Enhancing both oral bioavailability and brain penetration of puerarin using borneol in combination with preparation technologies

Comprehensive evaluation of Dragon's Blood in combination with borneol in ameliorating ischemic/reperfusion brain injury using RNA sequencing, metabolomics, and 16S rRNA sequencing

Ischemia/reperfusion (IR) can induce deleterious responses such as apoptosis, inflammation, and oxidative stress; however, there are currently no efficient therapeutics to treat IR brain injury. Dragon's blood (DB) plays a significant role in treating ischemic stroke in China. Borneol (B) is an upper ushering drug that guides drugs to the target organs, including the brain. Therefore, we hypothesized that the combination of DB and B (DB + B) would provide cooperative therapeutic benefits for IR brain injury. To confirm this, we first investigated the protective effect of DB + B in an IR brain injury rat model using the modified neurological severity score (mNSS), infarction size measure, HE staining, and laser speckle contrast imaging. Then, we comprehensively evaluated the mechanism of DB + B in ameliorating IR brain injury based on RNA sequencing, serum untargeted metabolomics, and 16S rRNA sequencing. We have confirmed that DB + B enhanced the efficacy of the ischemic stroke treatment compared to DB or B alone for the first time. Our study provisionally confirms that the mechanism by which DB + B prevents IR brain injury is related to the maintenance of intestinal microecological balance and regulation of metabolic dysfunction, thereby suppressing inflammation and regulating immunity. DB + B may effectively regulate intestinal flora including o_Pseudomonadales, s_Bacteroides_caecimuris, o_unidentified_Bacilli, f-Pseudomonadaceae, and g-Pseudomonas, mainly regulate serum metabolites including improve the protective benefit of IR brain injury lysoPCs and lysoPEs, thus inhibiting TLR4/MyD88/NF-κB and IL-17 signing pathway to reduce inflammatory reactions. hat this mechanism is associated with the maintenance of intestinal flora balance and the regulation of metabolic dysfunction, thereby suppressing inflammation and regulating immunity. This provides scientific support for the clinical translation of DB + B in the prevention and treatment of ischemic stroke and establishes a basis for further investigation of its therapeutic mechanism.

The beneficial health effects of puerarin in the treatment of cardiovascular diseases: from mechanisms to therapeutics

Cardiovascular diseases (CVDs) are the leading causes of death globally that seriously threaten human health. Although novel western medicines have continued to be discovered over the past few decades to inhibit the progression of CVDs, new drug research and development for treating CVDs with less side effects and adverse reactions are continuously being desired. Puerarin is a natural product found in a variety of medicinal plants belonging to the flavonoid family with potent biological and pharmacological activities. Abundant research findings in the literature have suggested that puerarin possesses a promising prospect in treating CVDs. In recent years, numerous new molecular mechanisms of puerarin have been explored in experimental and clinical studies, providing new evidence for this plant metabolite to protect against CVDs. This article systematically introduces the history of use, bioavailability, and various dosage forms of puerarin and further summarizes recently published data on the major research advances and their underlying therapeutic mechanisms in treating CVDs. It may provide references for researchers in the fields of pharmacology, natural products, and internal medicine.

Progress in the Treatment of Central Nervous System Diseases Based on Nanosized Traditional Chinese Medicine

Traditional Chinese Medicine (TCM) is widely used in clinical practice to treat diseases related to central nervous system (CNS) damage. However, the blood-brain barrier (BBB) constitutes a significant impediment to the effective delivery of TCM, thus substantially diminishing its efficacy. Advances in nanotechnology and its applications in TCM (also known as nano-TCM) can deliver active ingredients or components of TCM across the BBB to the targeted brain region. This review provides an overview of the physiological and pathological mechanisms of the BBB and systematically classifies the common TCM used to treat CNS diseases and types of nanocarriers that effectively deliver TCM to the brain. Additionally, drug delivery strategies for nano-TCMs that utilize in vivo physiological properties or in vitro devices to bypass or cross the BBB are discussed. This review further focuses on the application of nano-TCMs in the treatment of various CNS diseases. Finally, this article anticipates a design strategy for nano-TCMs with higher delivery efficiency and probes their application potential in treating a wider range of CNS diseases.

Recent Advancements and Strategies for Overcoming the Blood-Brain Barrier Using Albumin-Based Drug Delivery Systems to Treat Brain Cancer, with a Focus on Glioblastoma

Glioblastoma multiforme (GBM) is a highly aggressive malignant tumor, and the most prevalent primary malignant tumor affecting the brain and central nervous system. Recent research indicates that the genetic profile of GBM makes it resistant to drugs and radiation. However, the main obstacle in treating GBM is transporting drugs through the blood-brain barrier (BBB). Albumin is a versatile biomaterial for the synthesis of nanoparticles. The efficiency of albumin-based delivery systems is determined by their ability to improve tumor targeting and accumulation. In this review, we will discuss the prevalence of human glioblastoma and the currently adopted treatment, as well as the structure and some essential functions of the BBB, to transport drugs through this barrier. We will also mention some aspects related to the blood-tumor brain barrier (BTBB) that lead to poor treatment efficacy. The properties and structure of serum albumin were highlighted, such as its role in targeting brain tumors, as well as the progress made until now regarding the techniques for obtaining albumin nanoparticles and their functionalization, in order to overcome the BBB and treat cancer, especially human glioblastoma. The albumin drug delivery nanosystems mentioned in this paper have improved properties and can overcome the BBB to target brain tumors.

