Self-assembled Chitosan-Ceramide Nanoparticle for Enhanced Oral Delivery of Paclitaxel

Puspose

We aimed to synthesize novel ceramide-chitosan (CS-CE) conjugate that forms stable polymeric nanoparticle capable of functioning as efficient carriers of hydrophobic drug such as Paclitaxel (PTX) for oral delivery.

Methods

Chitosan (3–5 kDa) was conjugated with ceramide by using a DSC coupling reagent to improve its hydrophobic drug entrapment capacity. The structure of the conjugate was determined by proton (¹H) NMR and FT-IR spectrometry. Size distribution and zeta potential were measured by DLS and PTX content in the cells and plasma was determined by HPLC and LC-MS.

Results

Under suitable conditions, the CS-CE self assembled to form colloidally stable nanoparticles with a mean diameter of ~300 nm. Further, PTX was incorporated into the CS-CE nanoparticle with 96.9% loading efficiency and 12.1% loading capacity via an emulsion-solvent evaporation method. The PTX-loaded CS-CE (PTX-CS-CE) showed sustained release of PTX and a comparable cytotoxic efficacy to that of free PTX on B16F10 melanoma and MCF-7 human breast adenocarcinoma cell lines. The empty nanoparticles showed no toxicity, indicating that the copolymer is safe to use in drug delivery. In addition, higher cellular uptake and slightly better pharmacokinetic parameters were obtained for PTX-CS-CE nanoparticle compared to free PTX.

Conclusion

The polymeric nanoparticle of CS-CE represents a promising nanocarrier of hydrophobic drug for oral delivery.

     

pH-Sensitive Nanoparticles: An Effective Means to Improve the Oral Delivery of HIV-1 Protease Inhibitors in Dogs

Pharmaceutical Research -     

自组装Tween 20-SDS纳米混合胶束提高普罗布考口服吸收的研究

利用Tween-20与十二烷基硫酸钠的两亲性结构,与普罗布考混合,通过自组装技术制备了具有核-壳结构的纳米混合胶束,其中药物浓度可达到20 mg/ml.所得制品平均粒径为(44.6±1.6) nm,多分散系数为0.179±0.058,且用不同pH介质稀释后粒径未发生显著变化.采用共聚焦显微成像技术观察表明,制品能影响Caco-2细胞骨架蛋白,增强细胞膜流动性.建立了UPLC-UV法测定生物样品中普罗布考的浓度.Caco-2细胞单层模型的细胞摄取试验和大鼠体内药动学研究均表明,本品可显著提高普罗布考的口服吸收.     

Simvastatin Solid Lipid Nanoparticles for Oral Delivery: Formulation Development and In vivo Evaluation

Solid lipid nanoparticles have been increasingly utilised for improving oral bioavailability of drugs. Simvastatin is biopharmaceutical class 2 drug with poor oral bioavailability of 5%. In the present study, simvastatin solid lipid nanoparticles were successfully prepared by hot melt emulsification process and optimised with respect to surfactant and lipid concentration, and drug loading. The nanoparticles were characterised for entrapment efficiency, particle size, morphology, crystallinity and thermal behavior. Optimised formulations prepared from solid lipids glyceryl behenate and glyceryl palmitostearate containing Tween 80 as surfactant exhibited satisfactory entrapment efficiencies above 96% and mean particle size below 200 nm. The electron micrographs indicated that lipid nanocarriers were almost spherical in appearance. X-ray diffraction and differential calorimetric studies proved that the drug was amorphised in the lipid matrix and did not crystallise out. To improve the physical as well as chemical stability of formulations, dry adsorbed nanoparticles were prepared by evaporative drying method using a carrier. The adsorbed nanoparticles demonstrated good flow properties and satisfactory reconstitution properties. Pharmacodynamic studies of simvastatin solid lipid nanoparticles revealed improved reduction in total cholesterol values as compared to pure drug powder indicating improved bioavailability.     

