Design of a zero-order sustained release PLGA microspheres for palonosetron hydrochloride with high encapsulation efficiency

Chemically synthesized ciprofloxacin-PEG-FeO nanotherapeutic exhibits strong antibacterial and controlled cytotoxic effects

Aim: To develop a biocompatible conjugated ciprofloxacin-PEG-FeO nanodelivery system with increased efficacy of available therapeutics in a controlled manner. Materials & methods: FeO nanoparticles were synthesized by chemical and biological methods and modified as ciprofloxacin-PEG-FeO nanoformulations. After initial antibacterial and cytotoxicity studies, the effective and biocompatible nanoformulations was further fabricated as nanotherapeutics for in vivo studies in mouse models. Results: Chemically synthesized ciprofloxacin-PEG-FeO nanoformulations demonstrated boosted antibacterial activity against clinically isolated bacterial strains. Nanoformulations were also found to be compatible with baby hamster kidney 21 cells and red blood cells. In in vivo studies, nanotherapeutic showed wound-healing effects with eradication of Staphylococcus aureus infection. Conclusion: The investigations indicate that the developed nanotherapeutic can eradicate localized infections and enhance wound healing with controlled cytotoxicity.

Nanomaterials for detection of biomolecules and delivering therapeutic agents in theragnosis: A review

Nanomaterials are emerging facts used to deliver therapeutic agents in living systems. Nanotechnology is used as a compliment by implementing different kinds of nanotechnological applications such as nano-porous structures, functionalized nanomaterials, quantum dots, carbon nanomaterials, and polymeric nanostructures. The applications are in the initial stage, which led to achieving several diagnoses and therapy in clinical practice. This review conveys the importance of nanomaterials in post-genomic employment, which includes the design of immunosensors, immune assays, and drug delivery. In this view, genomics is a molecular tool containing large databases that are useful in choosing an apt molecular inhibitor such as drug, ligand and antibody target in the drug delivery process. This study identifies the expression of genes and proteins in analysis and classification of diseases. Experimentally, the study analyses the design of a disease model. In particular, drug delivery is a boon area to treat cancer. The identified drugs enter different phase trails (Trails I, II, and III). The genomic information conveys more essential entities to the phase I trials and helps to move further for other trails such as trails-II and III. In such cases, the biomarkers play a crucial role by monitoring the unique pathological process. Genetic engineering with recombinant DNA techniques can be employed to develop genetically engineered disease models. Delivering drugs in a specific area is one of the challenging issues achieved using nanoparticles. Therefore, genomics is considered as a vast molecular tool to identify drugs in personalized medicine for cancer therapy.

Resorbable Membranes for Guided Bone Regeneration: Critical Features, Potentials, and Limitations

Lack of horizontal and vertical bone at the site of an implant can lead to significant clinical problems that need to be addressed before implant treatment can take place. Guided bone regeneration (GBR) is a commonly used surgical procedure that employs a barrier membrane to encourage the growth of new bone tissue in areas where bone has been lost due to injury or disease. It is a promising approach to achieve desired repair in bone tissue and is widely accepted and used in approximately 40% of patients with bone defects. In this Review, we provide a comprehensive examination of recent advances in resorbable membranes for GBR including natural materials such as chitosan, collagen, silk fibroin, along with synthetic materials such as polyglycolic acid (PGA), polycaprolactone (PCL), polyethylene glycol (PEG), and their copolymers. In addition, the properties of these materials including foreign body reaction, mechanical stability, antibacterial property, and growth factor delivery performance will be compared and discussed. Finally, future directions for resorbable membrane development and potential clinical applications will be highlighted.

pH-Responsive Water-Soluble Chitosan Amphiphilic Core–Shell Nanoparticles: Radiation-Assisted Green Synthesis and Drug-Controlled Release Studies