Mercuric chloride induced brain toxicity in mice: The protective effects of puerarin-loaded PLGA nanoparticles

Mercury is a toxic, environmentally heavy metal that can cause severe damage to all organs, including the nervous system. The functions of puerarin include antioxidant, anti-inflammatory, nerve cell repair, regulation of autophagy, and so forth. But because of the limited oral absorption of puerarin, it affects the protective effect on brain tissue. The nano-encapsulation of Pue can improve its limitation. Therefore, this study investigated the protective effect of Pue drug-loaded PLGA nanoparticles (Pue-PLGA-nps) on brain injury induced by mercuric chloride (HgCl2 ) in mice. The mice were divided into normal saline (NS) group, HgCl2 (4 mg/kg) group, Pue-PLGA-nps (50 mg/kg) group, HgCl2  + Pue (4 mg/kg + 30 mg/kg) group, and HgCl2  + Pue-PLGA-nps (4 mg/kg + 50 mg/kg) group. After 28 days of treatment, the mice were observed for behavioral changes, antioxidant capacity, autophagy and inflammatory response, and mercury levels in the brain, blood, and urine were measured. The results showed that HgCl2 toxicity caused learning and memory dysfunction in mice, increased mercury content in brain and blood, and increased serum levels of interleukin (IL-6), IL-1β, and tumor necrosis factor-α in the mice. HgCl2 exposure decreased the activity of T-AOC, superoxide dismutase, and glutathione peroxidase, and increased the expression of malondialdehyde in the brain of mice. Moreover, the expression levels of TRIM32, toll-like receptor 4 (TLR4), and LC3 proteins were upregulated. Both Pue and Pue-PLGA-nps interventions mitigated the changes caused by HgCl2 exposure, and Pue-PLGA-nps further enhanced this effect. Our results suggest that Pue-PLGA-nps can ameliorate HgCl2 -induced brain injury and reduce Hg accumulation, which is associated with inhibition of oxidative stress, inflammatory response, and TLR4/TRIM32/LC3 signaling pathway.

An intravitreal-injectable hydrogel depot doped borneol-decorated dual-drug-coloaded microemulsions for long-lasting retina delivery and synergistic therapy of wAMD

Sustained retina drug delivery and rational drug combination are considered essential for enhancing the efficacy of therapy for wet age-related macular degeneration (wAMD) due to the conservative structure of the posterior ocular segment and the multi-factorial pathological mechanism. Designing a drug co-delivery system that can simultaneously achieve deep penetration and long-lasting retention in the vitreous is highly desired, yet remains a huge challenge. In this study, we fabricated Bor/RB-M@TRG as an intravitreal-injectable hydrogel depot for deep penetration into the posterior ocular segment and long-lasting distribution in the retinal pigment epithelium (RPE) layer. The Bor/RB-M@TRG consisted of borneol-decorated rhein and baicalein-coloaded microemulsions (Bor/RB-M, the therapy entity) and a temperature-responsive hydrogel matrix (the intravitreal depot). Bor/RB-M exhibited the strongest in vitro anti-angiogenic effects among all the groups studied, which is potentially associated with improved cellular uptake, as well as the synergism of rhein and baicalein, acting via anti-angiogenic and anti-oxidative stress pathways, respectively. Importantly, a single intravitreal (IVT) injection with Bor/RB-M@TRG displayed significant inhibition against the CNV of wAMD model mice, compared to all other groups. Particularly, coumarin-6-labeled Bor/RB-M@TRG (Bor/C6-M@TRG) could not only deeply penetrate into the retina but also stably accumulate in the RPE layer for at least 14 days. Our design integrates the advantages of borneol-decorated microemulsions and hydrogel depots, offering a promising new approach for clinically-translatable retinal drug delivery and synergistic anti-wAMD treatment.

Interactions Between Antidepressants and Intestinal Microbiota

The microbiota-gut-brain axis has been shown to influence human health and diseases, including depression. The interactions between drugs and intestinal microbiota are complex and highly relevant to treat diseases. Studies have shown an interaction between antidepressants and intestinal microbiota. Antidepressants may alter the abundance and composition of intestinal microbiota, which are closely related to the treatment outcomes of depression. Intestinal microbiota can influence the metabolism of antidepressants to change their availability (e.g., tryptophan can be metabolized to kynurenine by intestinal microbiota) and regulate their absorption by affecting intestinal permeability. In addition, the permeability of the blood-brain barrier can be altered by intestinal microbiota, influencing antidepressants to reach the central nervous system. Bioaccumulation is also a type of drug-microbiota interaction, which means bacteria accumulate drugs without biotransformation. These findings imply that it is important to consider intestinal microbiota when evaluating antidepressant therapy regimens and that intestinal microbiota can be a potential target for depression treatment.

Therapeutic potential of puerarin against cerebral diseases: From bench to bedside

The incidence of cerebral diseases is rapidly increasing worldwide, and they have become an important challenge for modern medicine. Most of the available chemical drugs used in the treatment of cerebral diseases are highly toxic and single-targeted. Therefore, novel drugs from natural resources have attracted much attention for their potential to manage cerebral diseases. Puerarin is a natural isoflavone isolated from the roots of Pueraria species such as P. lobata (Willd) Ohwi, P. thomsonii, and P. mirifica. Several authors have reported the beneficial effects of puerarin in cerebral ischemic disease, intracerebral hemorrhage, vascular dementia, Alzheimer's disease, Parkinson's disease, depression, anxiety, and traumatic brain injury. This review summarizes the brain pharmacokinetics, brain drug delivery system, clinical use (in cerebral diseases), toxicity, and the adverse clinical reactions of puerarin. We have systematically presented the pharmacological actions and the molecular mechanisms of puerarin in various cerebral diseases to provide a direction for future research on the therapeutic use of puerarin in cerebral diseases.

A Review of the Effects of Puerarin on Glucose and Lipid Metabolism in Metabolic Syndrome: Mechanisms and Opportunities

Chronic diseases, including metabolic syndrome related to sugar and lipid metabolic disorders, are the leading causes of premature death around the world. Novel treatment strategies without undesirable effects are urgently needed. As a natural functional ingredient, puerarin is a promising alternative for the treatment of sugar and lipid metabolic disorders. However, the applications of puerarin are limited due to its poor solubility and short half-life. Various drug delivery systems have been investigated to improve the bioavailability of puerarin. This review summarizes the mechanisms involved in the beneficial action of puerarin: suppressing the release of glucose and FFA; regulating the transport of glucose and fatty acids; acting on the PI3K-Akt and AMPK signaling pathways to decrease the synthesis of glucose and fatty acids; acting on the PPAR signaling pathway to promote β-oxidation; and improving insulin secretion and sensitivity. In addition, the preparation technologies used to improve the bioavailability of puerarin are also summarized in this review, in the hope of helping to promote the application of puerarin.