A Novel Approach to the Oral Delivery of Micro- or Nanoparticles

A novel oral multiple-unit dosage form which overcame many of the problems commonly observed during the compression of microparticles into tablets was developed in this study. Micro- or nano-particles were entrapped in beads formed by ionotropic gelation of the charged polysaccharide, chitosan or sodium alginate, in solutions of the counterion, tripolyphosphate (TPP) or calcium chloride (CaCl₂), respectively. The described technique did not change the physical properties of the microparticles, and it allowed a high microparticle loading (up to 98%). The ionic character of the polymers allowed pH-dependent release of the microparticles. Chitosan beads disintegrated and released the microparticles in 0.1 N HC1, while calcium alginate beads stayed intact in 0.1 N HC1 but rapidly disintegrated in simulated intestinal fluids. Coating the calcium alginate beads with cellulose acetate phthalate resulted in an enteric drug delivery system. Scanning electron microscopy and dissolution and disintegration tests were used to characterize the microparticle-containing beads. The disintegration time of the beads was studied as a function of the solution viscosity of the polysaccharide, gelation time, counterion concentration, and method of drying.     

Bicontinuous Cubic Liquid Crystalline Nanoparticles for Oral Delivery of Doxorubicin: Implications on Bioavailability,Therapeutic Efficacy,and Cardiotoxicity

Purpose

The present study explores the potential of bicontinous cubic liquid crystalline nanoparticles (LCNPs) for improving therapeutic potential of doxorubicin.

Methods

Phytantriol based Dox-LCNPs were prepared using hydrotrope method, optimized for various formulation components, process variables and lyophilized. Structural elucidation of the reconstituted formulation was performed using HR-TEM and SAXS analysis. The developed formulation was subjected to exhaustive cell culture experiments for delivery potential (Caco-2 cells) and efficacy (MCF-7 cells). Finally, in vivo pharmacokinetics, pharmacodynamic studies in DMBA induced breast cancer model and cardiotoxicity were also evaluated.

Results

The reconstituted formulation exhibited Pn3m type cubic structure, evident by SAXS and posed stability in simulated gastrointestinal fluids and at accelerated stability conditions for 6 months. Dox-LCNPs revealed significantly higher cell cytotoxicity (16.23-fold) against MCF-7 cell lines as compared to free drug owing to its preferential localization in the vicinity of nucleus. Furthermore, Caco-2 cell experiments revealed formation of reversible “virtual pathways” in the cell membrane for Dox-LCNPs and hence posed significantly higher relative oral bioavailability (17.74-fold). Subsequently, Single dose of Dox-LCNPs (per oral) led to significant reduction in % tumor burden (~42%) as compared that of ~31% observed in case of Adriamycin® (i.v.) when evaluated in DMBA induced breast cancer model. Moreover, Dox induced cardiotoxicity was also found to be significantly lower in case of Dox-LCNPs as compared to clinical formulations (Adriamycin® and Lipodox®).

Conclusion

Incorporation of Dox in the novel LCNPs demonstrated improved antitumor efficacy and safety profile and can be a viable option for oral chemotherapy.     

Nanoparticles for Local Drug Delivery to the Oral Mucosa: Proof of Principle Studies

Purpose  

To determine if solid lipid nanoparticles represent a viable strategy for local delivery of poorly water soluble and unstable chemopreventive compounds to human oral tissues.     

Synthesis,Characterization, and In vitro Studies of PLGA–PEG Nanoparticles for Oral Insulin Delivery

Therapeutic proteins and peptides are corresponding to a major area of research in biotechnology companies and current pharmaceutical. Because of their natural instability, the enormous majority of these drugs require parentéral administration. Oral insulin delivery would be a highly attractive alternative process of administration, though it continues to be a mysterious target due to the enzymatic digestion of insulin and low levels of absorption from the gastrointestinal region. Hydrogel polymers can be considered as potential carriers for oral insulin delivery. In particular, a pH responsive hydrogel composed of PLGA–PEG has shown the ability to protect insulin from enzymes in the gastric environment and release in small intestines. However, this material has not shown similar potential for oral protein delivery of further model drugs. To date, the unique interaction between PLGA–PEG and insulin, as a potential drug for oral delivery, is not completely understood. The focus of this research is synthetization and characterization of hydrogels PLGA–PEG insulin nanoparticles and also pH sensitivity of insulin nanoparticles was investigated.     

