Inhalable extracellular vesicle delivery of IL-12 mRNA to treat lung cancer and promote systemic immunity.

Lung carcinoma is one of the most common cancers and has one of the lowest survival rates in the world. Cytokines such as interleukin-12 (IL-12) have demonstrated considerable potential as robust tumour suppressors. However, their applications are limited due to off-target toxicity. Here we report on a strategy involving the inhalation of IL-12 messenger RNA, encapsulated within extracellular vesicles. Inhalation and preferential uptake by cancer cells results in targeted delivery and fewer systemic side effects. The IL-12 messenger RNA generates interferon-γ production in both innate and adaptive immune-cell populations. This activation consequently incites an intense activation state in the tumour microenvironment and augments its immunogenicity. The increased immune response results in the expansion of tumour cytotoxic immune effector cells, the formation of immune memory, improved antigen presentation and tumour-specific T cell priming. The strategy is demonstrated against primary neoplastic lesions and provides profound protection against subsequent tumour rechallenge. This shows the potential for locally delivered cytokine-based immunotherapies to address orthotopic and metastatic lung tumours.

Repeated controlled ovarian stimulation-induced ovarian and uterine damage in mice through the PI3K/AKT signaling pathway.

The effects of repeated controlled ovarian stimulation (COS) on the female reproductive system are still controversial. This study investigated the effects of repeated COS on the ovaries and uterus of mice and its possible mechanism. Female ICR (Institute of Cancer Research) mice were subjected to the COS using pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) for 1, 3, 5, and 7 cycles. Serum hormone levels, reactive oxidative stress (ROS), 8-hydroxy-2'-deoxyguanosine (8-OHdG), total antioxidant capacity (T-AOC), and superoxide dismutase (SOD) in the mouse ovary and uterus were analyzed by ELISA. The morphology of the ovary and endometrium, ovarian apoptosis, and expressions of the vascular endothelial growth factor (VEGF), leukemia inhibitory factor (LIF), PI3K, AKT, Bax, and Bcl-2 in the ovarian and uterine tissues were tested by hematoxylin-eosin (HE) staining, immunohistochemistry, and western blot. The results showed that repeated COS significantly decreased the hormone level (estradiol, progesterone and anti-Müllerian hormone), high-quality of the MII oocyte ratio, oocyte and embryo number, antioxidant capacity (T-AOC, SOD activity), and the protein level of Bcl-2, LIF, and VEGF, but increased the oxidative damage (ROS, 8-OHdG content), embryo fragment ratio, and expression of pro-apoptotic protein Bax. In addition, the expressions of p-PI3K and p-AKT also decreased with the increase of COS cycle. In conclusion, repeated COS causes ovarian and uterus damage possibly through the PI3K/AKT signaling pathway, and this finding may provide some experimental basis for guiding clinical treatment.

Exosomes decorated with a recombinant SARS-CoV-2 receptor-binding domain as an inhalable COVID-19 vaccine.

The first two mRNA vaccines against infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that were approved by regulators require a cold chain and were designed to elicit systemic immunity via intramuscular injection. Here we report the design and preclinical testing of an inhalable virus-like-particle as a COVID-19 vaccine that, after lyophilisation, is stable at room temperature for over three months. The vaccine consists of a recombinant SARS-CoV-2 receptor-binding domain (RBD) conjugated to lung-derived exosomes which, with respect to liposomes, enhance the retention of the RBD in both the mucus-lined respiratory airway and in lung parenchyma. In mice, the vaccine elicited RBD-specific IgG antibodies, mucosal IgA responses and CD4+ and CD8+ T cells with a Th1-like cytokine expression profile in the animals' lungs, and cleared them of SARS-CoV-2 pseudovirus after a challenge. In hamsters, two doses of the vaccine attenuated severe pneumonia and reduced inflammatory infiltrates after a challenge with live SARS-CoV-2. Inhalable and room-temperature-stable virus-like particles may become promising vaccine candidates.

Clinical efficacy of Wenjing decoction in the treatment of ovulatory disorder infertility: A systematic review and meta-analysis.