NIR-Assisted MgO-Based Polydopamine Nanoparticles for Targeted Treatment of Parkinson's Disease through the Blood-Brain Barrier

The blood-brain barrier (BBB) is a major limiting factor that prevents the treatment of Parkinson's disease (PD). In the present study, MgOp@PPLP nanoparticles are explored by using MgO nanoparticles as a substrate, polydopamine as a shell, wrapping anti-SNCA plasmid inside, and modifying polyethylene glycol, lactoferrin, and puerarin on the surface to improve the hydrophilicity, brain targeting and antioxidant properties of the particles, respectively. MgOp@PPLP exhibits superior near-infrared radiation (NIR) response. Under the guidance of photothermal effect, these MgOp@PPLP particles are capable of penetrating the BBB and be taken up by neuronal cells to exert gene therapy and antioxidant therapy. In both in vivo and in vitro models of PD, MgOp@PPLP exhibits good neuroprotective effects. Therefore, combined with noninvasive NIR radiation, MgOp@PPLP nanoplatform with good biocompatibility becomes an ideal material to combat neurodegenerative diseases.

Puerarin alleviates cadmium-induced rat neurocyte injury by alleviating Nrf2-mediated oxidative stress and inhibiting mitochondrial unfolded protein response

Cadmium (Cd) is a highly neurotoxic environmental pollutant. Puerarin (Pur) is a natural antioxidant isolated from Kudzu root that exhibits a powerful neuroprotective effect. Herein, we illustrated the mechanism underlying the protective effect of Pur on Cd-induced rat neurocyte injury in an in vivo rat model as well as in vitro using PC12 cells and primary rat cerebral cortical neurons. First, the results showed that Pur alleviated Cd-induced cerebral cortical pathological damage and decreased the viability of neurocytes. Furthermore, Cd activated the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, which plays a negative role in Cd-induced rat neurocyte injury. In addition, Pur alleviated Cd-induced oxidative stress by enhancing antioxidant defense, reducing reactive oxygen species (ROS) accumulation and lipid peroxidation, and inhibiting activation of the Nrf2 signaling pathway in rat neurocytes. Moreover, Pur inhibited the Cd-induced mitochondrial unfolded protein response (UPRmt) in rat neurocytes. Overall, Pur alleviated Cd-induced rat neurocyte injury by alleviating Nrf2-mediated oxidative stress and inhibiting UPRmt.

Towards updated understanding of brain metastasis

Brain metastasis (BM) is a common complication in cancer patients with advanced disease and attributes to treatment failure and final mortality. Currently there are several therapeutic options available; however these are only suitable for limited subpopulation: surgical resection or radiosurgery for cases with a limited number of lesions, targeted therapies for approximately 18% of patients, and immune checkpoint inhibitors with a response rate of 20-30%. Thus, there is a pressing need for development of novel diagnostic and therapeutic options. This overview article aims to provide research advances in disease model, targeted therapy, blood brain barrier (BBB) opening strategies, imaging and its incorporation with artificial intelligence, external radiotherapy, and internal targeted radionuclide theragnostics. Finally, a distinct type of BM, leptomeningeal metastasis is also covered.

Self-Emulsifying Drug Delivery Systems: An Alternative Approach to Improve Brain Bioavailability of Poorly Water-Soluble Drugs through Intranasal Administration

Efforts in discovering new and effective neurotherapeutics are made daily, although most fail to reach clinical trials. The main reason is their poor bioavailability, related to poor aqueous solubility, limited permeability through biological membranes, and the hepatic first-pass metabolism. Nevertheless, crossing the blood–brain barrier is the major drawback associated with brain drug delivery. To overcome it, intranasal administration has become more attractive, in some cases even surpassing the oral route. The unique anatomical features of the nasal cavity allow partial direct drug delivery to the brain, circumventing the blood–brain barrier. Systemic absorption through the nasal cavity also avoids the hepatic first-pass metabolism, increasing the systemic bioavailability of highly metabolized entities. Nevertheless, most neurotherapeutics present physicochemical characteristics that require them to be formulated in lipidic nanosystems as self-emulsifying drug delivery systems (SEDDS). These are isotropic mixtures of oils, surfactants, and co-surfactants that, after aqueous dilution, generate micro or nanoemulsions loading high concentrations of lipophilic drugs. SEDDS should overcome drug precipitation in absorption sites, increase their permeation through absorptive membranes, and enhance the stability of labile drugs against enzymatic activity. Thus, combining the advantages of SEDDS and those of the intranasal route for brain delivery, an increase in drugs’ brain targeting and bioavailability could be expected. This review deeply characterizes SEDDS as a lipidic nanosystem, gathering important information regarding the mechanisms associated with the intranasal delivery of drugs loaded in SEDDS. In the end, in vivo results after SEDDS intranasal or oral administration are discussed, globally revealing their efficacy in comparison with common solutions or suspensions.

Enhancing effect of borneol on pharmacokinetics of ginsenoside Rb1 , ginsenoside Rg1 and notoginsenoside R1 in healthy volunteers after oral administration of compound Danshen dropping pills (CDDP)

Borneol (Bingpian), a monoterpenoid pharmaceutical ingredient, is commonly used as a main composition in traditional Chinese medicine (TCM) preparations such as compound Danshen dropping pills (CDDP), and has also been approved by the US FDA as a flavoring substance or adjuvant in food. Borneol plays a regulating and guiding role as messenger drug in CDDP. However, the effect of borneol on the pharmacokinetics of the components of CDDP in human plasma is unclear. In this study, we investigate the effects of borneol on the pharmacokinetics of ginsenoside Rb₁ (Rb₁ ), ginsenoside Rg₁ (Rg₁ ) and notoginsenoside R₁ (NR₁ ) in CDDP. We used a double-cycle crossover-administration model in twelve healthy male volunteers, giving CDDP with borneol (drug T) and without borneol (drug R). The selective response monitoring (SRM) mode was used for mass spectrometry quantification in the positive mode. As a result, we found that borneol could significantly affect the pharmacokinetic parameters of notoginsenosides, and increase the absorption and systemic exposure of Rb₁ , Rg₁ and NR₁ in human plasma by about 1.85 to 3.71 times.