Oral Apomorphine Delivery from Solid Lipid Nanoparticles with Different Monostearate Emulsifiers: Pharmacokinetic and Behavioral Evaluations

Apomorphine, a dopamine receptor agonist for treating Parkinson's disease, has very poor oral bioavailability (< 2%) due to the first-pass effect. The aim of this work was to investigate whether the oral bioavailability and brain regional distribution of apomorphine could be improved by utilizing solid lipid nanoparticles (SLNs). Glyceryl monostearate (GMS) and polyethylene glycol monostearate (PMS) were individually incorporated into SLNs as emulsifiers. It was found that variations in the emulsifiers had profound effects on the physicochemical characteristics. Mean diameters of the GMS and PMS systems were 155 and 63 nm, respectively. More than 90% of the apomorphine was entrapped in the SLNs. The interfacial film was the likely location for most of apomorphine molecules. The PMS system, when incubated in simulated intestinal medium, was found to be more stable in terms of particle size and encapsulation efficiency than the GMS system. Using the GMS and PMS systems to orally administer apomorphine (26 mg/kg) equally enhanced the bioavailability in rats. SLNs showed 12- to 13-fold higher bioavailability than the reference solution. The drug distribution in the striatum, the predominant site of therapeutic action, also increased when using the SLNs. The anti-Parkinsonian activity of apomorphine was evaluated in rats with 6-hydroxydopamine-induced lesions, a model of Parkinson's disease. The contralateral rotation behavior was examined after oral apomorphine delivery. The total number of rotations increased from 20 to 94 and from 20 to 115 when the drug was administered from SLNs containing GMS and PMS, respectively. The experimental results suggest that SLNs may offer a promising strategy for apomorphine delivery via oral ingestion.     

Toxicity Studies of Poly(Anhydride) Nanoparticles as Carriers for Oral Drug Delivery

Purpose

To evaluate the acute and subacute toxicity of poly(anhydride) nanoparticles as carriers for oral drug/antigen delivery.

Methods

Three types of poly(anhydride) nanoparticles were assayed: conventional (NP), nanoparticles containing 2-hydroxypropyl-β-cyclodextrin (NP-HPCD) and nanoparticles coated with poly(ethylene glycol) 6000 (PEG-NP). Nanoparticles were prepared by a desolvation method and characterized in terms of size, zeta potential and morphology. For in vivo oral studies, acute and sub-acute toxicity studies were performed in rats in accordance to the OECD 425 and 407 guidelines respectively. Finally, biodistribution studies were carried out after radiolabelling nanoparticles with ^99mtechnetium.

Results

Nanoparticle formulations displayed a homogeneous size of about 180 nm and a negative zeta potential. The LD₅₀ for all the nanoparticles tested was established to be higher than 2000 mg/kg bw. In the sub-chronic oral toxicity studies at two different doses (30 and 300 mg/kg bw), no evident signs of toxicity were found. Lastly, biodistribution studies demonstrated that these carriers remained in the gut with no evidences of particle translocation or distribution to other organs.

Conclusions

Poly(anhydride) nanoparticles (either conventional or modified with HPCD or PEG6000) showed no toxic effects, indicating that these carriers might be a safe strategy for oral delivery of therapeutics.     

