold and 10.2-fold respectively, when compared to the drug-saturated solution-treated group. Nanostructured emulsion containing IPM and low amounts of mixed surfactant of Tween80/Span 20 showed highest permeation capacity. In vivo study showed that the plasma concentration of resveratrol could be maintained at high levels for a long time after topical application of drug-loaded nanostructured emulsion. The histological examination demonstrated that the free drug- and drug-loaded nanostructured emulsion demonstrated considerably less irritation than the standard irritation group (0.8% paraformaldehyde-treated). The residual contents of resveratrol in the tested formulations after 3 months of storage at 25°C and 40°C were more than 99.97±3.90%. The results of present work confirm the high potential of nanostructured emulsion as carriers for drug topical application.

Interexpert agreement on diagnosis of bacteriuria and urinary tract infection in hospitalized older adults.

CONTEXT: Although bacteriuria with acute coexisting illness is common in hospitalized older adults, distinguishing it from urinary tract infection (UTI) can be challenging. OBJECTIVES: To examine the rate of agreement between two geriatricians in distinguishing UTI from asymptomatic bacteriuria (ASB). To analyze the incidence of associated acute comorbidities and determine if an association exists between clinical manifestations and bacteriuria status on acute hospital admission. METHODS: Two physicians conducted a retrospective analysis of 296 inpatient records, including 142 records from age- and condition-matched nonbacteriuria control subjects. Using consensus criteria to diagnose UTI vs ASB, these independent experts evaluated inpatient records, including admission and discharge diagnoses as well as urinalysis results. A kappa statistic was used to determine reviewer agreement. Risk assessment was measured by odds ratio with a 95% confidence interval. RESULTS: Expert agreement for the diagnosis of UTI and ASB was 98% and 44%, respectively. Agreement was reached at a level greater than chance (z=6.74, P<.001, kappa=0.49). In the 30 cases where interexpert agreement was not reached, half of the subjects had acute pulmonary disease. Symptom crossover for this comorbid condition is the likely cause for lack of diagnostic agreement. Among other conditions observed, delirium was most common in UTI subjects. CONCLUSION: Limited interexpert agreement seemed to result from difficulty in diagnosing patients who had no local symptoms but acute comorbid conditions with potential symptom crossover. Among the conditions observed in our sample population, delirium was most closely associated with UTI.