Perspectives on systematic capacity building in pharmaceutical regulation for regulators of medical products

Having a robust, integrated regulatory system is important for ensuring the availability of safe and efficacious medical products of good quality and for protecting public health. However, less than 30% of countries globally have reached the required regulatory maturity level three, with low- and middle-income countries facing challenges in attracting and retaining qualified staff. World Health Organization (WHO) advocates for systematic workforce development, including competency-based education, to address these gaps. We provide perspectives on a systematic approach to capacity building of medicine regulators based on the experience and lessons learnt in developing and piloting the WHO global competency framework for medicine regulators through three scenarios. A systematic approach to capacity building, such as the human performance technology model, can be used to implement the WHO competency framework as part of organizational performance improvement while ensuring that initiatives are well-defined, targeted, and aligned with organizational goals. The competency framework can be used in different contexts, such as improving organization performance for individual regulatory authorities, strengthening regional collaborations, harmonization and reliance on medical products assessment and joint good manufacturing practices inspections of pharmaceutical manufacturers, and developing learning programs for medicine regulators. A competency-based learning approach for regulatory professionals ensures the transfer of learning to the workplace by integrating real-world practices in learning activities and assessments. Further work is required to develop and validate the assessment instruments, apply the competency framework in other contexts, expanding the learning programmes while continuously providing feedback for further refinement of the competency framework and implementation support tools.

Selenium Nanoparticle Activity against S. mutans Biofilms as a Potential Treatment Alternative for Periodontitis

The disruption of periodontal biofilms and prevailing antimicrobial resistance issues continue to pose a great challenge to the treatment of periodontitis. Here, we report on selenium nanoparticles (SeNPs) as a treatment alternative for periodontitis by determining their antibiofilm activity against S. mutans biofilms and the potential role of particle size in disrupting biofilms. SeNPs were synthesised via a reduction reaction. Various physicochemical characterisations were conducted on the NPs, including size and shape. The microbroth dilution method was used to conduct the biofilm and antibiofilm assay against S. mutans, which was analysed by absorbance. SeNPs displayed hydrodynamic sizes as low as 46 ± 4 nm at a volume ratio of 1:5 (sodium selenite/ascorbic acid) with good monodispersity and stability. Hydrodynamic sizes of SeNPs after resuspension in tryptic soy broth supplemented with 2.5% sucrose (TSB + 2.5% suc.) and incubated at 37 °C for 24 h, ranged from 112 to 263 nm, while the zeta potential values increased to greater than -11 mV. The biofilm assay indicated that S. mutans are weakly adherent, bordering on moderately adherent biofilm producers. The minimum biofilm inhibitory concentration (MBIC) was identified at 500 µg/mL. At a 1000 µg/mL concentration, SeNPs were able to inhibit S. mutan biofilms up to 99.87 ± 2.41% at a volume ratio of 1:1. No correlation was found between antibiofilm activity and particle size; however, antibiofilm activity was proven to be concentration-dependant. SeNPs demonstrate antibiofilm activity and may be useful for further development in treating periodontitis.

The process of ratifying the Treaty to establish the African Medicines Agency: perspectives of National Regulatory Agencies

The vision of the African Medicines Agency (AMA) is to ensure that all Africans have access to affordable medical products that meet internationally recognised standards of quality, safety and efficacy for priority diseases/conditions. The AMA is being established by a treaty which had to be ratified by a minimum of 15 African countries. Although there was no deadline, the ratification process has been slower than expected. This study therefore analysed the rationale, perceived benefits, enabling factors and challenges of the AMA's establishment. This study was a qualitative, cross-sectional, census survey of the national medicines regulatory authorities (NRAs) of 45 African countries. The heads of NRAs and a senior NRA staff member were contacted to complete self-administered questionnaires. The existence of mature NRAs, the desire to have harmonised regulatory systems, the presence of strong political will and appropriate advocacy to expedite treaty signing are all enabling factors for AMA treaty signing. The challenges reported include the fact that the process is slow and there is limited understanding of the process. Competing national priorities, changes in office bearers in the public system and stagnation of the process at the ministerial level were also challenges reported. This study has improved the understanding of the treaty signing and ratification process, and the perceived benefits and enabling factors of signing and ratification from African NRAs' perspective. NRAs also highlighted challenges encountered in the process. Addressing these challenges will result in effective medicines regulation by galvanising technical support, regulatory expertise and resources at a continental level.

Minimum Information for Conducting and Reporting In Vitro Intracellular Infection Assays

Bacterial pathogens are constantly evolving to outsmart the host immune system and antibiotics developed to eradicate them. One key strategy involves the ability of bacteria to survive and replicate within host cells, thereby causing intracellular infections. To address this unmet clinical need, researchers are adopting new approaches, such as the development of novel molecules that can penetrate host cells, thus exerting their antimicrobial activity intracellularly, or repurposing existing antibiotics using nanocarriers (i.e., nanoantibiotics) for site-specific delivery. However, inconsistency in information reported across published studies makes it challenging for scientific comparison and judgment of experiments for future direction by researchers. Together with the lack of reproducibility of experiments, these inconsistencies limit the translation of experimental results beyond pre-clinical evaluation. Minimum information guidelines have been instrumental in addressing such challenges in other fields of biomedical research. Guidelines and recommendations provided herein have been designed for researchers as essential parameters to be disclosed when publishing their methodology and results, divided into four main categories: (i) experimental design, (ii) establishing an in vitro model, (iii) assessment of efficacy of novel therapeutics, and (iv) statistical assessment. These guidelines have been designed with the intention to improve the reproducibility and rigor of future studies while enabling quantitative comparisons of published studies, ultimately facilitating translation of emerging antimicrobial technologies into clinically viable therapies that safely and effectively treat intracellular infections.

Ionome mapping and amino acid metabolome profiling of Phaseolus vulgaris L. seeds imbibed with computationally informed phytoengineered copper sulphide nanoparticles

This study reports the effects of a computationally informed and avocado-seed mediated Phyto engineered CuS nanoparticles as fertilizing agent on the ionome and amino acid metabolome of Pinto bean seeds using both bench top and ion beam analytical techniques. Physico-chemical analysis of the Phyto engineered nanoparticles with scanning-electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier Transform Infrared Spectroscopy confirmed the presence of CuS nanoparticles. Molecular dynamics simulations to investigate the interaction of some active phytocompounds in avocado seeds that act as reducing agents with the nano-digenite further showed that 4-hydroxybenzoic acid had a higher affinity for interacting with the nanoparticle's surface than other active compounds. Seeds treated with the digenite nanoparticles exhibited a unique ionome distribution pattern as determined with external beam proton-induced X-ray emission, with hotspots of Cu and S appearing in the hilum and micropyle area that indicated a possible uptake mechanism via the seed coat. The nano-digenite also triggered a plant stress response by slightly altering seed amino acid metabolism. Ultimately, the nano-digenite may have important implications as a seed protective or nutritive agent as advised by its unique distribution pattern and effect on amino acid metabolism.

