Polymer Blend Ratio Research Articles

Fabrication of heterogeneous porous bilayered nanofibrous vascular grafts by two-step phase separation technique

Innterconnected porous architecture is critical for tissue engineering scaffold as well as biomimetic nanofibrous structure. In addition, a paradigm shift is recently taking place in the scaffold design from homogeneous porous scaffold to heterogeneous porous scaffold for the complex tissues. In this study, a versatile and simple one-pot method, dual phase separation, is developed to fabricate macroporous nanofibrous scaffold by phase separating the mixture solutions of immiscible polymer blends without using porogens. The macropores in the scaffold are interconnected, and their size can be tuned by the polymer blend ratio. Moreover, benefiting from the easy operation of dual phase separation technique, an innovative, versatile and facile two-step phase separation method is developed to fabricate heterogeneous porous layered nanofibrous scaffolds with different shapes, such as bilayered tubular scaffold and tri-layered cylindrical scaffold. The bilayered tubular nanofibrous scaffold composed of poly(l-lactic acid) (PLLA)/poly(l-lactide-co-ε-caprolactone) (PLCL) microporous inner layer and PLLA/poly(ε-caprolactone) (PCL) macroporous outer layer matches simultaneously the functional growth of endothelial cells (ECs) and smooth muscle cells (SMCs), and shows the favorable performance for potential small diameter blood vessel application. Therefore, this study provides the novel and facile strategies to fabricate macroporous nanofibrous scaffold and heterogeneous porous layered nanofibrous scaffold for tissue engineering applications. Statement of SignificanceThe fabrication of porous tissue engineering scaffold made of non-water-soluble polymer commonly requires the use of porogen materials. This is complex and time-consuming, resulting in greater difficulty to prepare heterogeneous porous layered scaffold for multifunctional tissues repair, such as blood vessel and osteochondral tissue. Herein, a novel, versatile and simple one-pot dual phase separation technique is developed for the first time to fabricate porous scaffold without using porogens. Simultaneously, it also endows the resultant scaffold with the biomimetic nanofibrous architecture. Based on the easy operation of this dual phase separation technique, a facile two-step phase separation method is also put forward for the first time and applied in fabricating heterogeneous porous layered nanofibrous scaffold for tissue engineering applications.

Electrospinning polymer blend of PLA and PBAT: Electrospinnability–solubility map and effect of polymer solution parameters toward application as antibiotic‐carrier mats

ABSTRACTElectrospinning of a biodegradable polymer blend of poly(lactic acid) (PLA) and poly(butylene adipate‐co‐terephthalate) (PBAT) is reported for the first time. Effects of several solution parameters on electrospinning are explored, including types of single and binary solvents, binary solvent mixing ratio, polymer blend concentration, polymer blending ratio, and loading content of tetrabutyl titanate as a compatibilizer. An electrospinnability–solubility map of the PLA/PBAT blend is firstly developed for the facile selection of a suitable binary solvent system, thus simplifying the laborious, time‐consuming, trial‐and‐error process. A particular binary solvent system derived from good and non‐solvent serves as the most suitable medium for the successful preparation of homogeneous bead‐free electrospun PLA/PBAT nanofibers. It is revealed that the compatibilizer acts not only as a diameter size tuner for the PLA/PBAT fibers but also as a mechanical property enhancer for the immiscible PLA/PBAT electrospun mats. Moreover, the antibacterial activity of the drug‐loaded PLA/PBAT fibrous mats suggests their potential application as antibiotic‐carrier mats. Preparation of the composite mats comprising bead‐free fibers with an average size at sub‐micrometer scale is also demonstrated, additionally promoting the possibility of using the PLA/PBAT‐based electrospun mats as a matrix of various additives for a wide range of applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46486.

Investigation of 2-step technique for jute fabric reinforced polymer matrix composite

This paper focuses on the fabrication processes of jute reinforced polymer composites (FPC) made with the use of both untreated jute fabric and pultruded jute fabric. The pultruded jute fabric performs were processed and cured separately using polymer with different components blending ratio ‘α’ (resin/solvent ratio). 2-step technique where the composite specimens were prepared using a different combination of polymer blending ratio α1 for the pultruding jute fabric and used blending ratio α2 polymer for the matrix, which have contributed positively to fiber/matrix tensile stress, breaking strain, toughness and Young’s modulus. The best value of α1 and α2 to have composite with high tensile strength and Young’s modulus was 0.6 for both the pultruded matrix and final composite matrix.