Interactions between puerarin/daidzein and micellar casein

Puerarin (PUE) and daidzein (DAI) are polyphenols with extensive biological activities. In the present study, the interactions between PUE/DAI and micellar casein (MC) were investigated, and the physicochemical properties of their complexes were analyzed. The results of fluorescence spectrum analysis and molecular docking revealed that the main interactions between DAI and MC were hydrophobic forces, while that between PUE and MC was hydrogen bonding. The FTIR and XRD analyses confirmed the formation of complexes between MC and PUE/DAI. After binding to PUE/DAI, the size of MC increased. The weight loss rate of MC decreased after complexing with PUE/DAI, but its morphology was not extensively modified. The DPPH radical scavenging capacities of PUE-MC and DAI-MC complexes were higher than those of free PUE/DAI in both water and ethanol. In vitro release experiments showed that the release rate of PUE/DAI was inhibited by MC under simulated intestinal conditions. PRACTICAL APPLICATIONS: The low water solubility and poor bioavailability of PUE and DAI limit their application. Micellar casein has high affinity for PUE and DAI. After encapsulated by micellar casein, the release rates of PUE and DAI were prolonged during simulated intestinal digestion. The results would provide useful information for improving the solubility and bioavailability of PUE and DAI, and broadening the use of them in the food and pharmaceutical industry.

Drug Delivery Systems and Strategies to Overcome the Barriers of Brain

The transport of drugs to the central nervous system is the most challenging task for conventional drug delivery systems. Reduced permeability of drugs through the blood-brain barrier is a major hurdle in delivering drugs to the brain. Hence, various strategies for improving drug delivery through the blood-brain barrier are currently being explored. Novel drug delivery systems (NDDS) offer several advantages, including high chemical and biological stability, suitability for both hydrophobic and hydrophilic drugs, and can be administered through different routes. Furthermore, the conjugation of suitable ligands with these carriers tend to potentiate targeting to the endothelium of the brain and could facilitate the internalization of drugs through endocytosis. Further, the intranasal route has also shown potential, as a promising alternate route, for the delivery of drugs to the brain. This can deliver the drugs directly to the brain through the olfactory pathway. In recent years, several advancements have been made to target and overcome the barriers of the brain. This article deals with a detailed overview of the diverse strategies and delivery systems to overcome the barriers of the brain for effective delivery of drugs.

Camptothecin shows better promise than Curcumin in the inhibition of the Human Telomerase: A computational study

OBJECTIVES

The Human Telomerase enzyme has become a drug target in the treatment of cancers and age-related disorders. This study aims to identify potential natural inhibitors of the Human Telomerase from compounds derived from edible African plants.

MATERIALS AND METHODS

A library of 1,126 natural compounds was molecularly docked against the Telomerase Reverse Transcriptase (PDB ID: 5ugw), the catalytic subunit of the target protein. Curcumin, a known Telomerase inhibitor was used as the standard. The front-runner compounds were screened for bioavailability, pharmacokinetic properties, and bioactivity using the SWISSADME, PKCSM, and Molinspiration webservers respectively. The molecular dynamic simulation and analyses of the apo and holo proteins were performed by the Galaxy supercomputing webserver.

RESULTS

The results of the molecular docking and virtual screening reveal Augustamine and Camptothecin as lead compounds. Augustamine has better drug-likeness and pharmacokinetic properties while Camptothecin showed better bioactivity and stronger binding affinity (-8.2 kcal/mol) with the target. The holo structure formed by Camptothecin showed greater inhibitory activity against the target with a total RMSF of 169.853, B-Factor of 20.164, and 108 anti-correlating residues.

CONCLUSION

Though they both act at the same binding site, Camptothecin induces greater Telomerase inhibition and better molecular stability than the standard, Curcumin. Further tests are required to investigate the inhibitory activities of the lead compounds.

Puerarin-Na Chelate Hydrate Simultaneously Improves Dissolution and Mechanical Behavior

Puerarin monohydrate (PUEM), as the commercial solid form of the natural anti-hypertension drug puerarin (PUE), has low solubility, poor flowability, and mechanical properties. In this study, a novel solid form as PUE-Na chelate hydrate was prepared by a reactive crystallization method. Crystal structure analysis demonstrated that PUE-Na contains PUE^-, Na⁺, and water in a molar ratio of 1:1:7. It crystallizes in the monoclinic space group P2₁, and Na⁺ is linked with PUE^- and four water molecules through Na⁺ ← O coordination bonds. Another three crystal water molecules occupy channels along the crystallographic b-axis. Observing along the b-axis, the crystal structure features a distinct tubular helix and a DNA-like twisted helix. The complexation between Na⁺ and PUE^- in aqueous solution was confirmed by the Na⁺ selective electrode, indicating that PUE-Na chelate hydrate belongs to a type of chelate rather than organic metal salt. Compared with PUEM, PUE-Na exhibited a superior dissolution rate (i.e., ∼38-fold increase in water) owing to its lower solvation free energy and clear-enriched exposed polar groups. Moreover, PUE-Na enhanced the tabletability and flowability of PUEM, attributing to its better elastoplastic deformation and lower-friction crystal habit. The unique PUE-Na chelate hydrate with significantly enhanced pharmaceutical properties is a very promising candidate for future product development of PUE.

Kuanxiong Aerosol () in Treatment of Angina Pectoris: A Literature Review and Network Pharmacology

Angina pectoris (AP) is the most common symptom of cardiovascular diseases, which seriously affects the quality of life in cardiovascular patients. Kuanxiong (KX) Aerosol (), a compound preparation that consists of 5 traditional Chinese medicines: Herba Asari , Rhizoma Alpiniae Officinarum, Lignum Santali Albi, Fructus Piperis Longi, and Borneolum, has been used in the treatment of AP for many years, exhibiting a significant curative effect and less side-effect. For the convenience and comprehensive understanding of KX Aerosol, this review systematically summarizes evidence on KX Aerosol in the treatment of AP including the pharmacological effects of its composition, clinical research, animal experiments, and network pharmacology prediction. Meanwhile, we highlight the research limitation of KX Aerosol at present. This review may guide the clinical application of KX Aerosol and further provide a reference for the research of AP.