Nanophytomedicines as Therapeutic Agents for Parkinson's Disease

Phytochemicals are promising therapeutics for various neurodegenerative disorders, including Parkinson's disease (PD). However, their efficacy, pharmacokinetic properties, and penetration across the blood-brain barrier can be improved using delivery systems such as nanoparticles. We reviewed recently published work in which nanoparticles were used to deliver phytochemicals toward PD treatment. The studies show that nanoparticles not only improve the pharmacological effect of the phytochemicals but also enable targeting to the brain and crossing of the blood-brain barrier. Various ligands were added to the nanoparticles to improve blood-brain barrier transportation. The promising findings from the published studies reveal that more research into nanophytomedicine approaches as therapeutic targets for PD is warranted, especially since they have the potential to protect against key features of PD, including α-synuclein aggregation, mitochondrial dysfunction, and dopaminergic neuronal death. Furthermore, future directions should involve smart designs to tailor nanoparticles for improved therapeutic delivery by modifying their features, such as architecture, surface and material properties, targeting ligands, and responsiveness.

Investigation and Evaluation of the Transdermal Delivery of Ibuprofen in Various Characterized Nano-Drug Delivery Systems

The aim was to assess the suitability of three nano-based transdermal drug delivery systems containing ibuprofen: a nano-emulsion, a nano-emulgel, and a colloidal suspension with ibuprofen-loaded nanoparticles. Understanding the transdermal delivery of ibuprofen using nano-based drug delivery systems can lead to more effective pain relief and improved patient compliance. Characterization tests assessed the suitability of the developed drug delivery systems. Membrane release and skin diffusion studies, along with tape stripping, were performed to determine drug release and skin permeation of ibuprofen. In vitro cytotoxicity studies on HaCaT cells were conducted using MTT and neutral red assays to evaluate the safety of the developed drug delivery systems. Characterization studies confirmed stable drug delivery systems with ideal properties for transdermal delivery. Membrane release studies demonstrated the successful release of ibuprofen. In vitro skin diffusion experiments and tape stripping, detecting ibuprofen in the receptor phase, stratum corneum-epidermis, and epidermis-dermis, indicating successful transdermal and topical delivery. The in vitro cytotoxicity studies observed only minor cytotoxic effects on HaCaT cells, indicating the safety of the developed drug delivery systems. The investigation demonstrated promising results for the transdermal delivery of ibuprofen using the developed drug delivery systems, which contributes to valuable insights that may lead to improved pain management strategies.

Biosensors as early warning detection systems for waterborne Cryptosporidium

Waterborne disease is a global health threat contributing to a high burden of diarrhoeal disease, and growing evidence indicates a prospective increase in incidence coinciding with the profound effects of climate change. A major causative agent of gastrointestinal disease is Cryptosporidium, a protozoan waterborne parasite identified in over 70 countries. Cryptosporidium is a cause of high disease morbidity in children and the immunocompromised with limited treatment options for patients at risk of severe illness. The hardy nature of the organism leads to its persistence in various water sources, with certain water treatment procedures proving inefficient for its complete removal. While diagnostic methods for Cryptosporidium are well-defined in the clinical sphere, detection of Cryptosporidium in water sources remains suboptimal due to low dispersion of organisms in large sample volumes, lengthy processing times and high costs of equipment and reagents. A need for improvement exists to identify the organism as an emerging threat in domestic water systems, and the technological advantages that biosensors offer over current analytical methods may provide a preventative approach to outbreaks of Cryptosporidium. Biosensors are innovative, versatile and adaptable analytical tools that could provide highly sensitive, rapid, on-site analysis needed for Cryptosporidium detection in low-resource settings.

Chitosan-coated liposomes of Carrisa spinarum extract: synthesis, analysis and anti-pneumococcal potency

In the present study, a chitosan (CS)-coated liposome (LipCsP-Chitosan) nanocarrier was fabricated for the delivery of Carissa spinarum (CsP) polyphenols to improve bioavailability and anti-pneumococcal potential against Klebsiella pneumoniae. LipCsP-Chitosan was synthesized by the ion gelation method and characterized by using a Malvern zetasizer and Fourier Transform Infrared (FTIR); CsP encapsulation and release kinetics were investigated. Anti-pneumococcal activity of the nanoformulations was accessed by agar-well diffusion and microdilution assays. LipCsP-chitosan exhibited a hydrodynamic size and zeta potential of 365.22 ± 0.70 nm and +39.30 ± 0.61 mV, respectively. CsP had an encapsulation efficiency of 81.5%. FTIR analysis revealed the interaction of the liposomes with chitosan and the CsP. A biphasic CsP release profile followed by a sustained release pattern was observed. LiPCsP-Chitosan presented a higher bioaccessibility of polyphenols in the simulated gastric phase (74.1% ± 1.3) than in the simulated intestinal phase (63.32% ± 1.00). LipCsP-chitosan had a relative inhibition zone diameter of 84.33% ± 2.51 when compared to CsP. At minimum inhibition concentration of 31.25 mg/mL, LipCsP-Chitosan reduced the viability of Klebsiella pneumoniae by 57.45% ± 3.76 after 24 h. The results obtained from the current study offer a new approach to the utilization of LipCsP-Chitosan as nanocarriers for candidate anti-pneumococcal agents.

The domestication of the African Union model law on medical products regulation: Perceived benefits, enabling factors, and challenges

Introduction

In 2016, the African Union (AU) Model Law on Medical Products Regulation was endorsed by AU Heads of State and Government. The aims of the legislation include harmonisation of regulatory systems, increasing collaboration across countries, and providing a conducive regulatory environment for medical product/health technology development and scale-up. A target was set to have at least 25 African countries domesticating the model law by 2020. However, this target has not yet been met. This research aimed to apply the Consolidated Framework for Implementation Research (CFIR) in analysing the rationale, perceived benefits, enabling factors, and challenges of AU Model Law domestication and implementation by AU Member States.

Methods

This study was a qualitative, cross-sectional, census survey of the national medicines regulatory authorities (NRAs) of Anglophone and Francophone AU Member States. The heads of NRAs and a senior competent person were contacted to complete self-administered questionnaires.

Results

The perceived benefits of model law implementation include enabling the establishment of an NRA, improving NRA governance and decision-making autonomy, strengthening the institutional framework, having streamlined activities which attract support from donors, as well as enabling harmonisation, reliance, and mutual recognition mechanisms. The factors enabling domestication and implementation are the presence of political will, leadership, and advocates, facilitators, or champions for the cause. Additionally, participation in regulatory harmonisation initiatives and the desire to have legal provisions at the national level that allow for regional harmonisation and international collaboration are enabling factors. The challenges encountered in the process of domesticating and implementing the model law are the lack of human and financial resources, competing priorities at the national level, overlapping roles of government institutions, and the process of amending/repealing laws being slow and lengthy.

Conclusion

This study has enabled an improved understanding of the AU Model Law process, the perceived benefits of its domestication, and the enabling factors for its adoption from the perspective of African NRAs. NRAs have also highlighted the challenges encountered in the process. Addressing these challenges will result in a harmonised legal environment for medicines regulation in Africa and be an important enabler for the effective operation of the African Medicines Agency.

