Influence of excipients on spray-dried powders for inhalation

Two areas attracting considerable attention when developing effective pulmonary drug delivery systems include the improvement of aerosolisation efficiency of the inhaled formulation and the controlled release of drug from the formulation following deposition within the lung. In this study, four saccharides were employed as excipients in the preparation of spray-dried powder formulations for the pulmonary drug delivery. Beta-cyclodextrin-, starch-, and sodium carboxymethylcellulose (NaCMC)-based spray-dried powders showed a significant (one-way ANOVA, Duncan's test, p < 0.05) increase in lower stage drug deposition in the Next Generation Impactor (NGI) when compared to lactose-based spray-dried powders. Furthermore, NaCMC-based spray-dried powder formulations exhibited a sustained drug release profile in dissolution testing; approximately 80% of salbutamol sulphate was released after an hour, whereas drug from the lactose-based spray-dried powder formulation was released within 5 min. Our results clearly demonstrate that the inclusion of NaCMC in spray-dried powder formulations increases the aerosolisation efficiency of the powder and also offers the potential for sustained drug release, which may be of benefit in the treatment of local and systemic conditions

Amlexanox-loaded nanoliposomes showing enhanced anti-inflammatory activity in cultured macrophages: A potential formulation for treatment of oral aphthous stomatitis

Oral aphthous stomatitis is a common disorder treated with the immunomodulatory drug Amlexanox (AMX), that was administered as a mucoadhesive paste (Aphthasol®). This product was discontinued by FDA in 2014 due to the associated undesired adverse reactions of the formulation. Here, we have developed AMX-loaded nanoliposome formulation as a potential alternative for the localised oromucosal delivery of AMX. Nanoliposomes were prepared using Soya phosphatidylcholine (SPC) and Cholesterol (Chol) mixtures at three different molar ratios to formulate vesicles using thin-film hydration, and were characterised for size, zeta potential and entrapment efficiency. The optimal formulation was found to be SPC:Chol 3:1 with drug entrapment efficiency of 94%, post sonication. To evaluate anti-inflammatory activity, macrophages developed by differentiation of human leukaemia monocytic cell line, THP-1, were polarised by Interferon gamma (IFNγ) and lipopolysaccharide (LPS) to M1 state. Macrophages M1 cells treated with D-L1 formulation (SPC:Chol 3:1, 500 μg/mL total lipid, and 27.6 μM AMX) showed a significant suppression in TNF-α expression levels (43 ± 2.7% of untreated control, p < 0.05) compared to those treated with either empty liposomes or AMX alone. Notably, %TNF-α dramatically decreased to 57 ± 4.05% of control, for cells treated with drug-free liposomes (500μg/mL total lipid) indicating the anti-inflammatory activity of SPC lipid component per se, which led to synergistic effect as evident from the augmentation of AMX anti-inflammatory activity in D-L1 formulation. Our findings highlight the potential of using AMX nanoliposomes as a promising advanced formulation for reviving AMX treatment for management of inflammatory conditions of oral mucosa

Amlexanox-loaded nanoliposomes showing enhanced anti-inflammatory activity in cultured macrophages: A potential formulation for treatment of oral aphthous stomatitis

