Search

The objective of this study was to develop a sustained release dosage form of Trimetazidine dihydrochloride (TMZ) using a natural polymeric carrier prepared in a completely aqueous environment. TMZ was entrapped in calcium alginate beads prepared with sodium alginate by the ionotropic gelation method using calcium chloride as a crosslinking agent. The drug was incorporated either into preformed calcium alginate gel beads (sequential method) or incorporated simultaneously during the gelation stage (simultaneous method). The beads were evaluated for particle size and surface morphology using optical microscopy and SEM, respectively. Beads produced by the sequential method had higher drug entrapment. Drug entrapment in the sequential method was higher with increased CaCl2 and polymer concentration but lower with increased drug concentration. In the simultaneous method, drug entrapment was higher when polymer and drug concentration were increased and also rose to a certain extent with increase in CaCl2 concentration, where further increase resulted in lower drug loading. FTIR studies revealed that there is no interaction between drug and CaCl2. XRD studies showed that the crystalline drug changed to an amorphous state after formulation. Release characteristics of the TMZ loaded calcium alginate beads were studied in enzyme-free simulated gastric and intestinal fluid.O objetivo deste estudo foi desenvolver forma de liberação controlada de dicloridrato de trimetazidina (TMZ) utilizando transportador plomérico natural em ambiente completamente aquoso. A TMZ foi presa em pérolas de alginato de cálcio preparadas com alginato de sódio pelo método de gelatinização ionotrópica, usando cloreto de cálcio como agente de formação de ligações cruzadas. O fármaco foi incorporado nas pérolas de gel de alginato de cálcio (método sequencial) ou incorporado, simultaneamente, durante o estágio de gelificação (método simultâneo). As pérolas foram avaliadas quanto ao tamanho das partículas e morfologia da superfície utilizando microscopia óptica de SEM, respectivamente. As pérolas produzidas pelo método sequencial apresentaram maior capacidade de inclusão. No método sequencial, a inclusão de fármaco foi maior com o aumento de CaCl2 e da concentração do plímero, mas menor com o aumento da concentração de fármaco. No método simultâneo, a inclusão de fármaco foi mais alta quando as concentrações de fármaco e plímero foram aumentadas e, também, atingiram certa extensão com aumento na concentração de CaCl2, cujo aumento posterior resultou em carga menor de fármaco. Estudos de FTIR revelaram que não há interação entre fármaco e CaCl2. Estudos de XRD mostraram que o fármaco mudou do estado cristalino para o amorfo após a formulação. As características de liberação de TMZ das pérolas carregadas com alginato de cálcio foram estudadas em fluidos simulados, gástrico e intestinal, livres de enzima.

Nanoparticles can be used as a smart drug delivery system, when they release the drug only upon degradation by specific enzymes. A method to create such responsive materials is the formation of hydrogel nanoparticles, which have enzymatically degradable crosslinkers. Such hydrogel nanoparticles were prepared by ionotropic gelation sodium alginate with lysine-rich peptide sequences—either α-poly-L-lysine (PLL) or the aggrecanase-labile sequence KKKK-GRD-ARGSV↓NITEGE-DRG-KKKK. The nanoparticle suspensions obtained were analyzed by means of dynamic light scattering and nanoparticle tracking analysis. Degradation experiments carried out with the nanoparticles in suspension revealed enzyme-induced lability. Drugs present in the polymer solution during the ionotropic gelation can be encapsulated in the nanoparticles. Drug loading was investigated for interferon-β (IFN-β) as a model, using a bioluminescence assay with MX2Luc2 cells. The encapsulation efficiency for IFN-β was found to be approximately 25%. The nanoparticles suspension can be used to spray-coat titanium alloys (Ti-6Al-4V) as a common implant material. The coatings were proven by ellipsometry, reflection-absorption infrared spectroscopy, and X-ray photoelectron spectroscopy. An enzyme-responsive decrease in layer thickness is observed due to the degradation of the coatings. The Alg/peptide coatings were cytocompatible for human gingival fibroblasts (HGFIB), which was investigated by CellTiterBlue and lactate dehydrogenase (LDH) assay. However, HGFIBs showed poor adhesion and proliferation on the Alg/peptide coatings, but these could be improved by modification of the alginate with a RGD-peptide sequence. The smart drug release system presented can be further tailored to have the right release kinetics and cell adhesion properties.

