Search

The widespread use of silver nanoparticles (AgNPs) as a bactericide will ultimately result in their increased concentration in soils. We sought to determine the likely mobility, toxicity, and plant uptake of Ag applied to soil as either AgNPs or Ag+. We measured the solubility, toxicity, and plant uptake of both AgNPs and Ag+in an immature Pallic soil, a Templeton loamy silt (pH = 5.1), and a granular silt loam (pH = 6.0). The sorption of AgNPs by the test soils was significantly greater than Ag+, and both moieties were more strongly sorbed at lower concentrations and higher pH values. Between pH 4 and 8, distribution coefficient (KD) values increased from <10 up to ∼500 L kg−1for Ag+, and from 100 to 10,000 L kg−1for AgNPs. There was strong evidence that our citrate‐coated AgNPs were transformed into Ag+during the course of the plant growth experiments, and plant responses were similar for both the Ag+and AgNP treatments. Soil concentrations >100 mg kg−1significantly reduced the biomass of Lolium perenneL. and resulted in foliar concentrations of up to 10 mg kg−1dry matter. At a soil concentration of 70 mg kg−1, silverbeet [Beta vulgarisL. ssp. maritima(L.) Arcang.] and spinach (Spinacia oleraceaL.) accumulated 5 to 10 mg Ag kg−1, which may present a human health risk. Regarding citrate‐coated AgNPs, the environmental impact of release is largely determined by the equivalent mass concentration of Ag+, into which they will ultimately transform. Given the widespread interest in AgNPs, there is limited knowledge on the behavior of Ag+in soil and this should be the subject of future research. Citrate‐coated Ag nanoparticles had greater soil sorption than Ag+.Sorption of both Ag nanoparticles and Ag+increased at higher pH.Silver nanoparticles are ultimately unstable and transform to Ag+.Phytotoxicity occurs at soil Ag concentrations >100 mg kg−1.Silver uptake by spinach and silverbeet may present a human health risk.

Three-dimensional (3D) printing is an emerging manufacturing technology for biomedical and pharmaceutical applications. Fused deposition modelling (FDM) is a low cost extrusion-based 3D printing technique that can deposit materials layer-by-layer to create solid geometries. This review article aims to provide an overview of FDM based 3D printing application in developing new drug delivery systems. The principle methodology, suitable polymers and important parameters in FDM technology and its applications in fabrication of personalised tablets and drug delivery devices are discussed in this review. FDM based 3D printing is a novel and versatile manufacturing technique for creating customised drug delivery devices that contain accurate dose of medicine( s) and provide controlled drug released profiles.

Background: Blepharitis is considered one of the most common ocular surface conditions in optometry and ophthalmology practice. While azithromycin and dexamethasone have been used successfully to treat blepharitis, they are generally formulated as eye drops requiring frequent administration. Ocular inserts based on biodegradable polymers may overcome some of the problems associated with conventional eye drops such as the fast nasolacrimal drainage. Methods: Inserts with different β-glucan and hydroxypropyl methycellulose (HPMC) compositions were prepared using the solvent-casting method and evaluated in terms of their appearance, thickness, weight, pH, mechanical strength, bioadhesive properties and drug-polymer interactions. The ability of the ocular inserts to provide controlled release of the drugs was assessed through an in vitro release study of dexamethasone and an antibacterial assay for azithromycin. Results: All parameters were found acceptable for ocular use, with the film laminate exhibiting the highest tensile strength and mucoadhesion. Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) revealed that the drugs were molecularly dispersed within the polymer films with no obvious interactions. Dexamethasone release was fast with 100% released within 1 hr. Azithromycin also showed a high burst release achieving the minimum inhibitory concentration after only 5 min; however, antibacterial activity was maintained for 24 hrs. Conclusion: Ocular inserts were successfully prepared and delivered both drugs over prolonged periods compared to conventional eye drops. However, additional coating may be required to further control the drug release.

