Evaluation of thein vitrodifferential protein adsorption patterns of didanosine-loaded nanostructured lipid carriers (NLCs) for potential targeting to the brain

An emerging era in manufacturing of drug delivery systems: Nanofabrication techniques

Nanotechnology has the capability of making significant contributions to healthcare. Nanofabrication of multifunctional nano- or micro-character systems is becoming incredibly influential in various sectors like electronics, photonics, energy, and biomedical gadgets worldwide. The invention of such items led to the merger of moderate cost and excellent quality nano or micro-characters into 3D structures. Nanofabrication techniques have many benefits as the primary technology for manipulating cellular surroundings to research signaling processes. The inherent nanoscale mechanisms of cyto-reactions include the existence and death of cells, stem cell segmentation, multiplication, cellular relocation, etc. Nanofabrication is essential in developing various nano-formulations like solid lipid nanoparticles, nanostructured lipid carriers, liposomes, niosomes, nanoemulsions, microemulsions etc. Despite the initial development cost in designing the nanofabrication-based products, it has also reduced the total cost of the healthcare system by considering the added benefits compared to the other standard formulations. Thus, the current review mainly focuses on nanofabrication techniques, advantages, disadvantages, applications in developing various nanocarrier systems, challenges and future perspectives.

Lipid-Based Nanocarriers for Neurological Disorders: A Review of the State-of-the-Art and Therapeutic Success to Date

Neurodegenerative disorders including Alzheimer's, Parkinson's, and dementia are chronic and advanced diseases that are associated with loss of neurons and other related pathologies. Furthermore, these disorders involve structural and functional defections of the blood-brain barrier (BBB). Consequently, advances in medicines and therapeutics have led to a better appreciation of various pathways associated with the development of neurodegenerative disorders, thus focusing on drug discovery and research for targeted drug therapy to the central nervous system (CNS). Although the BBB functions as a shield to prevent toxins in the blood from reaching the brain, drug delivery to the CNS is hindered by its presence. Owing to this, various formulation approaches, including the use of lipid-based nanocarriers, have been proposed to address shortcomings related to BBB permeation in CNS-targeted therapy, thus showing the potential of these carriers for translation into clinical use. Nevertheless, to date, none of these nanocarriers has been granted market authorization following the successful completion of all stages of clinical trials. While the aforementioned benefits of using lipid-based carriers underscores the need to fast-track their translational development into clinical practice, technological advances need to be initiated to achieve appropriate capacity for scale-up and the production of affordable dosage forms.

Nanomedicine based approaches for combating viral infections

Millions of people die each year from viral infections across the globe. There is an urgent need to overcome the existing gap and pitfalls of the current antiviral therapy which include increased dose and dosing frequency, bioavailability challenges, non-specificity, incidences of resistance and so on. These stumbling blocks could be effectively managed by the advent of nanomedicine. Current review emphasizes over an enhanced understanding of how different lipid, polymer and elemental based nanoformulations could be potentially and precisely used to bridle the said drawbacks in antiviral therapy. The dawn of nanotechnology meeting vaccine delivery, role of RNAi therapeutics in antiviral treatment regimen, various regulatory concerns towards clinical translation of nanomedicine along with current trends and implications including unexplored research avenues for advancing the current drug delivery have been discussed in detail.

Nanostructured Lipid Carriers for Delivery of Chemotherapeutics: A Review

The efficacy of current standard chemotherapy is suboptimal due to the poor solubility and short half-lives of chemotherapeutic agents, as well as their high toxicity and lack of specificity which may result in severe side effects, noncompliance and patient inconvenience. The application of nanotechnology has revolutionized the pharmaceutical industry and attracted increasing attention as a significant means for optimizing the delivery of chemotherapeutic agents and enhancing their efficiency and safety profiles. Nanostructured lipid carriers (NLCs) are lipid-based formulations that have been broadly studied as drug delivery systems. They have a solid matrix at room temperature and are considered superior to many other traditional lipid-based nanocarriers such as nanoemulsions, liposomes and solid lipid nanoparticles (SLNs) due to their enhanced physical stability, improved drug loading capacity, and biocompatibility. This review focuses on the latest advances in the use of NLCs as drug delivery systems and their preparation and characterization techniques with special emphasis on their applications as delivery systems for chemotherapeutic agents and different strategies for their use in tumor targeting.