OBJECTIVES: Wenjing decoction (WJD) was widely used in the treatment for ovulatory disorder infertility (ODI) in China, while its efficacy was not clearly known. In this study, we evaluated the clinical efficacy of WJD by meta-analysis. METHODS: Eight electronic databases including Cochrane Library, PubMed, Embase, Web of Science, China National Knowledge Infrastructure, WanFang Data, VIP Database, and China Biology Medicine were searched for randomized controlled trials (RCTs) published from the inception of each database to July 1, 2021, of which the interventions involve WJD and clomiphene. Outcomes included clinical efficacy rate, pregnancy rate, ovulation rate, dominant follicle diameter, endometrial thickness, estradiol, follicle-stimulating hormone, and luteinizing hormone. Meta-analysis and risk of bias were performed by RevMan 5.3 software. RESULTS: Eleven RCTs including 915 patients, of which 476 in the intervention group and 439 in the control group. Meta-analysis showed that WJD was better than clomiphene for patients with ODI in terms of clinical effective rate (odds ratio [OR] = 1.22, 95% confidence interval [CI]: 1.08-1.34), pregnancy rate (OR = 1.54, 95% CI: 1.15-2.07), ovulation rate (OR = 1.34, 95% CI: 1.07-1.67), endometrial thickness (mean difference [MD] = 1.50, 95% CI: 0.90-2.10), and dominant follicle diameter (MD = 1.85, 95% CI: 0.68-3.02). The estradiol level (MD = 91.0, 95% CI: 80.3-101.88) in patients taking WJD was significantly higher than those taking clomiphene, while the follicle-stimulating hormone level (MD = -0.93, 95% CI: -1.13 to -0.72) and the luteinizing hormone level (MD = -4.41, 95% CI: -4.80 to -4.03) in patients taking WJD was significantly lower than those taking clomiphene. Our results also indicated that WJD combined with clomiphene was better than clomiphene alone for patients with ODI in terms of pregnancy rate (OR = 1.79, 95% CI: 1.37-2.35). CONCLUSIONS: WJD may be effective in the treatment of patients with ODI. Due to the quality and quantity of literature, RCT with large sample size and high quality need to be performed to verify our conclusion.

Cardiac fibrosis: Myofibroblast-mediated pathological regulation and drug delivery strategies.

Cardiac fibrosis remains an unresolved problem in heart diseases. After initial injury, cardiac fibroblasts (CFs) are activated and subsequently differentiate into myofibroblasts (myoFbs) that are major mediator cells in the pathological remodeling. MyoFbs exhibit proliferative and secretive characteristics, and contribute to extracellular matrix (ECM) turnover, collagen deposition. The persistent functions of myoFbs lead to fibrotic scars and cardiac dysfunction. The anti-fibrotic treatment is hindered by the elusive mechanism of fibrosis and lack of specific targets on myoFbs. In this review, we will outline the progress of cardiac fibrosis and its contributions to the heart failure. We will also shed light on the role of myoFbs in the regulation of adverse remodeling. The communication between myoFbs and other cells that are involved in the heart injury and repair respectively will be reviewed in detail. Then, recently developed therapeutic strategies to treat fibrosis will be summarized such as i) chimeric antigen receptor T cell (CAR-T) therapy with an optimal target on myoFbs, ii) direct reprogramming from stem cells to quiescent CFs, iii) "off-target" small molecular drugs. The application of nano/micro technology will be discussed as well, which is involved in the construction of cell-based biomimic platforms and "pleiotropic" drug delivery systems.

The impact of acute exercise on implicit cognitive reappraisal in association with left dorsolateral prefronta activation: A fNIRS study.

Despite findings showing that acute exercise may help enhance emotion regulation, the neurophysiological mechanisms of these effects remain poorly understood. In this study, we examined whether acute exercise influences cognitive emotion regulation, and, in particular, an implicit cognitive reappraisal. Twenty sedentary young women were randomly assigned to either a control group (n = 10) or an exercise group (n = 10). Participants underwent an implicit cognitive reappraisal task twice, before and after the 30-min acute exercise or control, alongside functional near-infrared spectroscopy recordings (NIRS). The left dorsolateral prefrontal cortex (dlPFC) and left orbital frontal cortex (OFC) were activated during implicit cognitive reappraisal at baseline, but only the left dlPFC activation was linked with behavioral performance. Acute exercise enhanced the activation of these regions, reflective of the partial neural bases of implicit cognitive reappraisal, in the left dlPFC and left OFC, but did not alter the behavioral performance. Results also showed that acute exercise moderated the positive effect of left dlPFC activation on implicit cognitive reappraisal performance; specifically, this effect was stronger in the exercise group. In conclusion, the enhanced activation of the left dlPFC by acute exercise and the increased link between behavioral performance and its neural indices may point to acute exercise as a promoter of implicit cognitive reappraisal.