Bundle Gel Fibers with a Tunable Microenvironment for in Vitro Neuron Cell Guiding.

As scaffolds for neuron cell guiding in vitro, gel fibers with a bundle structure, comprising multiple microfibrils, were fabricated using a microfluidic device system by casting a phase-separating polymer blend solution comprising hydroxypropyl cellulose (HPC) and sodium alginate (Na-Alg). The topology and stiffness of the obtained bundle gel fibers depended on their microstructure derived by the polymer blend ratio of HPC and Na-Alg. High concentrations of Na-Alg led to the formation of small microfibrils in a one-bundle gel fiber and stiff characteristics. These bundle gel fibers permitted for the elongation of the neuron cells along their axon orientation with the long axis of fibers. In addition, human-induced pluripotent-stem-cell-derived dopaminergic neuron progenitor cells were differentiated into neuronal cells on the bundle gels. The bundle gel fibers demonstrated an enormous potential as cell culture scaffold materials with an optimal microenvironment for guiding neuron cells.

Vapor sensing performance as a diagnosis probe to estimate the distribution of multi-walled carbon nanotubes in poly(lactic acid)/polypropylene conductive composites

Abstract Multi-walled carbon nanotubes (MWCNT)/poly (lactic acid) (PLA)/polypropylene (PP) with different polymer blend ratios were fabricated by melt processing method. When fixed the MWCNT content at 1.0 wt.%, A6P4 (PLA/PP 60w/40w) showed the lowest resistivity, which is attributed to the formation of a co-continuous structure. According to the thermodynamics prediction, MWCNT is estimated to be selectively distributed in PLA phase. To further investigate the MWCNT localization behavior in polymer blend, a two-step compounding sequence approach was utilized to fabricate Pre-PLA ( i.e. , MWCNT were firstly mixed with PLA) and Pre-PP composites. Morphology observation and rheology tests were then carried out to demonstrate the MWCNT distribution in the composites. Vapor sensing behaviors of CPCs towards organic vapors with different polarity were investigated in detail. CPCs with higher PLA content showed a higher responsivity to dichloromethane, a ‘good solvent’ to PLA. CPCs containing higher PP content exhibited a higher responsivity towards xylene due to the strong interaction between PP and the xylene vapor. While for cyclohexane, a ‘poor solvent’ to PLA and PP, all the CPCs demonstrate a low responsivity. Interestingly, the vapor sensing feature can be used to testify the MWCNT localization in the polymer blend as a diagnosis probe.

Antibiotic incorporation in jet-sprayed nanofibrillar biodegradable scaffolds for wound healing

In view of preparing antibiotic-loaded structures that can be used as dressing to prevent or contain wound infections, this study evaluates biodegradable nanofibrillar matrices obtained by jet-spraying and containing ciprofloxacin (CIF). The matrices were prepared from different blends of poly-(ε-caprolactone) (PCL) and poly-d,l-(lactic acid) (PDLLA) in view of controlling mechanical properties, biodegradation and antibiotic release rate. The effect of CIF incorporation was assessed in regard of matrices fiber diameter, mechanical properties and degradation while antibiotic release from the polymer blends of different PCL/PDLLA ratios was measured in buffers of different pH to better mimic the wound context. Finally, antibiotic activity of the nanofibrillar matrices and their ability to be colonized by skin cells were evaluated.Non-woven nanofibrillar matrices could be obtained from various polymer blends by jet-spraying and CIF crystals incorporation was easily obtained. The crystals were dispersed in the fibers, without complete embedding. Antibiotic incorporation resulted in a slight increase of fiber diameter and did not modified the mechanical properties of the various matrices composed of different polymer blends. Unlike fiber diameter, degradation and mechanical properties of the fibrillar matrices, CIF release profiles were not controlled by the polymer blend ratios. However, sustained release was observed over more than 23 days. Due to the antibiotic pH-dependent solubility, burst release was more prominent in acidic conditions, which mimic the pH of undamaged skin. Finally the incorporated antibiotic was efficient in inhibiting bacterial growth of E. coli and B. subtilis whereas human fibroblasts were able to colonize the CIF-loaded matrices.

Cellulose Acetate Butyrate: Ammonio Methacrylate Copolymer Blends as a Novel Coating in Osmotic Tablets.