The development and registration of pharmaceuticals often requires some degree of certainty around their in vivo performance. Many commonly used diagnostic and therapeutic imaging techniques have been attracting increasing interest to monitor the performance of dosage forms and drug delivery systems in vivo. The use of imaging and microscopy methods in dosage form design and drug delivery research is still in its infancy with only gamma scintigraphy being widely accepted by drug regulatory bodies as the method of choice for monitoring the gastrointestinal transit of oral dosage forms. The emerging use of ultrasonography and magnetic resonance imaging may potentially bring these techniques further to the scene with a more established role in the assessment of pharmaceutical dosage forms. This review compares and contrasts the scientific operation principles as well as advantages and disadvantages of some of these imaging techniques, including gamma scintigraphy, single photon emission computed tomography, positron emission tomography, radiology/computed tomography, ultrasonography magnetic resonance imaging and microscopy. Scientific articles are reviewed to give a broad overview of these techniques, their current applications and their future potential use in dosage form design and drug delivery research.

Suitable dosage forms are not always available for specific patient populations and must be extemporaneously compounded. Extemporaneous preparation is the manipulation of drugs and excipients for a particular patient using traditional compounding techniques; these are referred to as ‘off-label’ and ‘unlicensed’ medicines. Off-label use can include altered doses, dosage forms or indications for use. Registered medicines are produced to internationally recognized standards of Good Manufacturing Practices. Within the pharmaceutical manufacturing industry, quality, safety and efficacy are enforced by regulatory legislations. In contrast, the responsibility for acceptable standards for the compounding of ‘off-label’ medicines falls on the prescriber, pharmacist or hospital nurse. Studies have been conducted by researchers from Australia and throughout Europe, highlighting the frequency of off-label use for paediatrics, with one study reporting that most extemporaneous preparations (29.6) were for drugs required to treat metabolic diseases. Risks include compounding errors, adverse reactions to ingredients and excipients, and non-validated stability of the product. Sterile compounded products, including products for ophthalmic and palliative care, carry additional risks in these vulnerable patients. This paper provides an overview of off-label medicines highlighting biopharmaceutical, quality, safety and efficacy issues important to medical and allied health professionals.

Energy supplementation may reduce oxidative stress by correcting a negative energy balance, but in some contexts, it has been shown to increase oxidative stress, especially at peak lactation. The current experiment examined if a pelleted energy supplement with or without the addition of Lactobacillus-fermented seaweed or seaweed plus terrestrial plants extracts affected oxidative stress of ewes from late gestation through to weaning and ewe and lamb production from lambing to weaning. Treatments were either no supplement (CON−), a pelleted supplement only (CON+, 100 g/ewe per d), CON+ with seaweed extract only (SWO, 10 mL/ewe per day), or CON+ with seaweed plus an arrangement of terrestrial plant extract (SWP, 10 mL/ewe per d). Ewes (n= 160; mean initial BW = 72.3 ± 9.5 kg [mean ± SD]) were randomized to pastures (n= 4 pastures per treatment with 10 ewes each). After lambing, ewes with twins were reallocated to pastures (n= 3 pastures per treatment with 10 ewes each) according to lambing date. At 4 wk in milk, supplementation tended to reduce total antioxidant status (TAS; P= 0.10) and increased glutathione peroxidase (GPx) activity compared with nonsupplemented ewes (P= 0.04). The addition of seaweed and terrestrial plants extracts to the concentrate, that is, SWO and SWP, increased TAS and reduced GPx activity compared with CON+ (P< 0.01). Supplementation increased milk yield at weeks 4, 6, and 8 of lactation, and protein, lactose, and total milk solids yield at peak lactation (week 4; P< 0.05). The CON− ewes had greater somatic cell count than the supplemented ewes at weeks 4, 8, and 10 of lactation (P= 0.03). Our results suggest that energy supplementation, alone, increases oxidative stress of lactating ewes, which may relate to increased oxidative phosphorylation. Most importantly, these results indicate that in situations where energy supplementation is needed to increase animal performance, negative effects of energy supplementation around peak lactation can be offset by the addition of Lactobacillus-fermented plant extracts (SWO and SWP) to improve antioxidant status.