Potential Carriers For Oral Delivery Research Articles

Wheat germ agglutinin conjugated chitosan nanoparticles for gemcitabine delivery in MCF-7 cells; synthesis, characterisation and in vitro cytotoxicity studies.

Numerous clinical trials indicated combination regimens containing gemcitabine could extend progression-free survival of breast cancer patients without increasing the incidence of serious adverse effects. Orally administered gemcitabine is being metabolized by enzymes present in intestinal cells rapidly; thereupon, the current study was aimed to preparing, optimizing, and evaluating cytotoxicity of wheat germ agglutinin conjugated gemcitabine-chitosan nanoparticles (WGA-Gem-CNPs) in MCF-7 and HEK293 cells and to determining their cellular uptake by Caco-2 cells. Gem-CNPs were prepared by Ionic Gelation method and optimum formulation was implied for WGA conjugation optimisation. Nanoparticles formation was approved by FTIR and DSC analyses; then particles were characterized by DLS and release profile was prepared. MTT assay was performed in MCF-7 and HEK293. Optimized Gem-CNPs and WGA-Gem-CNPs particle size were estimated as 126.6 ± 21.8 and 144.8 ± 36.1 nm, respectively. WGA conjugation efficacy was calculated as 50.98 ± 2.32 percent and encapsulation efficiency in WGA-Gem-CNPs was 69.44 ± 3.41 percent. Three-hour Caco-2 cellular uptake from Gem-CNPs and WGA-Gem-CNPs were estimated as averagely 3.5 and 4.5 folds higher than free drug, respectively. Gem-CNPs and WGA-Gem-CNPs reduced IC50 in MCF-7 cells by 2 and 2.5 folds, respectively; such decrease for HEK293 cells was as much as 2.4 and 6.3 folds, in same order. Demonstrated significant in vitro uptake of WGA-Gem-CNPs and cytotoxicity might be considered for more studies as a potential carrier for oral delivery of gemcitabine.

Quality by Design-Based Development of Solid Self-Emulsifying Drug Delivery System (SEDDS) as a Potential Carrier for Oral Delivery of Lysozyme.

For many years, researchers have been making efforts to find a manufacturing technique, as well as a drug delivery system, that will allow for oral delivery of biopharmaceuticals to their target site of action without impairing their biological activity. Due to the positive in vivo outcomes of this formulation strategy, self-emulsifying drug delivery systems (SEDDSs) have been intensively studied in the last few years as a way of overcoming the different challenges associated with the oral delivery of macromolecules. The purpose of the present study was to examine the possibility of developing solid SEDDSs as potential carriers for the oral delivery of lysozyme (LYS) using the Quality by Design (QbD) concept. LYS was successfully ion paired with anionic surfactant, sodium dodecyl sulphate (SDS), and this complex was incorporated into a previously developed and optimized liquid SEDDS formulation comprising medium-chain triglycerides, polysorbate 80, and PEG 400. The final formulation of a liquid SEDDS carrying the LYS:SDS complex showed satisfactory in vitro characteristics as well as self-emulsifying properties (droplet size: 13.02 nm, PDI: 0.245, and zeta potential: -4.85 mV). The obtained nanoemulsions were robust to dilution in the different media and highly stable after 7 days, with a minor increase in droplet size (13.84 nm) and constant negative zeta potential (-0.49 mV). An optimized liquid SEDDS loaded with the LYS:SDS complex was further solidified into powders by adsorption onto a chosen solid carrier, followed by direct compression into self-emulsifying tablets. Solid SEDDS formulations also exhibited acceptable in vitro characteristics, while LYS preserved its therapeutic activity in all phases of the development process. On the basis of the results gathered, loading the hydrophobic ion pairs of therapeutic proteins and peptides to solid SEDDS may serve as a potential method for delivering biopharmaceuticals orally.

Characterization and optimization of de-esterified Tragacanth-chitosan nanocomposite as a potential carrier for oral delivery of insulin: In vitro and ex vivo studies.

Oral administration of insulin is one of the most challenging topics within this area, because insulin is degraded in stomach before it enters the bloodstream. In this study, for the first time, a nano-carrier for controlled and targeted oral delivery of insulin was developed using de-esterified Tragacanth and chitosan. The fabricated nanoparticles were synthesized using coacervation technique and their properties were optimized using response surface methodology. The effect of experimental variables on the particle size and loading efficiency was examined. In addition, the interactions between components were analyzed using Fourier transform infrared. The thermal stability of nanoparticles was studied by thermal gravimetric analysis. The insulin loading efficiency was measured and in vitro release profile and ex vivo insulin permeability was determined. Optimized nanoparticles showed spherical shape with a size less than 200 nm and zeta potential of +17 mV. Owing to their nanoscale dimensions and mucoadhesiveness, nanoparticles were synthesized using medium molecular weight of Chitosan. The insulin loading efficacy for the system was 6.4%, released under simulated gastrointestinal conditions in a pH-dependent manner. Based on all of the obtained results, it can be concluded that these nanoparticles can potentially be utilized as a carrier for the oral insulin delivery.