The objective of this work was the preparation of osmotic tablets using polymer blends of cellulose acetate butyrate (CAB) or ethylcellulose with ammonio methacrylate copolymer (Eudragit® RL). The advantage of these coatings in comparison to the traditionally used cellulose acetate is their solubility in safer organic solvents like ethanol. Polymer films were characterized with respect to their water uptake, dry mass loss, and mechanical properties. The effect of the polymer blend ratio on drug release and on the rupture force of the coating was investigated. In addition, the effect of drug solubility and content, pH and agitation rate of the release medium, and coating level and plasticizer content on the release were studied. With increased Eudragit® RL content in the coating blends, higher medium uptake of the film was observed, resulting in shorter lag times and faster drug release from the osmotic tablets. Replacing ethylcellulose with cellulose acetate butyrate as a coating material led to shorter lag times and faster drug release due to increased film permeability. In addition, CAB-based films had a higher strength and flexibility. The drug release was osmotically controlled and decreased with increasing coating level. It increased with increased drug solubility, plasticizer content, change of buffer species (acetate > phosphate), and decreased coating level. Agitation rate and drug content had no effect on the drug release. A 20% w/w coating level was sufficient for the tablet to tolerate forces of more than five times of the gastric destructive force reported in literature.

Formation mechanism of sPEEK hydrophilized PES supports for forward osmosis

Polyethersulfone/sulfonated polyetheretherketone (PES/sPEEK) supported osmotic thin film composite (TFC) membranes were fabricated with a focus on the optimization of the support layer of the TFC membrane by the phase inversion process. The polymer solution was cast directly on a glass substrate without any backing fabric to prepare the support layer. All resultant supports showed a fingerlike pore structure. The addition of a more hydrophilic polymer (sPEEK) to the polymer solution induced pores in the bottom layer of the support with average pore diameters ranging from 0.07 to 0.30μm, which improved water flux. Bottom surface porosities were simply controlled by adjusting the polymer blend ratios. FO experiments were carried out in a high-throughput (HT) crossflow FO cell with DI water and a 0.5 M NaCl solution as feed and draw solution, respectively. TFC membranes with 5% sPEEK showed a water flux in PRO mode of 14.3 LMH and in FO mode of 6.2 LMH, which is superior to the commercial cellulose triacetate (CTA) and TFC membranes (HTI). In addition, a mechanism for the bottom layer formation was proposed.

Combining Precipitation and Vitrification to Control the Number of Surface Patches on Polymer Nanocolloids.

In an effort to incorporate increasingly higher levels of functionality into soft nanoparticles, heterogeneously structured particles stand out as a simple means to enhance functionality by tailoring only particle architecture. Various means exist for the fabrication of particles with specific structural configurations; however, the tunability of particle morphology is still a challenging and often laborious task, especially in self-assembled systems where a single equilibrium configuration dominates. Improved strategies for multipatch particle assembly are therefore needed to allow for the tailoring of particle structure via a single, continuous assembly route. One means of accomplishing this is through kinetic trapping of particle morphologies along the path to the final equilibrium configuration in precipitation-induced, phase-separating polymer blends. Here, we demonstrate this capability by using rapid nanoprecipitation to control the overall size, composition, and patch distribution of soft colloids. In particular, we illustrate that polymer feed concentration, blend ratio, and polymer molecular weight can all serve as functional handles with which to consistently alter particle patch distributions in a self-assembling homopolymer system without redesigning the starting materials. We furthermore delineate the role of polymer vitrification in the determination of particle structure.

Carbon nanotube induced double percolation in polymer blends: Morphology, rheology and broadband dielectric properties

In this study, we investigate the effect of multi-walled carbon nanotube (MWCNT) on the rheology, morphology and broadband dielectric properties of polypropylene:polystyrene (PP:PS) blends (PP:PS—10:90, 50:50 and 90:10). Transmission electron microscopy showed that MWCNTs were localized at the interface and inside the PS phase, regardless of the polymer blend ratio. Employing scanning electron microscopy, we observed that addition of MWCNT led to a transition from dispersed to interconnected morphology for the blends with PS as minor phase (PP:PS/50:50 and PP:PS/90:10). We propose that the selective localization of MWCNT in PS and at the interface slowed down the breakup mechanisms, increasing the lifetime of PS/MWCNT elongated domains, thus decreasing the amount of PS/MWCNT needed to percolate in PP phase. In addition, it is proposed that MWCNT located at the interface act as bridges between PS/MWCNT domains, favouring the coarsening of PS/MWCNT domains. The dielectric properties of the polymer blends PP:PS/50:50 and PP:PS/90:10 confirmed that double percolation was achieved with increase in MWCNT content. This transition provided the possibility to tune dielectric properties of the PP:PS/MWCNT blends. The double percolated structure offered high imaginary permittivity, while the dispersed morphology presented low imaginary permittivity. In other words, this study reveals that manipulating blend morphology can lead to blends with capacitive or dissipative characteristics.

