Enhanced encapsulation and bioavailability of breviscapine in PLGA microparticles by nanocrystal and water-soluble polymer template techniques

In Vitro Characterization and In Vivo Performance of Vancomycin-Loaded PLGA Microspheres Prepared by Using Microfluidics for the Management of Orthopedic Infections

Periprosthetic joint infection (PJI) is a severe complication of total joint arthroplasty (TJA), leading to high rates of revision surgeries, long-term morbidity, and mortality. Conventional antibiotic treatments often suffer from limited bioavailability and systemic toxicity. This study explores a novel approach using vancomycin-loaded poly(lactic-co-glycolic) acid (PLGA) microparticles (VMP) formulated via a microfluidic double emulsion method for controlled, localized drug delivery for managing PJI. The PLGA microparticles were synthesized to achieve high loading capacity and sustained vancomycin release, aiming to maintain therapeutic intra-articular concentrations. In vitro characterization demonstrated optimal loading capacity (up to 28% w/w), morphology with a homogeneous particle size distribution (49-65 µm), and sustained release profiles over 8 weeks. In vivo efficacy was evaluated using a rat joint infection model, showing significant reductions in bacterial viability and enhanced bone healing compared to controls. Weight-bearing recovery assessments showed that VMP-treated rats regained functionality significantly earlier than controls (p < 0.05). Radiographic, histological, and immunofluorescent analyses confirmed reduced inflammation and improved bone integrity with VMP treatment. These findings suggest that microfluidic-synthesized PLGA microparticles provide a promising strategy for localized, controlled release of antibiotics, potentially helping the management of PJI and improving postsurgical outcomes. Future research should explore the long-term effects and scalability of clinical applications. This study lays the foundation for advancing controlled release systems in orthopedic postoperative care.

Advanced oral breviscapine sustained-release tablets for improved ischemic stroke treatment

This study aimed to address the challenges associated with the low oral bioavailability and the necessity for frequent dosing of breviscapine (BRE), a mainstream drug in the treatment of cardiovascular and cerebrovascular diseases. The poor solubility and permeability of BRE in the gastrointestinal tract were identified as significant barriers to effective drug absorption, thereby impacting therapeutic efficacy and patient compliance. To enhance the gastrointestinal absorption of BRE, particles loaded with BRE were engineered utilizing Cremophor EL (CrEL), an absorption enhancer, in conjunction with mesoporous silica, a biocompatible drug delivery vector, formulating mesoporous silica particles loaded with BRE and CrEL (BRE-CrEL@SiO2). The solubility and mucosal permeability of BRE were ameliorated, facilitating transepithelial transport and improving absorption kinetics. BRE-CrEL@SiO2 were subsequently integrated to prepare sustained-release tablets. The finite element simulation method was utilized in the study of non-planar circular BRE tablet process to ensure tablet quality. The superior bioavailability and therapeutic index of the absorption-promoting sustained-release tablets, compared to commercial tablets, were validated through in vivo pharmacokinetic and pharmacodynamic assessments, while safety was maintained. The oral relative bioavailability of the absorption-enhancing sustained-release tablets was 160.7 % relative to the commercial tablets, demonstrated in Beagle dogs, indicating higher absorption. This innovative formulation represents a significant advancement in improving therapeutic efficacy of ischemic stroke and reducing the treatment burden on patients. The study provides new insights into the development of novel dosage forms for BRE and other drugs with poor solubility and permeability, suggesting a promising approach to enhance their therapeutic effectiveness and improve patient compliance in treatment.

PVA-Stabilized and Coassembled Nano/Microparticles with High Payload of Dual Phytochemicals for Enhanced Antibacterial and Targeting Effect

