Improved brain uptake of peptide-based CNS drugs via alternative routes of administrations of its nanocarrier delivery systems: a promising strategy for CNS targeting delivery of peptides

Food-Derived Peptides: Beneficial CNS Effects and Cross-BBB Transmission Strategies

Food-derived peptides, as dietary supplements, have significant effects on promoting brain health and relieving central nervous system (CNS) diseases. However, the blood-brain barrier (BBB) greatly limits their in-brain bioavailability. Thus, overcoming the BBB to target the CNS is a major challenge for bioactive peptides in the prevention and treatment of CNS diseases. This review discusses improvement in the neuroprotective function of food-derived active peptides in CNS diseases, as well as the source of BBB penetrating peptides (BBB-shuttles) and the mechanism of transmembrane transport. Notably, this review also discusses various peptide modification methods to overcome the low permeability and stability of the BBB. Lipification, glycosylation, introduction of disulfide bonds, and cyclization are effective strategies for improving the penetration efficiency of peptides through the BBB. This review provides a new prospective for improving their neuroprotective function and developing treatments to delay or even prevent CNS diseases.

A Comprehensive Review on Nanomedicine: Promising Approach for Treatment of Brain Tumor through Intranasal Administration

Brain tumors have become one of the deadliest cancers; however, their treatment is still limited by conventional approaches. Brain tumors, among other CNS diseases, are the most lethal form of cancer due to ineffective diagnosis and profiling. The major limiting factor in treating brain tumors is the blood-brain barrier (BBB), and the required therapeutic concentration is not achieved. Hence, most drugs are prescribed at higher doses, which have several unwanted side effects. Nanotechnology has emerged as an interesting and promising new approach for treating neurological disorders, including brain tumors, with the potential to overcome concerns related to traditional therapeutic approaches. Moreover, biomimetic nanomaterials have been introduced to successfully cross the blood-brain barrier and be consumed by deep skin cancer for imaging brain tumors using multimodal functional nanostructures for more specific and reliable medical assessment. These nanomedicines can address several challenges by enhancing the bioavailability of therapeutics through controlled pharmacokinetics and pharmacodynamics. Further nasal drug delivery has been considered as an alternative approach for the brain's targeting for the treatment of several CNS diseases. A drug can be directly delivered to the brain by bypassing the BBB through intranasal administration. This review discusses intranasal nanomedicine-based therapies for brain tumor targeting, which can be explored from different perspectives.

Progress and perspectives of brain-targeting lipid-based nanosystems via the nasal route in Alzheimer's disease

Since health care systems dedicate substantial resources to Alzheimer's disease (AD), it poses an increasing challenge to scientists and health care providers worldwide, especially that many decades of research in the medical field revealed no optimal effective treatment for this disease. The intranasal administration route seems to be a preferable route of anti-AD drug delivery over the oral one as it demonstrates an ability to overcome the related obstacles reflected in low bioavailability, limited brain exposure and undesired pharmacokinetics or side effects. This delivery route can bypass the systemic circulation through the intraneuronal and extraneuronal pathways, providing truly needleless and direct brain drug delivery of the therapeutics due to its large surface area, porous endothelial membrane, the avoidance of the first-pass metabolism, and ready accessibility. Among the different nano-carrier systems developed, lipid-based nanosystems have become increasingly popular and have proven to be effective in managing the common symptoms of AD when administered via the nose-to-brain delivery route, which provides an answer to circumventing the BBB. The design of such lipid-based nanocarriers could be challenging since many factors can contribute to the quality of the final product. Hence, according to the authors, it is recommended to follow the quality by design methodology from the early stage of development to ensure high product quality while saving efforts and costs. This review article aims to draw attention to the up-to-date findings in the field of lipid-based nanosystems and the potential role of developing such forms in the management of AD by means of the nose-to-brain delivery route, in addition to highlighting the significant role of applying QbD methodology in this development.

