In vitro release of bovine serum albumin from alginate/HPMC hydrogel beads

Anionic species from multivalent metal salts are differentially retained during aqueous ionic gelation of sodium alginate and could fine-tune the hydrogel properties

The role of anionic counterions of divalent metal salts in alginate gelation and hydrogel properties has been thoroughly investigated. Three anions were selected from the Hofmeister series, namely sulphate, acetate and chloride, paired in all permutations and combinations with divalent metal cations like calcium, zinc and copper. Spectroscopic analysis revealed the presence of anions and their interaction with the respective metal cations in the hydrogel. The data showed that the gelation time and other hydrogel properties were largely controlled by cations. However, subtle yet significant variations in viscoelasticity, water uptake, drug release and cytocompatibility properties were anion dependent in each cationic group. Computational modelling based study showed that metal-anion-alginate configurations were energetically more stable than the metal-alginate models. The in vitro and in silico studies concluded that acetate anions preceded chlorides in the drug release, swelling and cytocompatibility fronts, followed by sulphate anions in each cationic group. Overall, the data confirmed that anions are an integral part of the metal-alginate complex. Furthermore, anions offer a novel option to further fine-tune the properties of alginate hydrogels for myriads of applications. In addition, full exploration of this novel avenue would enhance the usability of alginate polymers in the pharmaceutical, environmental, biomedical and food industries.

Comparison of the Adsorption and Desorption Dynamics of Biological Molecules on Alginate Hydrogel Microcapsules-The Case of Sugars, Polyphenols, and Proteins

The aim of this work was to analyze and compare the adsorption and desorption processes of carbohydrates (glucose as a model molecule), polyphenols (gallic acid as a model molecule), and proteins (bovine serum albumin, BSA as a model molecule) on alginate microcapsules. The adsorption and desorption processes were described by mathematical models (pseudo-first-order, pseudo-second-order, and Weber-Morris intraparticle diffusion model for adsorption, and first-order, Korsmeyer-Peppas, and the Higuchi model for desorption) in order to determine the dominant mechanisms responsible for both processes. By comparing the values of adsorption rate (k2) and initial adsorption rate (h0) based on the pseudo-first-order model, the lowest values were recorded for BSA (k1 = 0.124 ± 0.030 min-1), followed by glucose (k1 = 0.203 ± 0.041 min-1), while the model-obtained values for gallic acid were not considered significant at p < 0.05. For glucose and gallic acid, the limiting step of the adsorption process is the chemical sorption of substances, and the rate of adsorption does not depend on the adsorbate concentration, but depends on the capacity of the hydrogel adsorbent. Based on the desorption rates determined by the Korsmeyer-Peppas model (k), the highest values were recorded for gallic acid (k = 3.66236 ± 0.20776 g beads/mg gallic acid per min), followed by glucose (k = 2.55760 ± 0.16960 g beads/mg glucose per min) and BSA (k = 0.78881 ± 0.11872 g beads/mg BSA per min). The desorption process from alginate hydrogel microcapsules is characterized by the pseudo Fickian diffusion mechanism.

Effect of intragranular/extragranular tara gum on sustained gastrointestinal drug delivery from semi-IPN hydrogel matrices

The present research was undertaken to develop semi-IPN hydrogel matrix tablets of tara gum (TG) and carboxymethyl TG (CMTG) for sustained gastrointestinal delivery of highly water soluble tramadol hydrochloride (TH). The matrix tablets were developed by a hybrid process of wet granulation and direct compression technique. Carboxymethyl TG was crosslinked with dual cross-linking ions (Al3+/Ca2+). The uncross-linked component of the semi-IPN matrix was either incorporated within the granules (intragranular TG) or incorporated outside the granules (extragranular TG), prior to compression. The effect of intragranular/extragranular TG on the swelling, erosion and TH release characteristics from the semi-IPN hydrogel matrix tablets was investigated. The key finding of the investigation indicated that intragranular TG expedited TH release, while extragranular TG sustained TH release. Moreover, the effect of cross-linking ions on viscosity, rigidity, cross-link density and TH release behavior from hydrogel matrices was investigated. In-vivo pharmacokinetic performance of the optimized extragranular TG semi-IPN hydrogel matrix (F15) indicated sustained TH release in gastrointestinal milieu.