This work aims to apply water radiolysis-mediated green synthesis of amphiphilic core–shell water-soluble chitosan nanoparticles (WCS NPs) via free radical graft copolymerization in an aqueous solution using irradiation. Robust grafting poly(ethylene glycol) monomethacrylate (PEGMA) comb-like brushes were established onto WCS NPs modified with hydrophobic deoxycholic acid (DC) using two aqueous solution systems, i.e., pure water and water/ethanol. The degree of grafting (DG) of the robust grafted poly(PEGMA) segments was varied from 0 to ~250% by varying radiation-absorbed doses from 0 to 30 kGy. Using reactive WCS NPs as a water-soluble polymeric template, a high amount of DC conjugation and a high degree of poly(PEGMA) grafted segments brought about high moieties of hydrophobic DC and a high DG of the poly(PEGMA) hydrophilic functions; meanwhile, the water solubility and NP dispersion were also markedly improved. The DC-WCS-PG building block was excellently self-assembled into the core–shell nanoarchitecture. The DC-WCS-PG NPs efficiently encapsulated water-insoluble anticancer and antifungal drugs, i.e., paclitaxel (PTX) and berberine (BBR) (~360 mg/g). The DC-WCS-PG NPs met the role of controlled release with a pH-responsive function due to WCS compartments, and they showed a steady state for maintaining drugs for up to >10 days. The DC-WCS-PG NPs prolonged the inhibition capacity of BBR against the growth of S. ampelinum for 30 days. In vitro cytotoxicity results of the PTX-loaded DC-WCS-PG NPs with human breast cancer cells and human skin fibroblast cells proved the role of the DC-WCS-PG NPs as a promising nanoplatform for controlling drug release and reducing the side effects of the drugs on normal cells.

Polycaprolactone/epoxide-functionalized silica composite microparticles for long-term controlled release of trans-chalcone

In this study, controlled release of trans-chalcone was achieved by using a polycaprolactone-based hybrid system as the drug carrier material. Encapsulation efficiency was obtained in the range of 70–75% for various formulations and in vitro release studies, conducted at 37 °C and pH 7.4, revealed slow profile reaching 60% cumulative release. As interpreted from kinetic modelling, drug release was controlled mainly by Fickian diffusion; polymer erosion did not contribute to the TC release. Difference in drug loading efficiencies of the hybrid and neat PCL microparticles was observed such that PCL microparticles had lower loading efficiency than the hybrid microparticles whereas the release profiles were similar. pH of the release medium had affected release profiles; acidic medium enhanced drug release. Characterization of the microparticles were realized by FT-IR, TGA, DSC, SEM and WCA which revealed key properties such as molecular dispersion state and hydrophilicity. With the results obtained, we concluded that our hybrid system has a significant potential for long term release of trans-chalcone.

Enzymatic PCL-grafting to NH2-end grouped silica and development of microspheres for pH-stimulated release of a hydrophobic model drug

This study set out to evaluate novel PCL-based silica containing nanohybrids as the polymer matrix in a hydrophobic drug-loaded microsphere system. Nanohybrids were synthesized by PCL-grafting to NH₂-end grouped silica by in situ enzymatic ring opening polymerization of ε-caprolactone. Molecular weight and monomer conversion, PCL grafting percentage, thermal properties and crystallinity of the nanohybrids were determined by ¹H NMR, TGA, DSC and XRD. Synthesized nanohybrids had low crystallinity percentage (32 and 39 %) and molecular weight (4800 and 8700 g/mol), promising for controlled drug release applications. The nanohybrids were used for fabrication of trans-chalcone-loaded microspheres by O/W single emulsion solvent evaporation. Mean particle diameter of the microspheres were between 15 and 30 µm. The result of release studies showed that optimum microsphere formulations (AP4 and A2, respectively) had 61 and 64 % encapsulation efficiency. One of the more significant findings to emerge from this investigation is that TC release was extended to 16 and 37 days, in a controlled manner. TC release was significantly enhanced in acidic pH media (pH 3.6 and 5.6) indicating pH-dependent release from nanohybrid microspheres; releasing 80-100 % of the loaded drug in 4-14 days. Drug/polymer interactions and molecular structures were investigated by FT-IR spectroscopy and DSC analysis. According to the results obtained, enzymatically synthesized nanohybrids have potential for pH-dependent release of the model drug, trans-chalcone.

