Development and gamma-scintigraphy study of Hibiscus rosasinensis polysaccharide-based microspheres for nasal drug delivery

Objective: This work describes the application of natural plant polysaccharide as pharmaceutical mucoadhesive excipients in delivery systems to reduce the clearance rate through nasal cavity.

Methods: Novel natural polysaccharide (Hibiscus rosasinensis)-based mucoadhesive microspheres were prepared by using emulsion crosslinking method for the delivery of rizatriptan benzoate (RB) through nasal route. Mucoadhesive microspheres were characterized for different parameters and nasal clearance of technetium-99m (^99mTc)-radiolabeled microspheres was determined by using gamma-scintigraphy.

Results: Their Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies showed that the drug was stable during preparation of microspheres. Aerodynamic diameter of microspheres was in the range 13.23?±?1.83–33.57?±?3.69?µm. Change in drug and polysaccharide ratio influenced the mucoadhesion, encapsulation efficiency and in-vitro release property. Scintigraphs taken at regular interval indicate that control solution was cleared rapidly from nasal cavity, whereas microspheres showed slower clearance (p?Conclusion: Natural polysaccharide-based microspheres achieved extended residence by minimizing effect of mucociliary clearance with opportunity of sustained delivery for longer duration.     

Nanomedicine-Based Delivery Strategies for Breast Cancer Treatment and Management

Breast cancer is one of the most common types of cancer among women globally. It is caused by mutations in the estrogen/progesterone receptors and conventional treatment methods are commonly utilized. About 70–80 percent of individuals with the early-stage non-metastatic disease may be cured. Conventional treatment is far less than the optimal ratio, as demonstrated through the high mortality rate of women with this cancer. However, conventional treatment methods like surgery, radiotherapy, and chemotherapy are not as effective as expected and lead to concerns about low bioavailability, low cellular uptake, emerging resistance, and adverse toxicities. A nanomedicine-based approach is a promising alternative for breast cancer treatment. The present era is witnessing rapid advancements in nanomedicine as a platform for investigating novel therapeutic applications and modern intelligent healthcare management strategies. This paper focuses on nanomedicine-based therapeutic interventions that are becoming more widely accepted for improving treatment effectiveness and reducing undesired side effects in breast cancer patients. By evaluating the state-of-the-art tools and taking the challenges involved into consideration, various aspects of the proposed nano-enabled therapeutic approaches have been discussed in this review.     

Infraadditive diuretic efficacy of concurrent aminophylline and frusemide

Male albino rats weighing between 150-225 gm fasted over night but freed having water ad libitum were used to assess the diuretic efficacy of intramuscular aminophylline and frusemide separately and concurrently after intraperitoneal 10 ml of distilled water loading. The normal rate of diuretic weight loss was less augmented by aminophylline and more augmented by frusemide. The diuretic response was more by the concurrent intramuscular administration of aminophylline and frusemide in comparison with that due to either drug alone. However, the observed diuretic response of the two drugs administered concurrently was lesser (infraadditive) than the sum of the individual diuretic response (additive).     

Design issues for a single core transformer thyristor controlledphase-angle regulator

Power electronics have become increasingly reliable and cost effective at the transmission voltage level. New applications of FACTS devices are just emerging, the thyristor controlled phase-angle regulator (TCPAR) being one of them. This paper identifies and discusses several gate control and system issues for application of a single core transformer thyristor controlled phase-angle regulator. Alternative TCPAR designs are proposed     

Particle Swarm Optimization Technique Based Design of Pi Controller for a Real-Time Non-Linear Process

Abstract

The increasing complexity of modern control systems has emphasized the idea of applying new approaches in order to solve design problems for different control engineering applications. Proportional-Integral-Derivative (PID) control schemes have been widely used in most of process control systems represented by chemical processes for a long time. However, a very important problem is how to determine or tune the PID parameters, because these parameters have a great influence on the stability and the performance of the control system. Computational intelligence (CI), which has caught the eyes of researchers due to its simplicity, low computational cost, and good performance, makes it a possible choice for tuning of PID controllers, to increase their performance. This paper discusses, in detail, the Particle Swarm Optimization (PSO) algorithm, a CI technique, and its implementation in PID tuning for a controller of a real time process. Compared to other conventional PID tuning methods, the result shows that better performance can be achieved with the proposed method. The ability of the designed controller, in terms of tracking set point, is also compared and simulation results are shown.     

An evaluation of the effect of storage and processing temperatures on the microbiological status of sous vide extended shelf-life products

The microbiological and organoleptic quality of selected sous vide products was monitored over a storage period of up to five weeks at 3°C and 8°C, respectively. Sous vide products stored at the recommended temperature of 3°C showed negligible microbial growth and were found to be organoleptically acceptable throughout the storage period. Total plate counts at the end of the fourth week of storage were in the range <10–7×10³ CFU/g for all 19 products under study. Listeria monocytogenes, Salmonella, Clostridium perfringens, Bacillus cereus and Enterobacteriaceae were not detected in any of the processed samples. At 8°C, under temperature abuse conditions, while some products had acceptable microbial levels of 10²–10⁴ CFU/g after three weeks, others such as chicken chasseur had counts above 10⁶ CFU/g by the second week of storage. Lactic acid bacteria and Pseudomonas species were dominant in the microbial flora of spoilt samples and B. cereus (>3×10⁴ CFU/g) was isolated from spoilt chicken chasseur samples in the fourth week of storage at 8°C. Critical factors affecting sous vide product safety are discussed.     

Development of novel gastroretentive drug delivery system of gliclazide: hollow beads

Aim: The current communication deals with the development of hollow floating beads of gliclazide. The primary effect of this drug is to potentiate glucose-stimulated insulin release from pancreatic islet-β-cells by induction of a decrease in potassium efflux from these cells. Because of the poor aqueous solubility, its absorption is limited. Thus, an attempt was made to improve its release profile.