Fabrication of All-Trans Retinoic Acid loaded Chitosan/Tripolyphosphate Lipid Hybrid Nanoparticles as a Novel Oral Delivery Approach for Management of Diabetic Nephropathy in Rats

The present study aims to formulate all-trans retinoic acid (ATRA) loaded chitosan/tripolyphosphate lipid hybrid nanoparticles (CTLHNs) for enhancing its solubility and oral delivery. This is to improve ATRA therapeutic effect on diabetic nephropathy (DN). CTLHNs were prepared by o/w homogenization, employing stearic acid, to form lipid nanoparticles coated with chitosan that is stabilized against acidic pH via sodium tripolyphosphate crosslinking. Chitosan coated (F7) and naked lipid nanoparticles (F6) were also prepared for comparison with CTLHNs. In vitro characterization for the prepared formulations was performed comprising entrapment efficiency, particle size, zeta potential, transmission electron microscopy, FT-IR spectroscopy and x-ray diffraction. Stability of chitosan coat in GI fluid revealed that CTLHNs were more stable than F7. In vitro release indicated an enhanced release of ATRA from the developed formulations. In vitro mucoadhesion study proved a notable mucoadhesive property for CTLHNs. In DN rat model, serum levels of creatinine and urea were elevated, over expression of tumor necrosis factor alpha (TNF-α), granulocyte macrophage colony-stimulating factor (GM-CSF), vascular endothelial growth factor (VEGF) and intercellular adhesion molecule-1 (ICAM-1) were observed. In addition, adenosine monophosphate activated protein kinase (AMPK) and liver kinase B1 (LKB1) expressions were decreased in DN rats. Treatment with free ATRA and the selected formulations led to a significant amelioration of DN by reducing of creatinine, urea, TNF-α, ICAM-1, GM-CSF, VEGF levels as well as elevating AMPK and LKB1 levels. The order of activity was: CTLHNs > F7 > F6 > free ATRA, as proved by histopathological examination.     

Beta-casein Nanoparticles as an Oral Delivery System for Chemotherapeutic Drugs: Impact of Drug Structure and Properties on Co-assembly

Purpose  

To develop a novel oral drug delivery system comprising a hydrophobic chemotherapeutic drug entrapped within beta casein (β–CN), a major milk protein, which self-associates into micelles in aqueous solutions. The efficient gastric digestibility of β–CN suggests possible targeting to gastric cancers.     

Magnetized Aerosols Comprising Superparamagnetic Iron Oxide Nanoparticles Improve Targeted Drug and Gene Delivery to the Lung

Purpose

Targeted delivery of aerosols could not only improve efficacy of inhaled drugs but also reduce side effects resulting from their accumulation in healthy tissue. Here we investigated the impact of magnetized aerosols on model drug accumulation and transgene expression in magnetically targeted lung regions of unanesthetized mice.

Methods

Solutions containing superparamagnetic iron oxide nanoparticles (SPIONs) and model drugs (fluorescein or complexed plasmid DNA) were nebulized to unanesthetized mice under the influence of an external magnetic gradient directed to the lungs. Drug accumulation and transgene expression was subsequently measured at different time points.

Results

We could demonstrate 2?C3 fold higher accumulation of the model drug fluorescein and specific transgene expression in lung regions of mice which had been exposed to an external magnetic gradient during nebulization compared to the control mice without any exposure to magnetic gradient.

Conclusions

Magnetized aerosols present themselves as an efficient approach for targeted pulmonary delivery of drugs and gene therapeutic agents in order to treat localized diseases of the deeper airways.     

Protein and Peptide Drug Delivery: Oral Approaches

Till recent, injections remained the most common means for administering therapeutic proteins and peptides because of their poor oral bioavailability. However, oral route would be preferred to any other route because of its high levels of patient acceptance and long term compliance, which increases the therapeutic value of the drug. Designing and formulating a polypeptide drug delivery through the gastro intestinal tract has been a persistent challenge because of their unfavorable physicochemical properties, which includes enzymatic degradation, poor membrane permeability and large molecular size. The main challenge is to improve the oral bioavailability from less than 1% to at least 30-50%. Consequently, efforts have intensified over the past few decades, where every oral dosage form used for the conventional small molecule drugs has been used to explore oral protein and peptide delivery. Various strategies currently under investigation include chemical modification, formulation vehicles and use of enzyme inhibitors, absorption enhancers and mucoadhesive polymers. This review summarizes different pharmaceutical approaches which overcome various physiological barriers that help to improve oral bioavailability that ultimately achieve formulation goals for oral delivery.     

