The quest for non-invasive delivery of bioactive macromolecules: a focus on heparins

Inhaled heparin: Past, present, and future

While heparin has traditionally served as a key anticoagulant in clinical practice for nearly a century, recent years have witnessed a growing interest in its role as a potent antiinflammatory and antiviral agent, as well as an anticancer agent. To address challenges with injection-based delivery, exploring patient-friendly routes such as oral and pulmonary delivery is crucial. This review specifically highlights the multiple therapeutic benefits of inhaled heparin. In summary, this review serves as a valuable source of information, providing deep insights into the diverse therapeutic advantages of inhaled heparin and its potential applications within clinical contexts.

Novel Polymeric Nanomaterial Based on Poly(Hydroxyethyl Methacrylate-Methacryloylamidophenylalanine) for Hypertension Treatment: Properties and Drug Release Characteristics

In this study, a novel polymeric nanomaterial was synthesized and characterized, and it its potential usability in hypertension treatment was demonstrated. For these purposes, a poly(hydroxyethyl methacrylate-methacryloylamidophenylalanine)-based polymeric nanomaterial (p(HEMPA)) was synthesized using a mini-emulsion polymerization technique. The nanomaterials were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and zeta size analysis. The synthesized p(HEMPA) nanomaterial had a diameter of about 113 nm. Amlodipine-binding studies were optimized by changing the reaction conditions. Under optimum conditions, amlodipine's maximum adsorption value (Qmax) of the p(HEMPA) nanopolymer was found to be 145.8 mg/g. In vitro controlled drug release rates of amlodipine, bound to the nanopolymer at the optimum conditions, were studied with the dialysis method in a simulated gastrointestinal system with pH values of 1.2, 6.8 and 7.4. It was found that 99.5% of amlodipine loaded on the nanomaterial was released at pH 7.4 and 72 h. Even after 72 h, no difference was observed in the release of AML. It can be said that the synthesized nanomaterial is suitable for oral amlodipine release. In conclusion, the synthesized nanomaterial was studied for the first time in the literature as a drug delivery system for use in the treatment of hypertension. In addition, AML-p(HEMPA) nanomaterials may enable less frequent drug uptake, have higher bioavailability, and allow for prolonged release with minimal side effects.

Efficacy of ibuprofen gargle for postoperative pain after mandibular third molar extraction: protocol for a phase II, placebo-controlled, double-blind, randomized crossover trial

Background

Extraction of mandibular third molars is one of the most commonly performed oral surgical procedures, and nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for pain management. Oral NSAIDs are associated with adverse events such as gastrointestinal disorders, renal and hepatic dysfunction, and platelet dysfunction. Topical analgesics have been proposed as alternatives to oral and injectable medications to safely improve postoperative pain relief. We will conduct a single-center, placebo-controlled, double-blind, randomized crossover trial to assess the pain-relieving effect of an ibuprofen-containing gargle in patients undergoing extraction of mandibular third molars when compared with a placebo gargle.

Objective

This will be the first clinical study to compare the efficacy of an ibuprofen gargle with that of a placebo for relieving postoperative pain in addition to loxoprofen after mandibular third molar extraction.

Methods

This study will be performed at Kobe University Hospital. Participants (N=40) will be randomized equally to 1 of 2 groups. The ibuprofen-placebo group will receive an ibuprofen gargle on postoperative day (POD) 1 and a placebo gargle on POD 2. The placebo-ibuprofen group will receive a placebo gargle on POD 1 and an ibuprofen gargle on POD 2. Both groups will receive ibuprofen gargles on PODs 3-5 at least once daily. The primary objective is to estimate the within-subject difference on a visual analog scale (VAS) before and 5 minutes after using the ibuprofen or placebo gargle on PODs 1 and 2. The secondary objectives are to estimate the within-subject differences in ΔVAS before and 15 minutes after using the ibuprofen or placebo gargle on PODs 1 and 2, ΔVAS before and 5 or 15 minutes after using the ibuprofen gargle on PODs 3-5, overall efficacy (self-completion, 5 scales) on PODs 1-5, daily frequency of use (ibuprofen or placebo gargle and analgesics) on PODs 1-7, and the occurrence of adverse events.

Results

The Certified Review Board of Kobe University approved the study. The intervention was implemented in May 2021. For the primary analysis, we will calculate the mean and SD of ΔVAS₅ on PODs 1 and 2 and the within-study difference in ΔVAS₅. The treatment effect will be estimated by dividing the mean ΔVAS₅ in the within-subject difference by 2 and calculating the P value using an unpaired t test. For the secondary analysis, we will calculate the mean and SD of ΔVAS₁₅ on PODs 1 and 2 and the within-study difference in ΔVAS₁₅. The treatment effect will be estimated as in the primary analysis.

Conclusions

This trial will provide exploratory evidence of the efficacy and safety of an ibuprofen gargle for pain reduction after mandibular third molar extraction.