Encapsulation of Rosemary Extracts using High Voltage Electrical Discharge in Calcium Alginate/Zein/Hydroxypropyl Methylcellulose Microparticles

The increased demand for functional food with added health benefits is directing industrial procedures toward more sustainable production of naturally added bioactive compounds. The objective of this research was to investigate the potential of bioactive compounds from rosemary extract obtained using high-voltage electrical discharge as a green extraction method, for microencapsulation as a protective method for future application in functional food. Four types of microparticles were made via the ionic gelation method using alginate (Alg), zein (Z), and hydroxypropyl methylcellulose (HPMC) biopolymers and were analyzed considering the physicochemical properties. The diameter of dry microparticles ranged from 651.29 to 1087.37 μm. The shape and morphology analysis of microparticles showed that the obtained microparticles were quite spherical with a granular surface. The high encapsulation efficiency was obtained with a loading capacity of polyphenols up to 11.31 ± 1.47 mg GAE/g (Alg/Z microparticles). The microencapsulation method showed protective effects for rosemary polyphenols against pH changes during digestion. Specifically, the addition of both zein and HPMC to calcium-alginate resulted in microparticles with a prolonged release for better availability of polyphenols in the intestine. This research background indicates that the release of rosemary extract is highly dependent on the initial biopolymer composition with high potential for further functional food applications.

Fabrication of Polymeric Hydrogels Containing Esomeprazole for Oral Delivery: In Vitro and In Vivo Pharmacokinetic Characterization

Hydrogel is one of the most interesting and excellent candidates for oral drug delivery. The current study focuses on formulation development of hydrogels for controlled oral delivery of esomeprazole. The hydrogels were prepared by solution casting method by dissolving polymers in Polyvinyl alcohol (PVA) solution. Calcium alginate, Hydroxyl propyl methylcellulose (HPMC), acrylic acid and chondroitin sulfate were used in the preparation of hydrogels. Fourier transform infrared (FTIR) analysis showed no incompatibilities between drug and excipients used in the preparation of formulations. The hydrogels were characterized for size and surface morphology. Drug encapsulation efficiency was measured by Ultraviolet-visible (UV-VIS) spectroscopy. In vitro release studies were carried out using dissolution apparatus. The formulated hydrogels were then compared with the marketed product in vivo using rabbits. The result indicates that prepared hydrogels have a uniform size with a porous surface. The esomeprazole encapsulation efficiency of the prepared hydrogels was found to be 83.1 ± 2.16%. The esomeprazole-loaded hydrogel formulations showed optimum and Pharmacopeial acceptable range swelling behavior. The release of esomeprazole is controlled for 24 h (85.43 ± 0.32% in 24 h). The swelling and release of drug results make the prepared hydrogels a potential candidate for the controlled delivery of esomeprazole. The release of the drug from prepared hydrogel followed the super case transport-2 mechanism. The in vivo studies showed that prepared hydrogel formulations showed controlled and prolonged release of esomeprazole as compared to drug solution and marketed product. The formulations were kept for stability studies; there was no significant change observed in physical parameters, i.e., (appearance, color change and grittiness) at 40 °C ± 2/75% ± RH. There was a negligible difference in the drug content observed after the stability study suggested that all the formulations are stable under the given conditions for 60 days. The current study provides a valuable perspective on the controlled release profile of Hydroxyl propyl methylcellulose (HPMC) and calcium alginate-based esomeprazole hydrogels.

Natural Polymer-Based Graphene Oxide Bio-nanocomposite Hydrogel Beads: Superstructures with Advanced Potentials for Drug Delivery

The current study sought to create graphene oxide-based superstructures for gastrointestinal drug delivery. Graphene oxide has a large surface area that can be used to load anti-cancer drugs via non-covalent methods such as surface adsorption and hydrogen bonding. To enhance the bio-applicability of graphene oxide, nano-hybrids were synthesized by encapsulating the graphene oxide into calcium alginate hydrogel beads through the dripping-extrusion technique. These newly developed bio-nanocomposite hybrid hydrogel beads were evaluated in structural analysis, swelling study, drug release parameters, haemolytic assay, and antibacterial activity. Doxorubicin served as a model drug. The drug entrapment efficiency was determined by UV-spectroscopy analysis and was found to be high at ⁓89% in graphene oxide hybrid hydrogel beads. These fabricated hydrogel beads ensure the drug release from a hybrid polymeric matrix in a more controlled and sustained pattern avoiding the problems associated with a non-hybrid polymeric system. The drug release study of 12 h shows about 83% release at pH 6.8. In vitro drug release kinetics proved that drug release was a Fickian mechanism. The cytotoxic effect of graphene oxide hybrid alginate beads was also determined by evaluating the morphology of bacterial cells and red blood cells after incubation. Additionally, it was determined that the sequential encapsulation of graphene oxide in alginate hydrogel beads hides its uneven edges and lessens the graphene oxide's negative impacts. Also, the antibacterial study and biocompatibility of fabricated hydrogel beads made them potential candidates for gastrointestinal delivery.