The codelivery of multiple bioactive phytochemicals via nano/microparticles (NPs/MPs) represents a promising strategy for enhancing therapeutic efficacy. This study presents the development of novel poly(vinyl alcohol) (PVA)-stabilized hybrid particles designed for codelivery of palmatine hydrochloride (PAL) and glycyrrhizic acid (GL). Employing a straightforward coassembly method, we synthesized dual-drug particles achieving a high payload capacity of over 70%. The particles were characterized as uniform in size, within the nano/micron range, and exhibited a ζ-potential of -5.0 mV. The incorporation of PVA not only stabilized the particles but also refined the aggregation process, resulting in more uniform and finer particles approximately 1 μm in size. Spectral analysis and molecular dynamics simulations verified the presence of π-π stacking and hydrogen bonding between PAL and GL within the particles. In vitro antibacterial assays indicated that the hybrid particles had a lower minimum inhibitory concentration against Escherichia coli and Multidrug-Resistant Staphylococcus aureus than those of the pure drugs. In vivo biodistribution study in rats revealed that the PVA-stabilized particles revealed enhanced targeting to the liver, lung, and heart, demonstrating improved tissue selectivity compared with the solution group. In summary, the PVA-stabilized hybrid NPs/MPs represent an innovative and efficient platform for codelivery of multidrugs. These findings highlight the promise of coassembled particles for high loading, enhanced bioactivity, and targeted delivery, making them a strong candidate for future clinical applications.

Direct drug milling in organic PLGA solution facilitates the encapsulation of nanosized drug into PLGA microparticles

The objective of this study was to prepare poly(lactide-co-glycolide) (PLGA) microparticles loaded with nanosized drug by combining non-aqueous wet bead milling and microencapsulation. 200-300 nm dexamethasone, hydrocortisone and dexamethasone sodium phosphate nanosuspensions were successfully prepared by wet bead milling the drug in dichloromethane using PLGA as a stabilizer. PLGA microparticles loaded with nanosized drugs were then prepared by a solid-in-oil-in-water (S/O/W) solvent evaporation method or solid-in-oil-in-oil (S/O/O) organic phase separation method. The microparticles were characterized by laser diffraction (LD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD) and in vitro drug release. The nanosized drugs were homogeneously distributed within the microparticle matrix and remained crystalline, however, with a decrease in crystallinity. High drug encapsulation efficiencies >80 % were achieved at theoretical drug loadings between 5 and 30 %. Drug release profiles could be controlled by varying PLGA grades/blends, microparticle size and drug loadings. Quasi-linear release profiles without the PLGA-typical slow release phase were achieved with PLGA encapsulated nanosized drug.

Recent Advances in Improving the Bioavailability of Hydrophobic/Lipophilic Drugs and Their Delivery via Self-Emulsifying Formulations

Formulations based on emulsions for enhancing hydrophobic and lipophilic drug delivery and its bioavailability have attracted a lot of interest. As potential therapeutic agents, they are integrated with inert oils, emulsions, surfactant solubility, liposomes, etc.; drug delivering systems that use emulsion formations have emerged as a unique and commercially achievable accession to override the issue of less oral bioavailability in connection with hydrophobic and lipophilic drugs. As an ideal isotropic oil mixture of surfactants and co-solvents, it self-emulsifies and forms fine oil in water emulsions when acquainted with aqueous material. As droplets rapidly pass through the stomach, fine oil promotes the vast spread of the drug all over the GI (gastrointestinal tract) and conquers the slow disintegration commonly seen in solid drug forms. The current status of advancement in technologies for drug carrying has promulgated the expansion of innovative drug carriers for the controlled release of self-emulsifying pellets, tablets, capsules, microspheres, etc., which got a boost for drug delivery usage with self-emulsification. The present review article includes various kinds of formulations based on the size of particles and excipients utilized in emulsion formation for drug delivery mechanisms and the increase in the bioavailability of lipophilic/hydrophobic drugs in the present time.

Characterization of the Shells in Layer-By-Layer Nanofunctionalized Particles: A Computational Study

