Formulation design and characterization of a non-ionic surfactant based vesicular system for the sustained delivery of a new chondroprotective agent

A diacereína é usada para o alívio sintomático e para a regeneração da cartilagem na osteoartrite. Devido aos efeitos adversos gastrointestinais, baixa solubilidade aquosa e biodisponibilidade, o seu uso clínico tem sido restrito. O objetivo do presente estudo foi melhorar o perfil de dissolução deste fármaco e obter liberação prolongada através do planejamento de um novo sistema de liberação designado de niossoma. Cinco formulações distintas de niossomas (F1 a F5) contendo tensoativos não iônicos (monoestearato de sorbitano) e colesterol, em diferentes proporções, de 5:5, 6:4, 7:3, 8:2 e 9:1, foram desenvolvidas através da técnica de evaporacão de fase reversa. Os tamanhos e índices de polidispersibilidade (PDI) obtidos variam entre 0,608 e 1,01 µm e entre 0,409 e 0,7781, respectivamente. Imagens de microscopia electrônica de varrimento (SEM) da formulação selecionada (F3) revelaram vesículas esféricas. Obteve-se encapsulação de 79,8% com a formulação F3 (7:3). Estudos de dissolução usando o método de diálise demonstraram padrão de liberacão prolongada para todas as formulações. A proporção de tensoativo e colesterol (7:3) na formulacão F3 prolongou o tempo de liberação do fármaco (T50%) até 10 horas. Estudos de modelação cinética demonstraram ordem de liberacão zero (R2=0,9834) e o expoente de liberação "n" do modelo de Korsmayer-Peppas (n=0.90) confirmou a liberação não-fickiana e anômala. Os resultados deste estudo sugerem que a diacereína pode ser encapsulada com sucesso no interior de niossomas, utilizando monostearato de sorbitano, o qual tem potencial para liberar, eficientemente, a diacereína no local de absorção.Diacerein is used for symptomatic relief and cartilage regeneration in osteoarthritis. Due to gastrointestinal side effects, poor aqueous solubility and low bioavailability, its clinical usage has been restricted. The objective of the present study was to enhance its dissolution profile and to attain sustained release by designing a novel delivery system based on niosomes. Five niosomal formulations (F1-F5) with non-ionic surfactant (sorbitan monostearate) and cholesterol in varying ratios of 5:5, 6:4, 7:3, 8:2 and 9:1 were developed by the reverse-phase evaporation technique. The size and polydispersivity index (PDI) were found in the range of 0.608 µm to 1.010 µm and 0.409 to 0.781, respectively. Scanning electron microscopy (SEM) of the selected formulation (F3) revealed spherical vesicles, and 79.8% entrapment was achieved with F3 (7:3). Dissolution studies using the dialysis method showed sustained release behaviour for all formulations. The optimized surfactant-to-cholesterol concentration (7:3) in formulation F3sustained the drug-release time (T50%) up to 10 hours. Kinetic modelling exhibited a zero-order release (R2=0.9834) and the release exponent 'n' of the Korsmayer-Peppas model (n=0.90) confirmed non-fickian and anomalous release. The results of this study suggest that diacerein can be successfully entrapped into niosomes using sorbitan monostearate and that these niosomes have the potential to deliver diacerein efficiently at the absorption site

Probabilistic Analysis of Strength of Structural Concrete for Post-Code Buildings in Developing Countries

Code compliance and quality construction remain a point of interest for developing countries. For structural vulnerability studies on reinforced concrete buildings, researchers usually adopt random strength parameters to represent the compressive strength of concrete for various structural members. This matter becomes a challenge if researchers are dealing to quantify the structural response of code-compliant buildings. Since the research on the response of code-compliant buildings is limited hence this paper aims at data collection and presenting the probabilistic trends in compressive strength variation of structural concrete being used or has been used in multiple projects of the federal capital city of Pakistan for code-compliant buildings. The data has been collected from well-reputed academic and commercial testing labs in the area for past 10 years (the timeline after implementation of BCP 2007). Compressive strength testing records of concrete cylinders for 28 days strength have been sorted for different structural members i.e., beams, columns, shear walls, slabs and footings separately. From the selected data, histograms have been plotted for each member category and mean values with standard deviations have been highlighted. Obtained results are further compared with anticipated design compressive strengths which were obtained from different tagged reports, design offices and resident engineers of the sites. The produced results would lead to true representation of structural strength of concrete for code-compliant buildings, to be further studied for structural vulnerability and risk assessments of the desired areas in developing countries