Synthesis and Evaluation of Finasteride-Loaded HPMC-Based Nanogels for Transdermal Delivery: A Versatile Nanoscopic Platform

Herein, we report nanogels comprising diverse feed ratio of polymer hydroxypropyl methylcellulose (HPMC), monomer acrylic acid (AA), and cross-linker methylene bisacrylamide (MBA) fabricated for transdermal delivery of finasteride (FIN). Free radical solution polymerization method with subsequent condensation was employed for the synthesis using ammonium per sulfate (APS) and sodium hydrogen sulfite (SHS) as initiators. Carbopol-940 gel (CG) was formulated as assisting platform to deliver FIN nanogels transdermally. Developed formulations were evaluated by several in vitro, ex vivo, and in vivo parameters such as particle size and charge distribution analysis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffractogram (XRD), rheological testing, in vitro swelling and drug release, and ex vivo skin permeation, irritation, and toxicity assessment. The results endorsed the nanogel formation (117.3 ± 29.113 nm), and the impact of synthesizing method was signified by high yield of nanogels (≈91%). Efficient response for in vitro swelling and FIN release was revealed at pH 5.5 and 7.4. Skin irritation and toxicity assessment ensured the biocompatibility of prepared nanocomposites. On the basis of the results obtained, it can be concluded that the developed nanogels were stable with excellent drug permeation profile across skin.

Recent Trends in Assessment of Cellulose Derivatives in Designing Novel and Nanoparticulate-Based Drug Delivery Systems for Improvement of Oral Health

Natural polymers are revolutionizing current pharmaceutical dosage forms design as excipient and gained huge importance because of significant influence in formulation development and drug delivery. Oral health refers to the health of the teeth, gums, and the entire oral-facial system that allows us to smile, speak, and chew. Since years, biopolymers stand out due to their biocompatibility, biodegradability, low toxicity, and stability. Polysaccharides such as cellulose and their derivatives possess properties like novel mechanical robustness and hydrophilicity that can be easily fabricated into controlled-release dosage forms. Cellulose attracts the dosage design attention because of constant drug release rate from the precursor nanoparticles. This review discusses the origin, extraction, preparation of cellulose derivatives and their use in formulation development of nanoparticles having multidisciplinary applications as pharmaceutical excipient and in drug delivery, as bacterial and plant cellulose have great potential for application in the biomedical area, including dentistry, protein and peptide delivery, colorectal cancer treatment, and in 3D printable dosage forms.

Oral delivery of infliximab using nano-in-microparticles for the treatment of inflammatory bowel disease

The anti-tumor necrosis factor-α (anti-TNF-α) blocker, has shown great efficacy for the treatment of inflammatory bowel disease (IBD). However, systemic exposure to it can cause considerable safety problems due to reduced suppression of the systemic immune response and loss of response to the production of anti-drug antibodies. Thus, we try to devise a targeted vehicle system for oral administration of anti-TNF-α antibodies for the treatment of IBD. In the present study, we developed an oral Infliximab (IFX) loaded nano-in-microparticles, based on chitosan (CS)/carboxymethyl chitosan (CMC) and alginate (Alg), which could protect IFX from the harsh environment of the gastrointestinal tract and produce targeted drug delivery to the inflamed intestine. In vivo studies demonstrated that the IFX loaded nano-in-micro vehicle can alleviate colitis by ameliorating inflammation and maintaining the intestinal epithelial barrier.

Dual-drug delivery system based on the hydrogels of alginate and sodium carboxymethyl cellulose for colorectal cancer treatment

To improve the efficacy of chemotherapy and relieve the pain associated with colorectal cancer, a dual-drug delivery system (DDDS) is proposed. In this system, methotrexate (MTX) loaded CaCO₃ (CaCO₃/MTX) and aspirin (Asp) are co-entrapped in the hydrogels of alginate (Alg) and sodium carboxymethyl cellulose (CMC) crosslinked with Ca²⁺. The hydrogels can protect the anti-cancer drug of MTX from being absorbed in stomach and small intestine and ensure their efficacy at the target site of colorectum. More importantly, dual pH-responsive drug delivery can be achieved by the DDDS. Because the pH varies at small intestine and colorectum of human body, dual pH-responsive delivery of Asp and MTX can be achieved at the two organs, respectively, in response to ambient pH. These finding are of significant importance for medical science and pharmaceutics.

