Background: Tumor-associated macrophages (TAMs) are critical in tumor progression and metastasis. Selective targeting of TAMs holds great potential to ameliorate the immunosuppressive tumor microenvironment and enhance the efficacy of antitumor therapy. Various liposomes have been developed to target TAMs via cell-specific surface receptors either to deplete or re-educate TAMs. Since immuno-stimulation often initiates with the interaction of nanocarriers with the innate immunity cells such as macrophages, the intrinsic impact of drug-free liposomes on macrophage activation and polarization via cell interaction is one of the most critical issues in nanomedicine for promoting effective immunotherapy. Methods: In this study, conventional bare liposomes, PEGylated liposomes, and mannosylated liposomes were developed and the cytotoxicity, cellular internalization, immunostimulatory activity, targeting efficiency, antitumor efficacy, and mechanism were evaluated in vitro and in vivo. Results: All liposomes displayed an ideal particle size, good biocompatibility, and controlled release behavior. Mannosylated liposomes exhibited superior in vitro cellular internalization and tumor spheroid penetration with the aid of the mannose receptor-mediated TAMs-targeting effects. In particular, mannosylated liposomes promoted the polarization of both M0 and M2 to the M1 phenotype by enhancing the expression ratio of CD86/CD206 in vitro. Of note, mannosylated liposomes could inhibit G422 glioma tumor growth, which may be attributed to the polarization of TAMs, as evidenced by the reduction in expression level of the TAMs surface marker. Conclusion: These results indicate the potential value of mannosylated liposomes in the design of a rational delivery system to enhance the antitumor immune efficacy of immunomodulators by inducing a shift from the M2 to the M1 phenotype.

The effect of different high pressure homogenization energy input parameters on mean diameter droplet size (MDS) and droplets with > 5 μm of lipid injectable emulsions were evaluated. All emulsions were prepared at different water bath temperatures or at different rotation speeds and rotor-stator system times, and using different homogenization pressures and numbers of high-pressure system recirculations. The MDS and polydispersity index (PI) value of the emulsions were determined using the dynamic light scattering (DLS) method, and large-diameter tail assessments were performed using the light-obscuration/single particle optical sensing (LO/SPOS) method. Using 1000 bar homogenization pressure and seven recirculations, the energy input parameters related to the rotor-stator system will not have an effect on the final particle size results. When rotor-stator system energy input parameters are fixed, homogenization pressure and recirculation will affect mean particle size and large diameter droplet. Particle size will decrease with increasing homogenization pressure from 400 bar to 1300 bar when homogenization recirculation is fixed; when the homogenization pressure is fixed at 1000 bar, the particle size of both MDS and percent of fat droplets exceeding 5 μm (PFAT5) will decrease with increasing homogenization recirculations, MDS dropped to 173 nm after five cycles and maintained this level, volume-weighted PFAT5 will drop to 0.038% after three cycles, so the "plateau" of MDS will come up later than that of PFAT5, and the optimal particle size is produced when both of them remained at plateau. Excess homogenization recirculation such as nine times under the 1000 bar may lead to PFAT5 increase to 0.060% rather than a decrease; therefore, the high-pressure homogenization procedure is the key factor affecting the particle size distribution of emulsions. Varying storage conditions (4-25°C) also influenced particle size, especially the PFAT5.

α-glucosidase inhibitors (AGIs) have been an important category of oral antidiabetic drugs being widely exploited for the effective management of type 2 diabetes mellitus. However, the marketed AGIs not only inhibited the disaccharidases, but also exhibited an excessive inhibitory effect on α-amylase, resulting in undesirable gastrointestinal side effects. Compared to these agents, Ramulus Mori alkaloids (SZ-A), was a group of effective alkaloids from natural Morus alba L., and showed excellent hypoglycemic effect and fewer side effects in the Phase II/III clinical trials. Thus, this paper aims to investigate the selective inhibitory effect and mechanism of SZ-A and its major active ingredients (1-DNJ, FA and DAB) on different α-glucosidases (α-amylase and disaccharidases) by using a combination of kinetic analysis and molecular docking approaches. From the results, SZ-A displayed a strong inhibitory effect on maltase and sucrase with an IC₅₀ of 0.06 μg/mL and 0.03 μg/mL, respectively, which was similar to the positive control of acarbose with an IC₅₀ of 0.07 μg/mL and 0.68 μg/mL. With regard to α-amylase, SZ-A exhibited no inhibitory activity at 100 μg/mL, while acarbose showed an obvious inhibitory effect with an IC₅₀ of 1.74 μg/mL. The above analysis demonstrated that SZ-A could selectively inhibit disaccharidase to reduce hyperglycemia with a reversible competitive inhibition, which was primarily attributed to the three major active ingredients of SZ-A, especially 1-DNJ molecule. In the light of these findings, molecular docking study was utilized to analyze their inhibition mechanisms at molecular level. It pointed out that acarbose with a four-ring structure could perform desirable interactions with various α-glucosidases, while the three active ingredients of SZ-A, belonging to monocyclic compounds, had a high affinity to the active site of disaccharidases through forming a wide range of hydrogen bonds, whose affinity and consensus score with α-amylase was significantly lower than that of acarbose. Our study illustrates the selective inhibition mechanism of SZ-A on α-glucosidase for the first time, which is of great importance for the treatment of type 2 diabetes mellitus.