Borneol: a Promising Monoterpenoid in Enhancing Drug Delivery Across Various Physiological Barriers

Incorporation of permeation enhancers is one of the most widely employed approaches for delivering drugs across biological membranes. Permeation enhancers aid in delivering drugs across various physiological barriers such as brain capillary endothelium, stratum corneum, corneal epithelium, and mucosal membranes that pose resistance to the entry of a majority of drugs. Borneol is a natural, plant-derived, lipophilic, volatile, bicyclic monoterpenoid belonging to the class of camphene. It has been used under the names "Bing Pian" or "Long Nao" in Traditional Chinese Medicine for more than 1000 years. Borneol has been incorporated predominantly as an adjuvant in the traditional Chinese formulations of centrally acting drugs to improve drug delivery to the brain. This background knowledge and anecdotal evidence have led to extensive research in establishing borneol as a permeation enhancer across the blood-brain barrier. Alteration in cell membrane lipid structures and modulation of multiple ATP binding cassette transporters as well as tight junction proteins are the major contributing factors to blood-brain barrier opening functions of borneol. Owing to these mechanisms of altering membrane properties, borneol has also shown promising potential to improve drug delivery across other physiological barriers as well. The current review focuses on the role of borneol as a permeation enhancer across the blood-brain barrier, mucosal barriers including nasal and gastrointestinal linings, transdermal, transcorneal, and blood optic nerve barrier.

Screening, Optimization, and Bioavailability Research of Natural Deep Eutectic Solvent Extracts from Radix Pueraria

Natural deep eutectic solvent (NaDES) is generally considered as a greener alternative to fossil solvent, with great potential in various areas. In the present work, 25 different NaDESs were screened for the extraction of puerarin (PUE) and its two natural derivatives from Radix Pueraria (RP). As the main isoflavone in RP, PUE has a wide range of biological activities. However, its application is restricted due to its poor solubility in water and low oral bioavailability. In this study, the extraction of PUE with NaDESs showed significant advantages compared with traditional solvents. While using L-Pro-Maa (L-proline-malic acid) under optimal conditions, the optimized yields of PUE, 3-MPR and PRX were 98.7 mg/g, 16.3 mg/g and 9.9 mg/g, respectively, which were 2.2-, 2.9- and 3.4-fold higher than that of water. Furthermore, the oral bioavailability of PUE in NaDES extracts was comparatively investigated in rats with HPLC-MS technique. Pharmacokinetic analysis revealed that the relative bioavailability of PUE in L-Pro-Maa extract is 323%. The result indicated that NaDES is not only a sustainable ionic liquid with higher extraction efficiency, but also an enhancer of oral bioavailability of specific natural products.

Enhancing the Physiochemical Properties of Puerarin via L-Proline Co-Crystallization: Synthesis, Characterization, and Dissolution Studies of Two Phases of Pharmaceutical Co-Crystals

Puerarin (PUE) is a Chinese traditional medicine known to enhance glucose uptake into the insulin cells to downregulate the blood glucose levels in the treatment of type II diabetes. Nevertheless, the bioavailability of pristine PUE is limited due to its poor solubility and low intestinal permeability. In this work, we demonstrate that the solubility of PUE can be significantly enhanced via its co-crystallization with L-Proline (PRO). Two crystalline phases, namely, the solvate-free form [PUE][PRO] (I) and the solvated form [PUE]₂[PRO]∙EtOH∙(H₂O)₂ (II) are isolated. These two phases are characterized by single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), Fourier-transformed infrared (FT-IR) spectra, nuclear magnetic resonance (NMR), and thermogravimetric analysis in association with differential scanning calorimetry (TGA-DSC). The solubility and dissolution rate of both I and II in water, gastrointestinal tract at pH 1.2, and phosphate buffer at pH 6.8 indicates a nearly doubled increase as compared to the pristine PUE. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay of pristine PUE, I and II against murine colon cancer cell lines CT-26 and human kidney cell lines HEK-293 indicated that neither compound exhibits obvious cytotoxicity after 24 h. This work showcases that the readily available and biocompatible PRO can be a promising adjuvant to enhance the physicochemical properties of PUE toward orally administered drug formulation with improved pharmacokinetics.

Effects of Borneol on the Release of Compound Danshen Colon-Specific Osmotic Pump Capsule In Vitro and Pharmacokinetics Study in Beagle Dogs

Borneol can enhance the bioavailability of several other drugs by opening the blood-brain barrier and inhibiting P-glycoprotein (P-gp) efflux. However, whether borneol will impact the bioavailability and the mechanism of compound Danshen colon-specific osmotic pump capsule (CDCOPC) remains unclear. This study aimed to determine the effects of borneol on the in vitro release and in vivo pharmacokinetic characteristics of CDCOPC. Besides, the in vitro release behavior of CDCOPC was further assessed by chromatographic fingerprints. The in vitro release studies showed that borneol followed the zero-order release and hardly impacted the in vitro release of Salvia miltiorrhiza and Panax notoginseng in CDCOPC. Moreover, as revealed from the similarity results of fingerprints, the in vitro release of different components of CDCOPC was almost simultaneous. Compared with the commercially available tablets, the pharmacokinetics studies suggested that both CDCOPCs containing and lacking borneol could significantly prolong the retention time of these effective components; their average relative bioavailability values increased to 448.70% and 350.97%, respectively. Notably, borneol significantly improved the relative bioavailability of some components of CDCOPC, such as salvianolic acid B (SAB), tanshinone IIA (Tan IIA), notoginsenoside R₁ (R₁), ginsenoside Rg₁ (Rg₁), and ginsenoside Re (Re) from CDCOPC, while it slightly impacted ginsenoside Rb₁ (Rb₁) and ginsenoside Rd (Rd). Summarily, borneol is capable of improving the bioavailability of some effective components in CDCOPC, which is critical to design with CDCOPC for enhanced bioavailability. This study could also help reveal the composition principle of the compound Danshen formula (CDF).