Hepatic macrophages act as a central hub for relaxin-mediated alleviation of liver fibrosis.

Relaxin is an antifibrotic peptide hormone previously assumed to directly reverse the activation of hepatic stellate cells for liver fibrosis resolution. Using nanoparticle-mediated delivery, here we show that, although relaxin gene therapy reduces liver fibrosis in vivo, in vitro treatment fails to induce quiescence of the activated hepatic stellate cells. We show that hepatic macrophages express the primary relaxin receptor, and that, on relaxin binding, they switch from the profibrogenic to the pro-resolution phenotype. The latter releases exosomes that promote the relaxin-mediated quiescence of activated hepatic stellate cells through miR-30a-5p. Building on these results, we developed lipid nanoparticles that preferentially target activated hepatic stellate cells in the fibrotic liver and encapsulate the relaxin gene and miR-30a-5p mimic. The combinatorial gene therapy achieves synergistic antifibrosis effects in models of mouse liver fibrosis. Collectively, our findings highlight the key role that macrophages play in the relaxin-primed alleviation of liver fibrosis and demonstrate a proof-of-concept approach to devise antifibrotic strategies through the complementary application of nanotechnology and basic science.

Nano-puerarin regulates tumor microenvironment and facilitates chemo- and immunotherapy in murine triple negative breast cancer model.

Tumor associated fibroblasts (TAFs) are key stromal cells mediating the desmoplastic reaction and being partially responsible for the drug-resistance and immunosuppressive microenvironment formation in solid tumors. Delivery of genotoxic drugs off-targetedly to kill TAFs results in production of Wnt16 which renders the neighboring tumor cells drug resistant as shown in our previous study (PMC4623876). Our current approach looks for means to deactivate, rather than kill, TAFs. Reactive oxygen species (ROS) are the central hub of multiple profibrogenic pathways and indispensable for TAFs activation. Herein, puerarin was identified to effectively downregulate ROS production in the activated myofibroblast. In this study, a novel puerarin nanoemulsion (nanoPue) was developed to improve the solubility and bioavailability of puerarin. NanoPue significantly deactivated the stromal microenvironment (e.g., ~6-fold reduction of TAFs in nanoPue treated mice compared with the PBS control, p < 0.0001) and facilitated chemotherapy effect of nano-paclitaxel in the desmoplastic triple-negative breast cancer (TNBC) model. Moreover, the removal of the physical barrier increased intra-tumoral infiltration of cytotoxic T cell by 2-fold. This activated immune microenvironment allowed nanoPue to synergize PD-L1 blockade therapy in TNBC model.

Bispecific Antibody Inhalation Therapy for Redirecting Stem Cells from the Lungs to Repair Heart Injury.

Stem cell therapy is a promising strategy for cardiac repair. However, clinical efficacy is hampered by poor cell engraftment and the elusive repair mechanisms of the transplanted stem cells. The lung is a reservoir of hematopoietic stem cells (HSCs) and a major biogenesis site for platelets. A strategy is sought to redirect lung resident stem cells to the injured heart for therapeutic repair after myocardial infarction (MI). To achieve this goal, CD34-CD42b platelet-targeting bispecific antibodies (PT-BsAbs) are designed to simultaneously recognize HSCs (via CD34) and platelets (via CD42b). After inhalation delivery, PT-BsAbs reach the lungs and conjoined HSCs and platelets. Due to the innate injury-finding ability of platelets, PT-BsAbs guide lung HSCs to the injured heart after MI. The redirected HSCs promote endogenous repair, leading to increased cardiac function. The repair mechanism involves angiomyogenesis and inflammation modulation. In addition, the inhalation route is superior to the intravenous route to deliver PT-BsAbs in terms of the HSCs' homing ability and therapeutic benefits. This work demonstrates that this novel inhalable antibody therapy, which harnesses platelets derived from the lungs, contributes to potent stem cell redirection and heart repair. This strategy is safe and effective in a mouse model of MI.