Oral aphthous stomatitis is a common disorder treated with the immunomodulatory drug Amlexanox (AMX), that was administered as a mucoadhesive paste (Aphthasol®). This product was discontinued by FDA in 2014 due to the associated undesired adverse reactions of the formulation. Here, we have developed AMX-loaded nanoliposome formulation as a potential alternative for the localised oromucosal delivery of AMX. Nanoliposomes were prepared using Soya phosphatidylcholine (SPC) and Cholesterol (Chol) mixtures at three different molar ratios to formulate vesicles using thin-film hydration, and were characterised for size, zeta potential and entrapment efficiency. The optimal formulation was found to be SPC:Chol 3:1 with drug entrapment efficiency of 94%, post sonication. To evaluate anti-inflammatory activity, macrophages developed by differentiation of human leukaemia monocytic cell line, THP-1, were polarised by Interferon gamma (IFNγ) and lipopolysaccharide (LPS) to M1 state. Macrophages M1 cells treated with D-L1 formulation (SPC:Chol 3:1, 500 μg/mL total lipid, and 27.6 μM AMX) showed a significant suppression in TNF-α expression levels (43 ± 2.7% of untreated control, p < 0.05) compared to those treated with either empty liposomes or AMX alone. Notably, %TNF-α dramatically decreased to 57 ± 4.05% of control, for cells treated with drug-free liposomes (500 μg/mL total lipid) indicating the anti-inflammatory activity of SPC lipid component per se, which led to synergistic effect as evident from the augmentation of AMX anti-inflammatory activity in D-L1 formulation. Our findings highlight the potential of using AMX nanoliposomes as a promising advanced formulation for reviving AMX treatment for management of inflammatory conditions of oral mucosa

Amlexanox-loaded nanoliposomes showing enhanced anti-inflammatory activity in cultured macrophages: A potential formulation for treatment of oral aphthous stomatitis

open access articleOral aphthous stomatitis is a common disorder treated with the immunomodulatory drug Amlexanox (AMX), that was administered as a mucoadhesive paste (Aphthasol®). This product was discontinued by FDA in 2014 due to the associated undesired adverse reactions of the formulation. Here, we have developed AMX-loaded nanoliposome formulation as a potential alternative for the localised oromucosal delivery of AMX. Nanoliposomes were prepared using Soya phosphatidylcholine (SPC) and Cholesterol (Chol) mixtures at three different molar ratios to formulate vesicles using thin-film hydration, and were characterised for size, zeta potential and entrapment efficiency. The optimal formulation was found to be SPC:Chol 3:1 with drug entrapment efficiency of 94%, post sonication. To evaluate anti-inflammatory activity, macrophages developed by differentiation of human leukaemia monocytic cell line, THP-1, were polarised by Interferon gamma (IFNγ) and lipopolysaccharide (LPS) to M1 state. Macrophages M1 cells treated with D-L1 formulation (SPC:Chol 3:1, 500 μg/mL total lipid, and 27.6 μM AMX) showed a significant suppression in TNF-α expression levels (43 ± 2.7% of untreated control, p < 0.05) compared to those treated with either empty liposomes or AMX alone. Notably, %TNF-α dramatically decreased to 57 ± 4.05% of control, for cells treated with drug-free liposomes (500 μg/mL total lipid) indicating the anti-inflammatory activity of SPC lipid component per se, which led to synergistic effect as evident from the augmentation of AMX anti-inflammatory activity in D-L1 formulation. Our findings highlight the potential of using AMX nanoliposomes as a promising advanced formulation for reviving AMX treatment for management of inflammatory conditions of oral mucosa

Stretching the IR theoretical spectrum on Irish neutrality: a critical social constructivist framework

In a 2006 International Political Science Review article, entitled "Choosing to Go It Alone: Irish Neutrality in Theoretical and Comparative Perspective," Neal G. Jesse argues that Irish neutrality is best understood through a neoliberal rather than a neorealist international relations theory framework. This article posits an alternative "critical social constructivist" framework for understanding Irish neutrality. The first part of the article considers the differences between neoliberalism and social constructivism and argues why critical social constructivism's emphasis on beliefs, identity, and the agency of the public in foreign policy are key factors explaining Irish neutrality today. Using public opinion data, the second part of the article tests whether national identity, independence, ethnocentrism, attitudes to Northern Ireland, and efficacy are factors driving public support for Irish neutrality. The results show that public attitudes to Irish neutrality are structured along the dimensions of independence and identity, indicating empirical support for a critical social constructivist framework of understanding of Irish neutrality