Development of an electrospun biomimetic polyurea scaffold suitable for vascular grafting.

The optimization of biomechanical and biochemical properties of a vascular graft to render properties relevant to physiological environments is a major challenge today. These critical properties of a vascular graft not only regulate its stability and integrity, but also control invasion of cells for scaffold remodeling permitting its integration with native tissue. In this work, we have synthesized a biomimetic scaffold by electrospinning a blend of a polyurea, poly(serinol hexamethylene urea) (PSHU), and, a polyester, poly-ε-caprolactone (PCL). Mechanical properties of the scaffold were varied by varying polymer blending ratio and electrospinning flow rate. Mechanical characterization revealed that scaffolds with lower PSHU content relative to PCL content resulted in elasticity close to native mammalian arteries. We also found that increasing electrospinning flow rates also increased the elasticity of the matrix. Optimization of elasticity generated scaffolds that enabled vascular smooth muscle cells (SMCs) to adhere, grow and maintain a SMC phenotype. The 30/70 scaffold also underwent slower degradation than scaffolds with higher PSHU content, thereby, providing the best option for in vivo remodeling. Further, Gly-Arg-Gly-Asp-Ser (RGD) covalently conjugated to the polyurea backbone in 30/70 scaffold resulted in significantly increased clotting times. Reducing surface thrombogenicity by the conjugation of RGD is critical to avoiding intimal hyperplasia. Hence, biomechanical and biochemical properties of a vascular graft can be balanced by optimizing synthesis parameters and constituent components. For these reasons, the optimized RGD-conjugated 30/70 scaffold electrospun at 2.5 or 5 mL/h has great potential as a suitable material for vascular grafting applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 278-290, 2018.

PLA/PHBV electrospun membrane: Fabrication, coating with conductive PEDOT:PSS and antibacterial activity of drug loaded membrane

AbstractIn this study, biodegradable and biocompatible polylactic acid (PLA) and poly(3-hyroxybutyrate-co-3-hydroxyvalerate) (PHBV) blend polymer solutions were electrospun using electrospinning technique. Polymer blend ratio and electrospinning voltage were varied and optimized. The fabricated electrospun PLA/PHBV membranes were dipped into poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) solution to produce conductive PEDOT:PSS coated membranes. The coated and uncoated membranes were investigated using scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and water uptake measurement. PEDOT:PSS coated membranes were then loaded with drug (tetracycline hydrochloride) and their antibacterial activity was investigated. Beadless PLA/PHBV membranes were successfully fabricated. The fabricated PLA/PHBV membranes were rendered conductive by dipping them into poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) so...

Preparation and Characterization of Hydrophilically Modified PVDF Membranes by a Novel Nonsolvent Thermally Induced Phase Separation Method.

In this study, a nonsolvent thermally-induced phase separation (NTIPS) method was first proposed to fabricate hydrophilically-modified poly(vinylidene fluoride) (PVDF) membranes to overcome the drawbacks of conventional thermally-induced phase separation (TIPS) and nonsolvent-induced phase separation (NIPS) methods. Hydrophilically-modified PVDF membranes were successfully prepared by blending in hydrophilic polymer polyvinyl alcohol (PVA) at 140 °C. A series of PVDF/PVA blend membranes was prepared at different total polymer concentrations and blend ratios. The morphological analysis via SEM indicated that the formation mechanism of these hydrophilically-modified membranes was a combined NIPS and TIPS process. As the total polymer concentration increased, the tensile strength of the membranes increased; meanwhile, the membrane pore size, porosity and water flux decreased. With the PVDF/PVA blend ratio increased from 10:0 to 8:2, the membrane pore size and water flux increased. The dynamic water contact angle of these membranes showed that the hydrophilic properties of PVDF/PVA blend membranes were prominently improved. The higher hydrophilicity of the membranes resulted in reduced membrane resistance and, hence, higher permeability. The total resistance Rt of the modified PVDF membranes decreased significantly as the hydrophilicity increased. The irreversible fouling related to pore blocking and adsorption fouling onto the membrane surface was minimal, indicating good antifouling properties.