Sensitive method for endotoxin determination in nanomedicinal product samples

Aim: Nanomaterials and nanomedicinal products tend to interfere with various commonly used assays, including regulatory required endotoxin detection methods for medicines. We developed a method to quantify endotoxin levels that is compatible with nanomaterials and nanomedicinal products. Materials & methods: The method is based on measuring endotoxin indirectly via 3-hydroxylated fatty acids of lipid-A, using Ultra High Performance Liquid Chromatography coupled with mass spectrometry. The outcome was related to results of the commonly used Limulus Amebocyte Lysate method. Results: The ultra high performance liquid chromatography coupled with mass spectrometry method has clear advantages compared with other endotoxin determination assays; particularly the absence of nanospecific interference. Conclusion: The method is sensitive, straightforward and accurate in determining and quantifying endotoxin in nanomedicinal product samples.

Updates on thermosensitive hydrogel for nasal, ocular and cutaneous delivery

Thermosensitive hydrogels are in situ gelling systems composed of hydrophilic homopolymers or block copolymers which remain as solutions at room temperature and form gels after administration into the body. Its application in advanced drug delivery has gained significant attention in recent years. The tunable characteristics of thermosensitive hydrogels make them versatile and capable of incorporating both hydrophilic and lipophilic compounds and macromolecules. The drug molecules can be included as free molecules or preformulated into nano- or micro-particles or liposomes. Although there were several reviews on the materials of thermosensitive hydrogels, the compatibility between the drug and thermosensitive material as well as its in vitro release mechanisms and in vivo performance have barely been investigated. The current review is proposed aiming to not only provide an update on the recent development in thermosensitive hydrogel formulations for nasal, ocular and cutaneous deliveries, but also identify the relationship between the drug characteristics and the loading strategies, and their impacts on the release mechanisms and the in vivo performance. Our current update for the first time highlights the essential features for successful development of in situ thermosensitive hydrogels to facilitate nasal, ocular or cutaneous drug deliveries.

Brain-Targeting Delivery of Two Peptidylic Inhibitors for Their Combination Therapy in Transgenic Polyglutamine Disease Mice via Intranasal Administration

Polyglutamine diseases are a set of progressive neurodegenerative disorders caused by misfolding and aggregation of mutant CAG RNA and polyglutamin protein. To date, there is a lack of effective therapeutics that can counteract the polyglutamine neurotoxicity. Two peptidylic inhibitors, QBP1 and P3, targeting the protein and RNA toxicities, respectively, have been previously demonstrated by us with combinational therapeutic effects on the Drosophila polyglutamine disease model. However, their therapeutic efficacy has never been investigated in vivo in mammals. The current study aims to (a) develop a brain-targeting delivery system for both QBP1 and L1P3V8 (a lipidated variant of P3 with improved stability) and (b) evaluate their therapeutic effects on the R6/2 transgenic mouse model of polyglutamine disease. Compared with intravenous administration, intranasal administration of QBP1 significantly increased its brain-to-plasma ratio. In addition, employment of a chitosan-containing in situ gel for the intranasal administration of QBP1 notably improved its brain concentration for up to 10-fold. Further study on intranasal cotreatment with the optimized formulation of QBP1 and L1P3V8 in mice found no interference on the brain uptake of each other. Subsequent efficacy evaluation of 4-week daily QBP1 (16 μmol/kg) and L1P3V8 (6 μmol/kg) intranasal cotreatment in the R6/2 mice demonstrated a significant improvement on the motor coordination and explorative behavior of the disease mice, together with a full suppression on the RNA- and protein-toxicity markers in their brains. In summary, the current study developed an efficient intranasal cotreatment of the two peptidylic inhibitors, QBP1 and L1P3V8, for their brain-targeting, and such a novel therapeutic strategy was found to be effective on a transgenic polyglutamine disease mouse model.

Efficient brain uptake and distribution of an expanded CAG RNA inhibitor DB213 via intranasal administration