Oral delivery of lycopene-loaded microemulsion for brain-targeting: preparation, characterization, pharmacokinetic evaluation and tissue distribution

Lycopene is considered as a promising neuroprotector with multiple bioactivities, while its therapeutic use in neurological disorders is restricted due to low solubility, instability and limited bioavailability. Our work aimed to develop lycopene-loaded microemulsion (LME) and investigate its potentials in improving bioavailability and brain-targeting efficiency following oral administration. The blank microemulsion (ME) excipients were selected based on orthogonal design and pseudo-ternary phase diagrams, and LME was prepared using the water titration method and characterized in terms of stability, droplet size distribution, zeta potential, shape and lycopene content. The optimized LME encompassed lycopene, (R)-(+)-limonene, Tween 80, Transcutol HP and water and lycopene content was 463.03 ± 8.96 µg/mL. This novel formulation displayed transparent appearance and satisfactory physical and chemical stabilities. It was spherical and uniform in morphology with an average droplet size of 12.61 ± 0.46 nm and a polydispersity index (PDI) of 0.086 ± 0.028. The pharmacokinetics and tissue distributions of optimized LME were evaluated in rats and mice, respectively. The pharmacokinetic study revealed a dramatic 2.10-fold enhancement of relative bioavailability with LME against the control lycopene dissolved in olive oil (LOO) dosage form in rats. Moreover, LME showed a preferential targeting distribution of lycopene toward brain in mice, with the value of drug targeting index (DTI) up to 3.45. In conclusion, the optimized LME system demonstrated excellent physicochemical properties, enhanced oral bioavailability and superior brain-targeting capability. These findings provide a basis for the applications of ME-based strategy in brain-targeted delivery via oral route, especially for poorly water-soluble drugs.

Fabrication of Fine Puerarin Nanocrystals by Box-Behnken Design to Enhance Intestinal Absorption

Puerarin is widely used as a therapeutic agent to cardiovascular diseases in clinics in China through intravenous administration, which could elicit adverse drug reactions caused by cosolvents, hindering its application in clinics. Therefore, the development of oral dosage is urgently needed. In our previous studies, we proved that the bioavailability of puerarin increased as particle sizes of nanocrystals decreased; however, we have not optimized the best process parameters for nanocrystals. In this study, we aim to fabricate fine nanocrystals (with smallest particle size) by Box-Behnken design and study the intestinal permeability of puerarin and its nanocrystals via employing everted gut sac model and in situ perfusion model. The results showed that the Box-Behnken design could be used to optimize the producing parameters of puerarin nanocrystals, and the particle sizes of fine nanocrystals were about 20 nm. Results of everted gut sacs showed that the polyvinylpyrrolidone (PVP) and verapamil had no influence on the absorption of puerarin and nanocrystals, and the nanocrystals could increase the P_app of puerarin for 2.2-, 2.9-, and 2.9-folds, respectively, in duodenum, jejunum, and ileum. Enhanced Ka and Peff were observed on the nanocrystal group, compared with puerarin, and PVP and verapamil had no influence on the absorption of nanocrystals, while the absorption of puerarin was influenced by P-gp efflux. Combining the results mentioned above, we can conclude that the Box-Behnken design benefits the optimization for preparation of nanocrystals, and the nanocrystals could enhance the intestinal absorption of puerarin by enhanced permeability and inhibited P-gp efflux.

Borneol and poly (ethylene glycol) dual modified BSA nanoparticles as an itraconazole vehicle for brain targeting

Itraconazole (ITZ) can be used for the treatment of cryptococcus neoformans meningitis and aspergillus brain abscess. While, the inherent hydrophobicity of ITZ and the existence of blood brain barrier (BBB) limit its applications as a central nervous system drug. In this study, a novel brain targeting drug delivery system based on bovine serum albumin (BSA) was constructed for enhancing ITZ distribution in brain. Firstly, ITZ was loaded into BSA nanoparticles (ITZ-NPs) with 11.6% of drug loading. Subsequently, the nanoparticles were modified with borneol (BO) and polyethylene glycol (PEG) (PEG/BO-ITZ-NPs). The resulting nanoparticles retained their nanosize (186.3 nm), uniform and spherical morphology, and negative surface charge (-21.03 mV). Cell uptake studies showed that compared with ITZ-NPs, PEG/BO-ITZ-NPs had significantly increased uptake in bEnd.3 cells, and the increase in BO concentration was beneficial for the cellular uptake of NPs. Moreover, PEG/BO-ITZ-NPs displayed an approximately 3.5-fold higher area under the curve in rats and about 2-fold higher brain distribution in mice than that of Sporanox®, i.e. ITZ solubilized by hydroxylpropyl-β-cyclodetrin, after i.v. administration. In a word, BO and PEG dual modified BSA nanoparticles may potentially serve as an ITZ vehicle for brain targeting.

Pharmacokinetics and drug delivery systems for puerarin, a bioactive flavone from traditional Chinese medicine

Pueraria lobata (Willd.) Ohwi is a medicinal and edible homologous plant with a long history in China. Puerarin, the main component isolated from the root of Pueraria lobata, possesses a wide range of pharmacological properties. Daidzein and glucuronides are the main metabolites of puerarin and are excreted in the urine and feces. As active substrates of P-gp, multidrug resistance-associated protein and multiple metabolic enzymes, the pharmacokinetics of puerarin can be influenced by different pathological conditions and drug-drug interactions. Due to the poor water-solubility and liposolubility, the applications of puerarin are limited. So far, only puerarin injections and eye drops are on the market. Recent years, researches on improving the bioavailability of puerarin are developing rapidly, various nanotechnologies and preparation technologies including microemulsions and SMEDDS, dendrimers, nanoparticles and nanocrystals have been researched to improve the bioavailability of puerarin. In order to achieve biocompatibility and desired activity, more effective quality evaluations of nanocarriers are required. In this review, we summarize the pharmacokinetics and drug delivery systems of puerarin up to date.