β-cyclodextrin chitosan-based hydrogels with tunable pH-responsive properties for controlled release of acyclovir: design, characterization, safety, and pharmacokinetic evaluation

In this work, series of pH-responsive hydrogels (FMA1–FMA9) were synthesized, characterized, and evaluated as potential carrier for oral delivery of an antiviral drug, acyclovir (ACV). Different proportions of β-cyclodextrin (β-CD), chitosan (CS), methacrylic acid (MAA) and N′ N′-methylenebis-acrylamide (MBA) were used to fabricate hydrogels via free radical polymerization technique. Fourier transform infrared spectroscopy confirmed fabrication of new polymeric network, with successful incorporation of ACV. Scanning electron microscopy (SEM) indicated presence of slightly porous structure. Thermal analysis indicated enhanced thermal stability of polymeric network. Swelling studies were carried out at 37 °C in simulated gastric and intestinal fluids. The drug release data was found best fit to zero-order kinetics. The preliminary investigation of developed hydrogels showed a pH-dependent swelling behavior and drug release pattern. Acute oral toxicity study indicated no significant changes in behavioral, clinical, or histopathological parameters of Wistar rats. Pharmacokinetic study indicated that developed hydrogels caused a significant increase in oral bioavailability of ACV in rabbit plasma as compared to oral suspension when both were administered at a single oral dose of 20 mg kg−1 bodyweight. Hence, developed hydrogel formulation could be used as potential candidate for controlled drug delivery of an antiviral drug acyclovir.

Inclusion complex based on N-acetyl-L-cysteine and arginine modified hydroxypropyl-β-cyclodextrin for oral insulin delivery

Insulin is the most effective drug in the treatment of diabetes mellitus. At present, subcutaneous injection is still the common way for insulin delivery. However, oral delivery is considered as the most preferred way for its high patient compliance and the minimal invasiveness. In this study, a novel N-acetyl-L-cysteine and arginine modified hydroxypropyl-β-cyclodextrin (NAC-HP-β-CD-Arg) was successfully synthesized and characterized. The polymer was used as a carrier for oral delivery of insulin by forming NAC-HP-β-CD-Arg@insulin complex. Enzymatic degradation study indicated that the NAC-HP-β-CD-Arg could protect insulin from enzymolysis. Moreover, the polymer exhibited strong binding ability with mucin. The transportation efficiency of NAC-HP-β-CD-Arg@insulin across the Caco-2 cell monolayer was much greater than free insulin. The in vivo study demonstrated that the orally administered NAC-HP-β-CD-Arg@insulin exhibited an excellent and sustained hypoglycemic effect in diabetic rats. It can be concluded that the NAC-HP-β-CD-Arg is a potential carrier for oral delivery of insulin.

Delivery of polysaccharides from Ophiopogon japonicus (OJPs) using OJPs/chitosan/whey protein co-assembled nanoparticles to treat defective intestinal epithelial tight junction barrier

The polysaccharides from Ophiopogon japonicus (OJPs) were known to have protective effects against diabetes, and cardiovascular and chronic inflammatory diseases. However, OJPs were poorly absorbed after oral administration, resulting in limited efficacy because of the low bioavailability. In this study, OJPs extracted and fractionated from Ophiopogon japonicus were used to prepare OJPs/chitosan (CS)/whey protein (WP) co-assembled nanoparticles. The OJPs/CS/WP nanoparticles showed high biocompatibility and inhibited the cytotoxicity of RAW264.7 cells induced by nickel. With the assistance of CS and WP, the anti-inflammatory and antioxidant activities of OJPs were enhanced because the nanoparticles improved OJPs uptake by RAW264.7 macrophage cells as evidenced by efficient scavenging of DPPH and ABTS free radicals and effective inhibition of NO production and the gene expressions of iNOS, COX2, TNF-α, CCL2, and CXCL2 inflammatory signals. Determining the transepithelial electrical resistance and paracellular permeability of Caco-2 monolayer/macrophage co-cultured system suggested that the OJPs-loaded nanoparticles effectively protected the intestinal epithelial barrier integrity against the damage caused by LPS-stimulated macrophage inflammation and attenuated the defects of intestinal epithelial TJ barrier and permeability. These findings suggest that the OJPs/CS/WP nanoparticles may be potential carriers for oral delivery of OJPs to treat intestinal barrier defects, such as inflammatory bowel disease (IBD).