Background: Non-injectable delivery of peptides and proteins are not feasible due to its large molecular, high hydrophilic and gastrointestinal degradation. Therefore, proposing a new method to solve this problem is a burning issue. Purpose: The objective of this study was to propose a novel protein delivery strategy to vanquish the poor efficacy of buccal mucosa delivery systems for protein delivery and then investigate the detailed mechanisms of the enhanced buccal delivery of protein, using insulin as a model drug. Materials and methods: Insulin-phospholipid complex combined with deformable nanovesicles (IPC-DNVs) were prepared, using deformable nanovesicles based on insulin (INS-DNVs) and conventional nanovesicles based on insulin-phospholipid complex (IPC-NVs) as references. Besides, their physicochemical characterization, in vitro transport behavior, in vivo bioactivity and hypoglycemic effect were systematically characterized and compared. Finally, we evaluated the in vivo safety of IPC-DNVs. Results: First, IPC-DNVs increased insulin permeability through deposition of the IPC and deformability of the DNVs, which was revealed by an in vitro mucosal permeation study. Second, DNVs could act as a drug carrier and penetrate the mucosa to reach the receiver medium as intact nanovesicles, which was supported by the observation of intact nanovesicles in the receiver medium through transmission electron microscopy (TEM). Third, IPC-DNVs exhibited both transcellular and paracellular transport in the form of IPC and DNVs, respectively, which was proved by confocal laser scanning microscopy (CLSM). Unlike the other two formulations, IPC-DNVs exhibited a sustained mild hypoglycemic effect, with a relative bioavailability (Fp) of 15.53% (3.09% and 1.96% for INS-DNVs and IPC-NVs, respectively). Furthermore, buccal administration of IPC-DNVs resulted in no visible mucosal irritation to the buccal mucosa. Conclusion: Our work reveals the mechanisms underlying the enhanced buccal delivery of IPC-DNVs: the DNVs facilitate penetration through the main barrier, and the deposition of IPC enhances buccal absorption. Our results and proposed mechanisms could be an important reference to understand other nanocarriers based on protein (peptide)-phospholipid complexes that penetrate the mucosa and provide a theoretical basis for the future development of buccal delivery systems for insulin.

13a-(S)-3-pivaloyloxyl-6,7-dimethoxyphenanthro(9,10-b)-indolizidine (CAT3) is a novel oral anti-glioma pro-drug with a potent anti-tumor effect against temozolomide-resistant glioma in vivo. However, poor lipid solubility has limited the encapsulation efficacy during formulation development. Moreover, although the active metabolite of CAT3, 13a(S)-3-hydroxyl-6,7-dimethoxyphenanthro(9,10-b)-indolizidine (PF403), can penetrate the blood-brain barrier and approach the brain tissue with a 1000-fold higher anti-glioma activity than CAT3 in vitro, its bioavailability and C_max were considerably low in plasma, limiting the anti-tumor efficacy. In this study, a novel oleic acid-CAT3 conjugate (OA-CAT3) was synthesized at the first time to increase the lipid solubility of CAT3. The OA-CAT3 loaded solid lipid nanoparticles (OA-CAT3-SLN) were constructed using an ultrasonic technique to enhance the bioavailability and C_max of PF403 in plasma. Our results demonstrated that CAT3 was amorphous in the lipid core of OA-CAT3-SLN and the in vitro release was well controlled. Furthermore, the encapsulation efficacy and the zeta potential increased to 80.65 ± 6.79% and −26.7 ± 0.46 mV, respectively, compared to the normal CAT3 loaded SLN. As indicated by the high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) quantitation, the monolayer cellular transepithelial transport rate of OA-CAT3-SLN improved by 2.42-fold relied on cholesterol compared to the CAT3 suspension. Hence, the in vitro cell viability of OA-CAT3-SLN in C6 glioma cells decreased to 29.77% ± 2.13% and 10.75% ± 3.12% at 48 and 72 h, respectively. Finally, compared to the CAT3 suspension, the in vivo pharmacokinetics in rats indicated that the plasma bioavailability and C_max of PF403 as afforded by OA-CAT3-SLN increased by 1.7- and 5.5-fold, respectively. Overall, the results indicate that OA-CAT3-SLN could be an efficacious delivery system in the treatment of glioma.

Essential oil extracted from Houttuynia cordata Thunb. (H. cordata) is widely used in traditional Chinese medicine due to its excellent biological activities. However, impurities and deficient preparations of the essential oil limit its safety and effectiveness. Herein, we proposed a strategy to prepare H. cordata essential oil (HEO) safely and effectively by combining the solvent extraction and the macroporous resin purification flexibly, and then encapsulating it using microemulsion. The extraction and purification process were optimized by orthogonal experimental design and adsorption-desorption tests, respectively. The average houttuynin content in pure HEO was then validated at 44.3% ± 2.01%, which presented a great potential for industrial application. Subsequently, pure HEO-loaded microemulsion was prepared by high-pressure homogenization and was then fully characterized. Results showed that the pure HEO-loaded microemulsion was successfully prepared with an average particle size of 179.1 nm and a high encapsulation rate of 94.7%. Furthermore, safety evaluation tests and in vitro antiviral testing indicated that the safety and activity of HEO were significantly improved after purification using D101 resin and were further improved by microemulsion encapsulation. These results demonstrated that the purification of HEO by macroporous resin followed by microemulsion encapsulation would be a promising approach for industrial application of HEO for the antiviral therapies.