Effect of different doses of borneol on the pharmacokinetics of vinpocetine in rat plasma and brain after intraocular administration

The effect of different doses of borneol on the pharmacokinetics of vinpocetine after intraocular administration in the rat plasma and the brain was investigated.Intraocular administration of vinpocetine (3 mg/kg) was performed, in combination with different doses (0, 5, 10, and 20 mg/kg) of borneol. Intravenous administration of vinpocetine was used as a control (1 mg/kg). The concentrations of vinpocetine in the rat plasma and the brain were determined using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Using the non-compartmental models with the DSA 2.0 software, the main pharmacokinetics parameters and the brain-targeting effect evaluated.In comparison with intravenous administration, after intraocular administration of vinpocetine alone, the absolute bioavailability (F) of vinpocetine was 43.82% for the plasma, and the drug target index (DTI) was 1.05 for the brain. After intraocular administration of vinpocetine combined with different doses of borneol, the relative bioavailability (Fr) of vinpocetine in the plasma was increased by 130.46-182.90%. The relative bioavailability (Fr) of vinpocetine in the brain was improved (147.19-225.36%). The DTI was 1.12, 1.18, and 1.21 for 5, 10, and 20 mg/kg of borneol, respectively.Compared with the intraocular administration of vinpocetine alone, the co-administration of different doses of borneol resulted in an obvious brain targeting effect.

Borneol and Α-asarone as adjuvant agents for improving blood-brain barrier permeability of puerarin and tetramethylpyrazine by activating adenosine receptors

Puerarin (PUE) and tetramethylpyrazine (TMP) are central nervous system (CNS) drugs used in cerebrovascular diseases. Poor brain–blood barrier (BBB) permeability limited their clinical application. Borneol and α-asarone have been proposed as an oral brain-targeting enhancer. In this study, we aimed to first evaluate the ‘orifice-opening’ effect of borneol and α-asarone, both aromatic resuscitation drugs, on improvement of brain delivery of PUE and TMP and second to investigate whether the enhancing effects were associated with adenosine receptors (ARs)-mediated trans-BBB pathway. In vitro BBB model was established and borneol and α-asarone significantly increased the cumulative amount of permeated PUE and TMP and the enhancing effects could be counteracted by AR inhibitors. Borneol and α-asarone could decrease expression of ZO-1, an important BBB junction protein, but inversely increase the expression of A₁AR and A_2AAR. In vivo pharmacokinetic study also confirmed that oral co-administration of borneol or α-asarone significantly increased AUC_brain for PUE and TMP. These results suggested that borneol and α-asarone are both effective adjuvant agents for delivery of PUE and TMP to the brain.

Improved Oral Absorption of Poorly Soluble Curcumin via the Concomitant Use of Borneol

In this study, borneol, a natural active compound was applied to improve the bioavailability of curcumin (CUR). In order to increase CUR solubility and dissolution, solid dispersions (SDs) were prepared with the matrix of polyvinylpyrrolidone (PVP) at various ratios by solvent evaporation method. CUR was evidenced to exist as amorphous state in solid dispersion by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). Fourier-transform infrared spectroscopy (FT-IR) was utilized to confirm intermolecular hydrogen bonding. The SD at the ratio of 1:3 (CUR:PVP) exhibited the optimal solubility and dissolution rate in various media. The results of ex vivo permeability studies by everted gut sac method showed that the apparent permeability coefficients (P_app) of CUR in SD across the duodenum, jejunum, and ileum had been significantly improved by co-incubation of borneol, and the improvement degree relied on the concentration of borneol. The pharmacokinetic results in rats indicated that the AUC_0-t of CUR-SD (40 mg/kg) co-administration of borneol (90 mg/kg) were 2.53-fold higher than CUR-SD alone, and 19.41-fold higher than pure CUR (200 mg/kg) with borneol (90 mg/kg). Therefore, the combination of borneol and solid dispersion strategy provide a potential approach to enhance the oral bioavailability of CUR.

Improved lymphatic targeting: effect and mechanism of synthetic borneol on lymph node uptake of 7-ethyl-10-hydroxycamptothecin nanoliposomes following subcutaneous administration

Borneol as a penetration enhancer is widely used in guiding other components through the biological barrier into the targeting organs or tissues. This study aimed at studying effect and mechanism of synthetic borneol (S-BO) on improving lymphatic-targeting ability of 7-ethyl-10-hydroxycamptothecin liposomes (SN-38-Lips) via increasing lymph node uptake. At first, SN-38-Lips prepared had appropriate particle distribution, drug loading property and compatible stability with S-BO. Both in vitro cellular uptake and in vivo fluorescence imaging showed that 2 and 5 mg/mL S-BO, especially 2 mg/mL S-BO, enhanced cytoplasmic fluorescence signal of SN-38-Lips in the macrophages based on phagocytosis effect. And high-intensity zone appeared in the paracortex and medulla of popliteal lymph node. SN-38-Lips were subcutaneously (s.c.) injected into the right footpad of KM rats in the dose of 4 mg/kg following s.c. injection of 1, 2 and 5 mg/mL BO suspension. The lymphatic pharmacokinetics were investigated to explore the promotion law of S-BO, and combined with tissue irritation to optimize S-BO concentrations. The results indicated that 2 mg/mL S-BO could reduce injection-site retention, and prolong residence time and increase uptake of lymph nodes, which would not cause inflammatory reaction of injection site. In conclusion, the present study may provide a basic study for improving lymphatic-targeting ability of SN-38-Lips by the S-BO regulation, and to be the helpful guidance for further study in lymphatic targeting of delivery system.

Development of an Oral Compound Pickering Emulsion Composed of Nanocrystals of Poorly Soluble Ingredient and Volatile Oils from Traditional Chinese Medicine

In this study, an oral drug nanocrystals self-stabilized Pickering emulsion (NSSPE), which used nanocrystals of a poorly soluble ingredient from Puerariae Radix called puerarin as solid particle stabilizers and Ligusticumchuanxiong essential oil since the main oil phase had been developed to improve the oral bioavailability of puerarin. The appearance of emulsions, size and zeta potential of droplets, and content of puerarin in emulsified layer during a storage of six months at 4, 25, and 40 °C were investigated. The centrifugation stability at 4000× g was also studied. The micro-structure of emulsion droplets was characterized by a scanning electron micrograph (SEM), confocal laser scanning microscopy (CLSM), a fluorescence microscope (FM), and differential scanning calorimetry (DSC). The in vivo oral bioavailability of puerarin NSSPE was investigated in rats. Results showed that appearances of puerarin NSSPE kept stable after centrifugation at 4000× g for 15 min or storage for six months at 4, 25, and 40 °C. SEM, CLSM, FM, and DSC showed that the puerarin NSSPE had a stable core-shell structure of emulsion droplets formed by the adsorption of puerarin nanocrystals on the surface of oil droplets of mixed oil of Ligusticumchuanxiong essential oil and Labrafil M 1944 CS (9:1, v/v). The relative bioavailability of puerarin NSSPE to puerarin coarse powder suspension, nanocrystal suspension, and surfactant emulsion were 262.43%, 155.92%, and 223.65%, respectively. All these results indicated that puerarin nanocrystals could stabilize Pickering emulsion of Ligusticumchuanxiong essential oil without any other stabilizers and Pickering emulsion could improve the oral bioavailability of puerarin, which suggests that the drug nanocrystal self-stabilized Pickering emulsion as a promising oral drug delivery system for Traditional Chinese Medicine containing poorly soluble ingredients and volatile oils.