Formulation, Optimization, and Evaluation of Moringa oleifera Leaf Polyphenol-Loaded Phytosome Delivery System against Breast Cancer Cell Lines

Moringa oleifera leaf polyphenols (Mopp) were encapsulated with phytosomes to enhance their efficacy on 4T1 cancer cell lines. The Mopp were extracted via microwave-assisted extraction. Moringa oleifera polyphenol-loaded phytosomes (MoP) were prepared with the nanoprecipitation method and characterized using the dynamic light scattering and dialysis membrane techniques. The in vitro cytotoxic and antiproliferative activity were investigated with the (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazole) MTT assay. Acute toxicity was assessed using Swiss albino mice. An MoP particle size of 296 ± 0.29 nm, −40.1 ± 1.19 mV zeta potential, and polydispersity index of 0.106 ± 0.002 were obtained. The total phenolic content was 50.81 ± 0.02 mg GAE/g, while encapsulation efficiency was 90.32 ± 0.11%. The drug release profiles demonstrated biphasic and prolonged subsequent sustained release. In vitro assays indicated MoP had a low cytotoxicity effect of 98.84 ± 0.53 μg/mL, doxorubicin was 68.35 ± 3.508, and Mopp was 212.9 ± 1.30 μg/mL. Moreover, MoP exhibited the highest antiproliferative effect on 4T1 cancer cells with an inhibitory concentration of 7.73 ± 2.87 μg/mL and selectivity index > 3. The results indicated a significant difference (p ≤ 0.001) in MoP when compared to Mopp and doxorubicin. The in vivo investigation showed the safety of MoP at a dose below 2000 mg/kg. The present findings suggest that MoP may serve as an effective and promising formulation for breast cancer drug delivery and therapy.

Localized delivery of brain-derived neurotrophic factor from PLGA microspheres promotes peripheral nerve regeneration in rats

Background

Repair of peripheral nerve defect presents a considerable challenge for reconstructive surgeons. The aim of this study is to develop a brain-derived neurotrophic factor (BDNF) from poly(D,L-lactide-co-glycolide) (PLGA) microspheres for the treatment of the peripheral nerve defect.

Method

BDNF microspheres were prepared by using an oil-in-water emulsification-solvent evaporation method. The morphology, particle size, encapsulation efficiency, drug loading and sustained release performance of microspheres was observed and calculated. Adipose mesenchymal stem cells (ADSCs) were isolated and expanded. ADSCs were divided into four groups: control, BDNF, blank microsphere and BDNF microsphere groups. Cell count kit-8 (CCK-8) assays were used to assess cell proliferation. Cell migration was determined by Transwell assays. Twenty-eight male Sprague–Dawley rats underwent transection damage model on the right sciatic nerve. The wet weight ratio of the gastrocnemius muscle was calculated by comparing the weight of the gastrocnemius muscle from the operated side to that of the normal side. Neuroelectrophysiological testing was performed to assess nerve function recovery. Nerve regeneration was evaluated by histological analysis and immunohistochemical staining.

Results

The microspheres were spherical and had uniform size (46.38 ± 1.00 μm), high encapsulation efficiency and high loading capacity. In vitro release studies showed that BDNF-loaded microspheres had good sustained release characteristics. The duration of BDNF release was extended to more than 50 days. BDNF or BDNF microsphere promote the proliferation and migration of ADSCs than control group (P < 0.05). Compared with control group, BDNF significantly decreased the nerve conduction velocity (NCV) and compound amplitude (AMP) (P < 0.05). The nerve fibers in the BDNF microsphere group were closely arranged and uniformly distributed than control group.

Conclusion

BDNF/PLGA sustained-release microsphere could promote the migration of ADSCs and promoted neural differentiation of ADSCs. Moreover, BDNF/PLGA sustained-release microsphere ameliorated nerve conduction velocity and prevented neuralgic amyotrophy.

Glass Transition Temperature of PLGA Particles and the Influence on Drug Delivery Applications

Over recent decades, poly(lactic-co-glycolic acid) (PLGA) based nano- and micro- drug delivery vehicles have been rapidly developed since PLGA was approved by the Food and Drug Administration (FDA). Common factors that influence PLGA particle properties have been extensively studied by researchers, such as particle size, polydispersity index (PDI), surface morphology, zeta potential, and drug loading efficiency. These properties have all been found to be key factors for determining the drug release kinetics of the drug delivery particles. For drug delivery applications the drug release behavior is a critical property, and PLGA drug delivery systems are still plagued with the issue of burst release when a large portion of the drug is suddenly released from the particle rather than the controlled release the particles are designed for. Other properties of the particles can play a role in the drug release behavior, such as the glass transition temperature (T_g). The T_g, however, is an underreported property of current PLGA based drug delivery systems. This review summarizes the basic knowledge of the glass transition temperature in PLGA particles, the factors that influence the T_g, the effect of T_g on drug release behavior, and presents the recent awareness of the influence of T_g on drug delivery applications.