Isolation methods for particle protein corona complexes from protein-rich matrices

Background: Nanoparticles become rapidly encased by a protein layer when they are in contact with biological fluids. This protein shell is called a corona. The composition of the corona has a strong influence on the surface properties of the nanoparticles. It can affect their cellular interactions, uptake and signaling properties. For this reason, protein coronae are investigated frequently as an important part of particle characterization. Main body of the abstract: The protein corona can be analyzed by different methods, which have their individual advantages and challenges. The separation techniques to isolate corona-bound particles from the surrounding matrices include centrifugation, magnetism and chromatographic methods. Different organic matrices, such as blood, blood serum, plasma or different complex protein mixtures, are used and the approaches vary in parameters such as time, concentration and temperature. Depending on the investigated particle type, the choice of separation method can be crucial for the subsequent results. In addition, it is important to include suitable controls to avoid misinterpretation and false-positive or false-negative results, thus allowing the achievement of a valuable protein corona analysis result. Conclusion: Protein corona studies are an important part of particle characterization in biological matrices. This review gives a comparative overview about separation techniques, experimental parameters and challenges which occur during the investigation of the protein coronae of different particle types.

Recent strategies and advances in the fabrication of nano lipid carriers and their application towards brain targeting

In last two decades, the lipid nanocarriers have been extensively investigated for their drug targeting efficiency towards the critical areas of the human body like CNS, cardiac region, tumor cells, etc. Owing to the flexibility and biocompatibility, the lipid-based nanocarriers, including nanoemulsion, liposomes, SLN, NLC etc. have gained much attention among various other nanocarrier systems for brain targeting of bioactives. Across different lipid nanocarriers, NLC remains to be the safest, stable, biocompatible and cost-effective drug carrier system with high encapsulation efficiency. Drug delivery to the brain always remains a challenging issue for scientists due to the complex structure and various barrier mechanisms surrounding the brain. The application of a suitable nanocarrier system and the use of any alternative route of drug administration like nose-to-brain drug delivery could overcome the hurdle and improves the therapeutic efficiency of CNS acting drugs thereof. NLC, a second-generation lipid nanocarrier, upsurges the drug permeation across the BBB due to its unique structural properties. The biocompatible lipid matrix and nano-size make it an ideal drug carrier for brain targeting. It offers many advantages over other drug carrier systems, including ease of manufacturing and scale-up to industrial level, higher drug targeting, high drug loading, control drug release, compatibility with a wide range of drug substances, non-toxic and non-irritant behavior. This review highlights recent progresses towards the development of NLC for brain targeting of bioactives with particular reference to its surface modifications, formulations aspects, pharmacokinetic behavior and efficacy towards the treatment of various neurological disorders like AD, PD, schizophrenia, epilepsy, brain cancer, CNS infection (viral and fungal), multiple sclerosis, cerebral ischemia, and cerebral malaria. This work describes in detail the role and application of NLC, along with its different fabrication techniques and associated limitations. Specific emphasis is given to compile a summary and graphical data on the area explored by scientists and researchers worldwide towards the treatment of neurological disorders with or without NLC. The article also highlights a brief insight into two prime approaches for brain targeting, including drug delivery across BBB and direct nose-to-brain drug delivery along with the current global status of specific neurological disorders.

Stealth lipid polymer hybrid nanoparticles loaded with rutin for effective brain delivery - comparative study with the gold standard (Tween 80): optimization, characterization and biodistribution

The blood–brain barrier is considered the leading physiological obstacle hindering the transport of neurotherapeutics to brain cells. The application of nanotechnology coupled with surfactant coating is one of the efficacious tactics overcoming this barrier. The aim of this study was to develop lipid polymer hybrid nanoparticles (LPHNPs), composed of a polymeric core and a phospholipid shell entangled, for the first time, with PEG-based surfactants (SAA) viz. TPGS or Solutol HS 15 in comparison with the gold standard Tween 80, aiming to enhance brain delivery and escape opsonization. LPHNPs were successfully prepared using modified single-step nanoprecipitation technique, loaded with the flavonoid rutin (RU), extracted from the flowers of Calendula officinalis L., and recently proved as a promising anti-Alzheimer. The effect of the critical process parameters (CPP) viz. PLGA amount, W_lecithin/W_PLGA ratio, and Tween 80 concentration on critical quality attributes (CQA); entrapment, size and size distribution, was statistically analyzed via design of experiments, and optimized using the desirability function. The optimized CPP were maintained while substituting Tween 80 with other PEG-SAA. All hybrid particles exhibited spherical shape with perceptible lipid shells. The biocompatibility of the prepared NPs was confirmed by hemolysis test. The pharmacokinetic assessments, post-intravenous administration to rats, revealed a significant higher RU bioavailability for NPs relative to drug solution. Biodistribution studies proved non-significant differences in RU accumulation within brain, but altered phagocytic uptake among various LPHNPs. The present study endorses the successful development of LPHNPs using PEG-SAA, and confirms the prospective applicability of TPGS and Solutol in enhancing brain delivery.