Hybrid Nano-carriers for Potential Drug Delivery

Nanocarriers have provided the versatile platform for the delivery of various therapeutic and diagnostic agents. Liposome, niosomes, polymeric and solid lipid nanoparticles are the most promising nanocarriers that have been entered in the clinical trials and become commercially available. However, each system has been associated with some problems that can be minimized by using the combinatorial approach of hybrid nanocarriers. These hybrid systems combine the benefits of different structural components to synergize the outcome of the therapy. In this chapter, the different types of hybrid nanocarriers have been described with particular emphasis on the brief rationale for the development of these hybrid nanocarriers along with different fabrication approaches with greater emphasize on the lipid polymer hybrid nanoparticles. A brief description factors governing the optimized response characteristics and their potential application of these hybrid nanoparticles are also presented

Outdoor testing of photovoltaic modules during summer in Taxila, Pakistan

An experimental study has been carried out to measure the performance of commercially available photovoltaic modules during summer months in the climate of Taxila, near the capital of Pakistan. The modules used in the study are monocrystalline silicon (c-Si), polycrystalline silicon (p-Si) and single junction amorphous silicon (a-Si). The analysis has been focused on the measurement of module efficiency, performance ratio and temperature of each module at actual operating conditions using outdoor monitoring facility. The measured results are compared with the already published data of peak winter month at the same site. Overall, the monocrystalline module showed high average module efficiency while amorphous silicon module was better in term of average performance ratio. Furthermore, the module efficiency and performance ratio has shown decreasing trend with increase of module temperature. It was found that modules have much higher temperature in summer months (about 20°C higher) and showed low efficiency and performance ratio than peak winter month. The average ambient temperature varied from 18.1°C to 38.6°C from winter to summer

Novel lignocellulosic wastes for comparative adsorption of Cr(VI): equilibrium kinetics and thermodynamic studies

Cr(VI) adsorption was studied for abundantly available low-cost lignocellulosic adsorbents in Pakistan namely, tobacco stalks (TS), white cedar stem (WCS) and eucalyptus bark (EB). Several process variables like contact time, adsorbent dose, pH, metal concentration, particle size and temperature were optimized in batch mode. EB showed high Cr(VI) adsorption of 63.66% followed by WCS 62% and TS 57% at pH 2, which is higher than most of the reported literature. Langmuir isotherm (R2 = 0.999) was well fitted into the equilibrium Cr(VI) data of EB, suggesting homogeneous active sites and monolayer coverage of Cr(VI) onto the EB surface. Freundlich (R2 = 0.9982) isotherm was better fitted to the equilibrium data of TS and WCS, revealing the adsorption sites with heterogeneous energy distribution and multilayer Cr(VI) adsorption. Moreover, the Cr(VI) adsorption of studied adsorbents followed the pseudo-second order kinetic model. Thermodynamic properties were investigated in two temperature ranges, i.e., T1 (303–313 K) and T2 (313–323 K). TS and EB showed the exothermic at T1 and endothermic reactions at T2 with entropy controlled adsorption at the solid-liquid interface, and WCS exhibited an opposite thermal trend with decreasing disorderness at solid-liquid interface as temperature rises. Gibbs free energy (ΔG>0) confirmed the non-spontaneous adsorption process for all studied adsorbents

Socioeconomic and Environmental Impact Assessment of Different Power-Sourced Drip Irrigation Systems in Punjab, Pakistan

This research investigated the best economically viable power source with the least environmental impact and socially acceptable for the maize crop. Maize is one of the key economic crops in Pakistan. Solar-, electric-, and diesel-powered drip irrigation systems (DIS) were considered for comparative study. We selected 45 sites of maize crop to collect the data, with an area of 1–3 ha, from three divisions. For economic viability, the benefit:cost ratio, life cycle cost, and payback period were calculated, and CO2 emissions were calculated to assess the environmental impact. The SPSS model was used for one-way ANOVA followed by post hoc and chi-squared tests to check the significance level between all power sources. It was found that the B-C of electric power, solar, and diesel drip irrigation systems was 1.65, 1.52, and 1.44, respectively. Solar, diesel, and electricity power DIS have CO2 emissions of 0.02, 0.730, and 1.106 tons/ha, respectively. The research concludes that solar power and electric power are the best sources for the environment and economically, respectively. It is recommended that solar power DIS be subsidized, which will help to lower CO2 emissions and reduce the electricity shortfall in Pakistan