Drug delivery carriers are considered an encouraging approach for the localized treatment of disease with minimum effect on the surrounding tissue. Particularly, layer-by-layer releasing particles have gained increasing interest for their ability to develop multifunctional systems able to control the release of one or more therapeutical drugs and biomolecules. Although experimental methods can offer the opportunity to establish cause and effect relationships, the data collection can be excessively expensive or/and time-consuming. For a better understanding of the impact of different design conditions on the drug-kinetics and release profile, properly designed mathematical models can be greatly beneficial. In this work, we develop a continuum-scale mathematical model to evaluate the transport and release of a drug from a microparticle based on an inner core covered by a polymeric shell. The present mathematical model includes the dissolution and diffusion of the drug and accounts for a mechanism that takes into consideration the drug biomolecules entrapped into the polymeric shell. We test a sensitivity analysis to evaluate the influence of changing the model conditions on the total system behavior. To prove the effectiveness of this proposed model, we consider the specific application of antibacterial treatment and calibrate the model against the data of the release profile for an antibiotic drug, metronidazole. The results of the numerical simulation show that ∼85% of the drug is released in 230 h, and its release is characterized by two regimes where the drug dissolves, diffuses, and travels the external shell layer at a shorter time, while the drug is released from the shell to the surrounding medium at a longer time. Within the sensitivity analysis, the outer layer diffusivity is more significant than the value of diffusivity in the core, and the increase of the dissolution parameters causes an initial burst release of the drug. Finally, changing the shape of the particle to an ellipse produces an increased percentage of drugs released with an unchanged release time.

Intravenous Administration of Scutellarin Nanoparticles Augments the Protective Effect against Cerebral Ischemia-Reperfusion Injury in Rats

This study investigates the protective effect of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with scutellarin (SCU), a flavone isolated from the traditional Chinese medicineErigeron breviscapus (Vant.) Hand.-Mazz., in reducing cerebral ischemia/reperfusion (I/R) injury in vivo. The focal cerebral I/R injury model was established by occluding the middle cerebral artery for 1 h in male Sprague-Dawley (SD) rats. Our SCU-PLGA NPs exhibited an extended in vitro release profile and prolonged blood circulation in rats with cerebral ischemia. More importantly, when administered intravenously once a day for 3 days, SCU-PLGA NPs increased the SCU level in the ischemic brain, compared to free SCU, resulting in a significant reduction of the cerebral infarct volume after cerebral I/R. Furthermore, SCU-PLGA NPs reversed the histopathological changes caused by cerebral I/R injury, as well as attenuated cell apoptosis in the brain tissue, as confirmed by hematoxylin and eosin, and TUNEL staining. Our findings have revealed that our injectable SCU-PLGA NPs provide promising protective effects against cerebral I/R injury, which could be used in combination with the existing conventional thrombolytic therapies to improve stroke management.

Long-lasting rescue of schizophrenia-relevant cognitive impairments via risperidone-loaded microPlates

Schizophrenia is a disorder characterized by cognitive impairment and psychotic symptoms that fluctuate over time and can only be mitigated with the chronic administration of antipsychotics. Here, we propose biodegradable microPlates made of PLGA for the sustained release of risperidone over several weeks. Two microPlate configurations - short: 20 × 20 × 10 μm; tall: 20 × 20 × 20 μm - are engineered and compared to conventional ~ 10 μm PLGA microspheres in terms of risperidone loading and release. Tall microPlates realize the slowest release documenting a 35% risperidone delivery at 100 days with a residual rate of 30 ng/ml. Short microPlates and microspheres present similar release profiles with over 50% of the loaded risperidone delivered within the first 40 days. Then, the therapeutic efficacy of one single intraperitoneal injection of risperidone microPlates is compared to the daily administration of free risperidone in heterozygous knockout mice for dysbindin-1, a clinically relevant mouse model of cognitive and psychiatric liability. In temporal order object recognition tasks, mice treated with risperidone microPlates outperform those receiving free risperidone up to 2, 4, 8, and 12 weeks of observation. This suggests that the sustained release of antipsychotics from one-time microPlate deposition can rescue cognitive impairment in dysbindin mice for up to several weeks. Overall, these results demonstrate that risperidone-loaded microPlates are a promising platform for improving cognitive symptoms associated to schizophrenia. Moreover, the long-term efficacy with one single administration could be of clinical relevance in terms of patient's compliance and adherence to the treatment regimen. Single injection of long-acting risperidone-loaded µPL ameliorates the dysbindin-induced deficit in a clinically relevant mouse model of cognitive and psychiatric liability for up to 12 weeks.