Sustained-release liquisolid compact tablets containing artemether-lumefantrine as alternate-day regimen for malaria treatment to improve patient compliance

The present study aimed to develop low-dose liquisolid tablets of two antimalarial drugs artemether–lumefantrine (AL) from a nanostructured lipid carrier (NLC) of lumefantrine (LUM) and estimate the potential of AL as an oral delivery system in malariogenic Wistar mice. LUM-NLCs were prepared by hot homogenization using Precirol^® ATO 5/Transcutol^® HP and tallow fat/Transcutol^® HP optimized systems containing 3:1 ratios of the lipids, respectively, as the matrices. LUM-NLC characteristics, including morphology, particle size, zeta potential, encapsulation efficiency, yield, pH-dependent stability, and interaction studies, were investigated. Optimized LUM-NLCs were mixed with artemether powder and other dry ingredients and the resultant powder evaluated for micromeritics. Subsequent AL liquisolid tablets were tested for in vitro drug release and in vivo antiplasmodial activity in mice infected with Plasmodium berghei berghei (NK 65). Results showed that optimized LUM-NLC were stable, spherical, polydispersed but nanometric. Percentage yield and encapsulation efficiency were ~92% and 93% for Precirol^® ATO 5/Transcutol^® HP batch, then 81% and 95% for tallow fat/Transcutol^® HP batch while LUM was amorphous in NLC matrix. In vitro AL release from liquisolid compacts revealed initial burst release and subsequent sustained release. Liquisolid tablet compacts formulated with Precirol^® ATO 5/Transcutol^® HP-AL4 achieved higher LUM release in simulated intestinal fluid (84.32%) than tallow fat/Transcutol^® HP-BL3 (77.9%). Non-Fickian (anomalous) diffusion and super case II transport were the predominant mechanisms of drug release. Equal parasitemia reduction was observed for both batches of tablet compacts (~92%), superior to the reduction obtained with commercial antimalarial formulations: Coartem^® tablets (86%) and chloroquine phosphate tablets (66%). No significant difference (P<0.05) in parasite reduction between double (4/24 mg/kg) and single (2/12 mg/kg) strength doses of AL compacts was observed. Our result highlights that AL could be formulated in much lower doses (4/24 mg/kg), for once-in-two days oral administration to improve patient compliance, which is currently not obtainable with conventional AL dosage forms.

Preclinical safety of solid lipid nanoparticles and nanostructured lipid carriers: Current evidence from in vitro and in vivo evaluation

Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) were designed as exceptionally safe colloidal carriers for the delivery of poorly soluble drugs. SLN/NLC have the particularity of being composed of excipientsalready approved for use in medicines for human use, which offers a great advantage over any other nanoparticulate system developed from novel materials. Despite this fact, any use of excipients in new route of administration or in new dosage form requires evidence of safety. After 25 years of research on SLN and NLC, enough evidence on their preclinical safety has been published. In the present work, published data on in vitro and in vivo compatibility of SLN/NLC have been surveyed, in order to provide evidence of high biocompatibility distinguished by intended administration route. We also identified critical factors and possible weak points in SLN/NLC formulations, such as the effect of surfactants on the cell viability in vitro, which should be considered for further development.

Delivery of cancer therapeutics to extracellular and intracellular targets: Determinants, barriers, challenges and opportunities

Advances in molecular medicine have led to identification of worthy cellular and molecular targets located in extracellular and intracellular compartments. Effectiveness of cancer therapeutics is limited in part by inadequate delivery and transport in tumor interstitium. Parts I and II of this report give an overview on the kinetic processes in delivering therapeutics to their intended targets, the transport barriers in tumor microenvironment and extracellular matrix (TME/ECM), and the experimental approaches to overcome such barriers. Part III discusses new concepts and findings concerning nanoparticle-biocorona complex, including the effects of TME/ECM. Part IV outlines the challenges in animal-to-human translation of cancer nanotherapeutics. Part V provides an overview of the background, current status, and the roles of TME/ECM in immune checkpoint inhibition therapy, the newest cancer treatment modality. Part VI outlines the development and use of multiscale computational modeling to capture the unavoidable tumor heterogeneities, the multiple nonlinear kinetic processes including interstitial and transvascular transport and interactions between cancer therapeutics and TME/ECM, in order to predict the in vivo tumor spatiokinetics of a therapeutic based on experimental in vitro biointerfacial interaction data. Part VII provides perspectives on translational research using quantitative systems pharmacology approaches.