DB213 is an expanded CAG RNA inhibitor targeting polyglutamine diseases. This current study aims to investigate biopharmaceutic characteristics of DB213 as well as its brain uptake and distribution in C57 wild type mice, R6/2 Huntington's disease mice and Sprague-Dawley (SD) rats via intranasal administration. The biopharmaceutic characteristics of DB213 were investigated in vitro using Calu-3/MDCK/HEK293 cell lines and brain slices for its membrane transport, equilibrium dialysis for its plasma protein/brain tissue bindings and liver/brain microsomes incubation for its enzyme kinetics profiles. In vivo study of DB213 brain distribution was conducted in rats via intravenous and intranasal routes at 50 mg/kg followed by its brain uptake evaluation in mice at 25 mg/kg via intranasal route. In vitro membrane transport studies found that DB213 not only had a limited passive diffusion with a P_{app (a→b)} value of 1.75 × 10^-6 cm/s in Calu-3 cell monolayer model but also was substrate of MRP2, MRP3, and amino acid transporter. Furthermore, DB213 demonstrated higher binding towards brain homogenate (80%) than plasma (10%) with limited metabolism in liver and brain. After intranasal administration of DB213, both olfactory bulb and trigeminal nerve served as its entry points to reach brain as demonstrated in rats while efficient brain uptake was observed in mice. In summary, limited nasal epithelium permeability and MRP2/MRP3 mediated efflux transport of DB213 could be overcome by its influx transport via amino acid transporter and minimal liver and brain metabolism, which further contribute to its rapid brain uptake and distribution in mice and rats.

A comparison of immunotoxic effects of nanomedicinal products with regulatory immunotoxicity testing requirements

Nanomaterials (NMs) are attractive for biomedical and pharmaceutical applications because of their unique physicochemical and biological properties. A major application area of NMs is drug delivery. Many nanomedicinal products (NMPs) currently on the market or in clinical trials are most often based on liposomal products or polymer conjugates. NMPs can be designed to target specific tissues, eg, tumors. In virtually all cases, NMPs will eventually reach the immune system. It has been shown that most NMs end up in organs of the mononuclear phagocytic system, notably liver and spleen. Adverse immune effects, including allergy, hypersensitivity, and immunosuppression, have been reported after NMP administration. Interactions of NMPs with the immune system may therefore constitute important side effects. Currently, no regulatory documents are specifically dedicated to evaluate the immunotoxicity of NMs or NMPs. Their immunotoxicity assessment is performed based on existing guidelines for conventional substances or medicinal products. Due to the unique properties of NMPs when compared with conventional medicinal products, it is uncertain whether the currently prescribed set of tests provides sufficient information for an adequate evaluation of potential immunotoxicity of NMPs. The aim of this study was therefore, to compare the current regulatory immunotoxicity testing requirements with the accumulating knowledge on immunotoxic effects of NMPs in order to identify potential gaps in the safety assessment. This comparison showed that immunotoxic effects, such as complement activation-related pseudoallergy, myelosuppression, inflammasome activation, and hypersensitivity, are not readily detected by using current testing guidelines. Immunotoxicity of NMPs would be more accurately evaluated by an expanded testing strategy that is equipped to stratify applicable testing for the various types of NMPs.

Pharmacokinetics and brain uptake of HIV-1 replication inhibitor DB213 in Sprague-Dawley rats

The current study aims to investigate the pharmacokinetics and brain uptake of HIV-1 replication inhibitor DB213 via a developed LC/MS/MS analytical method. A sensitive, selective, accurate and reliable LC/MS/MS method for determination and quantification of DB213 in rat plasma and brain was developed and validated. A triple quadrupole mass spectrometer equipped with electrospray ionization (ESI) source was applied for the detection of DB213 and benzamidine (Internal Standard). The analytes were quantified by using multiple reaction monitoring (MRM) mode with m/z 333.4→86.1 and m/z 121.2→104 for DB213 and benzamidine respectively. Chromatographic separation of DB213 and benzamidine was achieved on a SunFire C8 (4.6×250mm, i.d. 5μm) analytical column with gradient elution of a mobile phase consisted of acetonitrile and 20mM ammonium formate buffer (containing 0.5% formic acid). The method achieved good linearity from 1.95∼1000ng/ml (r(2)=0.999) in plasma and 0.98∼125ng/ml (r(2)=0.999) in brain. The validated method was successfully applied to plasma pharmacokinetics (PK) and brain uptake of intravenous administration of DB213 water solution (1mg/kg) to Sprague-Dawley rats. It was found that the area under the plasma concentration-time curve from 0 to 360min (AUC0→360min) was 184422.1±42450.8ngmin/ml and the elimination half-life of DB213 after intravenous administration was 70.9±16.1min. In addition, DB213 has demonstrated a potential to cross the blood-brain barrier via intravenous administration with a brain tissue concentration of 11.3±3.6ng/g peaked at 30min post-dosing.