Nasal administration of ondansetron using a novel microspheres delivery system

Gellan gum microspheres of ondansetron hydrochloride, for intranasal delivery, were prepared to avoid the first pass metabolism as an alternative therapy to parentral, and to improve therapeutic efficiency in treatment of nausea and vomiting. The microspheres were prepared using conventional spray-drying method. The microspheres were evaluated for characteristics like particle size, incorporation efficiency, swelling ability, zeta potential, in-vitro mucoadhesion, thermal analysis, XRD study and in-vitro drug release. Treatment of in-vitro data to different kinetic equations indicated diffusion controlled drug delivery from gellan gum microspheres. The results of DSC and XRD studies revealed molecular amorphous dispersion of ondansetron into the gellan gum microspheres.     

Comparative Evaluation of the Binding Properties of Two Species of Khaya Gum Polymer in a Paracetamol Tablet Formulation

A study was made of the comparative effects of polymers obtained from two species of khaya tree – Khaya senegalensis and Khaya grandifoliola – as binding agents in a paracetamol tablet formulation. The mechanical properties of the tablets were assessed using the tensile strength (T), brittle fracture index (BFI) and friability (F) of the tablets while the drug release properties of the tablets were assessed using disintegration and dissolution times. The tensile strength, disintegration and the dissolution times of tablets increased with the increase in binder concentration while F and BFI decreased. K. senegalensis gum produced tablets with stronger mechanical properties with less tendency to laminate, and longer disintegration and dissolution times than K. grandifoliola gum. The results suggest that the polymer gum from K. senegalensis will be more appropriate as a binding agent than the gum from K. grandifoliola when higher mechanical strength and slower release profiles of tablets are desired.     

Formulation and In vitro assessment of sustained release terbutaline sulfate tablet made from binary hydrophilic polymer mixtures

In the present systematic study, a sustained release of terbutaline sulfate tablet (TBS) was developed and optimized by employing the hydrophilic polymers; chitosan and xanthan gum mixed with sodium bicarbonate as a release modifying agent. This formulation was developed using direct compression technology. In vitro release studies indicated rapid swelling and drug release in the initial period of the acid stage from a matrix composed of chitosan and xanthan gum solely. Addition of sodium bicarbonate to the matrix resulted in sustained drug release. Various formulation factors such as polymer to polymer ratio, polymer viscosity and particle size were altered and their effect on dissolution pattern was illustrated. Manufacturing variables such as compression force and lubricant percentage were investigated and found not to influence the drug release profile of the resulted tablets. The release mechanism follows Korsmeyer-Peppas equation with n value indicating non-Fickian diffusion. The release profiles were analyzed using statistical method (one-way ANOVA) and f₂ metric values and found to be similar to the commercial product Bricanyl^®. Reproducible data were obtained when scale-up of the formulation was performed.     

Injectable hybrid delivery system composed of gellan gum,nanoparticles and gentamicin for the localized treatment of bone infections

ABSTRACT

Objectives: Bone infections are treated with antibiotics administered intravenously, antibiotic-releasing bone cements or collagen sponges placed directly in the infected area. These approaches render limited effectiveness due to the lack of site specificity and invasiveness of implanting cements and sponges. To address these limitations, we developed a novel polysaccharide hydrogel-based injectable system that enables controlled delivery of gentamicin (GENT). Its advantages are minimal invasiveness, and localized and finely regulated release of the drug.

Methods: GENT was incorporated both directly within the gellan gum hydrogel and into poly(L-lactide-co-glycolide) nanoparticles embedded into the hydrogel.

Results: We confirmed the injectability of the system and measured extrusion force was 15.6 ± 1.0 N, which is suitable for injections. The system set properly after the injection as shown by rheological measurements. Desired burst release of the drug was observed within the first 12 h and the dose reached ~27% of total GENT. Subsequently, GENT was released gradually and sustainably: ~60% of initial dose within 90 days. In vitro studies confirmed antimicrobial activity of the system against Staphylococcus spp. and cytocompatibility with osteoblast-like cells.

Conclusions: Developed injectable system enables minimally invasive, local and sustained delivery of the pharmaceutically relevant doses of GENT to combat bone infections.     