Parenteral nanoemulsions as promising carriers for brain delivery of risperidone: Design, characterization and in vivo pharmacokinetic evaluation

This paper describes design and evaluation of parenteral lecithin-based nanoemulsions intended for brain delivery of risperidone, a poorly water-soluble psychopharmacological drug. The nanoemulsions were prepared through cold/hot high pressure homogenization and characterized regarding droplet size, polydispersity, surface charge, morphology, drug-vehicle interactions, and physical stability. To estimate the simultaneous influence of nanoemulsion formulation and preparation parameters--co-emulsifier type, aqueous phase type, homogenization temperature--on the critical quality attributes of developed nanoemulsions, a general factorial experimental design was applied. From the established design space and stability data, promising risperidone-loaded nanoemulsions (mean size about 160 nm, size distribution <0.15, zeta potential around -50 mV), containing sodium oleate in the aqueous phase and polysorbate 80, poloxamer 188 or Solutol(®) HS15 as co-emulsifier, were produced by hot homogenization and their ability to improve risperidone delivery to the brain was assessed in rats. Pharmacokinetic study demonstrated erratic brain profiles of risperidone following intraperitoneal administration in selected nanoemulsions, most probably due to their different droplet surface properties (different composition of the stabilizing layer). Namely, polysorbate 80-costabilized nanoemulsion showed increased (1.4-7.4-fold higher) risperidone brain availability compared to other nanoemulsions and drug solution, suggesting this nanoemulsion as a promising carrier worth exploring further for brain targeting.

Development of artemether-loaded nanostructured lipid carrier (NLC) formulation for topical application

NLC topical formulation as an alternative to oral and parenteral (IM) delivery of artemether (ART), a poorly water-soluble drug was designed. A Phospholipon 85G-modified Gelucire 43/01 based NLC formulation containing 75% Transcutol was chosen from DSC studies and loaded with gradient concentration of ART (100-750 mg). ART-loaded NLCs were stable (-22 to -40 mV), polydispersed (0.4-0.7) with d90 size distribution range of 247-530 nm without microparticles up to one month of storage. The encapsulation efficiency (EE%) for ART in the NLC was concentration independent as 250 mg of ART loading achieved ∼61%. DSC confirmed molecular dispersion of ART due to low matrix crystallinity (0.028J/g). Ex vivo study showed detectable ART amounts after 20h which gradually increased over 48h achieving ∼26% cumulative amount permeated irrespective of the applied dose. This proves that ART permeates excised human epidermis, where the current formulation served as a reservoir to gradually control drug release over an extended period of time. Full thickness skin study therefore may confirm if this is a positive signal to hope for a topical delivery system of ART.

Nanotechnology: a magic bullet for HIV AIDS treatment

Human immunodeficiency virus (HIV) infection has become devastating in last a few years. Nearly 7400 new infection cases are coming every day. Highly active antiretroviral therapy (HAART), which involves combination of at least three antiretroviral (ARV) drugs, has been used to extend the life span of the HIV-infected patients. HAART has played an important role to reduce mortality rate in the developed countries but in the developing countries condition is still worst with millions of people being infected by this disease. For the improvement of the situation, nanotechnology-based drug system has been explored for the HIV therapeutics. Nanosystems used for HIV therapeutics offer some unique advantage like enhancement of bioavailability, water solubility, stability, and targeting ability of ARV drugs. Main nanotechnology-based systems explored for HIV therapeutics are liposomes, nanoparticles, niosomes, polymeric micelles, and dendrimers. Present manuscript reviews conventional method of HIV therapeutics and recent advances in the field of nanotechnology-based systems for treatment of HIV-AIDS.

Nanostructure-based drug delivery systems for brain targeting

CONTEXT

It is well-known fact that blood brain barrier (BBB) hinders the penetrance and access of many pharmacotherapeutic agents to central nervous system (CNS). Many diseases of the CNS remain undertreated and the inability to treat most CNS disorders is not due to the lack of effective CNS drug discovery, rather, it is due to the ineffective CNS delivery. Therefore, a number of nanostructured drug delivery carriers have been developed and explored over the past couple of years to transport the drugs to brain.

OBJECTIVE

The present review will give comprehensive details of extensive research being done in field of nanostructured carriers to transport the drugs through the BBB in a safe and effective manner.

METHODS

The method includes both the polymeric- and lipid-based nanocarriers with emphasis on their utility, methodology, advantages, and the drugs which have been worked on using a particular approach to provide a noninvasive method to improve the drug transport through BBB.

RESULTS

Polymeric- and lipid-based nanocarriers enter brain capillaries before reaching the surface of the brain microvascular endothelial cells without the disruption of BBB. These systems are further modified with specific ligands vectors and pegylation aiming to target and enhance their binding with surface receptors of the specific tissues inside brain and increase long circulatory time which favors interaction and penetration into brain endothelial cells.

CONCLUSION

This review would give an insight to the researchers working on neurodegenerative and non-neurodegenerative diseases of the CNS including brain tumor.