Poly vinyl acetate and ammonio methacrylate copolymer as unconventional polymer blends increase the mechanical robustness of HPMC matrix tablets

The objective was to investigate poly vinyl acetate (Kollicoat® SR 30 D) and ammonio methacrylate copolymer (Eudragit® RL 30 D) blends as coatings to increase the mechanical robustness of hydroxypropyl methylcellulose (HPMC) matrix tablets. Poly vinyl acetate (Kollicoat® SR 30 D – KSR) was selected for its flexibility and ammonio methacrylate copolymer (Eudragit® RL 30 D – ERL) because of its high permeability. Films based on KSR:ERL blends were prepared by casting or spraying aqueous dispersions of these polymers and were characterized by water uptake, dry mass loss and mechanical properties. KSR:ERL blends were investigated as coating materials to improve the robustness, mechanical strength and drug release from the HPMC matrix tablets containing propranolol HCl, caffeine and carbamazepine as model drugs. Both HPMC and the polymer coating affected the propranolol release. The release and the mechanical properties could be easily adjusted by varying the polymer blend ratio. The flexibility increased with increasing KSR content. At an 8% w/w coating level, a force of 3.2N was required to rupture the coating of the swollen tablet after 16h in the release medium; the coated tablets were thus robust to withstand gastrointestinal forces. The coating level (6%–10%, w/w) and dissolution agitation rate (50rpm to 150rpm) had no effect on the drug release. The water-insoluble carbamazepine was not released from the coated tablets as HPMC erosion, which is necessary for the release of a poorly water-soluble drug was hindered by the coating. The release of the water-soluble propranolol increased with increasing drug content and decreased with increasing HPMC content. ConclusionPoly vinyl acetate and ammonio methacrylate copolymer could be a proper polymer blend for coating HPMC matrix tablets to increase mechanical robustness, which characterized by its flexibility and permeability.

Carbon Membranes Prepared from a Polymer Blend of Polyethylene Glycol and Polyetherimide

AbstractThrough a dip‐coating technique, carbon membranes were produced from a polymer blend consisting of the thermally stable polymer polyetherimide (PEI) and the thermally labile polymer polyethylene glycol (PEG). The PEG/PEI carbon membranes were synthesized on an alumina support coated with an Al2O3 intermediate layer. The polymer blend ratio and carbonization temperature influenced the structure and permeation performance of the derived carbon membranes. The porosity of the PEG/PEI carbon membranes increased with higher PEG content in the blends. However, the derived carbon membranes tended to lose gas permeability with raising the carbonization temperatures. The carbon membranes were successfully optimized in order to achieve the highest CO2/CH4 and CO2/N2 selectivities.

Development of natural and synthetic polymer-based semi-interpenetrating polymer network for controlled drug delivery: optimization and in vitro evaluation studies

This research paper describes the development, optimization and in vitro characterization of chemically cross-linked pectin–polyvinyl alcohol-co-poly(2-Acrylamido-2-methylpropane sulfonic acid) semi-interpenetrating polymer network hydrogel [pectin–PVA-co-poly(AMPS) semi-IPN hydrogel] for controlled delivery of model drug tramadol HCl. Response surface methodology based on 32 factorial design was used for optimization and investigating the effect of independent factors: polymer-blend ratio (pectin:PVA = X 1) and monomer (AMPS = X 2) concentration on the dependent variables, swelling ratio (q 18th), percent drug release (R 18th, %), time required for 80 % drug release (t 80 %, h), drug encapsulation efficiency (DEE, %) and drug loaded contents (DLC, mg/g) in pectin-PVA-co-poly(AMPS) gels prepared by free radical polymerization. The optimized semi-IPN gel (FPP-10) showed controlled in vitro drug release (R 18th) of 56.34 % in 18 h, t 80 % of 30 h, and DEE of 23.40 %. These semi-IPN hydrogels were also characterized through SEM, FTIR, sol–gel analysis, swelling studies and drug release characteristics. Therefore, this newly synthesized polymeric network could be a potential polymeric system for controlled drug delivery of tramadol HCl for prolonged drug release.