Drug delivery systems targeting tumor-associated fibroblasts for cancer immunotherapy.

Solid tumors especially desmoplastic tumors are complex organ-like structures. Tumor-associated fibroblasts (TAFs), one type of the stromal cells, support the initiation, progression, and metastasis of carcinomas. TAFs also contribute to immunosuppressive tumor microenvironment (TME) and hinder T lymphocytes in killing tumors. Here, the role of TAFs in TME is discussed. In specific, TAFs form barriers for the penetration of T lymphocytes. TAFs also act as negative regulators for T lymphocytes. These findings suggest that targeting TAFs is a promising strategy for improving cancer immunotherapy. Our previous studies have indicated the ability of therapeutic nanoparticles to distribute into, and deplete or inactivate TAFs. This approach is discussed in the context of developing specific and effective immunotherapies for cancer.

Crosslinked self-assembled nanoparticles for chemo-sonodynamic combination therapy favoring antitumor, antimetastasis management and immune responses.

Sonodynamic therapy (SDT) has been proposed as a new modality for cancer management through low-intensity ultrasound induced activation of sonosensitizers. Here, we designed a novel redox/enzyme/ultrasound responsive chondroitin sulfate-chlorin e6-lipoic acid nanoplatform loading docetaxel, combining SDT and chemotherapy, for antiproliferation and antimetastasis of melanoma. The reversibly crosslinked and self-assembled nanoparticles possessed monodispersive size distribution, stability in physical conditions, while showing increased uptake with rapid drug release in simulated tumor microenvironment (reductive potentials and degradative hyaluronidase-1). With synthesized ultrasound sensitive polymer backbones, SDT induced the generation of cellular reactive oxygen species and mitochondrial damage, exerting the apoptotic effect through the release of cytochrome C, the expression of cleaved caspase-9 followed by the functional cleaved caspase-3. Chemo-sonodynamic therapy not only inhibited tumor growth and metastasis with reduced metastatic protein expression, but also caused immune response via the release of tumor-associated antigens. It was initially demonstrated that SDT could induce the tumor cell death, therefore having potentials to recruit cytotoxic lymphocytes into tumor sites. Notably, the nanoplatforms exhibited good in vivo stability and blood compatibility, indicating the safety and efficiency in drug delivery. Our work thus presents a convenient approach to fabricate intelligent multifunctional nanoparticles and paves a path for effective cancer therapies.

Preparation and in vitro and in vivo evaluation of quercetin-loaded mixed micelles for oral delivery.

Quercetin (QT) is a plant polyphenol with various pharmacological properties. However, the low water solubility limits its therapeutic efficacy. In the present study, QT-loaded sodium taurocholate-Pluronic P123 (QT-loaded ST/P123) mixed micelles were developed and characterized, and the effect of the formulation on improving the water solubility of QT was investigated. QT-loaded ST/P123 mixed micelles were prepared by thin film hydration-direct dissolution and optimized by uniform design. The optimal formulation possessed high drug loading (12.6%) and entrapment efficiency (95.9%) in small (16.20 nm) spherically-shaped micelles. A low critical micelle concentration indicated that the micelles were stable, and they showed a sustained release pattern, as determined in vitro in simulated gastric fluid and intestinal fluid. Pharmacokinetic evaluation showed the Cmax and AUC0-24 were 1.8-fold and 1.6-fold higher than the QT suspension. The present results indicate that QT-loaded ST/P123 micelles are potential candidates to improve the solubility and oral bioavailability of QT.

Redox/enzyme sensitive chondroitin sulfate-based self-assembled nanoparticles loading docetaxel for the inhibition of metastasis and growth of melanoma.

In this report, redox/enzyme responsive chondroitin sulfate-ss-deoxycholic acid (CSCD) conjugates were synthesized using cystamine as the linkage which could self-assemble to form self-assembled nanoparticles (175.6 + 5.2 nm) in the aqueous environment. Docetaxel (DTX) was loaded in nanoparticles with desired loading efficiency for the inhibition of tumor growth and metastasis of melanoma. Interestingly, nanoparticles were demonstrated to respond to hyaluronidase-1 (Hyal-1) which could degrade chondroitin sulfate (CS) backbones. In this case, we designed dual-sensitive nanoparticles with enhanced drug release pattern under the presence of glutathione (GSH)/Hyal-1. Compared with Taxotere®, CSCD nanoparticles significantly improved the DTX distribution in tumors and lungs with about 4.4-fold higher area-under-the-curve (AUC) value. In situ tumor volume and pulmonary metastatic formation were reduced upon the administration of DTX-loaded CSCD nanoparticles via DTX-induced apoptosis and decreased metastasis-promotion protein expression. With only minor cytotoxicity, CSCD nanoparticles could be promising nano-drug delivery systems for successful management of melanoma.