Trial Registration

Japan Registry of Clinical Trials jRCTs051210022; https://tinyurl.com/39ej23zu

International Registered Report Identifier (IRRID)

DERR1-10.2196/35533

Synthesis of Eudragit® L100-coated chitosan-based nanoparticles for oral enoxaparin delivery

Enoxaparin is an effective biological molecule for prevention and treatment of coagulation disorders. However, it is poorly absorbed in the gastrointestinal tract. In this study, we developed an Eudragit® L100 coated chitosan core shell nanoparticles for enoxaparin oral delivery (Eud/CS/Enox NPs) through a completely eco-friendly method without employing any high-energy homogenizer technique and any organic solvents. Spherical nanocarriers were successfully prepared with particle size lower than 300 nm, polydispersity index about 0.12 and zeta potential higher than +25 mV, entrapment efficiency greater than 95% and the in vitro release behavior confirms the good colloidal stability and the successful Eudragit® L100 coating process demonstrated by negligible cumulative enoxaparin release (<10%) when the particles are submitted to simulated gastric fluid conditions. Finally, we demonstrated that the core-shell structure of the particle influenced the drug release mechanism of the formulations, indicating the presence of the Eudragit® L100 on the surface of the particles. These results suggested that enteric-coating approach and drug delivery nanotechnology can be successfully explored as potential tools for oral delivery of enoxaparin.

Transdermal delivery of heparin using low-frequency sonophoresis in combination with sponge spicules for venous thrombosis treatment

This study reports that the use of low-frequency sonophoresis (LFS) in combination with sponge Haliclona sp. spicules (SHS), referred to as cSoSp (combined Sonophoresis and Spicules), can enhance the transdermal drug delivery in a synergistic manner. The topical application of cSoSp in vitro significantly enhanced the skin absorption of Fluorescent-Dextrans (4000 Da, FD-4K), a model drug of low-molecular-weight heparin (LMWH). The utilization of cSoSp dramatically increased the transdermal flux of FD-4K (188.6 ± 93.7 ng cm^-2 h^-1) compared to LFS (5.8 ± 3.1 ng cm^-2 h^-1) and SHS (3.2 ± 1.2 ng cm^-2 h^-1) among others. The mechanism of action of cSoSp could be attributed to the synergism between plenty of long-lasting nano-channels created by SHS and the disorders of SC lipids made by shock waves of LFS, which improves the homogeneity of the cavitation effects. Furthermore, LMWH (3000 Da) was transdermally delivered by using cSoSp to treat both superficial venous thrombosis (SVT) and deep venous thrombosis (DVT) in the marginal ear vein of rabbits with a good therapeutic effect. Furthermore, skin irritation and toxicity studies using guinea pigs indicated that cSoSp was nonirritating without any morphological changes in the keratinocytes. cSoSp offers a promising strategy to enhance the transdermal delivery of hydrophilic macromolecules such as heparin.

Development and evaluation of a heparin gel for transdermal delivery via laser-generated micropores

Aim: Our study investigated the feasibility of transdermal delivery of heparin, an anticoagulant used against venous thromboembolism, as an alternative to intravenous administration. Materials & methods: Skin was pretreated using ablative laser (Precise Laser Epidermal System [P.L.E.A.S.E.^®] technology) for enhanced delivery of heparin. In vitro permeation studies using static Franz diffusion cells provided a comparison between delivery from 0.3% w/v heparin-loaded poloxamer gel and solution across untreated and laser-treated dermatomed porcine ear skin. Results: No passive delivery of heparin was observed. Laser-assisted delivery from solution (26.07 ± 1.82 μg/cm²) was higher (p < 0.05) than delivery from heparin gel (11.28 ± 5.32 μg/cm²). However, gel is likely to sustain the delivery over prolonged periods like a maintenance dose via continuous intravenous infusion. Conclusion: Thus, ablative laser pretreatment successfully delivered heparin, establishing the feasibility of delivering hydrophilic macromolecules using the transdermal route.

COVID-19 and thrombosis: From bench to bedside

Coronavirus disease of 2019 (COVID-19) is the respiratory viral infection caused by the coronavirus SARS-CoV2 (Severe Acute Respiratory Syndrome Coronavirus 2). Despite being a respiratory illness, COVID-19 is found to increase the risk of venous and arterial thromboembolic events. Indeed, the link between COVID-19 and thrombosis is attracting attention from the broad scientific community. In this review we will analyze the current available knowledge of the association between COVID-19 and thrombosis. We will highlight mechanisms at both molecular and cellular levels that may explain this association. In addition, the article will review the antithrombotic properties of agents currently utilized or being studied in COVID-19 management. Finally, we will discuss current professional association guidance on prevention and treatment of thromboembolism associated with COVID-19.