Situation analysis on the regulation of nanomedicines in Southern Africa

Background

Medical products incorporating nanoparticle drug delivery systems (nanomedicines) are therapeutic or imaging agents, which comprise a delivery system within the nanometer size range (1 - 1000 nm). As medical products, nanomedicines meet definitions of medicines according to various national legislations for regulation of medicines. However, for the regulation of nanomedicines, additional assessments including toxicological issues have to be considered. These complexities require extra regulatory effort. In the resource-limited context of low- and middle-income countries, many National Medicines Regulatory Authorities (NMRAs) lack resources and capacities to effectively assure the quality of medicinal products in their countries. With emerging trends in innovative technologies, including nanotechnology, this burden is worsened. The need to overcome regulatory challenges drove the formation of a work sharing initiative in the Southern African Development Community (SADC), ZaZiBoNA in 2013. Regulatory agencies participating in this initiative cooperate in the assessment of applications for registration of medicines.

Methods

A cross-sectional exploratory study design with qualitative techniques was used to investigate the status of the regulation of nanomedicines in Southern African countries in particular those participating in the ZaZiBoNA initiative.

Results

The study found that in general, NMRAs are aware of the existence of nanomedicines and they apply legislation applicable to other medical products. The NMRAs however neither have specific definition for nanomedicines and technical guidance documents, nor technical committees specific for consideration of nanomedicines. Collaboration with external experts or organisations in the regulation of nanomedicines was also found to be lacking.

Discussion

Capacity building and collaboration in the area of regulation of nanomedicines is strongly encouraged.

Collaborative reliance in medicine safety and quality regulation: Investigation of experiences in handling N-nitrosamine impurities among ZaZiBoNa participating countries

Introduction

The presence of N-nitrosamine impurities in medicines raised concerns globally as they are genotoxic and probable human carcinogens. A review of N-nitrosamine impurities in medicines provides an opportunity for National Regulatory Authorities (NRAs) to ensure that corrective and preventive actions are applied so that safe and good quality medicines are made available to the public. This study aimed to investigate the experiences on reviews conducted by NRAs from various Southern African Development Community countries which participate in the regional work-sharing forum, ZaZiBoNa, on the quality and safety data due to the presence of N-nitrosamine impurities in medicines.

Methods

A comparative, descriptive study using mixed methods was conducted. Purposive sampling was applied in selecting research participants based on their participation status in the ZaZiBoNa initiative. A standardized questionnaire structured into five parts was completed by ZaZiBoNa focal persons/nominated individuals to determine the experience of each NRA in addressing the safety and quality issues related to the presence of N-nitrosamine impurities in the affected medicines. Profiled medicines included sartans, ranitidine, metformin, rifampicin, and rifapentine.

Results

Sartan medicines had been reviewed by all countries participating in the ZaZiBoNa initiative. Although most NRAs have yet to conduct reviews on other profiled medicines, evaluations have been implemented to ensure access to safe and good quality medicines within the region. Most countries experienced challenges in communicating with applicants or marketing authorization holders (MAHs) on reviewing N-nitrosamine impurities in their medicines. The majority of NRAs agree that there is a need for further collaboration efforts to review N-nitrosamine impurities in medicines.

Conclusion

The review of N-nitrosamine impurities in the profiled medicines by NRAs within the region has demonstrated the importance of enhanced regulatory oversight to safeguard against the risks associated with medicines. Collaborative reliance on the review of the safety and quality of medicine, continuous monitoring, implementation and review of processes, testing methods, and regular engagements with stakeholders could be essential in ensuring adequate control of N-nitrosamine impurities in medicines.

Cathelicidins and defensins antimicrobial host defense peptides in the treatment of TB and HIV: Pharmacogenomic and nanomedicine approaches towards improved therapeutic outcomes

Tuberculosis (TB) and human immunodeficiency virus (HIV) represent a significant burden of disease on a global scale. Despite improvements in the global epidemic status, largely facilitated by increased access to pharmacotherapeutic interventions, slow progress in the development of new clinical interventions coupled with growing antimicrobial resistance to existing therapies represents a global health crisis. There is an urgent need to expand the armamentarium of TB and HIV therapeutic strategies. Host mediated immune responses represent an untapped reservoir of novel approaches for TB and HIV. Antimicrobial peptides (AMPs) are an essential aspect of the immune system. Cathelicidins and defensins AMPs have been studied for their potential applications in TB and HIV therapeutic interventions. Genetic polymorphism across different population groups may affect endogenous expression or activity of AMPs, potentially influencing therapeutic outcomes. However, certain genetic polymorphisms in autophagy pathways may alter the downstream effects of nano-delivery of cathelicidin. On the other hand, certain genetic polymorphisms in beta-defensins may provide a protective role in reducing HIV-1 mother-to-child-transmission. Pharmaceutical development of cathelicidins and defensins is disadvantaged with complex challenges. Nanoparticle formulations improve pharmacokinetics and biocompatibility while facilitating targeted drug delivery, potentially minimising the risk of immunogenicity or non-specific haemolytic activity. This review aims to explore the potential viability of using cathelicidins and defensins as novel pharmacotherapy in the management of TB and HIV, highlight potential pharmacogenomic implications in host mediated immunity and AMP therapeutic applications, as well as propose novel drug delivery strategies represented by nanomedicine for AMPs.

Physicochemical and Biological Evaluation of Curdlan-Poly(Lactic-Co-Glycolic Acid) Nanoparticles as a Host-Directed Therapy Against Mycobacterium Tuberculosis

Nanoparticles (NPs) that can activate macrophages infected with the tuberculosis causative pathogen Mycobacterium tuberculosis, could be an effective host directed therapy for the disease. In this study, curdlan was conjugated to poly(lactic-co-glycolic acid) (PLGA) to produce immunotherapeutic NPs. Various physicochemical characterizations were used to evaluate the curdlan-PLGA copolymer and the NPs. Molecular dynamics and simulation studies were used to characterize the interaction between curdlan, on the polymer and on NPs, with the Dectin-1 macrophage receptor. NPs with varying curdlan densities were evaluated for their effects on the production of pro- and anti-inflammatory cytokines in M. tuberculosis infected RAW264.7 macrophages. The killing efficacy of the NPs against intracellular M. tuberculosis was assessed. Physicochemical characterization of the curdlan-PLGA copolymer and NPs indicated successful formation of curdlan-PLGA copolymer and NPs of varying curdlan density (0-8% w/w) had sizes between 330 and 453 nm. Modelling studies showed curdlan to have a strong affinity for Dectin-1. Cytotoxicity assays showed the NPs to be non-toxic over 72 h. The proinflammatory cytokine TNF-α was found to be significantly upregulated by the NPs. The NPs reduced intracellular M. tuberculosis burden over 72 h. These NPs are a promising host directed therapy for intracellular eradication of M. tuberculosis.

A Perspective on Nanotechnology and COVID-19 Vaccine Research and Production in South Africa

Advances in nanotechnology have enabled the development of a new generation of vaccines, which are playing a critical role in the global control of the COVID-19 pandemic and the return to normalcy. Vaccine development has been conducted, by and large, by countries in the global north. South Africa, as a major emerging economy, has made extensive investments in nanotechnology and bioinformatics and has the expertise and resources in vaccine development and manufacturing. This has been built at a national level through decades of investment. In this perspective article, we provide a synopsis of the investments made in nanotechnology and highlight how these could support innovation, research, and development for vaccines for this disease. We also discuss the application of bioinformatics tools to support rapid and cost-effective vaccine development and make recommendations for future research and development in this area to support future health challenges.