Progress in brain targeting drug delivery system by nasal route.

The blood-brain barrier (BBB) restricts the transport of potential therapeutic moieties to the brain. Direct targeting the brain via olfactory and trigeminal neural pathways by passing the BBB has gained an important consideration for delivery of wide range of therapeutics to brain. Intranasal route of transportation directly delivers the drugs to brain without systemic absorption, thus avoiding the side effects and enhancing the efficacy of neurotherapeutics. Over the last several decades, different drug delivery systems (DDSs) have been studied for targeting the brain by the nasal route. Novel DDSs such as nanoparticles (NPs), liposomes and polymeric micelles have gained potential as useful tools for targeting the brain without toxicity in nasal mucosa and central nervous system (CNS). Complex geometry of the nasal cavity presented a big challenge to effective delivery of drugs beyond the nasal valve. Recently, pharmaceutical firms utilized latest and emerging nasal drug delivery technologies to overcome these barriers. This review aims to describe the latest development of brain targeted DDSs via nasal administration. CHEMICAL COMPOUNDS STUDIED IN THIS ARTICLE: Carbopol 934p (PubChem CID: 6581) Carboxy methylcellulose (PubChem CID: 24748) Penetratin (PubChem CID: 101111470) Poly lactic-co-glycolic acid (PubChem CID: 23111554) Tween 80 (PubChem CID: 5284448).

Insight into the role of dual-ligand modification in low molecular weight heparin based nanocarrier for targeted delivery of doxorubicin.

Low molecular weight heparin nanoparticles (LMWH) modified by glycyrrhetinic acid (GA) (LMWH-GA) and further decorated by lactobionic acid (LA) (LA-LMWH-GA) were reported as novel hepatocellular carcinoma (HPC)-targeted carriers to overcome multidrug resistance (MDR) of doxorubicin (DOX). The drug-loaded nanoparticles had negative charge of around -25mV and average size range of 70-170nm. These nanoparticles performed sustained drug release in vitro and prolonged DOX residence time in blood circulation in vivo. Compared to free DOX, DOX-loaded nanoparticles demonstrated increased DOX accumulation in drug-resistance HepG2/ADR cells and enhanced in vitro therapeutic efficacy. However, DOX/LA-LMWH-GA with dual ligands didn't show higher cellular uptake and cytotoxicity than single GA modified DOX/LMWH-GA, although both GA-mediated and LA-mediated endocytosis were involved in their cell internalization. Uptake pathway inhibition study revealed the less efficacy of DOX/LA-LMWH-GA in cellular level could be attributed to the reduced effect of micropinocytosis and caveolae-mediated endocytosis in cellular uptake. Interestingly, the DOX-loaded nanoparticles developed from lower drug/carrier feeding ratio possessed higher performance in cell internalization and in vitro efficacy compared to those developed from higher drug/carrier feeding ratio, which could highlight the role of carrier in drug delivery process.

Advances in Functionalized Mesoporous Silica Nanoparticles for Tumor Targeted Drug Delivery and Theranostics.

In recent years, nanocarriers have played increasingly significant roles in cancer therapy. Among various nanoplatforms, mesoporous silica nanoparticles (MSNs) have been given serious attention due to their good colloidal stablity, tunable pore sizes, extensive drug loading capacity and easily modified surface. In this review, functionalized MSNs are introduced as an efficient nanocarrier for cancer treatment. First, MSN preparation strategies are generally introduced. Next, passive and active tumor targeting methods for the functionalization of MSNs are reviewed. Then, several types of stimuli-responsive strategies for on-demand drug release, a wide variety of designs integrating with magnetic resonance imaging agents, optical imaging agents, and positron emission tomography imaging agents, etc. for theranostic purpose are summarized. A discussion relating to the future perspectives of MSNs for clinical translocation is also included in this review.