Colonic delivery of vasoactive intestinal peptide nanomedicine alleviates colitis and shows promise as an oral capsule

Aim: To evaluate the efficacy of locally delivered nanomedicine, vasoactive intestinal peptide in sterically stabilized micelles (VIP-SSM) to the colon and conduct in vitro release studies of a potential oral formulation. Materials & methods: Intracolonic instillation of VIP-SSM was tested in a mouse model of dextran sulfate sodium-induced colitis. Based on the effective mouse dose, human equivalent dose containing nanomedicine powder was filled into enteric coated capsules for in vitro release testing. Results: Colonic delivery of VIP-SSM significantly alleviated colitis. VIP-SSM containing capsules completely dissolved at colonic pH allowing micelles to reform with active VIP. Capsule formulations exhibited reproducible release profiles when stored up to 6 weeks demonstrating stability. Conclusion: VIP-SSM is an effective nanomedicine formulation which appears to have potential for oral treatment of colitis in humans. [Formula: see text].

Advanced delivery strategies facilitating oral absorption of heparins

Heparins show great anticoagulant effect with few side effects, and are administered by subcutaneous or intravenous route in clinics. To improve patient compliance, oral administration is an alternative route. Nonetheless, oral administration of heparins still faces enormous challenges due to the multiple obstacles. This review briefly analyzes a series of barriers ranging from poorly physicochemical properties of heparins, to harsh biological barriers including gastrointestinal degradation and pre-systemic metabolism. Moreover, several approaches have been developed to overcome these obstacles, such as improving stability of heparins in the gastrointestinal tract, enhancing the intestinal epithelia permeability and facilitating lymphatic delivery of heparins. Overall, this review aims to provide insights concerning advanced delivery strategies facilitating oral absorption of heparins.

Development of Lipid-Polymer Hybrid Nanoparticles for Improving Oral Absorption of Enoxaparin

Enoxaparin, an anticoagulant that helps prevent the formation of blood clots, is administered parenterally. Here, we report the development and evaluation of lipid-polymer hybrid nanoparticles (LPHNs) for the oral delivery of enoxaparin. The polymer poloxamer 407 (P407) was incorporated into lipid nanoparticles to form gel cores and ensure high encapsulation efficiency and the controlled release of enoxaparin. In vitro results indicated that 30% of P407 incorporation offered higher encapsulation efficiency and sustained the release of enoxaparin. Laser confocal scanning microscopy (LCSM) images showed that LPHNs could not only significantly improve the accumulation of enoxaparin in intestinal villi but also facilitate enoxaparin transport into the underlayer of intestinal epithelial cells. In vivo pharmacokinetic study results indicated that the oral bioavailability of enoxaparin was markedly increased about 6.8-fold by LPHNs. In addition, its therapeutic efficacy against pulmonary thromboembolism was improved 2.99-fold by LPHNs. Moreover, LPHNs exhibited excellent biocompatibility in the intestine. Overall, the LPHN is a promising delivery carrier to boost the oral absorption of enoxaparin.

Low-Molecular-Weight Heparins: Reduced Size Particulate Systems for Improved Therapeutic Outcomes

A wide range of diseases have been treated using low-molecular-weight heparins (LMWHs), the drug of choice for anticoagulation. Owing to their better pharmacokinetic features compared to those of unfractionated heparin (uFH), several systems incorporating LMWHs have been investigated to deliver and improve their therapeutic outcomes, especially through development of their micro- and nano-particles. This review article describes current perspectives on the fabrication, characterization, and application of LMWHs-loaded micro- and nano-particles to achieve ameliorated bioavailability. The valuable applications of LMWH will continue to encourage researchers to identify efficient delivery systems that have specific release characteristics and ameliorated bioavailability, overcoming the challenges presented by biological obstructions and the physicochemical properties of LMWHs.

Effect of Diclofenac Mouthwash on Postoperative Pain after Periodontal Surgery

INTRODUCTION

Non-Steroidal AntiInflammatory Drugs (NSAIDs) are widely used drugs for the management of pain. Oral administration of NSAIDs has various adverse events like gastrointestinal alterations - nausea, dyspepsia and gastrointestinal bleeding, hepatotoxicity and blood dyscrasias. As orally given NSAIDs are associated with systemic side effects, it is preferred to alleviate pain and inflammation using topical medication. Thus, recently the focus has been on the development of topical administration of NSAIDs in the form of gels, toothpastes and rinses.

AIM

To determine if diclofenac mouthwash, would be a better alternative to its systemic administration post surgery, in terms of patient acceptance and to minimize the adverse effects of orally administered drug.

MATERIALS AND METHODS

The study was designed as a single blinded, randomized, controlled clinical trial. Thirty chronic periodontitis patients scheduled for full mouth flap surgeries were randomized to receive either Diclofenac Mouthwash (MW) or Diclofenac Tablets (TB), post surgery. The MW group patients (15) were advised to rinse undiluted 15 ml solution for 30 secs, twice daily for three days. TB group (15) was advised to take 50 mg tablet twice daily for three days. A 10 point Visual Analog Scale (VAS) and Wong Baker Facial Rating Scale (FRS) was recorded to measure the pain perception by the patients. Gingival status was assessed by the Modified Gingival Index (MGI) at Baseline and seventh day. Data pertaining to pain perception were analysed using repeated measures of ANOVA (Analysis of Variance) with post-hoc LSD test.