Fabrication, Evaluation, In Vivo Pharmacokinetic and Toxicological Analysis of pH-Sensitive Eudragit S-100-Coated Hydrogel Beads: a Promising Strategy for Colon Targeting

The aim of present research aims to fabricate a system of enteric coating of hydrogel beads with pH-sensitive polymer, which shows solubility at pH > 7, and explore their potential to target the colon for drug delivery. Hydrogel beads were fabricated through the extrusion-dripping technique followed by ion gelation crosslinking. Moreover, freeze-thaw cycle was implemented for crosslinking of polyvinyl alcohol (PVA)/Ca-alginate blend beads. The oil-in-oil solvent evaporation method was adopted for the Eudragit coating of hydrogel beads using different coat: core ratios (4:1 or 8:1). Coated and uncoated hydrogel beads were evaluated by in vitro physicochemical properties, swelling and drug release behaviours, and in vivo pharmacokinetics, swelling, and toxicity evaluation. Diclofenac sodium was loaded as an experimental drug. Drug entrapment efficiency for the PVA/Ca-alginate beads was calculated as 98%, and for Ca-alginate beads, it came out to a maximum of 74%. Drug release study at various pH suggested that, unlike uncoated hydrogel beads, the coated beads delay the release of diclofenac sodium in low pH of the gastric and intestinal environment, thus targeting the colon for the drug release. It was concluded that Eudragit S-100-coated hydrogel beads could serve as a more promising and reliable way to target the colon for drug delivery.Graphical abstract.

Characteristic Evaluation of Gel Formulation Containing Niosomes of Melatonin or Its Derivative and Mucoadhesive Properties Using ATR-FTIR Spectroscopy

Chitosan or polyvinyl pyrrolidone (PVP) were used in combination with hydroxypropyl methylcellulose (HPMC) and poloxamer 407 (P407) as gelling agents for oral drug delivery. The performance interaction with mucin of chitosan-composed gel (F1) and PVP-composed gel (F2) was compared using attenuated total reflectance-Fourier-transform infrared (ATR-FTIR) spectroscopy at controlled temperatures of 25 and 37 °C for 1 and 5 min. F1 containing niosome-entrapped melatonin or its derivatives was investigated for mucoadhesive interaction on mucosa by ATR-FTIR spectroscopy under the same conditions. The results showed that F1-treated mucin gave a significantly lower amide I/amide II ratio than untreated mucin and F2-treated mucin did within 1 min, suggesting improved rapid affinity between mucin and chitosan. The spectra of mucosa treated with F1 incorporating niosomes of melatonin or its derivatives showed peak shifts at C=O (amide I), N-H (amide II), and carbohydrate regions and an associated decrease in the amide I/amide II ratio and increase in the carbohydrate/amide II ratio. These results indicated electrostatic interaction and hydrogen bonding between chitosan and mucin on the mucosa. In conclusion, the molecular interaction between gels and mucin/mucosa detected at amide I and amide II of proteins and the carbohydrate region could lead to an improved mucoadhesive property of the gel on the mucosa.

Fabrication and Characterization of Diclofenac Sodium Loaded Hydrogels of Sodium Alginate as Sustained Release Carrier

The aim of the current study was to fabricate naturally derived polymer based hydrogels for controlled release of diclofenac sodium (DS) for a long duration of time. In this research work, sodium alginate-co-poly(2-acrylamido-2-methyl propane sulphonic acid) (SA-co-poly(AMPS)) hydrogels were prepared by the free radical polymerization technique, where sodium alginate (SA) and 2-acrylamido-2-methyl propane sulphonic acid (AMPS) were used as the polymer and monomer while ammonium peroxodisulfate (APS) and N,N′-Methylene bisacrylamide (MBA) were used as the initiator and cross-linker, respectively. A swelling study was performed to determine the swelling index of developed hydrogels in both acidic (pH 1.2) and basic (pH 7.4) media and pH-independent swelling was observed due to the presence of AMPS. An in vitro release study was conducted to evaluate the percentage of drug released, and a high release of the drug was found at the higher pH of 7.4. Sol–gel analysis was performed to analyze the crosslinked and uncrosslinked part of the hydrogels, and results showed a rise in gel fraction as the composition of SA, AMPS and MBA increased while the sol fraction decreased and vice versa. This work demonstrated a potential for sustained delivery of diclofenac sodium by employing various concentration of SA, AMPS and MBA.