Internal stimuli-responsive nanocarriers for drug delivery: Design strategies and applications.

The design of internal stimuli-responsive nanocarriers has been extensively used for delivery of various active compounds including drugs, peptides and genes. These nanosystems are not only designed for improved solubility, enhanced bioavailability, and prolonged blood circulation time, furthermore, they can be tailored chemically to achieve selective drug release at the desired sites of action, which can enable them to bypass physiological or pathological obstacles and achieve enhanced therapeutic efficacy. This review presents current functional moieties responsive to a variety of internal stimuli, including pH, redox, enzyme, temperature. Their design strategies and biomedical applications are also highlighted in detail. It is expected that this review can provide inspiration and impetus for exploiting more promising internal stimuli-responsive nano-systems for drug delivery.

Self-assembled nanoparticles based on chondroitin sulfate-deoxycholic acid conjugates for docetaxel delivery: Effect of degree of substitution of deoxycholic acid.

Hydrophobically-modified polymers based on chondroitin sulfate with different degree of substitution (DS) of deoxycholic acid (DOCA) were developed for docetaxel delivery. Chondroitin sulfate-deoxycholic acid (CSAD) bioconjugates were synthesized via the linker of adipic dihydrazide by amide bond. They were characterized with spherical shape, mean diameter of around 165.2nm and negative zeta potential (-14.87 to -20.53mV). An increase of DOCA DS reduced size of nanoparticles, while increasing drug loading efficiency. Drug release in vitro showed a triphasic sustained pattern and higher accumulative drug release percentage was observed with increased DS of DOCA on polymer. Self-assemblies with higher DS also had enhanced internalization of nanoparticles and stronger cytotoxicity at the cellular level. The self-assemble nanoparticles demonstrate to be excellent targeting drug delivery systems and the desired therapeutics can be achieved via the alteration of DS.

pH-responsive copolymers based on pluronic P123-poly(ß-amino ester): Synthesis, characterization and application of copolymer micelles.

A novel amphiphilic and pH-responsive copolymer, pluronie P123-poly(ß-amino ester) (P123-PAE), was firstly designed and synthesized using a Michael-type step polymerization. Nano-sized polymeric micelles based on P123-PAE block copolymer were prepared by self-assembly. Curcumin (Cur), a potential cancer therapy drug, was efficiently encapsulated into the P123-PAE micelles to enhance anticancer efficacy. The obtained Cur loaded P123-PAE micelles (Cur-P123-PAE) presented a spherical shape and high drug loading (18.4%). Interestingly, when the media pH decreased from 7.4 to 5.5, the particle size of the micelles shrank from 152.5nm to 122.1nm due to the protonation of PAE blocks, and the zeta potential of the P123-PAE micelles changed from weakly positive (1.5mV) to highly positive (9.0mV) over a pH range from 7.4 to 5.5. In vitro drug release studies demonstrated that the release rate of Cur was markedly influenced by pH. In vitro cytotoxicity tests showed that all the blank micelles were non-toxic. Cur-P123-PAE exhibited similar antitumor effect against MCF-7 and HepG2 cells compared to solubilized Cur solution. Using Coumarin-6 as a fluorescence probe, it was observed that Cur-P123-PAE micelles experienced longer circulation followed by accumulation at tumor tissues with stronger fluorescence intensity. The results of pharmacokinetics studies showed that the P123-PAE micelles could significantly prolong the retention time of Cur in vivo.

Recent progresses in bioadhesive microspheres via transmucosal administration.

Based on the advantages of adhesion preparations and the application status of microspheres (MSs) in mucous delivery, this paper primarily reviews the bioadhesive MSs via transmucosal administration routes, including the mucosa in alimentary tract and other lumens. Particularly, the detailed researches about of celladhesive MSs and some new-style bioadhesive MSs are mentioned. Furthermore, this review attempts to reveal the advances of bioadhesive MSs as cell-selective bioadhesion systems and the stimuli-responsive MSs as location-specific drug delivery systems. Although these MSs show powerful strength, some far-sighted ideas should be brought on agendas. In the future, mechanisms should be put under tight scrutiny and more attention should be focused on the excellent bioadhesive materials and the 'second generation mucoadhesives'. Meaningful clinical applications of these novel MSs are also of current concerns and need more detailed researches.