RESULTS

Intra group comparisons showed a significant reduction in pain, post surgery. Inter group comparisons showed a significant reduction only in the MGI scores of MW group, when compared to TB group. Intergroup comparisons showed no significant reduction in pain scores between both the groups, stating that diclofenac mouthwash is as effective as oral administration.

CONCLUSION

Diclofenac mouthwash is a better alternative to the systemic administration post surgery, in terms of patient acceptance and to minimize the adverse effects of orally administrated drug.

Design and strategies for bile acid mediated therapy and imaging

Bioinspired materials have received substantial attention across biomedical, biological, and drug delivery research because of their high biocompatibility and lower toxicity compared with synthetic materials.

Supercritical carbon dioxide design strategies: from drug carriers to soft killers

The integrated use of supercritical carbon dioxide (scCO(2)) and micro- and nanotechnologies has enabled new sustainable strategies for the manufacturing of new medications. 'Green' scCO(2)-based methodologies are well suited to improve either the synthesis or materials processing leading to the assembly of three-dimensional multifunctional constructs. By using scCO(2) either as C1 feedstock or as solvent, simple, economic, efficient and clean routes can be designed to synthesize materials with unique properties such as polyurea dendrimers and oxazoline-based polymers/oligomers. These new biocompatible, biodegradable and water-soluble polymeric materials can be engineered into multifunctional constructs with antimicrobial activity, targeting moieties, labelling units and/or efficiently loaded with therapeutics. This mini-review highlights the particular features exhibited by these materials resulting directly from the followed supercritical routes.

Development of enoxaparin sodium polymeric microparticles for colon-specific delivery

Background and aims

Recent studies have shown that low molecular weight heparins are effective in the treatment of inflammatory bowel disease. Therefore, there is considerable interest in the development of an oral colonic delivery pharmaceutical system allowing targeted release of heparin in the inflamed tissue. The objective of this study was to prepare microparticles for the oral administration and colonic release of enoxaparin and to evaluate the influence of certain formulation factors on their characteristics.

Methods

Microparticles were prepared by water/oil/water double emulsion technique followed by solvent evaporation. The influence of several formulation factors on the characteristics of microparticles were evaluated. The formulation factors were alginate concentration in the inner aqueous phase, polymer (Eudragit^® FS 30D and Eudragit^® RS PO) concentration in the organic phase and ratios between the two polymers. The microparticles were characterized in terms of morphology, size, entrapment efficiency and enoxaparin release.

Results

The results showed that increasing sodium alginate percentage reduced the encapsulation efficiency of enoxaparin and accelerated enoxaparin release. Regarding the influence of the two polymers, reducing polymer concentration in the organic phase led to a smaller size of microparticles, a lower entrapment efficiency and an important retardation of enoxaparin release. The formulation prepared with Eudragit^® FS 30D limited the release to a maximum of 3% in gastric simulated environment, a specific characteristic of oral systems for colonic delivery, and fulfilled our objective to delay the release.

Conclusions

Microparticles prepared with Eudragit^® FS 30D represent a suitable and potential oral system for the colonic delivery of enoxaparin.

Trends in the development of oral anticoagulants

Anticoagulation remains the therapy of choice for the prevention and treatment of venous and arterial thromboembolic disorders which can cause major organ damage or death. Heparins represent the antithrombotic drugs of choice in short and medium-term prophylaxis and therapy of thromboembolic diseases. Fondaparinux, a synthetic and structural analog of the antithrombin-binding pentasaccharide domain of heparin, has selective anti-Xa activity and longer half-life. However, anticoagulants are poorly absorbed by oral route because of their high molecular weight, hydrophilicity and negative charges. Long-term anticoagulation therapy is problematic because of side effects and frequent monitoring. Formulation approaches are particularly promising.

Enhancing the buccal mucosal delivery of peptide and protein therapeutics

With continuing advances in biotechnology and genetic engineering, there has been a dramatic increase in the availability of new biomacromolecules, such as peptides and proteins that have the potential to ameliorate the symptoms of many poorly-treated diseases. Although most of these macromolecular therapeutics exhibit high potency, their large molecular mass, susceptibility to enzymatic degradation, immunogenicity and tendency to undergo aggregation, adsorption, and denaturation have limited their ability to be administered via the traditional oral route. As a result, alternative noninvasive routes have been investigated for the systemic delivery of these macromolecules, one of which is the buccal mucosa. The buccal mucosa offers a number of advantages over the oral route, making it attractive for the delivery of peptides and proteins. However, the buccal mucosa still exhibits some permeability-limiting properties, and therefore various methods have been explored to enhance the delivery of macromolecules via this route, including the use of chemical penetration enhancers, physical methods, particulate systems and mucoadhesive formulations. The incorporation of anti-aggregating agents in buccal formulations also appears to show promise in other mucosal delivery systems, but has not yet been considered for buccal mucosal drug delivery. This review provides an update on recent approaches that have shown promise in enhancing the buccal mucosal transport of macromolecules, with a major focus on proteins and peptides.