Alginate is a natural polysaccharide that is widely used in industrial applications. Here, beads of alginic acid, calcium, and copper alginate were prepared by the addition of soluble sodium alginate to a solution of hydrochloric acid or the corresponding cation. The progress of gelation inside the beads was followed by the degree of opacity at different times, which corresponded well to an apparent morphology change observed in freeze-dried bead cross sections analyzed by scanning electron microscopy. Furthermore, diffusion of Cu2+ions across the beads was followed by energy dispersive X-ray spectroscopy, which revealed colocalization of the cross-linking cation and the morphologically distinct bead regions. [ABSTRACT FROM AUTHOR]

Lysozyme was integrated into chitosan nanoparticles (CS-NPs) to improve the antibacterial activity. CS-NPs and chitosan-lysozyme nanoparticles (CS-Lys-NPs) were prepared according to the ionic gelation technique and then characterized by average size, zeta potential, polydispersity index (PDI), atomic force microscopy (AFM), fourier transform infrared (FT-IR), small-angle X-ray scattering (SAXS), circular dichroism (CD) and UV–visible spectroscopy. Antibacterial properties were investigated by transmission electron microscopy (TEM) based on observation of the inhibition zone and measurement of the minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) of CS-NPs and CS-Lys-NPs against E. coli and B. subtilis . The CS-NPs had particle sizes of 476.2–548.1 nm, while an increase to ∼488.8 to 613.5 nm was observed upon loading with lysozyme. The results suggested that the integration of lysozyme into CS-NPs enhanced the antibacterial activity against E. coli and B. subtilis , which may show great potential for use in the food industry and other applications in the form of direct addition or incorporation into packaging. [ABSTRACT FROM AUTHOR]

In the present work, sodium alginate (SA), low methoxyl pectin (PEC) and κ-carrageenan (κ-CAR) were evaluated for their intragastric structuring ability by means of light microscopy and dynamic oscillatory rheology. SA and PEC solutions, their Ca 2+ complexed gel analogues as well as their binary blends with ionically or thermally set sheared κ-CAR gels, were subjected to in vitro orogastric conditions. SA and PEC – Ca 2+ complexed sheared gels exerted the highest vulnerability to digestive fluid exposure due to the dialysis of egg-box dimer structures via proton-calcium exchange. Incorporation of SA and PEC systems to κ-CAR gels prevented the loss of mechanical strength of the gastric gels due to the ability of κ-CAR to undergo spontaneous gelation in the presence of Na + and K + ions. Binary blends of SA and PEC – Ca 2+ complexed sheared gels with κ-CAR-Ca 2+ gels exerted a significantly lower mechanical strength loss sensitivity against pH and counterion composition of the gastric fluids. [ABSTRACT FROM AUTHOR]

Multifunctional biopolymer-piezoelectric composite worm structures (wavy and linear) derived by ionotropic gelation technique is fundamentally reported. Mass production of composite wavy pattern worms (CWPWs) enable high energy conversion from low frequency mechanical energy to electrical energy, tunable piezoelectricity by tailored length dependent CWPWs, weight ratio of piezoelectric nanoparticles. Interestingly we found that, the peak–peak voltage and current decreases around 87% and 71% for CWPW devices when the CWPWs length decreased to 56.4% (L = 1.95 to 0.85 cm) respectively. We also tested, the pH dependent conductivity of composite linear worm (CLW) for clinical, food monitoring applications. Next, we demonstrate the generated piezoelectric potential of CWPW device holds as a promising independent power source unit to drive the CLW sensor under different pH solutions. The proposed work is non-invasive, flexible with robustness in long-term effective usage, biocompatibility, and battery-less operation for self powered biosensor in theranostics, blood pH measurement. [ABSTRACT FROM AUTHOR]