Journey to the Market: The Evolution of Biodegradable Drug Delivery Systems

Biodegradable polymers have been used as carriers in drug delivery systems for more than four decades. Early work used crude natural materials for particle fabrication, whereas more recent work has utilized synthetic polymers. Applications include the macroscale, the microscale, and the nanoscale. Since pioneering work in the 1960’s, an array of products that use biodegradable polymers to encapsulate the desired drug payload have been approved for human use by international regulatory agencies. The commercial success of these products has led to further research in the field aimed at bringing forward new formulation types for improved delivery of various small molecule and biologic drugs. Here, we review recent advances in the development of these materials and we provide insight on their drug delivery application. We also address payload encapsulation and drug release mechanisms from biodegradable formulations and their application in approved therapeutic products.

Long-acting microspheres of Human Chorionic Gonadotropin hormone: In-vitro and in-vivo evaluation

Human Chorionic Gonadotropin (hCG) hormone is used to cause ovulation, treat infertility in women, and increase sperm count in men. Conventional hCG solution formulations require multiple administration of hCG per week and cause patient noncompliance. The long-acting PLGA depot microspheres (MS) approach with hCG can improve patient compliance, increase the efficacy of hCG with a lower total dose and improve quality of life. Therefore, hCG was encapsulated by a modified double emulsion solvent evaporation technique within PLGA MS by high-speed homogenizer and industrially scalable in-line homogenizer, respectively. MS was characterized for particle size, encapsulation efficiency (EE), surface morphology, and in-vitro release. The spherical, dense, non-porous microspheres were obtained with a size of 58.88 ± 0.18 µm. Microspheres showed high EE (77.4% ± 5.9%) with low initial burst release (12.82% ± 2.07%). Circular Dichroism and SDS-PAGE analysis indicated good stability and structural integrity of hCG in the microspheres. Its bioactivity was proven further by a bioassay study in immature Wistar rats. Pharmacokinetic analysis showed that the hCG PLGA MS maintained serum hCG concentration up to 13 days compared to multiple injections of a marketed conventional parenteral injectable formulation of hCG. Thus, it can be ascertained that the hCG PLGA MS may have great potential for clinical use in long-term therapy.

Controllable preparation of bioactive open porous microspheres for tissue engineering

Biodegradable microspheres have been widely applied as cell carriers for tissue engineering and regenerative medicine. However, most cell carriers only have simple planar structure and show poor biological activity and...

Changing the daily injection of glatiramer acetate to a monthly long acting product through designing polyester-based polymeric microspheres

Introduction: Glatiramer acetate (GA) is a newly emerged therapeutic peptide to reduce the frequency of relapses in multiple sclerosis (MS). Despite its good performance in controlling MS, it is not widely used due to daily or biweekly subcutaneous injections due to rapid degradation and body clearance. Therefore, implant design with sustained release leads to prolonged biological effects by gradually increasing drug exposure and protecting GA from rapid local degradation. Methods: Different emulsion methods, PLGA type, surfactant concentration, drug/polymer ratio, drying processes, stirring method, and other variables in preliminary studies modified the final formulation. The release kinetics were studied through mechanistic kinetic models such as zero-order, Weibull, Higuchi, etc. In this study, all challenges for easy scale-up, methodological detail, and a simple, feasible setup in mass production were discussed. Results: The optimized formulation was obtained by 1:6 drug/PLGA, 0.5% w/w polyvinyl alcohol, and 0.75% w/w NaCl in the external aqueous phase, 1:10 continuous phase to dispersed phase ratio, and without any surfactant in the primary emulsion. The final freeze-dried particles presented a narrow distributed size of 1-10 µm with 7.29% ± 0.51 drug loading and zero-order release behavior with appropriate regression correlation (R2 98.7), complete release, and only 7.1% initial burst release. Conclusion: Therefore, to achieve improvement in patient compliance through better and longer efficacy, designing the parenteral sustained release microspheres (MPSs) of this immune modulator is a promising approach that should be considered.