Surface-modified mucoadhesive microparticles as a controlled release system for oral delivery of insulin

To overcome barriers and improve oral bioavailability of insulin delivery has been a mirage to formulation scientists due to instability of the insulin after oral administration. Microparticle (MP) composed of chitosan and snail mucin was prepared via double emulsion method for oral delivery of insulin. Microparticles were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy and scanning electron microscopy. The encapsulation efficiency (EE) of the insulin-loaded MPs were evaluated. Insulin release behavior was evaluated in acidic and phosphate buffer (pH 1.2 and 7.4) at 37 °C. Bioactivities of insulin-loaded MPs were evaluated in a diabetic animal model after oral administration. The insulin-loaded MPs showed irregular shape with a zeta potential (>29 mV). The encapsulation efficiency and drug loading were >75 and 28 %, respectively. The in vitro release shows >80 % release of insulin over 12 h in a sustained manner. The insulin-MPs significantly reduced blood glucose levels (>50 %) compared to positive control and the effect lasted for over 8 h. This study suggests that insulin-MPs as prepared would be potential carriers for oral delivery of insulin.

Investigation of cationized triblock and diblock poly(ε-caprolactone)-co-poly(ethylene glycol) copolymers for oral delivery of enoxaparin: In vitro approach.

The anionic drugs such as proteins, peptides or polysaccharides are generally administered via invasive route causing patient incompliance and high cost of hospitalization. The development of biomaterials for non-invasive delivery of those drugs has gained much attention, especially for oral delivery. However, they have limitation due to non-biocompatibility and poor drug bioavailability. In this study, the novel poly(ε-caprolactone)-co-poly(ethylene glycol) copolymers grafted with propargyltrimethyl ammonium iodide, a small cationic ligand, were introduced to use as a carrier for oral delivery of enoxaparin, a highly negatively charged drug. The study showed that these cationized copolymers could achieve high enoxaparin entrapment efficiency, protect drug release in an acidic environment and enhance enoxaparin permeability across Caco-2 cells, the intestinal cell model. These characteristics of the cationized copolymers make them a potential candidate for oral delivery of anionic drugs for biomaterial applications.

Comparisons between a self‐microemulsifying system and lipid nanoparticles of oxyresveratrol on the physicochemical properties and Caco‐2 cell permeability

The lipid‐based formulations including an oily self‐microemulsifying drug delivery system (SMEDDS), solid lipid nanoparticles (SLN), and nanostructured lipid carriers (NLC) were developed for the oral delivery of oxyresveratrol (OXYR). Each system was successfully formulated using different optimized compositions and methods. The obtained SMEDDS appeared as a yellow oily liquid, while the SLN and NLC as low viscous suspensions. The physical properties, cytotoxicity, and drug permeability across the Caco‐2 monolayer of the different systems were compared. The non‐aqueous SMEDDS had about a 13‐fold higher drug loading than the lipid nanoparticles. The particle sizes (26.94 ± 0.08 nm) of OXYR‐SMEDDS were significantly smaller than that of the NLC and SLN (p < 0.05). Also, a narrow size distribution of the SMEDDS (PDI, 0.073 ± 0.010) was obtained compared to the lipid nanoparticles (PDI, 0.2–0.3). By using the MTT assay, the OXYR‐SMEDDS showed a fourfold greater toxicity on the Caco‐2 cells than the SLN and NLC containing OXYR. At the non‐toxic concentration of 100 μM of OXYR, the SMEDDS and the lipid nanoparticles had 2.5–3‐fold enhanced permeability and 1.3–1.8‐fold reduced efflux transport compared to the unformulated OXYR (p < 0.05).Practical applications: The improvement of the in vitro oral absorption of the lipid‐based formulations resulted from the increased permeability and inhibited efflux mediated mechanisms. These lipid‐based systems have raised the possibility of the oral OXYR in treating and preventing some importance diseases in future. In addition, these systems could also be used as a potential carrier for oral delivery of other compounds which are substrates for efflux transporters. However, in vivo studies are needed to further investigate oral drug bioavailability. Moreover, for use as a commercial product, it is necessary to improve the storage stability and the toxicity of the oily SMEDDS.The lipid nanoparticles (SLN and NLC) and self‐microemulsifying drug delivery systems (SMEDDS) of oxyresveratrol (OXYR) were produced using different compositions and methods. The appearance and characteristics of the lipid‐based systems were different. However, all of three lipid‐based formulations significantly improved intestinal permeability and reduced efflux transport of OXYR. Therefore, these systems could be used as a potential carrier for oral delivery of OXYR or other compounds which are substrates for efflux transporters.