Nanogels with High Loading of Anesthetic Nanocrystals for Extended Duration of Sciatic Nerve Block

The development of thermoresponsive nanogels loaded with nanocrystals of the local anesthetic bupivacaine nanocrystals (BNCs) for prolonged peripheral nerve pain relief is reported here. BNCs were prepared using the antisolvent precipitation method from the hydrophobic form of bupivacaine (bupivacaine free base). The as-prepared BNCs were used stand-alone or encapsulated in temperature-responsive poly(ethylene glycol) methyl ether methacrylate (OEGMA)-based nanogels, resulting in bupivacaine NC-loaded nanogels (BNC-nanogels) of monodisperse size. The synthesis protocol has rendered high drug loadings (i.e., 93.8 ± 1.5 and 84.8 ± 1.2 wt % for the NC and BNC-nanogels, respectively) and fast drug dissolution kinetics in the resulting composite material. In vivo tests demonstrated the efficacy of the formulation along with an extended duration of sciatic nerve block in murine models of more than 8 h with a formulation containing only 2 mg of the local anesthetic thanks to the thermoresponsive character of the polymer, which, at body temperature, becomes hydrophobic and acts as a diffusion barrier for the encapsulated drug nanocrystals. The hydrophobicity of the encapsulated bupivacaine free base probably facilitates its pass through cell membranes and also binds strongly to their hydrophobic lipid bilayer, thereby protecting molecules from diffusion to extracellular media and to the bloodstream, reducing their clearance. When using BNC-nanogels, the duration of the anesthetic blockage lasted twice as long as compared to the effect of just BNCs or a conventional bupivacaine hydrochloride solution both containing equivalent amounts of the free drug. Results of the in vivo tests showed enough sensory nerve block to potentially relieve pain, but still having mobility in the limb, which enables motor function when required. The BNC-nanogels presented minimal toxicity in the in vivo study due to their sustained drug release and excellent biocompatibility. The encapsulation of nano-sized crystals of bupivacaine provides a prolonged regional anesthesia with reduced toxicity, which could be advantageous in the management of chronic pain.

Nose-to-Brain Delivery by Nanosuspensions-Based in situ Gel for Breviscapine

Purpose

Nose-to-brain drug delivery is an effective approach for poorly soluble drugs to bypass the blood–brain barrier. A new drug intranasal delivery system, a nanosuspension-based in situ gel, was developed and evaluated to improve the solubility and bioavailability of the drug and to prolong its retention time in the nasal cavity.

Materials and Methods

Breviscapine (BRE) was chosen as the model drug. BRE nanosuspensions (BRE-NS) were converted into BRE nanosuspension powders (BRE-NP). A BRE nanosuspension in situ gelling system (BRE-NG) was prepared by mixing BRE-NP and 0.5% gellan gum (m/v). First, the BRE-NP were evaluated in terms of particle size and by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Subsequently, the critical ionic concentration of the gellan gum phase transition, influence of the deacetylated gellan gum (DGG) concentration on the expansion coefficient (S%), water-holding capacity, rheological properties and in vitro release behaviour of the BRE-NG were investigated. The pharmacokinetics and brain distribution of the BRE-NG after intranasal administration were compared with those of the intravenously injected BRE-NP nanosuspensions in rats.

Results

The rheology results demonstrated that BRE-NG was a non-Newtonian fluid with good spreadability and bioadhesion performance. Moreover, the absolute bioavailability estimated for BRE-NG after intranasal administration was 57.12%. The drug targeting efficiency (DTE%) of BRE in the cerebrum, cerebellum and olfactory bulb was 4006, 999 and 3290, respectively. The nose-to-brain direct transport percentage (DTP%) of the cerebrum, cerebellum and olfactory bulb was 0.975, 0.950 and 0.970, respectively.

Conclusion

It was concluded that the in situ gel significantly increased the drug retention time at the administration site. Therefore, the nanosuspension-based in situ gel could be a convenient and effective intranasal formulation for the administration of BRE.