Mucoadhesive DL-Lactide/Glycolide Copolymer Nanospheres Coated with Chitosan to Improve Oral Delivery of Elcatonin

The purpose of this work was to develop a novel mucoadhesive DL-lactide/glycolide copolymer (PLGA) nanosphere system to improve peptide absorption and prolong the physiological activity following oral administration. The desired PLGA nanospheres with elcatonin were prepared by the emulsion solvent diffusion method to coat the surface of the resultant nanospheres with a mucoadhesive polymer such as chitosan, poly(acrylic acid), and sodium alginate. Their mucoadhesive properties were evaluated by measuring the nanospheres adsorbed to a rat everted intestinal sac (in vitro). The chitosan-coated nanospheres showed higher mucoadhesion to the everted intestinal tract in saline than the other polymer-coated nanospheres. There was no mucoadhesion site-specificity of the chitosan-coated nanospheres between duodenal, jejunal, and ileal sacs. The payload of drug in the chitosan-coated nanospheres was successfully increased by using the solvent diffusion method in oil. The pattern of drug release of the resultant nanospheres did not differ markedly from that of uncoated nanospheres. The chitosan-coated nanospheres with elcatonin were administered intragastrically to fasted Wistar rats. The chitosan-coated nanosphere reduced significantly the blood calcium level compared with elcatonin solution and uncoated nanospheres, and the reduced calcium level was sustained for a period of 48 hr. Even under nonfasting conditions, the mucoadhesion of chitosan-coated nanospheres was unaltered and the reduction in blood Ca levels was maintained satisfactorily.     

Transforming Lipid-Based Oral Drug Delivery Systems into Solid Dosage Forms: An Overview of Solid Carriers, Physicochemical Properties, and Biopharmaceutical Performance

The diversity of lipid excipients available commercially has enabled versatile formulation design of lipid-based drug delivery systems for enhancing the oral absorption of poorly water-soluble drugs, such as emulsions, microemulsions, micelles, liposomes, niosomes and various self-emulsifying systems. The transformation of liquid lipid-based systems into solid dosage forms has been investigated for several decades, and has recently become a core subject of pharmaceutical research as solidification is regarded as viable means for stabilising lipid colloidal systems while eliminating stringent processing requirements associated with liquid systems. This review describes the types of pharmaceutical grade excipients (silica nanoparticle/microparticle, polysaccharide, polymer and protein-based materials) used as solid carriers and the current state of knowledge on the liquid-to-solid conversion approaches. Details are primarily focused on the solid-state physicochemical properties and redispersion capacity of various dry lipid-based formulations, and how these relate to the in vitro drug release and solubilisation, lipid carrier digestion and cell permeation performances. Numerous in vivo proof-of-concept studies are presented to highlight the viability of these dry lipid-based formulations. This review is significant in directing future research work in fostering translation of dry lipid-based formulations into clinical applications.     

Nanostructured Lipid Carriers for Oral Delivery of a Corticosteroid: Role of Formulation on Biopharmaceutical Performance

Corticosteroids are potent anti-inflammatory and immunosuppressive drugs widely used world-wide for treatment of diverse conditions. However, their use is restricted by their poor bioavailability and high risk-benefit ratio. Therefore, the aim of this study was to develop nanostructred lipid carriers (NLC) of prednisolone acetate (PA) to improve the drug's therapeutic outcome by altering its pharmacokinetic profile and/or allow preferential targeting to inflammatory tissues. PA-loaded NLCs were formulated by solvent injection method using Compritol (solid lipid), oleic acid (liquid lipid) and Tween 80 or Pluronic F68 (surfactant). Formulation conditions, such as liquid lipid concentration, total lipids, drug:lipid ratio and surfactant type were optimized based on particle size (PS), polydispersity index (PDI), and encapsulation efficiency (EE%) results. Optimized formulation was further characterized for its surface morphology, thermal properties, storage stability and anti-inflammatory activity in an animal acute inflammation model. Selected NLCs displayed PS of 170.7 nm, EE% of 67.4%, sustained release over 72 h and good stability for 30 days at refrigeration conditions. PA NLCs displayed superior anti-inflammatory activity of 83.9 ± 4.46% compared to PA suspension (40.5 ± 7.03%) and drug-free NLCs (54.7 ± 6.12%). The current work delineates the potential of NLCs for distinctly improved biopharmaceutical performance of PA.     