Development and optimization of Fe3+-crosslinked sodium alginate-methylcellulose semi-interpenetrating polymer network beads for controlled release of ibuprofen

In this study, ionically crosslinked beads of sodium alginate (NaAlg) and methylcellulose (MC) were prepared as semi-interpenetrating polymer networks (semi-IPN) in the size range of 1.97 ± 0.09-1.22 ± 0.13 mm by crosslinking with FeCl₃ and loaded with ibuprofen (IBU), which is a nonsteroidal anti-inflammatory drug. The highest 93.33% entrapment efficiency of IBU was achieved, and the drug release behaviors, mean particle size, and entrapment efficiency of beads were investigated in terms of the polymer composition, a ratio of ibuprofen to polymer, exposure time to crosslinker, and concentration of the crosslinking agent. Semi-IPN formulations prepared were also characterized using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), X-ray Diffraction (X-RD), and scanning electron microscopy (SEM). It was observed that IBU-loaded beads displayed better release performance with an increase amount of NaAlg in the structure. Finally, the optimum IBU release was obtained as 93.9% for beads containing 66.7% (w/w) NaAlg, 33.3% (w/w) MC, IBU/polymer ratio of 1/4, FeCl₃ concentration of 0.1 M, and crosslinking time of 90 min. The in vitro release rate was fitted to five empirical equations, and the diffusion exponent n, which indicated that the release mechanism of IBU from beads followed the Anomalous and Case II transport mechanism.

Preparation and performance characteristics of an environmentally-friendly agglomerant to improve the dry dust removal effect for filter material

The incomplete and uneven dust removal of a pulse filter greatly reduces the dust removal efficiency, which affects the efficiency, service life, and running resistance of dust removers. Therefore, due to improve the pulse cleaning effect, an agglomerant developed by free radical polymerization was added during dust removal. The optimal process conditions were determined by measuring the viscosity, surface tension, and atomization effect of the agglomerant solution. The phases, chemical composition, surface morphology, and morphology of the agglomerant and coal dust were characterized by infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy. Molecular dynamics simulations were used to study the interaction mechanism between the agglomerant and coal dust. Finally, the dust removal performance under water mist conditions and agglomerate solution atomization was tested using a pulse filter. The results showed that a 0.3 % agglomerant solution effectively reduced the surface tension of the solution and displayed good wetting and bonding properties. Compared with water misting, the agglomerant solution subjected to an atomization rate of 2400 m³/h prolonged the filtration period, reduced the filtration resistance, and reduced the dust emission concentration. These results have important theoretical and practical significance for improving the dust removal effect of pulse filters.

Microencapsulation of Tangeretin in a Citrus Pectin Mixture Matrix

The objectives of this research were to microencapsulate tangeretin, and to evaluate the basic characteristics of the microcapsule products. Tangeretin is a polymethoxyflavone (PMF) which has been revealed to possess various health benefits and is abundant in tangerine and other citrus peels. Microencapsulation technology is widely employed in the food and pharmaceutical industries to exploit functional ingredients, cells, and enzymes. Spray drying is a frequently applied microencapsulation method because of its low cost and technical requirements. In this research, tangeretin dissolved at different concentrations in bergamot oil was microencapsulated in a citrus pectin/sodium alginate matrix. The resulting microcapsule powder showed promising physical and structural properties. The retention efficiency of tangeretin was greater at a concentration of 2.0% (98.92%) than at 0.2% (71.05%), probably due to the higher temperature of the emulsion during the homogenizing and spray-drying processes. Encapsulation efficiency was reduced with increased concentration of tangeretin. Our results indicate that tangeretin could be successfully encapsulated within a citrus pectin/sodium alginate matrix using bergamot oil as a carrier.

3D bioprinting spatiotemporally defined patterns of growth factors to tightly control tissue regeneration

Therapeutic growth factor delivery typically requires supraphysiological dosages, which can cause undesirable off-target effects. The aim of this study was to 3D bioprint implants containing spatiotemporally defined patterns of growth factors optimized for coupled angiogenesis and osteogenesis. Using nanoparticle functionalized bioinks, it was possible to print implants with distinct growth factor patterns and release profiles spanning from days to weeks. The extent of angiogenesis in vivo depended on the spatial presentation of vascular endothelial growth factor (VEGF). Higher levels of vessel invasion were observed in implants containing a spatial gradient of VEGF compared to those homogenously loaded with the same total amount of protein. Printed implants containing a gradient of VEGF, coupled with spatially defined BMP-2 localization and release kinetics, accelerated large bone defect healing with little heterotopic bone formation. This demonstrates the potential of growth factor printing, a putative point of care therapy, for tightly controlled tissue regeneration.