Recent advances in the formulation of PLGA microparticles for controlled drug delivery

Polymeric microparticles (MPs) are recognized as very popular carriers to increase the bioavailability and bio-distribution of both lipophilic and hydrophilic drugs. Among different kinds of polymers, poly-(lactic-co-glycolic acid) (PLGA) is one of the most accepted materials for this purpose, because of its biodegradability (due to the presence of ester linkages that are degraded by hydrolysis in aqueous environments) and safety (PLGA is a Food and Drug Administration (FDA)-approved compound). Moreover, its biodegradability depends on the number of glycolide units present in the structure, indeed, lower glycol content results in an increased degradation time and conversely a higher monomer unit number results in a decreased time. Due to this feature, it is possible to design and fabricate MPs with a programmable and time-controlled drug release. Many approaches and procedures can be used to prepare MPs. The chosen fabrication methodology influences size, stability, entrapment efficiency, and MPs release kinetics. For example, lipophilic drugs as chemotherapeutic agents (doxorubicin), anti-inflammatory non-steroidal (indomethacin), and nutraceuticals (curcumin) were successfully encapsulated in MPs prepared by single emulsion technique, while water-soluble compounds, such as aptamer, peptides and proteins, involved the use of double emulsion systems to provide a hydrophilic compartment and prevent molecular degradation. The purpose of this review is to provide an overview about the preparation and characterization of drug-loaded PLGA MPs obtained by single, double emulsion and microfluidic techniques, and their current applications in the pharmaceutical industry.Graphic abstract.

Targeted drug nanocrystals for pulmonary delivery: a potential strategy for lung cancer therapy

INTRODUCTION

Lung cancer and metastases are major concerns worldwide. Although systemic chemotherapy is the recommended treatment, it is associated with various disadvantages, including nonselective drug distribution and systemic toxicity. In contrast, the pulmonary route ensures the localized delivery of drugs to the lung. Still, the pulmonary route is prone to clearance, limited drug dissolution, and local toxicity to healthy lung cells. Drug nanocrystals provide a potential strategy to enhance the therapeutic efficacy and mitigate the limitations of pulmonary delivery.

AREAS COVERED

The development and potential application of nanocrystals in pulmonary delivery, their role in overcoming associated barriers, and strategies for site-specific and stimuli-responsive pulmonary delivery are outlined. This review also traces different in-vitro pulmonary models for assessments of the performance of drug nanocrystals and nanocrystals loaded carriers in pulmonary delivery.

EXPERT OPINION

Enhanced stability, high aerosolization performance, better particle size distribution, improved penetration, sustained release of the drug, and minimal excipients usage makes drug nanocrystal an ideal candidate for pulmonary delivery. Besides, drug nanocrystals may provide selective cellular internalization with minimum clearance and maximum deposition. Furthermore, surface modified nanocrystals and nanocrystals in nanocarriers can exhibit a more prolonged, and site-specific release of the drug to cancer cells in the lungs.

Improving Solubility and Bioavailability of Breviscapine with Mesoporous Silica Nanoparticles Prepared Using Ultrasound-Assisted Solution-Enhanced Dispersion by Supercritical Fluids Method

Background

Breviscapine (BRE) has significant efficacy in cardiovascular disease, but the poor water solubility of breviscapine affects its oral absorption and limits its clinical application. In this study, supercritical carbon dioxide (SCF-CO₂) technology was used to improve the solubility and bioavailability of BRE loaded into mesoporous silica nanoparticles (MSNs).

Methods

The solubility of BRE in SCF-CO₂ was measured under various conditions to investigate the feasibility of preparing drug-loaded MSNs by using ultrasound-assisted solution-enhanced dispersion by supercritical fluids (USEDS). The preparation process of drug-loaded MSNs was optimized using the central composite design (CCD), and the optimized preparation was comprehensively characterized. Furthermore, the drug-loaded MSNs prepared by the conventional method were compared. Finally, the dissolution and bioavailability of the preparations were evaluated by in vitro release and pharmacokinetics study.

Results

The solubility of BRE in SCF-CO₂ was extremely low which was suitable to prepare BRE-loaded MSNs by USEDS technology. The particle size of the preparation was 177.24 nm, the drug loading was 8.63%, and the specific surface area was 456.3m²/g. As compared to the conventional preparation method of solution impregnation-evaporation (SIV), the formulation prepared by USEDS technology has smaller particle size, higher drug loading, less residual solvent and better stability. The results of the in vitro release study showed that drug-loaded MSNs could significantly improve drug dissolution. The results of pharmacokinetics showed that the bioavailability of drug-loaded MSNs was increased 1.96 times compared to that of the BRE powder.