Permeation Challenges of Drugs for Treatment of Neurological Tuberculosis and HIV and the Application of Magneto-Electric Nanoparticle Drug Delivery Systems

The anatomical structure of the brain at the blood-brain barrier (BBB) creates a limitation for the movement of drugs into the central nervous system (CNS). Drug delivery facilitated by magneto-electric nanoparticles (MENs) is a relatively new non-invasive approach for the delivery of drugs into the CNS. These nanoparticles (NPs) can create localized transient changes in the permeability of the cells of the BBB by inducing electroporation. MENs can be applied to deliver antiretrovirals and antibiotics towards the treatment of human immunodeficiency virus (HIV) and tuberculosis (TB) infections in the CNS. This review focuses on the drug permeation challenges and reviews the application of MENs for drug delivery for these diseases. We conclude that MENs are promising systems for effective CNS drug delivery and treatment for these diseases, however, further pre-clinical and clinical studies are required to achieve translation of this approach to the clinic.

Recent Advances in the Development of Antimicrobial and Antifouling Biocompatible Materials for Dental Applications

The risk of secondary bacterial infections resulting from dental procedures has driven the design of antimicrobial and antifouling dental materials to curb pathogenic microbial growth, biofilm formation and subsequent oral and dental diseases. Studies have investigated approaches based primarily on contact-killing or release-killing materials. These materials are designed for addition into dental resins, adhesives and fillings or as immobilized coatings on tooth surfaces, titanium implants and dental prosthetics. This review discusses the recent developments in the different classes of biomaterials for antimicrobial and antifouling dental applications: polymeric drug-releasing materials, polymeric and metallic nanoparticles, polymeric biocides and antimicrobial peptides. With modifications to improve cytotoxicity and mechanical properties, contact-killing and anti-adhesion materials show potential for incorporation into dental materials for long-term clinical use as opposed to short-lived antimicrobial release-based coatings. However, extended durations of biocompatibility testing, and adjustment of essential biomaterial features to enhance material longevity in the oral cavity require further investigations to confirm suitability and safety of these materials in the clinical setting. The continuous exposure of dental restorative and regenerative materials to pathogenic microbes necessitates the implementation of antimicrobial and antifouling materials to either replace antibiotics or improve its rational use, especially in the day and age of the ever-increasing problem of antimicrobial resistance.

Establishment of the African Medicines Agency: progress, challenges and regulatory readiness

Insufficient access to quality, safe, efficacious and affordable medical products in Africa has posed a significant challenge to public health for decades. In part, this is attributed to weak or absent policies and regulatory systems, a lack of competent regulatory professionals in National Medicines Regulatory Authorities (NMRAs) and ineffective regional collaborations among NMRAs. In response to national regulatory challenges in Africa, a number of regional harmonisation efforts were introduced through the African Medicines Regulatory Harmonisation (AMRH) initiative to, among others, expedite market authorisation of medical products and to facilitate the alignment of national legislative frameworks with the AU Model Law on Medical Products Regulation. The goals of the model law include to increase collaboration across countries and to facilitate the overall regional harmonisation process. The AMRH initiative is proposed to serve as the foundation for the establishment of the African Medicines Agency (AMA). The AMA will, as one of its mandates, coordinate the regional harmonisation systems that are enabled by AU Model Law domestication and implementation. In this paper, we review the key entities involved in regional and continental harmonisation of medicines regulation, the milestones achieved in establishing the AMA as well as the implementation targets and anticipated challenges related to the AU Model Law domestication and the AMA's establishment. This review shows that implementation targets for the AU Model Law have not been fully met, and the AMA treaty has not been ratified by the minimum required number of countries for its establishment. In spite of the challenges, the AU Model Law and the AMA hold promise to address gaps and inconsistencies in national regulatory legislation as well as to ensure effective medicines regulation by galvanising technical support, regulatory expertise and resources at a continental level. Furthermore, this review provides recommendations for future research.

Curdlan-Chitosan Electrospun Fibers as Potential Scaffolds for Bone Regeneration

Polysaccharides have received a lot of attention in biomedical research for their high potential as scaffolds owing to their unique biological properties. Fibrillar scaffolds made of chitosan demonstrated high promise in tissue engineering, especially for skin. As far as bone regeneration is concerned, curdlan (1,3-β-glucan) is particularly interesting as it enhances bone growth by helping mesenchymal stem cell adhesion, by favoring their differentiation into osteoblasts and by limiting the osteoclastic activity. Therefore, we aim to combine both chitosan and curdlan polysaccharides in a new scaffold for bone regeneration. For that purpose, curdlan was electrospun as a blend with chitosan into a fibrillar scaffold. We show that this novel scaffold is biodegradable (8% at two weeks), exhibits a good swelling behavior (350%) and is non-cytotoxic in vitro. In addition, the benefit of incorporating curdlan in the scaffold was demonstrated in a scratch assay that evidences the ability of curdlan to express its immunomodulatory properties by enhancing cell migration. Thus, these innovative electrospun curdlan–chitosan scaffolds show great potential for bone tissue engineering.

The Macrophage Response to Mycobacterium tuberculosis and Opportunities for Autophagy Inducing Nanomedicines for Tuberculosis Therapy

The major causative agent of tuberculosis (TB), i.e., Mycobacterium tuberculosis (Mtb), has developed mechanisms to evade host defense responses and persist within host cells for prolonged periods of time. Mtb is also increasingly resistant to existing anti-TB drugs. There is therefore an urgent need to develop new therapeutics for TB and host directed therapies (HDTs) hold potential as effective therapeutics for TB. There is growing interest in the induction of autophagy in Mtb host cells using autophagy inducing compounds (AICs). Nanoparticles (NPs) can enhance the effect of AICs, thus improving stability, enabling cell targeting and providing opportunities for multimodal therapy. In this review, we focus on the macrophage responses to Mtb infection, in particular, the mechanistic aspects of autophagy and the evasion of autophagy by intracellular Mtb. Due to the overlap between the onset of autophagy and apoptosis; we also focus on the relationship between apoptosis and autophagy. We will also review known AICs in the context of Mtb infection. Finally, we discuss the applications of NPs in inducing autophagy with the intention of sharing insights to encourage further research and development of nanomedicine HDTs for TB therapy.

Hybrid Curdlan Poly(γ -Glutamic Acid) Nanoassembly for Immune Modulation in Macrophage

A nanoformulation composed of curdlan, a linear polysaccharide of 1,3-β-linked d-glucose units, hydrogen bonded to poly(γ -glutamic acid) (PGA), was developed to stimulate macrophage. Curdlan/PGA nanoparticles (C-NP) are formulated by physically blending curdlan (0.2 mg mL^-1 in 0.4 m NaOH) with PGA (0.8 mg mL^-1 ). Forster resonance energy transfer (FRET) analysis demonstrates a heterospecies interpolymer complex formed between curdlan and PGA. The ¹ H-NMR spectra display significant peak broadening as well as downfield chemical shifts of the hydroxyl proton resonances of curdlan, indicating potential intermolecular hydrogen bonding interactions. In addition, the cross peaks in ¹ H-¹ H 2D-NOESY suggest intermolecular associations between the OH-2/OH-4 hydroxyl groups of curdlan and the carboxylic-/amide-groups of PGA via hydrogen bonding. Intracellular uptake of C-NP occurs over time in human monocyte-derived macrophage (MDM). Furthermore, C-NP nanoparticles dose-dependently increase gene expression for TNF-α, IL-6, and IL-8 at 24 h in MDM. C-NP nanoparticles also stimulate the release of IL-lβ, MCP-1, TNF-α, IL-8, IL-12p70, IL-17, IL-18, and IL-23 from MDM. Overall, this is the first demonstration of a simplistic nanoformulation formed by hydrogen bonding between curdlan and PGA that modulates cytokine gene expression and release of cytokines from MDM.

