Formulation and Evaluation of Polymeric Nanoparticles of Felodipine

In the present study an attempt was made to develop nanoparticles of felodipine in order to enhance its solubility and dissolution rate by decreasing its particle size to nano level and to sustain its therapeutic activity using Eudragit L and Eudragit S 100. IR spectroscopy studies confirmed that there was no interaction between drug and polymers. The felodipine loaded polymeric nanoparticles were successfully prepared by nanoprecipitation technique using Eudragit L100 and Eudragit S100 as polymers in the presence of stabilizers (Pluronic F 68 and Polyvinyl alcohol). The drug content analysis showed minimum variations suggesting uniform distribution of drug. The entrapment efficiency of all the formulations increased with increasing the concentration of polymers and decreased with increasing concentration of stabilizers. Particle size analyzer used to explore the particle size of felodipine loaded polymeric nanoparticles showed a suitable particle size in the range of 192.4 nm -302.4nm. The polydispersity index of polymeric nanoparticle formulation was less than 0.3, which indicated a relative homogenous dispersion. Zeta potential of felodipine loaded polymeric nanoparticles showed a negative surface charge due to the presence of terminal carboxylic groups in the polymers. The in vitro drug release studies displayed a biphasic drug release pattern with a burst release within 2 hours followed by sustained release for 12 hours. In vitro drug release kinetics showed sustained release and non fickian diffusion mechanism. On the basis of release data and kinetic analysis F7 showed a good sustained release profile with maximum entrapment efficiency. The solubility of felodipine loaded polymeric nanoparticles increased to ten folds when compared to pure drug solution. SEM analysis of the polymeric nanoparticles showed the spherical shape of the nanoparticles. The results of ex vivo intestinal permeability studies showed an increase in the permeation of felodipine loaded polymeric nanoparticles across small intestinal segments when compared to pure drug solution. Conclusion Hence, it was concluded that the polymeric nanoparticles prepared by nanoprecipitation is one of the useful method for the successful incorporation of felodipine with high entrapment efficiency. The solubility and ex vivo intestinal permeability studies suggested that the nanoparticle formulations can improve the bioavailability of felodipine by improving its solubility. Furthermore, it could be presumed that if the nanometer range of particles were obtained, the bioavailability might be increased. Hence, we can conclude that polymeric nanoparticles enhanced the bioavailability of poorly water soluble lipophilic drug like felodipine as a drug delivery system

Screening for potential susceptibility to rubella in an antenatal population: A multivariate analysis

Rubella causes disease in the fetus. Immunity to rubella is therefore, routinely screened in pregnant women. In this retrospective observational study, we assessed the levels of potential susceptibility to rubella in the population of a north London antenatal clinic. Risk factors for potential susceptibility to rubella and changes in potential susceptibility to rubella over time were studied. Almost all women were screened for potential susceptibility to rubella (99.8%). The majority were predicted to be immune (96.8%). Women booking in later years within the study period showed higher levels of potential susceptibility to rubella. Booking during each subsequent year in the study gave women an odds ratio of 0.91 (CI:0.84, 0.98, P = 0.009) of being predicted to have immunity against rubella. Age was associated with predicted immunity to rubella, with a 5.1% (CI:3.3%, 6.9%, P < 0.001) increased likelihood for every year older. Previous pregnancy was predictive of immunity against rubella with an odds ratio of 1.41 (CI 1.21, 1.61, P = 0.001). Those from a non‐white ethnicity were less likely to have antibodies predictive of immunity (OR: 0.730, CI: 0.581, 0.879 P < 0.001). Country of birth was associated with differences in potential susceptibility, with those being born outside of the British Isles having an odds ratio for predicted immunity of 0.63 (CI:0.35,0.91, P = 0.001). Being born in a high‐risk country for rubella non‐immunity was also a risk factor, giving an odds ratio of predicted immunity to rubella of 0.55 (CI:0.32, 0.77, P < 0.001)

Oral Fluid Testing during 10 Years of Rubella Elimination, England and Wales

Surveillance of rubella in England and Wales has included immunoglobulin M testing of oral (crevicular) fluid from reported case-patients since 1994. The need for laboratory confirmation to monitor rubella elimination is emphasized by poor sensitivity (51%, 95% confidence interval 48.9%–54.0%) and specificity (55%, 95% confidence interval 53.7%–55.6%) of the clinical case definition. During 1999–2008, oral fluid from 11,709 (84%) of 13,952 reported case-patients was tested; 143 (1.0%) cases were confirmed and 11,566 (99%) were discarded (annual investigation and discard rate of clinically suspected rubella cases was 2,208/100,000 population). Incidence of confirmed rubella increased from 0.50 to 0.77/1 million population when oral fluid testing was included. Oral fluid tests confirmed that cases were more likely to be in older, unvaccinated men. Testing of oral fluid has improved ascertainment of confirmed rubella in children and men and provided additional information for assessing UK progress toward the World Health Organization elimination goal

The epidemiology of chickenpox in UK 5-year olds: An analysis to inform vaccine policy

Varicella vaccine is not routinely administered to children in many countries including the UK. Longitudinal data are lacking to inform optimal schedules. We report the prevalence of VZV infection at 5 years of age, cumulative incidence between 3 and 5 years and socio-demographic associations with risk of infection using longitudinal data on 12,509 children from the UK Millennium Cohort Study. VZV prevalence by 5 years was 76.9% [95% CI: 75.9%, 78.0%]. The cumulative incidence between 3 and 5 years was 32.2% [95% CI: 31.1%, 33.3%]. Risk of infection by 5 years was associated with higher maternal socio-economic status, larger household size and formal day-care attendance at 9 months and 3 years. If universal varicella immunisation were introduced in the UK, where 40% children have attended some formal day-care by 3 years, a schedule commencing early in the second year of life would be indicated. (C) 2010 Elsevier Ltd. All rights reserved