Polymeric nanoparticles for oral delivery of 5-fluorouracil: Formulation optimization, cytotoxicity assay and pre-clinical pharmacokinetics study

Poly(lactic acid) (PLA) or poly(lactic acid)–poly(ethylene glycol) (PLA–PEG) blend nanoparticles were developed loading 5-fluorouracil (5-FU), an antitumor agent broadly used in therapy. A 23 factorial experimental design was conducted to indicate an optimal formulation and demonstrate the influence of the interactions of components on the mean particle size and drug encapsulation efficiency. Optimized PLA nanoparticles presented 294nm and 51% of 5-FU encapsulation efficiency and PLA–PEG blend nanoparticles presented 283nm and 55% of 5-FU encapsulation efficiency. In vitro release assay demonstrated after 320h about 50% of 5-FU was released from PLA and PLA–PEG blend nanoparticles. Release kinetics of 5-FU from nanoparticles followed second order and the release mechanism calculated by Korsmeyer–Peppas model was diffusion and erosion. In the assessment of cytotoxicity over Hep-2 tumor cells, PLA or PLA–PEG blend nanoparticles presented similar IC50 value than free 5-FU. Pharmacokinetic parameters after oral administration of 5-FU were improved by nanoencapsulation. Bioavailability, Cmax, Tmax, t1/2 and distribution volume were significantly improved, while clearance were decreased. PEG presence in nanoparticles didn't influence physicochemical and biological parameters evaluated. PLA and PLA–PEG nanoparticles can be potential carriers for oral delivery of 5-FU.

Glucan microparticles thickened with thermosensitive gels as potential carriers for oral delivery of insulin.

Although glucan microparticles (GMs) can be efficiently taken up and transported by M cells, their subsequent accumulation in lymphatic tissues of sub-follicle-associated epithelia (FAE) in Peyer's patches might present a barrier to the oral delivery of insulin by GMs into the systemic circulation. The goal of this study is to weigh the potential of GMs as carriers for oral delivery of systemic therapeutics using insulin (INS) as a model drug. INS is encapsulated into the inner cavities of GMs by repeated soaking in INS solution at acidic pH values and switching to an isoelectric pH of 5.6 to precipitate INS. To immobilize INS, a thermosensitive poloxamer 407 (P407) gel is introduced into the interior of GMs. Interiorly thickened GMs show significantly decreased in vitro release and well protected INS stability against enzyme-enriched media, highlighting the importance of thickening with P407 gels. A mild and prolonged hypoglycaemic effect is achieved in both normal and diabetic rats for a duration of at least 20 h with pharmacological bioavailability as high as about 9-10%. Lymphatic transportation of GMs is investigated by labelling with a near-infrared water-quenching fluorescent probe in a conscious mesentery lymphatic duct cannulation rat model following oral administration. GMs appear in lymph within the first 2 h, peak at around 6 h and slow down after 10 h with a cumulative amount of over 8% in 24 h. The high correlation between lymphatic transportation and pharmacological bioavailability implies that GMs are principally absorbed via the lymphatic route. An in vitro study on phagocytosis by macrophages confirms the easy and fast uptake of GMs by J774A.1 cell lines with as many as over 10 particles within the cytoplasm of a single cell. Intracellular pharmacokinetics indicates robustness and persistent residence of GMs within the cells. Little effect on cell viability and tight junctions was observed in Caco-2 cell models. It is concluded that GMs are mainly absorbed via the lymphatic route and show potential as carriers for oral delivery of labile therapeutics, though with limited bioavailability due to the sub-FAE residence barriers.

Proliposomes for oral delivery: progress and challenges.

Proliposomes are phospholipid based drug delivery systems that are finding important applications in the field of pharmaceutics. Proliposomes have been extensively studied as a potential carrier for oral delivery of drugs with poor bioavailability, but the mechanism of absorption and cellular uptake pathways has not yet been clearly understood. An in-depth insight into the physical and biological behavior of proliposomes is necessary for designing an effective delivery system for enhancing the availability of drug at the intended site. Reformulation of sub optimal drugs using proliposomes has given an opportunity to improve the therapeutic indices of various drugs predominantly by altering their uptake mechanism. This work reviews the proliposomal drug delivery field, summarizes the success of proliposomes for the oral delivery of drugs with poor bioavailability; indicating the key issues to be addressed to affirm that proliposomes can effectively work as a drug carrier in clinical settings with a clear understanding of its behavior in biological environment, as they are now an established platform technology with considerable clinical acceptance.