Comparative whole corona fingerprinting and protein adsorption thermodynamics of PLGA and PCL nanoparticles in human serum

Nanoparticles (NPs) based on biocompatible and biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) and polycaprolactone (PCL) represent effective systems for systemic drug delivery. Upon injection into the blood circuit, the NP surface is rapidly modified due to adsorption of proteins that form a 'protein corona' (PC). The PC plays an important role in cellular targeting, uptake and NP bio-distribution. Hence, the study of interactions between NPs and serum proteins appears as key for biomedical applications and safety of NPs. In the present work, we report on the comparative protein fluorescence quenching extent, thermodynamics of protein binding and identification of proteins in the soft and hard corona layers of PLGA and PCL NPs. NPs were prepared via a single emulsion-solvent evaporation technique and characterized with respect to size, zeta potential, surface morphology and hydrophobicity. Protein fluorescence quenching experiments were performed against human serum albumin. The thermodynamics of serum protein binding onto the NPs was studied using isothermal titration calorimetry. Semi-quantitative analysis of proteins in the PC layers was conducted using gel electrophoresis and mass spectrometry using human serum. Our results demonstrated the influence of particle hydrophobicity on the thermodynamics of protein binding. Human serum proteins bind to a greater extent and with greater affinity to PCL NPs than PLGA NPs. Several proteins were detected in the hard and soft corona of the NPs, representing their unique proteome fingerprints. Some proteins were unique to the PCL NPs. We anticipate that our findings will assist with rational design of polymeric NPs for effective drug delivery applications.

Encapsulation of Variabilin in Stearic Acid Solid Lipid Nanoparticles Enhances Its Anticancer Activity in Vitro

The use of natural products as chemotherapeutic agents is well established; however, many of these are associated with undesirable side effects, including high toxicity and instability. Furthermore, the development of drug resistant cancers makes the search for new anticancer lead compounds a priority. In this study, the extraction of an Ircinia sp. sponge resulted in the isolation of an inseparable mixture of (7E,12E,20Z)-variabilin (1) and (7E,12Z,20Z)-variabilin (2) and structural assignment was established using standard 1D and 2D NMR experiments. The cytotoxic activity of the compound against three solid tumour cell lines displayed moderate anti-cancer activity through apoptosis, together with a general lack of selectivity among the cancer cell lines studied. Structural assignment and cytotoxic evaluation of variabilin was complicated and further aggravated by its inherent instability. Variabilin was therefore incorporated into solid lipid nanoparticles (SLNs) and the stability and cytotoxic activity evaluated. Encapsulation of variabilin into SLNs led to a marked improvement in stability of the natural product coupled with enhanced cytotoxic activity, particularly against the prostate (PC-3) cancer cell line, with IC50 values of 87.74 μM vs. 8.94 μM for the variabilin alone and Var-SLN, respectively. Both variabilin and Var-SLN revealed comparable activity to Ceramide against the MCF-7 breast cancer cell line, revealing IC50 values of 34.8, 38.1 and 33.6 μM for variabilin, Var-SLN and Ceramide, respectively. These samples revealed no activity (>100 μM for all) against HT-29 (colon) cell lines and MCF-12 (normal breast) cell lines. Var-SLNs induced 47, 48 and 59% of apoptosis in HT-29, MCF-7 and PC-3 cells, respectively, while variabilin alone revealed 38, 29 and 29% apoptotic cells for HT-29, MCF-7 and PC-3 cell lines, respectively. The encapsulation of natural products into SLNs may provide a promising approach to overcome some of the issues hindering the development of new anticancer drugs from natural products.

Synthesis, physicochemical characterization, toxicity and efficacy of a PEG conjugate and a hybrid PEG conjugate nanoparticle formulation of the antibiotic moxifloxacin

Moxifloxacin was conjugated to polyethylene glycol to segregate host cell toxicity from antimicrobial activity. The conjugate was then encapsulated into a polycaprolactone nanoparticle to assist the simultaneous delivery of multiple drugs to the site of microbial infection.

Mentored postdoctoral training in Zimbabwe: A report on a successful collaborative effort

Low-and-middle-income countries (LMICs) have high disease burdens, necessitating increased research. However, LMIC research output constitutes only 2% of global total. To increase output, researchers must be capacitated. The University of Zimbabwe (UZ) and the University at Buffalo (UB), developed and implemented the AIDS International Research Training Program (AITRP), in 2008, that focused on graduate scholars. The subsequent HIV Research Training Program (HRTP), begun in 2016, and piloted post-doctoral training to enhance research productivity at UZ. This report discusses the collaboration. As of 2016, prospective candidates applied by submitting letters of intent, research proposals, curriculum vitae and biographical sketches. The scholars research training included hypothesis and project development, completion of grant applications, research project budgets, research presentations to diverse audiences and the application of advanced statistics to research data. The first cohort of five postdoctoral scholars were trained at UZ and UB, between 2016 and 2019. Through the formalized postdoctoral training approach, scholars identified areas of focus. In 2017, one of the scholars obtained a National Institutes of Health (NIH) Emerging Global Leader Award and is now a highly-rated researcher based in South Africa. A second scholar made NIH D43 and K43 grant applications, while the remaining three are academicians and early researchers at UZ. Although research output in Africa and many LMICs is low, it can be built through cooperation similar to the UZ-UB HRTP. This manuscript reports on an effort aimed at building individual and institutional research capacity in Zimbabwe. This can serve as a model for building other similar training programs.

Nanotechnology advances towards development of targeted-treatment for obesity

Obesity through its association with type 2 diabetes (T2D), cancer and cardiovascular diseases (CVDs), poses a serious health threat, as these diseases contribute to high mortality rates. Pharmacotherapy alone or in combination with either lifestyle modification or surgery, is reliable in maintaining a healthy body weight, and preventing progression to obesity-induced diseases. However, the anti-obesity drugs are limited by non-specificity and unsustainable weight loss effects. As such, novel and improved approaches for treatment of obesity are urgently needed. Nanotechnology-based therapies are investigated as an alternative strategy that can treat obesity and be able to overcome the drawbacks associated with conventional therapies. The review presents three nanotechnology-based anti-obesity strategies that target the white adipose tissues (WATs) and its vasculature for the reversal of obesity. These include inhibition of angiogenesis in the WATs, transformation of WATs to brown adipose tissues (BATs), and photothermal lipolysis of WATs. Compared to conventional therapy, the targeted-nanosystems have high tolerability, reduced side effects, and enhanced efficacy. These effects are reproducible using various nanocarriers (liposomes, polymeric and gold nanoparticles), thus providing a proof of concept that targeted nanotherapy can be a feasible strategy that can combat obesity and prevent its comorbidities.

Influence of PEGylation on PLGA nanoparticle properties, hydrophobic drug release and interactions with human serum albumin

Objective

To evaluate the impact of PEG content on poly(lactic-co-glycolic acid) (PLGA) NP physicochemical properties, hydrophobic drug release (rifampicin as a model drug) and human serum protein binding.