Lotus leaf-inspired design of calcium alginate particles with superhigh drug encapsulation efficiency and pH responsive release

Drug delivery systems with high drug encapsulation efficiency and controlled release are of great importance in biomedical fields. Herein, we report an ingenious approach inspired from the lotus leaf possessing the ability of strong repellency to water, which enables the rapid fabrication of drug-loaded calcium alginate (Ca-Alg) particles with high drug encapsulation efficiency and controlled drug delivery. The design is achieved by introducing aqueous droplets containing the mixture of dilute sodium alginate solution, dilute calcium chloride solution, and drug onto the superhydrophobic substrate. Due to water evaporation both the concentration of sodium alginate and calcium chloride within the droplets will gradually increase, and the ionic crosslinking reaction of sodium alginate with Ca²⁺ is further occurred to form the drug-embedded Ca-Alg hydrogel particles. The results indicate that the controllable fabrication of Ca-Alg particles can be easily achieved on the superhydrophobic surface, and the swelling behavior can be tuned by the pH of the buffer solution. Importantly, the drug encapsulation efficiencies are measured to be over 88% and the drug exhibits obvious pH responsive release. Findings from this study are expected to contribute to the rational design of drug delivery systems with high drug encapsulation efficiency and controlled release for pharmaceutic science and tissue engineering.

Optimizing microencapsulation of α-tocopherol with pectin and sodium alginate

α-Tocopherol is a well-known fat-soluble antioxidant and is widely used in the food industry for stabilizing free radicals. Incorporation and stability of it into food is another challenge as directly added α-tocopherol is prone to inactivation by food constituents. This study was aimed at optimizing conditions for encapsulation of α-tocopherol using combination of sodium alginate (0.5, 1.0, 1.5 and 2.0%) as primary wall material and pectin (2.0%) as filler. The optimum conditions were selected on the basis of encapsulation efficiency, shape, size, bulk density, yield and swelling index with syringe method. The encapsulation efficiency of α-tocopherol in microencapsules produced under optimal conditions was 52.91% using sodium alginate 1.5% w/v and pectin 2.0% w/v. α-Tocopherol was encapsulated with encapsulator using standard conditions and was compared with syringe method. The encapsulation efficiency was found more (55.97%) in microencapsules prepared with encapsulator and 52.11% in microencapsules prepared with syringe.

Pharmaceutical Applications of Cellulose Ethers and Cellulose Ether Esters

Cellulose ethers have proven to be highly useful natural-based polymers, finding application in areas including food, personal care products, oil field chemicals, construction, paper, adhesives, and textiles. They have particular value in pharmaceutical applications due to characteristics including high glass transition temperatures, high chemical and photochemical stability, solubility, limited crystallinity, hydrogen bonding capability, and low toxicity. With regard to toxicity, cellulose ethers have essentially no ability to permeate through gastrointestinal enterocytes and many are already in formulations approved by the U.S. Food and Drug Administration. We review pharmaceutical applications of these valuable polymers from a structure-property-function perspective, discussing each important commercial cellulose ether class; carboxymethyl cellulose, methyl cellulose, hydroxypropylcellulose, hydroxypropyl methyl cellulose, and ethyl cellulose, and cellulose ether esters including hydroxypropyl methyl cellulose acetate succinate and carboxymethyl cellulose acetate butyrate. We also summarize their syntheses, basic material properties, and key pharmaceutical applications.

Nanostructured DPA-MPC-DPA triblock copolymer gel for controlled drug release of ketoprofen and spironolactone

OBJECTIVE

Uncontrolled rapid release of drugs can reduce their therapeutic efficacy and cause undesirable toxicity; however, controlled release from reservoir materials helps overcome this issue. The aims of this study were to determine the release profiles of ketoprofen and spironolactone from a pH-responsive self-assembling DPA-MPC-DPA triblock copolymer gel and elucidate underlying physiochemical properties.

METHODS

Drug release profiles from DPA₅₀ -MPC₂₅₀ -DPA₅₀ gel (pH 7.5), over 32 h (37 °C), were determined using UV-Vis spectroscopy. Nanoparticle size was measured by dynamic light scattering (DLS) and critical micelle concentration (CMC) by pyrene fluorescence. Polymer gel viscosity was examined via rheology, nanoparticle morphology investigated using scanning transmission electron microscopy (STEM) and the gel matrix observed using cryo-scanning electron microscopy (Cryo-SEM).