Methods: The hollow drug-loaded alginate beads in combination with low methoxyl pectin and hydroxypropylmethylcellulose (HPMC) were prepared by a simple ionotropic gelation method. The beads were evaluated for particle size and morphology using optical microscopy and scanning electron microscopy (SEM), respectively. Mucoadhesion test was done using goat stomach mucosal membrane. Release characteristics of the gliclazide-loaded hollow beads were studied in 0.1?N HCl (pH 1.2) and phosphate buffer (pH 5.8).

Results: The developed beads were spherical in shape with hollow internal structure and had a particle size in the range of 0.730?±?0.05 to 0.890?±?0.03?mm. The incorporation efficiency of alginate -pectin beads was higher than alginate -HPMC beads. The Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction analysis showed stable character of drug in the drug-loaded hollow beads and revealed the absence of any drug -polymer interactions. The beads remained buoyant for more than 12?h. The drug release from beads followed Fickian diffusion with swelling.

Conclusion: The preliminary results of this study suggest that the developed beads containing gliclazide could enhance drug entrapment efficiency, reduce the initial burst release and modulate the drug release.     

Evaluation of the microbial quality of water supplies to municipal, mining and squatter communities in the Bindura urban area of Zimbabwe.

A survey of the microbiological and chemical quality of water supplies in the Bindura urban and peri-urban area was carried out over a three-year period from January 2000 to July 2003. Bindura is the provincial city of Mashonaland Central, situated 88 km from the national capital, Harare. Large-scale farming and mining activities in the area predispose water bodies to eutrophication and chemical pollutants, raising concerns about the safety of local water supplies. In this study, thermotolerant (faecal) coliform levels, total aerobic bacterial counts and physicochemical profiles were determined for municipal and borehole water as well as water supplies to mining and squatter communities. Although municipal and mining compound water supplies were of satisfactory microbial and chemical quality, borehole water supplies showed a seasonal fluctuation, with higher coliform counts in the wet season from November to March. Stream water supplies to a squatter camp in the peri-urban area consistently recorded coliform levels >1,800/100 mL and total aerobic plate counts of <2.8 x 10(6) CFU/mL. All cholera incidents recorded in 1999 and 2000 at the Provincial hospital were from peri-urban settlements and surrounding commercial farms while 1,045 to 2,632 cases of dysentery were also reported each year at the provincial hospital during the period 1997-2002.     

First‐principles spectroscopic screening of hybrid perovskite (CH3CH2NH3PbI3) with fundamental physical properties: A potential photovoltaic absorber

Herein, we have discussed the ethyl‐ammonium based hybrid perovskite (viz. CH₃CH₂NH₃PbI₃ or EAPbI₃) as the potential candidate material for the development of photovoltaic devices having low processing cost and high power conversion efficiency (PCE). To address the stability and environmental issues due to leaching of lead from MAPbI₃, we urge to replace cation CH₃NH₃⁺ (MA⁺) with an appropriate cation CH₃CH₂NH₃⁺ (EA⁺) and hope that the EAPbI₃ perovskite would prove to be a stable and eco‐friendly photovoltaic absorber (PVA) material yielding high PCE. We have investigated physical properties like energy bandgap, electron density distribution and optical coefficients by FP‐LAPW+lo and density functional theory (DFT). The present study reveals that EAPbI₃ has a direct energy bandgap of 1.55 eV with absorption coefficient exceeding 2 × 10⁴ per cm, which confirms its suitability as PVA material. The dependence of thermoelectric (TE) coefficients on chemical potential and carrier concentration at various temperatures has also been discussed. We have also carried out the calculations of spectroscopic limited maximum efficiency (SLME) parameter (30.5%), and the thermodynamic (TD) properties in the realm of quasi‐harmonic approximation. A detailed investigation on some of the properties of EAPbI₃ perovskite relevant to PVA material is being done for the first time, the present study may motivate researchers for more comprehensive theoretical and experimental investigations in search of stable and economically and environmentally viable PVA materials.     

Survival characteristics and the applicability of predictive mathematical modelling to Listeria monocytogenes growth in sous vide products

Survival and growth of Listeria monocytogenes isolates during sous vide processing and storage, and the applicability of predictive modelling in determining the potential for growth of L. monocytogenes in broth models and in sous vide products was investigated. L. monocytogenes grew in anaerobic tryptose phosphate broth and in chicken and beef samples by 2 log cycles in 8 days at 3 degrees C and 4-5 log cycles in 6 days at 8 degrees C. However, heating to an internal temperature of 70 degrees C resulted in a 4-5 log reduction and 70 degrees C/2 min resulted in a reduction greater than 7 log cycles. Lowering the product pH to 5.0 was effective in inhibiting L. monocytogenes growth, whereas a sodium chloride concentration of 2% had a negligible effect on growth rates. The square root model (Ratkowsky et al., 1983) predicted L. monocytogenes growth rates at 0-25 degrees C with a coefficient of determination (R2 value) of 98.36-99.63% and a bias factor of 1.08 to 1.21 in beef, chicken and broth substrates of unmodified pH. In addition, the Response Surface Polynomial Model (Version 3.1, Buchanan et al., 1989) predicted generation times at 5-25 degrees C with a 0-17.4% difference between observed and expected generation times in tryptose phosphate broth at pH 7.3. There were however, large differences (25.5 vs. 5.3 h) between observed generation times at pH 5.6 (8 degrees C) and those predicted by the Pathogen Modelling Program in tryptose phosphate broth. A divergence from predicted values was also noted at lower temperatures (0-3.5 degrees C) in the square root model.