Nanocrystals of Poorly Soluble Drugs: Drug Bioavailability and Physicochemical Stability

Many approaches have been developed over time to overcome the bioavailability limitations of poorly soluble drugs. With the advances in nanotechnology in recent decades, science and industry have been approaching this issue through the formulation of drugs as nanocrystals, which consist of “pure drugs and a minimum of surface active agents required for stabilization”. They are defined as “carrier-free submicron colloidal drug delivery systems with a mean particle size in the nanometer range, typically between 10–800 nm”. The primary importance of these nanoparticles was the reduction of particle size to nanoscale dimensions, with an increase in the particle surface area in contact with the dissolution medium, and thus in bioavailability. This approach has been proven successful, as demonstrated by the number of such drug products on the market. Nonetheless, despite the definition that indicates nanocrystals as a “carrier-free” system, surface active agents are necessary to prevent colloidal particles aggregation and thus improve stability. In addition, in more recent years, nanocrystal properties and technologies have attracted the interest of researchers as a means to obtain colloidal particles with modified biological properties, and thus their interest is now also addressed to modify the drug delivery and targeting. The present work provides an overview of the achievements in improving the bioavailability of poorly soluble drugs according to their administration route, describes the methods developed to overcome physicochemical and stability-related problems, and in particular reviews different stabilizers and surface agents that are able to modify the drug delivery and targeting.

Current Strategies for Brain Drug Delivery

The blood-brain barrier (BBB) has been a great hurdle for brain drug delivery. The BBB in healthy brain is a diffusion barrier essential for protecting normal brain function by impeding most compounds from transiting from the blood to the brain; only small molecules can cross the BBB. Under certain pathological conditions of diseases such as stroke, diabetes, seizures, multiple sclerosis, Parkinson's disease and Alzheimer disease, the BBB is disrupted. The objective of this review is to provide a broad overview on current strategies for brain drug delivery and related subjects from the past five years. It is hoped that this review could inspire readers to discover possible approaches to deliver drugs into the brain. After an initial overview of the BBB structure and function in both healthy and pathological conditions, this review re-visits, according to recent publications, some questions that are controversial, such as whether nanoparticles by themselves could cross the BBB and whether drugs are specifically transferred to the brain by actively targeted nanoparticles. Current non-nanoparticle strategies are also reviewed, such as delivery of drugs through the permeable BBB under pathological conditions and using non-invasive techniques to enhance brain drug uptake. Finally, one particular area that is often neglected in brain drug delivery is the influence of aging on the BBB, which is captured in this review based on the limited studies in the literature.

Lipid-based nanosystem of edaravone: development, optimization, characterization and in vitro/in vivo evaluation

Edaravone (EDR) is a well-recognized lipophilic free radical scavenger for diseases including neurodegenerative disease, cardiovascular disease, and cancer. However, its oral use is restricted due to poor oral bioavailability (BA). The aim of present research was to enable its oral use by developing a lipid-based nanosystem (LNS). The components of LNS including oil, surfactants, and co-surfactants were selected based on their potential to maximize the solubilization in gastrointestinal (GI) fluids, reduce its glucuronidation and improve transmembrane permeability. The liquid LNS (L-LNS) with Capryol™ PGMC (Oil), Cremophor® RH 40:Labrasol®:TPGS 1000 (1:0.8:0.2) (Surfactant) and Transcutol P® (Co-surfactant) were optimized to form microemulsion having droplet size (16.25 nm), polydispersity index (0.039), % Transmittance (99.85%), and self-emulsification time (32 s). It significantly improved the EDR loading as well as its metabolism and permeability profile during transport across the GI tract. To overcome the possible drawbacks of L-LNS, Aerosil® 200 was used to formulate solid LNS (S-LNS), and its concentration was optimized based on flow properties. S-LNS possessed all quality attributes of L-LNS confirmed by solid-state characterization, reconstitution ability, and stability study. The dissolution rate of EDR was significantly enhanced with L-LNS and S-LNS in simulated gastric, and intestinal fluids. The pharmacokinetic study revealed significant improvement in relative BA, Cmax, and t1/2 with L-LNS and S-LNS against EDR suspension. Moreover, S-LNS showed superior cellular uptake and neuroprotective effect compared to EDR in SH-SY5Y695 cell line. An appropriate selection of the components of LNS could enable effective oral delivery of challenging therapeutics that are conventionally used by the parenteral administration.

GC-MS/MS method for the determination and pharmacokinetic analysis of borneol and muscone in rat after the intravenous administration of Xingnaojing injection

A simple and sensitive gas chromatography with tandem mass spectrometry method was developed and validated for the simultaneous determination of borneol and muscone in rat plasma. The analytes and internal standard, naphthalene, were extracted using a convenient one-step liquid-liquid extraction method with ethyl acetate. The chromatographic separation was realized on a HP-5MS capillary column and detected in multiple reaction monitoring mode. Excellent linearity (R²  ≥ 0.996) was shown over 10.0-5000 ng/mL for borneol and 2.5-250 ng/mL for muscone. The lower limit of quantitation was 10 and 2.5 ng/mL for borneol and muscone, respectively. The intra- and interday precisions were less than 7.52%, and the accuracy values were between  -8.03 and 14.52%. The extraction recovery, matrix effect, and stability were sufficient to meet the Food and Drug Administration criteria. Meanwhile, the assay was successfully applied to the preclinical pharmacokinetic study of borneol and muscone following intravenous administration of Xingnaojing injection, a modern Chinese herbal medicine preparation.