Methods

Rifampicin loaded and unloaded nanoparticles with PEG content of 0–17% (w/w) were prepared by an emulsification–evaporation technique. Nanoparticles were characterized for size, zeta potential and morphology. PEGlyation was confirmed using proton nuclear magnetic resonance (1H NMR). Fluorescence spectroscopy and dynamic light scattering were used to determine nanoparticle-protein binding, binding constants and stability of nanoparticles in human serum, respectively. Drug loading and release were determined by UV-VIS spectroscopy and drug release data was mathematically modelled.

Key findings

A NP PEG content of 17% w/w significantly retarded release of rifampicin from PLGA NPs and altered kinetics of drug release. Stern–Volmer (Ksv) protein binding constants decreased upon PEG incorporation. A 2% w/w PEG was sufficient to significantly reduce protein binding extent to PLGA NPs and maintain particle size distributions.

Conclusion

The ability to fine tune drug release and formation of protein corona around nanoparticles is crucial to formulation scientists. This study suggests that PLGA NPs with low PEG content might be suitable for extended circulation and rapid drug release and that higher PEG content retards hydrophobic drug release.

Comparative in vitro transportation of pentamidine across the blood-brain barrier using polycaprolactone nanoparticles and phosphatidylcholine liposomes

Nanoparticles (NPs) have gained importance in addressing drug delivery challenges across biological barriers. Here, we reformulated pentamidine, a drug used to treat Human African Trypanosomiasis (HAT) in polymer based nanoparticles and liposomes and compared their capability to enhance pentamidine penetration across blood brain barrier (BBB). Size, polydispersity index, zeta potential, morphology, pentamidine loading and drug release profiles were determined by various methods. Cytotoxicity was tested against the immortalized mouse brain endothelioma cells over 96 h. Moreover, cells monolayer integrity and transportation ability were examined for 24 h. Pentamidine-loaded polycaprolactone (PCL) nanoparticles had a mean size of 267.58, PDI of 0.25 and zeta potential of -28.1 mV and pentamidine-loaded liposomes had a mean size of 119.61 nm, PDI of 0.25 and zeta potential 11.78. Pentamidine loading was 0.16 µg/mg (w/w) and 0.17 µg/mg (w/w) in PCL NPs and liposomes respectively. PCL nanoparticles and liposomes released 12.13% and 22.21% of pentamidine respectively after 24 h. Liposomes transported 87% of the dose, PCL NPs 66% of the dose and free pentamidine penetration was 63% of the dose. These results suggest that liposomes are comparatively promising nanocarriers for transportation of pentamidine across BBB.

Polymeric Micellar Formulation Enhances Antimicrobial and Anticancer Properties of Salinomycin

PURPOSE

Salinomycin (SAL) is a polyether compound that exhibits strong antimicrobial as well as anticancer activity. Nanomedicine has been at the forefront of drug delivery research with the aim of increasing the efficacy, specificity and reduce toxicity of drugs. There is an intersection between infection and cancer, and cancer patients are prone to bacterial infections. In this study, polymeric micelles were prepared using Pluronic® F127 (PM) to encapsulate SAL (PM_SAL) with the view of enhancing antimicrobial and anticancer activity.

METHODS

A Quality by Design (QbD) approach was utilized to synthesize PM_SAL, and nanoformulation activity was determined against bacterial (S. aureus, MRSA and E. coli). Effects on cancer cell line A549, i.e. cell viability, prevention of P-gp efflux, vimentin expression, effects on migratory ability of A549 cells. Anticancer activity was determined by ability to eradicate cancer stem-like cells.

RESULTS

PM_SAL demonstrated only efficacy against MRSA, being even higher than that obtained with SAL. In A549 cells, a 15-fold increase in P-gp's expression as well as a significant decrease of the cell's migration, was observed.

CONCLUSIONS

PM_SAL can interfere with the oncogenic protein VIM, involved in the crucial mechanisms EMT, downregulating its expression. Altogether data obtained indicates that this antibiotic and the developed polymeric micelle system is a very promising inhibitor of tumor cell growth.

Mycobacterium Tuberculosis and Interactions with the Host Immune System: Opportunities for Nanoparticle Based Immunotherapeutics and Vaccines

Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a deadly infectious disease. The thin pipeline of new drugs for TB, the ineffectiveness in adults of the only vaccine available, i.e. the Bacillus Calmette-Guerin vaccine, and increasing global antimicrobial resistance, has reinvigorated interest in immunotherapies. Nanoparticles (NPs) potentiate the effect of immune modulating compounds (IMC), enabling cell targeting, improved transfection of antigens, enhanced compound stability and provide opportunities for synergistic action, via delivery of multiple IMCs. In this review we describe work performed in the application of NPs towards achieving immune modulation for TB treatment and vaccination. Firstly, we present a comprehensive review of M. tuberculosis and how the bacterium modulates the host immune system. We find that current work suggest great promise of NP based immunotherapeutics as novel treatments and vaccination systems. There is need to intensify research efforts in this field, and rationally design novel NP immunotherapeutics based on current knowledge of the mycobacteriology and immune escape mechanisms employed by M. tuberculosis.

Functionalization of PLGA Nanoparticles with 1,3-β-glucan Enhances the Intracellular Pharmacokinetics of Rifampicin in Macrophages

PURPOSE

Mycobacterium tuberculosis which causes tuberculosis, is primarily resident within macrophages. 1,3-β-glucan has been proposed as a ligand to target drug loaded nanoparticles (NPs) to macrophages. In this study we characterized the intracellular pharmacokinetics of the anti-tubercular drug rifampicin delivered by 1,3-β-glucan functionalized PLGA NPs (Glu-PLGA). We hypothesized that Glu-PLGA NPs would be taken up at a faster rate than PLGA NPs, and consequently deliver higher amounts of rifampicin into the macrophages.

METHODS

Carbodiimide chemistry was employed to conjugate 1,3-β-glucan and rhodamine to PLGA. Rifampicin loaded PLGA and Glu-PLGA NPs as well as rhodamine functionalized PLGA and Glu-PLGA NPs were synthesized using an emulsion solvent evaporation technique. Intracellular pharmacokinetics of rifampicin and NPs were evaluated in THP-1 derived macrophages. A pharmacokinetic model was developed to describe uptake, and modelling was performed using ADAPT 5 software.

RESULTS

The NPs increased the rate of uptake of rifampicin by a factor of 17 and 62 in case of PLGA and Glu-PLGA, respectively. Expulsion of NPs from the macrophages was also observed, which was 3 fold greater for Glu-PLGA NPs than for PLGA NPs. However, the ratio of uptake to expulsion was similar for both NPs. After 24 h, the amount of rifampicin delivered by the PLGA and Glu-PLGA NPs was similar. The NPs resulted in at least a 10-fold increase in the uptake of rifampicin.

CONCLUSIONS

Functionalization of PLGA NPs with 1,3-β-glucan resulted in faster uptake of rifampicin into macrophages. These NPs may be useful to achieve rapid intracellular eradication of Mycobacterium tuberculosis.