Novel self assembling nanoparticles for the oral administration of fondaparinux: synthesis, characterization and in vivo evaluation

Fondaparinux (Fpx) is the anticoagulant of choice in the treatment of short- and medium-term thromboembolic disease. To overcome the low oral bioavailability of Fpx, a new nanoparticulate carrier has been developed. The nanoparticles (NPs) contain squalenyl derivatives, known for their excellent oral bioavailability. They spontaneously self-assemble upon both electrostatic and hydrophobic interactions between the polyanionic Fpx and cationic squalenyl (CSq) derivatives. The preparation conditions were optimized to obtain monodisperse, stable NPs with a mean diameter in the range of 150–200 nm. The encapsulation efficiencies were around 80%. Fpx loadings reached 39 wt.%. According to structural and morphological analysis, Fpx and CSq organized in spherical multilamellar (“onion-type”) nanoparticles. Furthermore, in vivo studies in rats suggested that Fpx was well absorbed from the orally administered NPs, which totally dissociated when reaching the blood stream, leading to the release of free Fpx. The Fpx:CSq NPs improved the plasmatic concentration of Fpx in a dose-dependent manner. However, the oral bioavailability of these new NPs remained low (around 0.3%) but of note, the C_max obtained after oral administration of 50 mg/kg NPs was close to the prophylactic plasma concentration needed to treat venous thromboembolism. Moreover, the oral bioavailability of Fpx could be dramatically increased up to 9% by including the nanoparticles into gastroresistant capsules. This study opens up new perspectives for the oral administration of Fpx and paves the way towards elaborating squalene-based NPs which self assemble without the need of covalently grafting the drug to Sq.

Uptake, transport and peroral absorption of fatty glyceride grafted chitosan copolymer-enoxaparin nanocomplexes: influence of glyceride chain length

The objective of this paper is to elucidate the influence of fatty glyceride chain length in chitosan copolymers on the peroral absorption of enoxaparin. First of all, a series of chitosan copolymers with glyceryl monocaprylate (GM8), glyceryl monolaurate (GM12) and glyceryl monostearate (GM18) as the hydrophobic part were synthesized. The structure of the copolymers was characterized using proton nuclear magnetic resonance. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay demonstrated that all the copolymers were non-toxic. Enoxaparin nanocomplexes were prepared by self-assembly. Mucoadhesion of the nanocomplexes was characterized using the mucin particle method. Nanocomplex uptake and transport were quantified in Caco-2 cells and cellular localization was visualized by confocal laser scanning microscopy. Enoxaparin uptake was enhanced by nanocomplex formation, and was dependent on incubation time, concentration, temperature and glyceride chain length. The GM8 grafted chitosan-enoxaparin nanocomplex exhibited the strongest bioadhesion and the best uptake and transport in both cell culture and in vivo absorption in rats. The uptake mechanism was assumed to be adsorptive endocytosis via clathrin- and caveolae-mediated processes. In conclusion, oral absorption of enoxaparin can be further enhanced by using GM8 grafted chitosan copolymer as the carrier to form nanocomplexes.

In vitro and in vivo evaluation of chitosan graft glyceryl monooleate as peroral delivery carrier of enoxaparin

In this paper a novel copolymer, chitosan graft glyceryl monooleate (CS-GO) was synthesized and its potential as the nanocarrier for enhancing the peroral delivery of enoxaparin was studied systemically. The successful synthesis was characterized by (1)H NMR. Enoxaparin nanocomplexes were prepared by self-assembly. Mucoadhesive properties of the nanocomplexes were evaluated using mucin particle method. Uptake and transport of the nanocomplexes were investigated in Caco-2 cells. In vivo absorption was studied in rats. The therapeutic effects of the nanocomplexes were evaluated using pulmonary thromboembolism model in mice. This study demonstrated that compared to chitosan based system, hydrophobic modification of CS with GO enhanced the oral absorption of enoxaparin significantly, which is in good agreement with the enhanced mucoadhesion, cellular internalization and transport in cell culture. Cellular uptake of CS-GO based enoxaparin nanocomplexes was incubation time, enoxaparin concentration and incubation temperature dependent. The uptake mechanism was assumed to be adsorptive endocytosis via clathrin- and caveolae-mediated process. Its therapeutic efficacy was further demonstrated by pharmacodynamic study with pulmonary thromboembolism inhibition percentage 47.1%. In conclusion, CS-GO copolymer is a promising nanocarrier for enhancing the oral absorption of enoxaparin.