Assessing the thermal adaptability of tree provenances: an example using Eucalyptus tereticornis

ABSTRACT

A 2017 paper intended to assist climate-change studies concluded that provenances of the widely distributed Eucalyptus tereticornis ‘are not differentiated in their thermal responses’ in terms of photosynthesis, respiration and growth. The aim here was to place this surprising result, based on a short-term (48-day) experiment with seedlings of just three provenances, into the broader context of several years’ growth of provenances of the same species. To do this, a re-analysis of results from trials of 14 provenances of E. tereticornis was undertaken. These were grown for 3.5 or 5.0 years at four contrasting sites in southern China spanning mean annual temperatures (MAT) from 15.0°C to 23.5°C. The analysis described here compares MATs at climate-of-origin with volume growth. It demonstrates an approach that could easily be applied to provenance studies of other commercially important species. It makes use of the ready access to distributional and climatic data provided by a modern biodiversity database, the Atlas of Living Australia. Some of the provenances showed a surprising level of adaptability to climates markedly different to those of their origin. At the warmest site in China, however, the growth of the provenances was significantly related to the MAT at their climate-of-origin. It is concluded that researchers considering the likely impacts of climate change on tree species may find it useful to examine results from commercial provenance trials as well as from glasshouse experiments with seedlings.     

三七总皂苷离子敏感型鼻用原位凝胶的制备

目的 制备离子敏感型三七总皂苷（PNS）鼻用原位凝胶。方法 以去乙酰结冷胶为材料,采用旋转黏度计测定溶液-凝胶相转变特性筛选处方;采用HPLC法测定PNS中人参皂苷Rg₁,并以不同动物模型对制剂进行安全性评价。结果 离子敏感型原位凝胶的黏度随着去乙酰结冷胶质量分数的增加而上升,加入模拟鼻液后形成具有一定强度的凝胶。该制剂的pH值为6.0～6.5,人参皂苷Rg₁在0.2～50 μg/mL线性关系良好（r＝0.999 5）,平均回收率为101.72%,RSD为1.74%。本制剂能延长药物与鼻黏膜的接触时间。结论 该制剂制备工艺简便,性质稳定,安全无明显刺激性,在PNS鼻腔给药方面表现出良好的发展潜力。     

Near-infrared spectroscopic study on the effects of chewing on short-term memory

Using near-infrared spectroscopy, we examined whether chewing gum improves performance in a short-term memory task - immediate recall of random eight-digit numbers - by assessing cerebral hemodynamic response in the prefrontal cortex. We found that the oxyhemoglobin concentration during and after chewing gum was higher than that before chewing; further, the concentration increased during the task, and this increase was reduced with chewing, although non-significantly. Chewing did not improve task performance. Therefore, chewing-induced hemodynamic responses were unrelated to the performance in short-term memory tasks.     

Title: Differentiating the effects of whey protein and guar gum preloads on postprandial glycemia in type 2 diabetes

Background and aimsWhey protein and guar gum have both been reported to reduce postprandial glycemia in health and type 2 diabetes, associated with stimulation of glucagon-like peptide-1 (GLP-1) and/or slowing of gastric emptying. Our aim was to evaluate, in type 2 diabetes, the acute effects of low dose “preloads” of whey and guar, given alone or in combination before a meal, on postprandial glycemia, insulin, GLP-1, and gastric emptying.Methods21 patients with type 2 diabetes, managed by diet or metformin alone, were each studied on 4 days. They received a preload “shake” 15min before a mashed potato meal (368.5 kcal) labeled with ¹³C-octanoic-acid. The preloads comprised either (i) 17 g whey (W), (ii) 5 g guar (G), (iii) 17 g whey + 5 g guar (WG) each sweetened with 60 mg sucralose, and (iv) 60 mg sucralose alone (control; C), all dissolved in 150 mL water. Venous blood was sampled frequently for measurements of glucose, insulin, and GLP-1 concentrations. Gastric half-emptying time (T50) was calculated from breath ¹³CO₂ excretion over 240 min.ResultsPostprandial blood glucose concentrations were lower with W and WG compared to C (each P < 0.0001, treatment × time interaction), and lower after G than C only at 30min. Insulin, GLP-1, and glucagon concentrations were higher after W than WG, G, or C (P < 0.05, treatment × time interaction), without differences between the latter three. Gastric emptying was slower with W (T50: 179.6 ± 6.1 min, P < 0.05) and WG (T50: 197.6 ± 9.7 min, P < 0.0001) when compared to C (T50: 162.9 ± 6.2 min), but did not differ between G (T50: 171.3 ± 7.0) and C (P > 0.99).ConclusionBoth whey and whey/guar preloads reduced postprandial glycemia, associated with slowing of gastric emptying. Low dose guar was less effective as a preload for glucose-lowering and did not slow gastric emptying.Clinical Trial Registry number and websiteAustralian and New Zealand Clinical Trials Registry, Trial ID ACTRN12615001272583, http://www.anzctr.org.au