Conclusion

Drug-loaded MSNs can significantly improve the solubility and bioavailability of BRE, indicating a good application prospect for MSNs in improving the oral absorption of drugs. In addition, as a solid dispersion preparation technology, USEDS technology has incomparable advantages.

Encapsulation of Red Propolis in Polymer Nanoparticles for the Destruction of Pathogenic Biofilms

Microbial biofilms, structured communities of microorganisms, have been often associated to the infection and bacterial multiresistance problem. Conventional treatment of infection involves the use of antibiotics, being an alternative approach is the use of red propolis, a natural product, to prepare polymer nanoparticles. The aim of the present study was to encapsulate red propolis extract in poly(lactic-co-glycolic acid) (PLGA) nanoparticles for destruction in vitro of pathogenic biofilms. Poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) containing red propolis hydroethanolic extract (2 mg/mL) were produced by emulsification solvent diffusion method. The extract and developed nanoparticles were analyzed for antimicrobial activity and inhibition of bacterial biofilm formation in vitro against Staphylococcus aureus and Pseudomonas aeruginosa. Transmission electron microscopy images confirmed spherical nanoparticles in the range size from 42.4 nm (PLGA NPs) to 69.2 nm (HERP PLGA NPs), with encapsulation efficiencies of 96.99%. The free extract and encapsulated in polymer nanoparticle presented antimicrobial potential, with a minimum inhibitory concentration from 15.6 to 125 μg mL^-1 and from 100 to 1560 μg mL^-1 to inhibit biofilm formation for the Staphylococcus aureus and Pseudomonas aeruginosa, respectively.

Verteporfin-Loaded Polymeric Microparticles for Intratumoral Treatment of Brain Cancer

Glioblastoma (GBMs) is the most common and aggressive type of primary brain tumor in adults with dismal prognosis despite radical surgical resection coupled with chemo- and radiotherapy. Recent studies have proposed the use of small-molecule inhibitors, including verteporfin (VP), to target oncogenic networks in cancers. Here we report efficient encapsulation of water-insoluble VP in poly(lactic- co-glycolic acid) microparticles (PLGA MP) of ∼1.5 μm in diameter that allows tunable, sustained release. Treatment with naked VP and released VP from PLGA MP decreased cell viability of patient-derived primary GBM cells in vitro by ∼70%. Moreover, naked VP treatment significantly increased radiosensitivity of GBM cells, thereby enhancing overall tumor cell killing ability by nearly 85%. Our in vivo study demonstrated that two intratumoral administrations of sustained slow-releasing VP-loaded PLGA MPs separated by two weeks significantly attenuated tumor growth by ∼67% in tumor volume in a subcutaneous patient-derived GBM xenograft model over 26 d. Additionally, our in vitro data indicate broader utility of VP for treatment for other solid cancers, including chordoma, malignant meningioma, and various noncentral nervous system-derived carcinomas. Collectively, our work suggests that the use of VP-loaded PLGA MP may be an effective local therapeutic strategy for a variety of solid cancers, including unresectable and orphan tumors, which may decrease tumor burden and ultimately improve patient prognosis.

Formation Mechanism, In vitro and In vivo Evaluation of Dimpled Exenatide Loaded PLGA Microparticles Prepared by Ultra-Fine Particle Processing System

Spherical poly (D, L-lactic-co-glycolic acid) microparticles (PLGA-MPs) have long been investigated in order to achieve sustained delivery of proteins/peptides. However, the formation mechanism and release characteristics of the specific shape MPs were still unknown. This study aimed to develop a novel-dimpled exenatide-loaded PLGA-MPs (Exe-PLGA-MPs) using an ultra-fine particle processing system (UPPS) and investigate the formation mechanism and release characteristics. Exe-PLGA-MPs were prepared by UPPS and optimized based on their initial burst within the first 24 h and drug release profiles. Physicochemical properties of Exe-PLGA-MPs, including morphology, particle size, and structural integrity of Exe extracted from Exe-PLGA-MPs, were evaluated. Furthermore, pharmacokinetic studies of the optimal formulation were conducted in Sprague-Dawley (SD) rats to establish in vitro-in vivo correlations (IVIVC) of drug release. Exe-PLGA-MPs with dimpled shapes and uniform particle sizes achieved a high encapsulation efficiency (EE%, 91.50 ± 2.65%) and sustained drug release for 2 months in vitro with reduced initial burst (20.42 ± 1.64%). Moreover, the pharmacokinetic studies revealed that effective drug concentration could be maintained for 3 weeks following a single injection of dimpled Exe-PLGA-MPs with high IVIVC. Dimpled PLGA-MPs prepared using the UPPS technique could thus have great potential for sustained delivery of macromolecular proteins/peptides.