pH-responsive thiolated chitosan nanoparticles for oral low-molecular weight heparin delivery: in vitro and in vivo evaluation

The aim of present study was to investigate a pH-responsive and mucoadhesive nanoparticle system for oral bioavailability enhancement of low-molecular weight heparin (LMWH). The thioglycolic acid (TGA) was first covalently attached to chitosan (CS) with 396.97 ± 54.54 μmol thiol groups per gram of polymer and then the nanoparticles were prepared with thiolated chitosan (TCS) and pH-sensitive polymer hydroxypropyl methylcellulose phthalate (HPMCP) by ionic cross-linking method. The obtained nanoparticles were characterized for the shape, particle size, zeta potential, drug entrapment efficiency and loading capacity. In vitro results revealed the acid stability of pH-responsive nanoparticles, which had a significant control over LMWH release and could effectively protect entrapped drugs in simulated gastric conditions. By the attachment of the thiol ligand, an improvement of permeation-enhancing effect on freshly excised carp intestine (1.86-fold improvement) could be found. The mucoadhesive properties were evaluated using fluorescently labeled TCS or CS nanoparticles. As compared with the controls, a significant improvement of mucoadhesion on rat intestinal mucosa was observed in TCS/HPMCP nanoparticles via confocal laser scanning microscopy. The activated partial thromboplastin time (APTT) was significantly prolonged and an increase in the oral bioavailability of LMWH was turned out to be pronounced after oral delivered LMWH-loaded TCS/HPMCP nanoparticles in rats, which suggested enhanced anticoagulant effects and improved absorption of LMWH. In conclusion, pH-responsive TCS/HPMCP nanoparticles hold promise for oral delivery of LMWH.

Synthesis of a targeted library of heparan sulfate hexa- to dodecasaccharides as inhibitors of β-secretase: potential therapeutics for Alzheimer's disease

Heparan sulfates (HS) are a class of sulfated polysaccharides that function as dynamic biological regulators of the functions of diverse proteins. The structural basis of these interactions, however, remains elusive, and chemical synthesis of defined structures represents a challenging but powerful approach for unravelling the structure-activity relationships of their complex sulfation patterns. HS has been shown to function as an inhibitor of the β-site cleaving enzyme β-secretase (BACE1), a protease responsible for generating the toxic Aβ peptides that accumulate in Alzheimer's disease (AD), with 6-O-sulfation identified as a key requirement. Here, we demonstrate a novel generic synthetic approach to HS oligosaccharides applied to production of a library of 16 hexa- to dodecasaccharides targeted at BACE1 inhibition. Screening of this library provided new insights into structure-activity relationships for optimal BACE1 inhibition, and yielded a number of potent non-anticoagulant BACE1 inhibitors with potential for development as leads for treatment of AD through lowering of Aβ peptide levels.

Laser-engineered dissolving microneedles for active transdermal delivery of nadroparin calcium

There is an urgent need to replace the injection currently used for low molecular weight heparin (LMWH) multidose therapy with a non- or minimally invasive delivery approach. In this study, laser-engineered dissolving microneedle (DMN) arrays fabricated from aqueous blends of 15% w/w poly(methylvinylether-co-maleic anhydride) were used for the first time in active transdermal delivery of the LMWH nadroparin calcium (NC). Importantly, an array loading of 630IU of NC was achieved without compromising the array mechanical strength or drug bioactivity. Application of NC-DMNs to dermatomed human skin (DHS) using the single-step 'poke and release' approach allowed permeation of approximately 10.6% of the total NC load over a 48-h study period. The cumulative amount of NC that permeated DHS at 24h and 48h attained 12.28±4.23IU/cm(2) and 164.84±8.47IU/cm(2), respectively. Skin permeation of NC could be modulated by controlling the DMN array variables, such as MN length and array density as well as application force to meet various clinical requirements including adjustment for body mass and renal function. NC-loaded DMN offers great potential as a relatively low-cost functional delivery system for enhanced transdermal delivery of LMWH and other macromolecules.

Recent trends in oral transmucosal drug delivery systems: an emphasis on the soft palatal route

INTRODUCTION

The oral mucosa is an appropriate route for drug delivery systems, as it evades first-pass metabolism, enhances drug bioavailability and provides the means for rapid drug transport to the systematic circulation. This delivery system offers a more comfortable and convenient delivery route compared with the intravenous route. Although numerous drugs have been evaluated for oral mucosal delivery, few of them are available commercially. This is due to limitations such as the high costs associated with developing such drug delivery systems.

AREAS COVERED

The present review covers recent developments and applications of oral transmucosal drug delivery systems. More specifically, the review focuses on the suitability of the oral soft palatal site as a new route for drug delivery systems.

EXPERT OPINION

The novelistic oral soft palatal platform is a promising mucoadhesive site for delivering active pharmaceuticals, both systemically and locally, and it can also serve as a smart route for the targeting of drugs to the brain.