Research Highlights

Research Highlights

Ionotropically cross-linked pH-sensitive IPN hydrogel matrices as potential carriers for intestine-specific oral delivery of protein drugs

Background: The oral delivery of proteins and peptide drugs is considered a major challenge. These types of therapeutics are readily degraded, if taken orally, due to the harsh high acidity of stomach and enzymatic attack in the upper small intestinal tract. Methods: Water-soluble copolymers of sodium acrylate (AAs) grafted onto carboxymethyl cellulose (CMC) were prepared and characterized using Fourier transform spectroscopy, differential scanning calorimetry, and X-ray diffraction. The obtained graft copolymers were then used in a combination with sodium alginate to develop a new series of pH-sensitive interpenetrating polymeric network (IPN) hydrogels through ionotropic gelation with divalent ions (Ca2+). Morphology of the developed hydrogels was investigated using SEM. Swelling characteristics, at distinct compositions, were also studied at 37°C in two consecutive buffer solutions of pH 2.1 and 7.4 (similar to that of gastric and intestinal fluids, respectively). The release profiles of bovine serum albumin, as a model protein, from test IPN hydrogel films were studied in simulated gastric and intestinal fluids. In addition, the drug release process was confirmed by means of SEM. Results: Swelling studies of the developed IPN hydrogels at different pH values confirmed their pH-sensitive nature. The equilibrium swelling extents of the hydrogels were found to be dependent on the grafting yield of CMC/AAs graft copolymer. The IPN hydrogels attained equilibrium swelling percentages in the range 445–740%. In addition, the amount of bovine serum albumin released within 2 hours in pH 2.1 was relatively low (less than 18.1%). This amount increased up to 68% after 8 hours in pH 7.4. Conclusions: From the obtained preliminary data, it seems that the IPN hydrogels developed in this contribution can be tailored to act as good potential carriers for oral delivery of protein drugs. These hydrogels showed a promising protection of protein drugs from the harsh acidity of stomach and, at the same time, they conferred sustained drug release in the intestinal fluid.

Enhanced pH-responsive carrier system based on alginate and chemically modified carboxymethyl chitosan for oral delivery of protein drugs: Preparation and in-vitro assessment

In this investigation a new series of biodegradable pH-responsive hydrogel microspheres were prepared, characterized and in-vitro evaluated as potential carriers for oral delivery of protein drugs. The microspheres are based on ionotropically-crosslinked mixture of sodium alginate and chemically modified carboxymethyl chitosan and coated through polyelectrolyte complexation with chitosan grafted with poly(ethylene glycol). The main objective of the developed microspheres is to survive the harsh acidity of stomach and preferably release peptide and protein drugs in intestine. Both ionotropic gelation and coating process were carried out under mild aqueous conditions, which should be appropriate for retention of biological activity of protein drugs. Swelling studies were carried out for the microspheres at 37 °C in simulated gastric and intestinal fluids. Morphology, size and in-vitro biodegradation of the microspheres were also investigated. A model protein drug was entrapped and the in-vitro drug release profiles were established. The preliminary investigation of the microspheres developed in this study showed a consistent swelling pattern, high entrapment efficiency and promising sustained release profiles of the model protein drug.

The characteristics, biodistribution and bioavailability of a chitosan-based nanoparticulate system for the oral delivery of heparin

Heparin is a potent anticoagulant; however, it is poorly absorbed in the gastrointestinal tract. In this study, we developed a nanoparticle (NP) system shelled with chitosan (CS) for oral delivery of heparin; the NPs were prepared by a simple ionic gelation method without chemically modifying heparin. The drug loading efficiency of NPs was nearly 100% because a significantly excess amount of CS was used for the CS/heparin complex preparation. The internal structure of the prepared NPs was examined by small angle X-ray scattering (SAXS). The obtained SAXS profiles suggest that the NPs are associated with a two-phase system and consist of the CS/heparin complex microdomains surrounded by the CS matrix. The stability of NPs in response to pH had a significant effect on their release of heparin. No significant anticoagulant activity was detected after oral administration of the free form heparin solution in a rat model, while administration of NPs orally was effective in the delivery of heparin into the blood stream; the absolute bioavailability was found to be 20.5%. The biodistribution of the drug carrier, 99mTc-labeled CS, in rats was studied by the single-photon emission computed tomography after oral administration of the radio-labeled NPs. No significant radioactivity was found in the internal organs, indicating a minimal absorption of CS into the systemic circulation. These results suggest that the NPs developed in the study can be employed as a potential carrier for oral delivery of heparin.