Novel breviscapine nanocrystals modified by panax notoginseng saponins for enhancing bioavailability and synergistic anti-platelet aggregation effect

Breviscapine (BVP) is a flavonoid compound with strong neuroprotective and anti-platelet aggregation effect. The objective of this study is to design novel BVP nanocrystals modified by natural panax notoginseng saponins (PNS) for enhancing dissolution and anti-platelet aggregation effect of BVP. BVP nanocrystals modified by PNS (BVP-NC/PNS) were firstly prepared by coupling homogenization technology and freeze-drying technology, and BVP nanocrystals modified by RH40 (BVP-NC/RH40) as reference for comparison. The morphology, crystals characterization, dissolution behavior and anti-platelet aggregation effect of BVP-NC/PNS was systemically evaluated. The results demonstrated that the PNS could effectively maintain stability of BVP-NC at suspensions state dependent of its surface activity and the electrostatic repulsion effect. Combination of PNS and trehalose could prevent the aggregation of BVP-NC/PNS during freeze-drying. The PXRD and DSC results demonstrated that the BVP crystal state in BVP-NC/PNS was not changed owing to PNS modification and homogenization treatment. And the freeze-dried BVP-NC could easily recover back to BVP-NS and significantly improve the dissolution of BVP. The AUC_(0-∞) of the BVP-NC/PNS was 4.54 times as high as that of the coarse BVP, but not significantly different compared to that of BVP-NC/RH40 (p < 0.05). The anti-platelet aggregation results demonstrated that, BVP-NC/PNS group showed more effective inhibition on PAF-induced platelet aggregation compared with corresponding control groups, which might attribute to the enhanced bioavailability of BVP and synergistic effect of PNS with BVP. In conclusion, PNS could be used as an alternative stabilizer for preparation of BVP-NC, and BVP-NC modified by PNS is a promising formulation strategy for enhancing oral bioavailability and anti-platelet aggregation of BVP.

Novel apigenin-loaded sodium hyaluronate nano-assemblies for targeting tumor cells

We aimed to construct a novel nano-assembly carrying apigenin (APG), a hydrophobic drug, and to evaluate its in vitro targeting ability for A549 cells overexpressing CD44 receptors. The apigenin-loaded sodium hyaluronate nano-assemblies (APG/SH-NAs) were assembled by multiple non-covalent interactions between sodium hyaluronate (SH) and APG. The prepared APG/SH-NAs exhibited a small average size and narrow particle size distribution. In addition, satisfactory encapsulation efficiency and drug loading were obtained. The drug release curves indicated that APG/SH-NAs achieved a sustainable drug-release effect due to the presence of hydrophilic materials. The in vitro cytotoxicity of APG/SH-NAs against A549 cells and HepG2 cells was evaluated, and the results indicated that the prepared APG/SH-NA showed higher cytotoxicity compared to apigenin suspensions. When CD44 receptors on the surface of A549 cells were blocked by the addition of excess SH, the cytotoxicity of APG/SH-NA was significantly reduced. However, similar phenomena were not observed in HepG2 cells with relatively low CD44 receptor expression. The resulting APG/SH-NAs could efficiently facilitate the internalization of APG into A549 cells, which might be due to their high affinity for CD44 receptors. Moreover, the apoptotic rate of APG/SH-NAs through receptor-mediated endocytosis mechanism was higher than that of the other groups in A549 cells. Thus, such nano-assemblies were considered to be an effective transport system with excellent affinity for CD44 receptors to allow the SH-mediated targeted delivery of APG.