Application of Microarray and Functional-Based Screening Methods for the Detection of Antimicrobial Resistance Genes in the Microbiomes of Healthy Humans

The aim of this study was to screen for the presence of antimicrobial resistance genes within the saliva and faecal microbiomes of healthy adult human volunteers from five European countries. Two non-culture based approaches were employed to obviate potential bias associated with difficult to culture members of the microbiota. In a gene target-based approach, a microarray was employed to screen for the presence of over 70 clinically important resistance genes in the saliva and faecal microbiomes. A total of 14 different resistance genes were detected encoding resistances to six antibiotic classes (aminoglycosides, β-lactams, macrolides, sulphonamides, tetracyclines and trimethoprim). The most commonly detected genes were erm(B), blaTEM, and sul2. In a functional-based approach, DNA prepared from pooled saliva samples was cloned into Escherichia coli and screened for expression of resistance to ampicillin or sulphonamide, two of the most common resistances found by array. The functional ampicillin resistance screen recovered genes encoding components of a predicted AcrRAB efflux pump. In the functional sulphonamide resistance screen, folP genes were recovered encoding mutant dihydropteroate synthase, the target of sulphonamide action. The genes recovered from the functional screens were from the chromosomes of commensal species that are opportunistically pathogenic and capable of exchanging DNA with related pathogenic species. Genes identified by microarray were not recovered in the activity-based screen, indicating that these two methods can be complementary in facilitating the identification of a range of resistance mechanisms present within the human microbiome. It also provides further evidence of the diverse reservoir of resistance mechanisms present in bacterial populations in the human gut and saliva. In future the methods described in this study can be used to monitor changes in the resistome in response to antibiotic therapy

The Influence of Formulation Components on the Aerosolisation Properties of Spray-dried Powders

Dry powders suitable for inhalation containing β-estradiol, leucine as a dispersibility enhancer and lactose as a bulking agent were prepared by spray-drying from aqueous ethanol formulations. The influence of formulation components on the characteristics of the resultant spray-dried powders was examined through the use of a range of ethanol concentrations (10–50% v/v) in the solvent used to prepare the initial formulations. Additionally, the amount of leucine required to act as a dispersibility enhancer was investigated by varying the amount of leucine added to the formulation prior to spray-drying. Following spray-drying, resultant powders were characterised using scanning electron microscopy, laser diffraction and tapped density measurements, and the aerosolisation performance determined using Twin Stage Impinger and Andersen Cascade Impactor analysis. We demonstrate that selection of appropriate solvent systems and leucine concentration allows the preparation of spray-dried powders that display enhanced aerosolisation properties, and would be predicted to exhibit high deposition in the lower regions of the respiratory tract

Carbomer-modified Spray-dried Respirable Powders for Pulmonary Delivery of Salbutamol Sulphate

The present study investigates the feasibility of using two types of carbomer (971 and 974) to prepare inhalable dry powders that exhibit modified drug release properties. Powders were prepared by spray-drying formulations containing salbutamol sulphate, 20-50% w/w carbomer as a drug release modifier and leucine as an aerosolization enhancer. Following physical characterization of the powders, the aerosolization and dissolution properties of the powders were investigated using a Multi-Stage Liquid Impinger and a modified USP II dissolution apparatus, respectively. All carbomer 974-modified powders and the 20% carbomer 971 powder demonstrated high dispersibility, with emitted doses of at least 80% and fine particle fractions of approximately 40%. The release data indicated that all carbomer-modified powders displayed a sustained release profile, with carbomer 971-modified powders obeying first order kinetics, whereas carbomer 974-modified powders obeyed the Higuchi root time kinetic model; increasing the amount of carbomer 971 in the formulation did not extend the duration of drug release, whereas this was observed for the carbomer 974-modified powders. These powders would be anticipated to deposit predominately in the lower regions of the lung following inhalation and then undergo delayed rather than instantaneous drug release, offering the potential to reduce dosing frequency and improve patient compliance