Novel preparation techniques for alginate-poloxamer microparticles controlling protein release on mucosal surfaces

The objective of this study was to develop novel preparation techniques for protein-loaded, controlled release alginate-poloxamer microparticles with a size range suitable for pulmonary administration. Bovine serum albumin (BSA)-loaded microparticles were prepared by spray-drying aqueous polymer-drug solutions, followed by cross-linking the particles in aqueous or ethanolic CaCl(2) or aqueous ZnSO(4) solutions. The microparticles were characterized with respect to their morphology (optical and scanning electron microscopy), particle size (laser light diffraction), calcium content (atom absorption spectroscopy), alginate content (complexation with 1,9-dimethyl methylene blue) and in vitro drug release (modified Franz diffusion cell). The spray-dried microparticles were spherical in shape with a size range of 4-6μm. Aqueous cross-linking led to a significant size increase (10-15μm), whereas ethanolic cross-linking did not. The substantial drug loss (∼50%) during aqueous CaCl(2) cross-linking could be avoided by using aqueous ZnSO(4) or ethanolic CaCl(2) solutions. Protein release from microparticles cross-linked with ethanolic CaCl(2) solutions was much faster than in the case of aqueous CaCl(2) solutions, probably due to the lower calcium content. The salt concentration and temperature of the cross-linking solutions also affected the composition of and drug release from the microparticles. Cross-linked alginate-poloxamer microparticles can be produced in a size range appropriate for deep lung delivery and with controlled protein release kinetics (time frame: hours to days) with these novel preparation techniques. The systems offer an interesting potential for the controlled mucosal delivery of protein drugs.

Oral fondaparinux: use of lipid nanocapsules as nanocarriers and in vivo pharmacokinetic study

Oral anticoagulant therapy could be advanced using lipid-based nanoparticulate systems. This study examined lipid nanocapsules for their oral absorption potential as the first step in developing oral fondaparinux (Fp) novel carriers. Using phase inversion method and cationic surfactants such as hexadecyltrimethyl ammonium bromide (CTAB) or stearylamine (SA), cationic lipid nanocapsules (cLNCs), loaded with Fp on their surface, were prepared and characterized (zeta potential, size and Fp association efficiency and content). In vivo studies were conducted after single oral increasing doses of Fp-loaded cLNCs (0.5 to 5 mg/kg of Fp) in rats and the concentration of Fp in the plasma was measured by anti-factor Xa activity assay. The monodisperse, (~50 nm), positively charged Fp-cLNCs with high drug loadings demonstrated linear pharmacokinetic profiles of the drug with an increased oral absolute bioavailability (up to ~21%) compatible with therapeutic anticoagulant effect (>0.2 μg/mL).

The effect of diclofenac mouthwash on periodontal postoperative pain

BACKGROUND

The need to relieve pain and inflammation after periodontal surgery and the side effects of systemic drugs and advantages of topical drugs, made us to evaluate the effect of Diclofenac mouthwash on periodontal postoperative pain.

METHODS

In this double-blind, randomized clinical trial study 20 quadrants of 10 patients(n = 20) aged between 22-54 who also acted as their own controls, were treated using Modified Widman Flap procedure in two quadrants of the same jaw with one month interval between the operations. After the operation in addition to ibuprofen 400 mg, one quadrant randomly received Diclofenac mouthwash (0/01%) for 30 seconds, 4 times a day (for a week) and for the contrary quadrant, ibuprofen and placebo mouthwash was given to be used in the same manner. The patients scored the number of ibuprofen consumption and their pain intensity based on VAS index in a questionnaire in days 1, 2, 3 and the first week after operation. The findings were analysed using two-way ANOVA, t-test and Wilcoxon. P-value less than 0.05 considered to be significant.

RESULTS

There was a significant difference between the mean values of pain intensity of two quadrants in four periods (P = 0.031). But, there was no significant difference between the average ibuprofen consumption in two groups (P = 0.51). Postoperative satisfaction was not significantly different in two quadrants (P = 0.059). 60% of patients preferred Diclofenac mouthwash.

CONCLUSION

Diclofenac mouthwash was effective in reducing postoperative periodontal pain but it seems that it isn't enough to control postoperative pain on its own.

Statistical analysis of low molecular mass heparin nanoencapsulation

The objective of this study was to use Box-Behnken design (BBD) to investigate the influence of formulation variables on the properties of heparin-loaded poly(lactic-coglycolic acid) (PLGA)-polymethacrylate-RLPO (E-RLPO) nanoparticles (NP) in terms of mean diameter (as size) and drug encapsulation efficiency. The NPs were prepared by the double emulsion solvent evaporation method. The independent variables were: X1 - polymer mass ratio (PLGA:E-RLPO) in the oil phase, X2 - concentration of polyvinyl alcohol (PVA) as emulsion stabilizer, and X3 - volume of the external aqueous phase (W2). Particle size (analyzed by dynamic light scattering) and encapsulation efficiency (EE, estimated by spectrophotometry) were the investigated responses. The polynomial equation obtained from regression analysis of the reduced model (p = 0.0002, F = 25.7952 and R2 = 0.96) provided an excellent fit. The optimal size for the NP was found to be 134.2 ± 16.5 nm with formulation variables of 48.2:61.8, 0.321 (%,m/V) and 263 mL for X1, X2 and X3, respectively. Probably, due to electrostatic interaction between the negatively charged drug and the positively charged E-RLPO, the percent EE of heparin was between 74.4 ± 6.5 % (lowest value) and 92.1 ± 5.3 % (highest value). The data suggest that BBD is a useful tool in rational design of heparin-loaded NPs.