HPMC-based gastroretentive dual working matrices coated with Ca+ 2 ion crosslinked alginate-fenugreek gum gel membrane

Novel alginate-fenugreek gum (FG) gel membrane coated hydroxypropylmethylcellulose (HPMC) based matrix tablets were developed for intragastric quetiapine fumarate (QF) delivery by combining floating and swelling mechanisms. The effects of polymer blend ratios [HPMC K4M:HPMC E15] and citric acid contents on time taken for 50% drug release (t50%, min) and drug release at 8h (Q8h, %) were studied to optimize the core tablets by 32 factorial design. The optimized tablets (F-O) exhibited t50% of 247.67±3.51min and Q8h of 71.11±0.32% with minimum errors in prediction. The optimized tablets were coated with Ca+2 ions crosslinked alginate-FG gel membrane by diffusion-controlled interfacial complexation technique. The biopolymeric-coated optimized matrices exhibited superior buoyancy, preferred swelling characteristics and slower drug release rate. The drug release profiles of the QF-loaded uncoated and coated optimized matrices were best fitted in Korsmeyer-Peppas model with anomalous diffusion driven mechanism. The uncoated and coated tablets containing QF were also characterized for drug-excipients compatibility, thermal behaviour and surface morphology by FTIR, DSC and SEM analyses, respectively. Thus, the newly developed alginate-FG gel membrane coated HPMC matrices are appropriate for intragastric delivery of QF over a prolonged period of time with greater therapeutic benefits.

Alginate-okra gum blend beads of diclofenac sodium from aqueous template using ZnSO4 as a cross-linker

Zinc (Zn2+)-ion induced diclofenac sodium (DS)-loaded alginate-okra (Hibiscus esculentus) gum (OG) blend beads was successfully formulated through Zn2+-ion induced ionic-gelation cross-linking method in a complete aqueous environment. Effects of polymer-blend ratio and cross-linker concentration on drug encapsulation efficiency (DEE) and cumulative drug release at 8h (R8h) were optimized by 32-factorial design. The optimized formulation of Zn2+-ion induced DS-loaded alginate-OG beads demonstrated 89.27±3.58% of DEE and 43.73±2.83% of R8h. The bead sizes were within 1.10±0.07 to 1.38±0.14mm. The bead surface morphology was analyzed by SEM. The drug–polymer interaction in the optimized bead matrix was analyzed by FTIR and P-XRD. These beads exhibited sustained in vitro drug release over a prolonged period of 8h and followed controlled-release (zero-order) pattern with super case-II transport mechanism. The swelling and degradation of the optimized beads was influenced by the pH of test mediums, which might be suitable for intestinal drug delivery.

Alginate gel-coated oil-entrapped alginate–tamarind gum–magnesium stearate buoyant beads of risperidone

A novel alginate gel-coated oil-entrapped calcium-alginate–tamarind gum (TG)–magnesium stearate (MS) composite floating beads was developed for intragastric risperidone delivery with a view to improving its oral bioavailability. The TG-blended alginate core beads containing olive oil and MS as low-density materials were accomplished by ionotropic gelation technique. Effects of polymer-blend ratio (sodium alginate:TG) and crosslinker (CaCl2) concentration on drug entrapment efficiency (DEE, %) and cumulative drug release after 8h (Q8h, %) were studied to optimize the core beads by a 32 factorial design. The optimized beads (F–O) exhibited DEE of 75.19±0.75% and Q8h of 78.04±0.38% with minimum errors in prediction. The alginate gel-coated optimized beads displayed superior buoyancy and sustained drug release property. The drug release profiles of the drug-loaded uncoated and coated beads were best fitted in Higuchi kinetic model with Fickian and anomalous diffusion driven mechanisms, respectively. The optimized beads yielded a notable sustained drug release profile as compared to marketed immediate release preparation. The uncoated and coated Ca-alginate–TG–MS beads were also characterized by SEM, FTIR and P-XRD analyses. Thus, the newly developed alginate-gel coated oil-entrapped alginate–TG–MS composite beads are suitable for intragastric delivery of risperidone over a prolonged period of time.

Effects of Chitosan Concentration on the Protein Release Behaviour of Electrospun Poly(ε‐caprolactone)/Chitosan Nanofibers

Poly(ε‐caprolactone)/chitosan (PCL/chitosan) blend nanofibers with different ratios of chitosan were electrospun from a formic acid/acetic acid (FA/AA) solvent system. Bovine serum albumin (BSA) was used as a model protein to incorporate biochemical cues into the nanofibrous scaffolds. The morphological characteristics of PCL/chitosan and PCL/chitosan/BSA Nanofibers were investigated by scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) was used to detect the presence of polymeric ingredients and BSA in the Nanofibers. The effects of the polymer blend ratio and BSA concentration on the morphological characteristics and consequently on the BSA release pattern were evaluated. The average fiber diameter and pore size were greater in Nanofibers containing BSA. The chitosan ratio played a significant role in the BSA release profile from the PCL/chitosan/BSA blend. Nanofibrous scaffolds with higher chitosan ratios exhibited less intense bursts in the BSA release profile.