Novel 3D ultrasound system for midline single-operator epidurals: a feasibility study on a porcine model

BACKGROUND

We developed a real-time 3D ultrasound thick slice rendering technique and innovative Epiguide needle-guide as an adjunct to single-operator midline epidural needle insertions. Study goals were to determine feasibility of the technique in a porcine model and compare the visibility of standard and echogenic needles.

METHODS

Thirty-four lumbar needle insertions were performed on six intact porcine spines ex vivo. Ultrasound scanning identified the insertion site and, using an Epiguide, the needle was guided into the epidural space through the ligamentum flavum in the midline plane, watched in real-time on the 3D ultrasound. Entry into the epidural space was judged by a loss-of-resistance technique. Needle visibility was rated by the anesthesiologist performing the technique using a 4-point scale; (0=cannot see, 1=poor, 2=satisfactory, 3=excellent), and later by an independent assessor viewing screenshots. The procedure was repeated at all lumbar levels using either the standard or echogenic needle.

RESULTS

Successful loss-of-resistance to fluid was achieved in 76% of needle insertions; needle visibility with echogenic needles (94.2% rated satisfactory/excellent) was significantly better than with standard needles (29.4% satisfactory/excellent, P<0.0001). Successful loss-of-resistance was 93% when mean needle visibility was rated as 'excellent'. Inter-observer agreement between assessors was 'near-perfect' (weighted kappa=0.83).

CONCLUSION

It is feasible to perform 3D ultrasound-guided real-time single-operator midline epidural insertions, in a porcine model. Echogenic needles were found to consistently improve needle visibility; and improved needle visibility tended to increase successful entry into epidural space.

Spectroscopic investigations on the binding of an iodinated chlorin p6-copper complex to human serum albumin

An iodinated chlorin p₆ copper complex showed high affinity to bind human serum albumin, the binding site was predicted and it was demonstrated that binding did not affect protein conformation.

A randomized controlled trial comparing Ametop™ with placebo for reducing pain associated with local anesthetic skin infiltration before neuraxial anesthesia in parturients

BACKGROUND

Between 10-22% of the general population experience needle phobia. Needle phobic parturients are at increased risk of adverse outcomes. We assessed the efficacy of topical Ametop™ (tetracaine 4%) gel in reducing the pain associated with local anesthetic skin infiltration before neuraxial block in non-laboring women.

METHODS

This was a prospective, randomized, double-blind, placebo-controlled study. Ametop™ or placebo was applied to the skin of the lower back at least 20min before neuraxial block using a standardized technique with 1% lidocaine skin infiltration. The primary outcome was numeric pain score (0-10) 30s after lidocaine infiltration. Groups were compared using Welch's t-test.

RESULTS

Thirty-six subjects in each group were analyzed. There was a statistically significant difference in the mean (standard deviation) pain score between the Ametop™ and the placebo groups: 2.36±1.80 and 3.51±2.22, respectively (P=0.019). There were no significant adverse events.

CONCLUSION

The mean numeric pain score in the Ametop™ group was 33% lower compared to the placebo group. Topical Ametop™ gel applied at least 20min before local anesthetic infiltration of the skin prior to neuraxial block in elective cesarean delivery may be a useful adjunct in needle phobic women.

Immunoprotective responses of T helper type 1 stimulatory protein-S-adenosyl-L-homocysteine hydrolase against experimental visceral leishmaniasis

It is well known that a patient in clinical remission of visceral leishmaniasis (VL) remains immune to reinfection, which provides a rationale for the feasibility of a vaccine against this deadly disease. In earlier studies, observation of significant cellular responses in treated Leishmania patients as well as in hamsters against leishmanial antigens from different fractions led to its further proteomic characterization, wherein S-adenosyl-L-homocysteine hydrolase (AdoHcy) was identified as a helper type 1 (Th1) stimulatory protein. The present study includes immunological characterization of this protein, its cellular responses [lymphoproliferation, nitric oxide (NO) production and cytokine responses] in treated Leishmania-infected hamsters and patients as well as prophylactic efficacy against Leishmania challenge in hamsters and the immune responses generated thereof. Significantly higher cellular responses were noticed against recombinant L. donovani S-adenosyl-L-homocysteine hydrolase (rLdAdoHcy) compared to soluble L. donovani antigen in treated samples. Moreover, stimulation of peripheral blood mononuclear cells with rLdAdoHcy up-regulated the levels of interferon (IFN)-γ, interleukin (IL)-12 and down-regulated IL-10. Furthermore, vaccination with rLdAdoHcy generated perceptible delayed-type hypersensitivity response and exerted considerably good prophylactic efficacy (∼70% inhibition) against L. donovani challenge. The efficacy was confirmed by the increased expression levels of inducible NO synthase and Th1-type cytokines, IFN-γ and IL-12 and down-regulation of IL-4, IL-10 and transforming growth factor (TGF)-β. The results indicate the potentiality of rLdAdoHcy protein as a suitable vaccine candidate against VL.

Immunostimulatory potential and proteome profiling of Leishmania donovani soluble exogenous antigens

Isolation of the soluble exogenous antigens (SEAgs), its immune response study and proteome profiling is an essential prerequisite for understanding the molecular pathogenesis of Leishmania donovani. The immunostimulatory potential of L. donovani SEAgs, purified from culture of L. donovani clinical isolate, was evaluated for their ability to induce cellular responses in treated/cured hamsters. SEAgs induced significant proliferative responses in lymphocytes (SI 5.6 ± 2.3; P < 0.01) isolated from cured hamster. In addition, significant NO production in response to SEAgs was also noticed in macrophages of hamsters, mouse and human cell lines (J774A-1 and THP1). Western blot analyses with antibodies against proteophosphoglycan (PPG; surface-expressed and secreted molecule) of L. donovani revealed that PPG molecules are also present in L. donovani SEAgs. Mass spectrometry (MS)-based proteome analysis of 12 protein bands of SEAgs through MALDI-TOF/TOF endorsed the identification of some Th1-stimulatory immunogenic proteins. These immunogenic proteins may offer increased hope for the discovery of new promising vaccine candidates against visceral leishmaniasis (VL). The overall results suggest that immunostimulatory molecules are present in the SEAgs, which may be further exploited, for developing a subunit vaccine against VL a fatal human disease.

Macrophage Targeted Nanoparticles for Antiretroviral (ARV) Delivery

OBJECTIVE

To reduce the amount of the antiretroviral (ARV) nevirapine necessary to achieve therapeutic concentrations using macrophage targeted nanoparticles.

METHODS

Core-shell nanoparticles were prepared from FDA approved, biodegradable and biocompatible polymers, with poly(lactic-co-glycolic) acid (PLGA) as the core and chitosan (CS) as the shell using a water/oil/water method. Nevirapine was encapsulated in the core of the nanoparticles. β-glucan (GLU) was adsorbed to the surface of the nanoparticle. Macrophage uptake and intracellular nevirapine concentrations were determined by fluorescence imaging and ultra-performance liquid chromatography/mass spectroscopy (UPLC-MS). Optical imaging was employed to characterize the biodistribution of nanoparticles following intravenous injection in CD-1 mice.