Novel Cyclopeptides for the Design of MMP Directed Delivery Devices: A Novel Smart Delivery Paradigm

Purpose  

Matrix metalloproteinases (MMP) are a family of proteolytic enzymes, the expression of which in a key step of tumor progression has been better defined recently. The studies highlighted the ongoing need for very specific inhibitors, substrates or release devices designed to be selective for one or at least very few MMPs.     

Fabrication and Evaluation of Curcumin-loaded Nanoparticles Based on Solid Lipid as a New Type of Colloidal Drug Delivery System

Curcumin has very broad spectrum of biological activities; however, photodegradation, short half-life and low bioavailability have limited its clinical application. Curcumin-loaded solid lipid nanoparticles were studied to overcome these problems. The aim of this study was to optimize the best formulation on curcumin-loaded solid lipid nanoparticles. Emulsion-evaporation and low temperature-solidification technique was applied with monostearin as lipid carriers. The single factor analysis and orthogonal design were used to optimize formulation and various parameters were investigate. By the optimisation of a single factor analysis and orthogonal test, the particles size, polydispersity index, zeta potential, encapsulation efficiency and drug loading capacity of the optimised formulation were 99.99 nm, 0.158, −19.9 mV, 97.86%, and 4.35%, respectively. The differential scanning calorimetry and X-ray diffraction analysis results demonstrated new structure was formed in nanoparticles. The release kinetics in vitro demonstrated curcumin-loaded solid lipid nanoparticles can control drug release. These studies confirmed that curcumin-loaded solid lipid nanoparticles could be prepared successfully with high drug entrapment efficiency and loading capacity. Curcumin-loaded solid lipid nanoparticles may be a promising drug delivery system to control drug release and improve bioavailability.     

An In-vitro and In-vivo Correlative Approach to the Evaluation of Ester Prodrugs to Improve Oral Delivery of Propranolol

Abstract— A series of ester prodrugs of propranolol was synthesized by incorporating substituents (straight alkyl, branched alkyl, acyloxyalkyl and cycloalkyl) into the β-hydroxy function of propranolol with the aim of protecting the drug against first-pass metabolism following oral administration. The in-vitro hydrolysis rates of the prodrugs were, in increasing order, liver homogenate ? plasma > buffers. The pH-rate profile of the prodrugs showed maximum stability around pH 4·0; the hydrolysis rates were drastically increased over pH 6·8. QSAR analysis revealed hydrophobic (π) and electronic (σ) effects of the substituents play the main roles for prodrug hydrolysis in buffers and plasma, while hydrolysis in liver homogenate could not be well explained by any of these parameters. Four prodrugs (O-acetyl-, O-butyryl-, O-isovaleryl- and O-cyclopropanoyl-propranolol) were selected for oral administration based on their hydrolysis in-vitro. Following oral administration of prodrugs to beagle dogs the absolute bioavailabilities (F) of propranolol were about 2–4-fold that after an equivalent dose of propranolol. The prodrugs were rapidly absorbed and regenerated propranolol to attain peak plasma levels at 0–0·5 h. Intact prodrug levels were also observed, which varied depending on their respective stabilities in in-vitro media. A linear relationship between F of propranolol and log P was obtained. F further appeared to be parabolically dependent on the observed hydrolysis rates of prodrugs in liver homogenate suggesting optimal design manipulation. The overall in-vitro and in-vivo results showed that lipophilic prodrugs having higher chemical and enzymatic stability in buffers and plasma, but susceptible to hydrolysis in the liver homogenate, to be the most promising prodrugs for improving oral bioavailability of propranolol.