Short oligoguluronates, oligoG’s, are reported to affect the ionotropic gelation of alginates both with respect to altered gelation kinetics and elastic properties of the resulting gels. The local structure of Ca 2+ induced changes in oligoguluronates and blends of oligoguluronates and alginates was determined by small angle X-ray scattering (SAXS). Calcium was introduced in the aqueous polysaccharide solutions by in situ release of Ca 2+ from Ca-EGTA. The scattering profiles of the Ca 2+ -induced structures in the alginate–oligoG blends were accounted for by a two-component broken rod-like model, also with an additional term representing structural inhomogeneity by a Debye-Bueche term. Adding oligoG to the alginate yields an increase in the largest cross-sectional radius in the region of fractional Ca 2+ saturation of α- l -GulA units from 0.5 to 1. The time-lapse characterization during the Ca-induced changes in the alginate-oligoG blends shows that oligoG delays the emergence of the more extensive laterally aggregated junction zones. [ABSTRACT FROM AUTHOR]

Ionotropic gelation of chitosan by means of opposite charged ions represents an efficient alternative to covalent reticulation because of milder condition of use and, in general, higher biocompatibility of the resulting systems. In this work 90° light scattering (turbidimetry), circular dichroism (CD) and 1 H NMR measurements have been performed to study the interactions between the biopolymer and ionic cross-linkers tripolyphosphate (TPP) and pyrophosphate (PPi) in dilute solutions. Thereafter, a dialysis-based technique was exploited to fabricate tridimensional chitosan hydrogels based on both polyanions. Resulting matrices showed a different mechanical behavior because of their peculiar mesh-texture at micro/nano-scale: in the present contribution we demonstrate that TPP and PPi favor the formation of homogeneous and inhomogeneous systems, respectively. The different texture of networks could be exploited in future for the preparation of systems for the controlled release of molecules. [ABSTRACT FROM AUTHOR]

For the separation of chiral anesthetic gases suitable support materials for the selectors are necessary. Due to the controlled texture properties porous glass shows a high potential for such applications. In this study porous glass beads with particle diameters of 40 - 400 µm and 2 - 4 mm could be obtained via a special fluidized-bed reactor and the method of ionotropic gelation. Furthermore, the first core-shell beads on the basis of porous glasses could be synthesized via the combination of an ion-exchange induced phase separation and a selective leaching step. The new materials are characterized by a defined mesoporous shell and a non-porous glass core. [ABSTRACT FROM AUTHOR]

Pulsatile Drug delivery systems are gaining a lot of interest as they deliver the drug at the right site of action, at the right time and in the right amount, as per the pathophysiological needs of the diseases, resulting in increasing patient compliance. A combination of floating, pulsatile and multiparticulate systems is now widely employed for the treatment of various diseases. Floating pulsatile beads release drug after a lag time with no release during floating in the stomach after which a burst release in the upper part of the g.i.t. so drugs can be delivered at right time, in right amount and at right site of action by use of floating pulsatile beads. [ABSTRACT FROM AUTHOR]

Active nanoparticles based on chitosan could be applied as a support for the modulation of gallic acid delivery. In this sense, these nanostructures could be employed in different fields such as food, packaging, and pharmaceutical areas. The design parameters of chitosan-based nanoparticles functionalized with gallic acid (GA) were optimized through RSM by means of the analysis of zeta potential (ZP) and percentage encapsulation efficiency (PEE). The nanoparticles were prepared by ionotropic gelation using tripolyphosphate (TPP), at different combinations of chitosan (CH) concentration, CH:TPP ratio and GA. Global desirability methodology allowed finding the optimum formulation that included CH 0.76% (w/w), CH:TPP ratio of 5 and 37 mg GA /g CH leading to ZP of + 50 mV and 82% of PEE. Analysis through QuickScan and turbidity demonstrated that the most stable nanoparticle suspensions were achieved combining concentrations of chitosan ranging between 0.5 and 0.75% with CH:TPP ratios higher than 3. These suspensions had high stability confirmed by means ZP and transmittance values which were higher than + 25 mV and 0.21 on average, respectively, as well as nanoparticle diameters of about 140 nm. FTIR revealed the occurrence of both hydrogen bond and ionic interactions of CH-TPP which allowed the encapsulation and the improvement of the stability of the active agent. [ABSTRACT FROM AUTHOR]