KEY FINDINGS

DPA₅₀ -MPC₂₅₀ -DPA₅₀ copolymer (15% w/v) formed a free-standing gel (pH 7.5) that controlled drug release relative to free drugs. The copolymer possessed a low CMC, nanoparticle size increased with copolymer concentration, and DLS data were consistent with STEM. The gel displayed thermostable viscosity at physiological temperatures, and the gel matrix was a nanostructured aggregation of smaller nanoparticles.

CONCLUSIONS

The DPA₅₀ -MPC₂₅₀ -DPA₅₀ copolymer gel could be used as a drug delivery system to provide the controlled drug release of ketoprofen and spironolactone.

Redox-responsive supramolecular hydrogel based on 10-hydroxy camptothecin-peptide covalent conjugates with high loading capacity for drug delivery

A redox-responsive supramolecular hydrogel system was developed for delivering 10-hydroxy camptothecin (HCPT). The hydrogel was formed by cleaving disulfide bond. The combination of hydrophobic HCPT with hydrogel was a simple and effective way to improve the solubility of HCPT and the drug loading capacity of delivery system. The transmission electron microscopy (TEM) image revealed the self-assembled hydrogel was long and thin nanofibers with a width of <10nm. Rheological test verified the hydrogel had fine physical properties. In vitro release experiment showed that the accumulative releasing percentages within 72h of HCPT-peptide hydrogels at 3.0%, 4.0%, 5.0% were 16.8%, 21.3%, and 26.8% respectively, which indicated the HCPT-peptide hydrogels had a significantly sustained-release characteristic. Besides, in vitro anticancer assay showed that HCPT-peptide hydrogels possessed a favorable anticancer efficacy. These results indicated that HCPT-peptide hydrogel had great potential for cancer treatment as a novel injectable drug delivery system.

Sequentially dual-targeting vector with nano-in-micro structure for improved docetaxel oral delivery in vivo

AIM

In this study, we constructed a novel vector (BioPf-M-loaded Alg-microparticles [Alg-BioPf-M]) with nano-in-micro structure to improve the oral absorption of docetaxel (DTX) by sequentially dual-targeting functions toward intestine and sodium-dependent multivitamin transporter based on entrapping biotin-modified micelles into alginate microparticles.

METHODS

A series of characteristics of this system was investigated, such as drug release, cellular uptake, transport pathway and the comprehensive in vivo studies including pharmacokinetic studies, anti-tumor activity and toxicity study.

RESULTS

The bioavailability of DTX-loaded Alg-BioPf-M was 27.4-fold higher than that of free DTX after oral administration and achieved superior tumor inhibition of 84.6% against sarcoma 180 tumors.

CONCLUSION

These results demonstrated that the Alg-BioPf-M was a promising vector for oral delivery of DTX.

Formulation and Coating of Alginate and Alginate-Hydroxypropylcellulose Pellets Containing Ranolazine

The formulation and the coating composition of biopolymeric pellets containing ranolazine were studied to improve their technological and biopharmaceutical properties. Eudragit L100 (EU L100) and Eudragit L30 D-55-coated alginate and alginate-hydroxypropylcellulose (HPC) pellets were prepared by ionotropic gelation using 3 concentrations of HPC (0.50%, 0.65%, and 1.00% wt/wt) and applying different percentages (5%, 10%, 20%, and 30% wt/wt) of coating material. The uncoated pellets were regular in shape and had mean diameter between 1490 and 1570 μm. The rate and the entity of the swelling process were affected by the polymeric composition: increasing the HPC concentration, the structure of the pellets became more compact and slowed down the penetration of fluids. Coated alginate-HPC formulations were able to control the drug release at neutral pH: a higher quantity of HPC in the system determined a slower release of the drug. The nature of the coating polymer and the coating level applied affected the drug release in acidic environment: EU L100 gave better performance than Eudragit L30 D-55 and the best coating level was 20%. The pellets containing 0.65% of HPC and coated with 20% EU L100 represented the best formulation, able to limit the drug release in acidic environment and to control it at pH 6.8.