Soluble urokinase receptor conjugated to carrier red blood cells binds latent pro-urokinase and alters its functional profile

Coupling plasminogen activators to carrier red blood cells (RBC) prolongs their life-time in the circulation and restricts extravascular side effects, thereby allowing their utility for short-term thromboprophylaxis. Unlike constitutively active plasminogen activators, single chain urokinase plasminogen activator (scuPA) is activated by plasmin proteolysis or binding to its receptor, uPAR. In this study we conjugated recombinant soluble uPAR (suPAR) to rat RBC, forming RBC/suPAR complex. RBC carrying suPAR circulated in rats similarly to naïve RBC and markedly prolonged the circulation time of suPAR. RBC/suPAR carrying approximately 3x10(4) suPAR molecules per RBC specifically bound up to 2x10(4) molecules of scuPA, retained approximately 75% of scuPA-binding capacity after circulation in rats and markedly altered the functional profile of bound scuPA. RBC carrying directly conjugated scuPA adhered to endothelial cells, while showing no appreciable fibrinolytic activity. In contrast, RBC/suPAR loaded with scuPA did not exhibit increased adhesion to endothelium, while effectively dissolving fibrin clots. This molecular design, capitalizing on unique biological features of the interaction of scuPA with its receptor, provides a promising modality to deliver a pro-drug for prevention of thrombosis.

Novel hollow microcapsules based on iron-heparin complex multilayers

Iron-polysaccharide complex have been extensively utilized in the treatment of iron deficiency anemia for parenteral administration. Herein, a novel iron-heparin complexed hollow capsules with nanoscaled wall thickness have been fabricated by means of alternating deposition of ferric ions (III) (Fe+) and heparin (Hep) onto the surface of submicroscaled (488 nm) and microscaled (10.55 microm) polystyrene latex particles via both electrostatic interaction and chemical complexation processes, followed by dissolution of the cores using tetrahydrofuran. Confocal micrographs and atomic force microscopy (AFM) images prove that iron-heparin complexed submicroscaled hollow capsules keep spherical shapes in solution and even after drying. The activated partial thromboplastin time (APTT) assay shows that complexing with ferric ions do not compromise the catalytic capacity of heparin to promote antithrombin III-mediated thrombin inactivation. The anticoagulant activity value of (Fe3+/Hep)8 capsules is evaluated to be about 95.7 U/mg, indicating that approximately 0.55 mg heparin was in 1 mg powder of submicroscaled (Fe3+/Hep)8 hollow capsules. Compared with the same dosage of heparin, iron-heparin complexed hollow capsules display a more prolonged anticoagulant duration than heparin. All these results reveal that such submicroscaled iron-heparin complexed hollow capsules have application potential as an injectable anticoagulant vehicle.

Melittin exhibits necrotic cytotoxicity in gastrointestinal cells which is attenuated by cholesterol

Melittin, a cationic antimicrobial peptide isolated from the venom of Apis mellifera, has shown potential as a permeability enhancer, transiently increasing intestinal permeability and enhancing the absorption of paracellular markers. Although it is cytotoxic to eukaryotic cells, its cytotoxicity is significantly lower in polarised epithelia compared to non-polarised cells. The aim of this study was to explore the mechanism of melittin cytotoxicity in gastrointestinal cells and to determine whether cytotoxicity was mediated by a necrotic or an apoptotic pathway. The role of cholesterol in melittin cytotoxicity was also examined. Using four distinct assays for apoptosis, phosphatidylserine translocation, caspase activation, DNA ladder formation and cell cycle analysis, no evidence of apoptotic pathway for cell death was observed with any of these approaches. It can therefore be concluded that cytotoxicity was likely to be mediated by necrosis in gastrointestinal epithelial cells. However, at low concentrations of melittin (<1 microM), BRDU uptake was enhanced, demonstrating proliferative effects of melittin at sub-lethal concentrations. Furthermore, melittin cytotoxicity was further enhanced by depletion of cholesterol, using methyl-beta-cyclodextrin, indicating that cholesterol depleting agents could be contradictory to its potential as an enhancer. Overall, although melittin appears to stimulate necrosis, with careful dosage selection the peptide could be considered for the oral delivery of poorly bioavailable drugs.