Six pectins with 35% to 91% methoxylation degree were purified and characterized to encapsulate Crystal Violet (CV). Amidated low methoxylated pectin (ALMP) was selected based on microsphere morphologies, aqueous solubility, viscosity and the effect of calcium concentration. Pectin microspheres were stabilized with Arabic gum (AG) and optimized according to the loading. Microspheres composed of 2.0% ALMP-1.0% AG crosslinked with 450 mM calcium(II) were able to encapsulate 217 ± 2 μM CV. Optical microscopy of the gels revealed spheroid microspheres with 250 ± 50 μm diameter containing homogenous CV distribution. Dried microspheres observed by SEM and epifluorescence showed a highly shrinkable matrix keeping the spheroidal morphology. Low relative viscosity of the ALMP-AG-CV solutions was found compared to ALMP and ALMP-AG. The Young moduli (60–80 Pa) of ALMP-AG microspheres by texturometric analysis indicated that the CV could interfere with the gel crosslinking. Raman spectroscopy analysis suggested some interaction of CV nucleophilic center within the matrix. FTIR of the matrix showed largest shifts in the carbonyl and carboxylate groups probably associated to H-bridges. CV stability studies performed on ALMP-AG microspheres, synthetized from polymer solutions with pH values above and below pectin pKa and showed faster CV release rates in presence of ionic strength. [ABSTRACT FROM AUTHOR]

The effect of adding shorter alginate fragments highly enriched in α- l -guluronic acid (oligoG) on the Young’s modulus of the Ca-induced alginate hydrogels were determined using nanoindentation. Ca-alginate gels using two low and one high molecular weight alginate, with increasing amount of added oligoG, were prepared at constant 20 mM total Ca 2+ by in situ release of the cation. Differences in the effect on the mechanical properties of increasing amount of oligoG to the various alginate samples were attributed to their different capability to support network connectivity by junction zone formation. Upon decreasing the fractional Ca-saturation of all the α- l -guluronic acid residues (G) present, F sat , by increasing the oligoG concentration, the lower molecular weight alginates displayed the largest reduction in Young’s modulus. This was suggested to be due to the few sequences of α- l -guluronic acid residues making up potential zones engaging in network connectivity of this alginate. Similar trends were observed for a low molecular weight alginate with larger fraction of G. The higher molecular weight sample displayed less reduction of Young’s modulus associated with increasing concentration of oligoG. The consequences of reduction in effective, mean junction zone functionality and associated increase in sol fraction with added oligoG on the elastic properties thus depend on the chain length of the alginates. These finding suggest that effects of added oligoG on Ca-induced alginate gelation should connect the effect on junction zone formation to those mediating network connectivity. [ABSTRACT FROM AUTHOR]

Gellan gum microspheres were obtained by ionotropic gelation technique, using the trivalent ion Al3+. The percentage of entrapment efficiency ranged from 48.76 to 87.52% and 22randomized full factorial design demonstrated that both the increase of polymer concentration and the decrease of crosslinker concentration presented a positive effect in the amount of encapsulated drug. Microspheres size and circularity ranged from 700.17 to 938.32 μm and from 0.641 to 0.796 μm, respectively. The increase of polymer concentration (1–2%) and crosslinker concentration (3–5%) led to the enlargement of particle size and circularity. However, the association of increased crosslinker concentration and reduced polymer content made the particles more irregular.In vitroandex vivotests evidenced the high mucoadhesiveness of microspheres. The high liquid uptake ability of the microspheres was demonstrated and the pH variation did not affect this parameter. Drug release was pH dependent, with low release rates in acid pH (42.40% and 44.93%) and a burst effect in phosphate buffer pH (7.4). The Weibull model had the best correlation with the drug release data, demonstrating that the release process was driven by a complex mechanism involving the erosion and swelling of the matrix or by non-Fickian diffusion. [ABSTRACT FROM PUBLISHER]