RESULTS

We synthesized spherical shaped 190 nm GLU-CS-PLGA nanoparticles that provide controlled release of nevirapine. In THP-1 macrophage the uptake of PLGA and CS- PLGA nanoparticles was less compared to targeted GLU-CS-PLGA nanoparticles. THP-1 macrophage were dosed with free nevirapine (10 μg/well) and GLU-CS- PLGA nanoparticles containing 1/10 the concentration of free nevirapine (1 μg nevirapine/well). The intracellular concentration of nevirapine was the same for both nanoparticles and free nevirapine at 2 and 24 hrs. No significant change in THP-1 macrophage viability was observed in the presence of nanoparticles relative to the control. Ex vivo imaging demonstrates that nanoparticles are predominantly found in the liver and kidney and at 24 hr there is still a large amount of nanoparticles in the body.

CONCLUSION

These data demonstrate that the total dose of nevirapine delivered by GLU-CS-PLGA nanoparticles can be greatly reduced, to limit side effects, while still providing maximal ARV activity in a known cellular reservoir.

Nanomedicine: Past, present and future - A global perspective

Nanomedicine is an emerging and rapidly evolving field and includes the use of nanoparticles for diagnosis and therapy of a variety of diseases, as well as in regenerative medicine. In this mini-review, leaders in the field from around the globe provide a personal perspective on the development of nanomedicine. The focus lies on the translation from research to development and the innovation supply chain, as well as the current status of nanomedicine in industry. The role of academic professional societies and the importance of government funding are discussed. Nanomedicine to combat infectious diseases of poverty is highlighted along with other pertinent examples of recent breakthroughs in nanomedicine. Taken together, this review provides a unique and global perspective on the emerging field of nanomedicine.

Curdlan-Conjugated PLGA Nanoparticles Possess Macrophage Stimulant Activity and Drug Delivery Capabilities

PURPOSE

There is significant interest in the application of nanoparticles to deliver immunostimulatory signals to cells. We hypothesized that curdlan (immune stimulating polymer) could be conjugated to PLGA and nanoparticles from this copolymer would possess immunostimulatory activity, be non-cytotoxic and function as an effective sustained drug release system.

METHODS

Carbodiimide chemistry was employed to conjugate curdlan to PLGA. The conjugate (C-PLGA) was characterized using (1)H and (13)C NMR, FTIR, DSC and TGA. Nanoparticles were synthesized using an emulsion-solvent evaporation technique. Immunostimulatory activity was characterized in THP-1 derived macrophages. MTT assay and real-time impedance measurements were used to characterize polymer and nanoparticle toxicity and uptake in macrophages. Drug delivery capability was assessed across Caco-2 cells using rifampicin as a model drug.

RESULTS

Spectral characterization confirmed successful synthesis of C-PLGA. C-PLGA nanoparticles enhanced phosphorylated ERK production in macrophages indicating cell stimulation. Nanoparticles provided slow release of rifampicin across Caco-2 cells. Polymers but not nanoparticles altered the adhesion profiles of the macrophages. Impedance measurements suggested Ca(2+) dependent uptake of nanoparticles by the macrophages.

CONCLUSIONS

PLGA nanoparticles with macrophage stimulating and sustained drug delivery capabilities have been prepared. These nanoparticles can be used to stimulate macrophages and concurrently deliver drug in infectious disease therapy.

Oral lipid-based nanoformulation of tafenoquine enhanced bioavailability and blood stage antimalarial efficacy and led to a reduction in human red blood cell loss in mice

Tafenoquine (TQ), a new synthetic analog of primaquine, has relatively poor bioavailability and associated toxicity in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. A microemulsion formulation of TQ (MTQ) with sizes <20 nm improved the solubility of TQ and enhanced the oral bioavailability from 55% to 99% in healthy mice (area under the curve 0 to infinity: 11,368±1,232 and 23,842±872 min·μmol/L) for reference TQ and MTQ, respectively. Average parasitemia in Plasmodium berghei-infected mice was four- to tenfold lower in the MTQ-treated group. In vitro antiplasmodial activities against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum indicated no change in half maximal inhibitory concentration, suggesting that the microemulsion did not affect the inherent activity of TQ. In a humanized mouse model of G6PD deficiency, we observed reduction in toxicity of TQ as delivered by MTQ at low but efficacious concentrations of TQ. We hereby report an enhancement in the solubility, bioavailibility, and efficacy of TQ against blood stages of Plasmodium parasites without a corresponding increase in toxicity.

Coating doxorubicin-loaded nanocapsules with alginate enhances therapeutic efficacy against Leishmania in hamsters by inducing Th1-type immune responses

BACKGROUND AND PURPOSE

The aim of the present study was to evaluate the immunomodulatory and chemotherapeutic potential of alginate-(SA) coated nanocapsule (NCs) loaded with doxorubicin (SA-NCs-DOX) against visceral leishmaniasis in comparison with nano-emulsions containing doxorubicin (NE-DOX).

EXPERIMENTAL APPROACH

NE-DOX was prepared using low-energy emulsification methods. Stepwise addition of protamine sulphate and SA in a layer-by-layer manner was used to form SA-NCs-DOX. SA-NCs-DOX, NE-DOX and Free DOX were compared for their cytotoxicity against Leishmania donovani-infected macrophages in vitro and generation of T-cell responses in infected hamsters in vivo.

KEY RESULTS

Size and ζ potential of the NE-DOX and SA-NCs-DOX formulations were 310 ± 2.1 nm and (-)32.6 ± 2.1 mV, 342 ± 4.1 nm and (-)29.3 ± 1.2 mV respectively. SA-NCs-DOX was better (1.5 times) taken up by J774A.1 macrophages compared with NE-DOX. SA-NCs -DOX showed greater efficacy than NE-DOX against intramacrophagic amastigotes. SA-NCs-DOX treatment exhibited enhanced apoptotic efficiency than NE-DOX and free DOX as evident by cell cycle analysis, decrease in mitochondrial membrane potential, ROS and NO production. T-cell responses, when assessed through lymphoproliferative responses, NO production along with enhanced levels of iNOS, TNF-α, IFN-γ and IL-12 were found to be up-regulated after SA-NCs-DOX, compared with responses to NE-DOX in vivo. Parasitic burden was decreased in Leishmania-infected hamsters treated with SA-NCs-DOX, compared with NE-DOX.

CONCLUSIONS AND IMPLICATIONS

Our results provide insights into the development of an alternative approach to improved management of leishmaniasis through a combination of chemotherapy with stimulation of the innate immune system.

State of the art and future directions in nanomedicine for tuberculosis

INTRODUCTION

Tuberculosis (TB) ranks the second leading cause of death from an infectious disease worldwide. However, treatment of TB is affected by poor patient compliance due to the requirement for daily drug administration, for lengthy periods of time, often with severe drug-induced side effects. Nanomedicines have the potential to improve treatment outcomes by providing therapies with reduced drug doses, administered less frequently, under shortened treatment durations.

AREAS COVERED

In this article, we present the pathophysiology of the disease, focusing on pulmonary TB and the characteristics of drugs used in treatment and discuss the application of nanomedicines within this scope. We also discuss new formulation approaches for TB nanomedicines and directions for future research.

EXPERT OPINION

Nanomedicines have the potential to improve TB treatment outcomes. New approaches such as nanoparticle systems able to impact the immune response of macrophages and deliver drug intracellularly, as well as the use of polymer-drug conjugates for drug delivery, are likely to play an important role in TB nanomedicines in future. However, further research is required before TB nanomedicines can be translated to the clinic.