Three months extended-release microspheres prepared by multi-microchannel microfluidics in beagle dog models

To evaluate in vivo drug release profiles in beagle dogs, finasteride-loaded PLGA microspheres were prepared using a novel method of IVL-PPF Microsphere® microfluidic device. Briefly, the dispersed phase (PLGA and finasteride in dichloromethane) was mixed with the continuous phase (0.25% w/v PVA aqueous solution) in the parallelized microchannels. After lyophilization, the diameter of the microspheres was around 40 μm (PLGA 7502A or 5002A) and around 30 µm (PLGA/PLA02A mixture). Their CV and span values suggested a narrow size distribution in repeated batch preparations. The in vivo drug release from the PLGA microspheres exhibited three substantial phases: an initial burst, a moderate release, and then a plateau. The microspheres based on PLGA 7502A (75:25 co-polymer) demonstrated extended drug release for around 1 month with a minimized initial burst release compared to PLGA 5002A (50:50 co-polymer). Moreover, the in vivo drug release profile in beagle dogs was proportionally related to the amount of drug loading. Furthermore, the addition of PLA02A into the fabrication of the microsphere synergistically extended the drug release up to 3 months. These results demonstrated the value of this method to achieve uniform microspheres and extend the drug release properties with interpretative in vivo PK profiles.

Engineering Quick- and Long-acting Naloxone Delivery Systems for Treating Opioid Overdose

Purpose

Opioids have been the main factor for drug overdose deaths in the United States. Current naloxone delivery systems are effective in mitigating the opioid effects only for hours. Naloxone-loaded poly(lactide-co-glycolide) (PLGA) microparticles were prepared as quick- and long-acting naloxone delivery systems to extend the naloxone effect as an opioid antidote.

Methods

The naloxone-PLGA microparticles were made using an emulsification solvent extraction approach with different formulation and processing parameters. Two PLGA polymers with the lactide:glycolide (L:G) ratios of 50:50 and 75:25 were used, and the drug loading was varied from 21% to 51%. Two different microparticles of different sizes with the average diameters of 23 μm and 50 μm were produced using two homogenization-sieving conditions. All the microparticles were critically characterized, and three of them were evaluated with β-arrestin recruitment assays.

Results

The naloxone encapsulation efficiency (EE) was in the range of 70–85%. The EE was enhanced when the theoretical naloxone loading was increased from 30% to 60%, the L:G ratio was changed from 50:50 to 75:25, and the average size of the particles was reduced from 50 μm to 23 μm. The in vitro naloxone release duration ranged from 4 to 35 days. Reducing the average size of the microparticles from 50 μm to 23 μm helped eliminate the lag phase and obtain the steady-state drug release profile. The cellular pharmacodynamics of three selected formulations were evaluated by applying DAMGO, a synthetic opioid peptide agonist to a μ-opioid receptor, to recruit β-arrestin 2.

Conclusions

Naloxone released from the three selected formulations could inhibit DAMGO-induced β-arrestin 2 recruitment. This indicates that the proposed naloxone delivery system is adequate for opioid reversal during the naloxone release duration.

Phenomenology of the Initial Burst Release of Drugs from PLGA Microparticles

Poly(lactic-co-glycolic acid) (PLGA) is the most prevalent polymer drug delivery vehicle in use today. There are about 20 commercialized drug products in which PLGA is used as an excipient. In more than half of these formulations, PLGA is used in the form of microparticles (with sizes in the range between 60 nm and 100 μm). The primary role of PLGA is to control the kinetics of drug release toward achieving sustained release of the drug. Unfortunately, most drug-loaded PLGA microparticles exhibit a common drawback: an initial uncontrolled burst of the drug. After 30 years of utilization of PLGA in controlled drug delivery systems, this initial burst drug release still remains an unresolved challenge. In this Review, we present a summary of the proposed mechanisms responsible for this phenomenon and the known factors affecting the burst release process. Also, we discuss examples of recent efforts made to reduce the initial burst release of the drug from PLGA particles.