Development and evaluation of a calcium alginate based oral ceftriaxone sodium formulation

The purpose of this work was to develop a multiparticulate system exploiting the pH-sensitive property and biodegradability of calcium alginate beads for intestinal delivery of ceftriaxone sodium (CS). CS was entrapped in beads made of sodium alginate and sodium carboxymethylcellulose (CMC), acacia, HPMC K4M and HPMC K15M as drug release modifiers. Beads were prepared using calcium chloride as a cross-linking agent, followed by enteric coating with cellulose acetate phthalate (CAP). The beads were then evaluated for entrapment efficiency using HPLC, in vitro drug release examined in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8), swellability, particle size and surface characterization using optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Thermal gravimetric analysis (TGA) was utilized to check the polymer matrix strength and thermal stability. The drug entrapment efficiency of the optimized formulation was determined to be 75 ± 5 %. Swelling properties of drug-loaded beads were found to be in a range of 0.9–3.4. Alginate beads coated with CAP and containing CMC as a second polymer exhibited sustained release. The drug release followed first-order kinetics via non-Fickian diffusion and erosion mechanism. The particle size of the beads was between 1.04 ± 0.20 and 2.15 ± 0.36 mm. TGA, AFM, and SEM data showed composition and polymer-dependent variations in cross-linking, thermal stability, surface structure, morphology, and roughness. The physico-chemical properties of the developed formulation indicate suitability of the formulation to deliver CS orally.

Hydrogel: Preparation, characterization, and applications: A review

Hydrogel products constitute a group of polymeric materials, the hydrophilic structure of which renders them capable of holding large amounts of water in their three-dimensional networks. Extensive employment of these products in a number of industrial and environmental areas of application is considered to be of prime importance. As expected, natural hydrogels were gradually replaced by synthetic types due to their higher water absorption capacity, long service life, and wide varieties of raw chemical resources. Literature on this subject was found to be expanding, especially in the scientific areas of research. However, a number of publications and technical reports dealing with hydrogel products from the engineering points of view were examined to overview technological aspects covering this growing multidisciplinary field of research. The primary objective of this article is to review the literature concerning classification of hydrogels on different bases, physical and chemical characteristics of these products, and technical feasibility of their utilization. It also involved technologies adopted for hydrogel production together with process design implications, block diagrams, and optimized conditions of the preparation process. An innovated category of recent generations of hydrogel materials was also presented in some details.

Release and swelling studies of an innovative antidiabetic-bile acid microencapsulated formulation, as a novel targeted therapy for diabetes treatment

In previous studies carried out in our laboratory, a bile acid formulation exerted a hypoglycaemic effect in a rat model of type 1 diabetes (T1D). When the antidiabetic drug gliclazide was added to the bile acid, it augmented the hypoglycaemic effect. In a recent study, we designed a new formulation of gliclazide-deoxycholic acid (G-DCA), with good structural properties, excipient compatibility and which exhibited pseudoplastic-thixotropic characteristics. The aim of this study is to test the slow release and pH controlled properties of this new formulation. The aim is also to examine the effect of DCA on G release kinetics at various pH values and different temperatures. Microencapsulation was carried out using our Buchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared including: G-SA (control) and G-DCA-SA (test) at a constant ratio (1:3:30), respectively. Microcapsules were examined for efficiency, size, release kinetics, stability and swelling studies at pH 1.5, 3, 7.4 and 7.8 and temperatures of 25 °C and 37 °C. The new formulation is further optimised by the addition of DCA. DCA reduced bead-swelling of the microcapsules at pH 7.8 and 3 at 25 °C and 37 °C, and even though bead size remains similar after DCA addition, the percentage of G release was enhanced at high pH values (pH 7.4 and 7.8, p < 0.01). The new formulation exhibits colon-targeted delivery and the addition of DCA prolonged G release suggesting its suitability for the sustained and targeted delivery of G and DCA to the lower intestine.

The influence of different polymers on viability of Bifidobacterium lactis 300b during encapsulation, freeze-drying and storage

Seven different types of natural polymers namely hydroxypropyl methylcellulose (HPMC), sodium-carboxymethyl cellulose (Na-CMC), microcrystalline cellulose (MCC), starch BR-07, starch BR-08, dextrin and pullulan were used in order to develop the optimal formula for the entrapment of Bifidobacterium lactis 300B in Ca-alginate based granules. Laminar flow drip casting with Brace-Encapsulator was used in order to prepare the granules. The results showed that alginate/pullulan and alginate/HPMC formulation provide high protection for the bacterial strain used for encapsulation. These two formulations were further used to obtain freeze dried granules, for which the viability in time and at different temperatures was tested. The final results showed a higher viability than the level of the therapeutic minimum (>10(7) CFU/g) after 15 days of storage. Other parameters like entrapment efficiency, production rate, sphericity, flowability were also discussed.