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. [ABSTRACT FROM AUTHOR]

In the present work, 5% (w/w) canola oil-in-water submicron emulsions containing sodium alginate were investigated as β-carotene (0.05% w/w) carriers. O/w emulsions prepared via spontaneous emulsification were Tween-80 (SA, 1 and 1.5% w/w) stabilised. Ionotropic gelation of the o/w emulsions' continuous phase via in situ Ca 2+ release, in the presence (sheared o/g emulsions) or absence (quiescent o/g emulsions) of mechanical stirring (1000 rpm, 6 h) was conducted. β-Carotene chemical stability in both o/w and o/g emulsions following 65 day storage periods at 4, 20 and 37 °C, as well as its bioaccessibility under in vitro oro-gastro-intestinal digestion conditions were evaluated. Oxidative degradation rates of β-carotene ranged from 0.22 to 2.77%/day. Although Ca 2+ -mediated gelation of o/w emulsions’ aqueous phase enhanced β-carotene chemical stability, oxidative degradation rates between quiescent o/g (0.07–1.42%/day) and sheared o/g (0.19–1.50%/day) emulsions were comparable. Based on the activation energies of β-carotene degradation calculated by the Arrhenius kinetic model, sheared o/g emulsions exerted the lowest storage temperature dependency, followed by the quiescent o/g and SA containing o/w emulsions. Moderate (ca. 27%) to high (ca. 48%) bioaccessibility of β-carotene was achieved in quiescent and sheared o/g emulsions respectively, showing no dependency on SA content. Contrarily, β-carotene bioaccessibility was reduced from ca. 29–16% for 1 and 1.5% SA containing o/w emulsions. Digesta micellar fractions of o/g emulsions exerted smaller lipid droplet size and lower surface tension values compared to the SA containing o/w emulsions. Therefore, it was postulated that enhanced β-carotene bioaccessibility in o/g emulsions was associated with their higher colloidal stability throughout gastrointestinal passage. [ABSTRACT FROM AUTHOR]

Target-specific MRI contrast agent based on super-paramagnetic iron oxide–chitosan-folic acid (SPIONP-CS-FA) nanoparticles was fabricated by using an ionotropic gelation method, which involved the loading of SPIONPs at various concentrations into CS-FA nanoparticles by electrostatic interaction. The SPIONP-CS-FA nanoparticles were characterized by ATR-FTIR, XRD, TEM, and VSM techniques. This study revealed that the advantages of this system would be green fabrication, low cytotoxicity at iron concentrations ranging from 0.52 mg/L to 4.16 mg/L, and high water stability (pH 6) at 4 °C over long periods. Average particle size and positive zeta-potential of the SPIONP-CS-FA nanoparticles was found to be 130 nm with narrow size distribution and 42 mV, respectively. In comparison to SPIONP-0.5-CS nanoparticles, SPIONP-0.5-CS-FA nanoparticles showed higher and specific cellular uptake levels into human cervical adenocarcinoma cells due to the presence of folate receptors, while in vivo results (Wistar rat) indicated that only liver tissue showed significant decreases in MR image intensity on T 2 weighted images and T 2 * weighted images after post-injection, in comparison with other organs. Our results demonstrated that SPIONP-CS-FA nanoparticles can be applied as an either tumor or organ specific MRI contrast agents. [ABSTRACT FROM AUTHOR]

The synergistic effects of the polysaccharides chitosan (CS) and hyaluronic acid (HA) formulated into hybrid nanoparticles are promising for drug delivery. In the present work, we performed a detailed analysis of the molecular interactions involved in the TPP-assisted ionotropic gelation of CS hybrid nanoparticles with the objective of investigating the impact of HA inclusion on the particle formulation and on the in vitro release of insulin (INS) as a protein cargo. To do that, an in-depth thermodynamic study was carried out by isothermal titration calorimetry (ITC), nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC) techniques. Such analysis allowed us to elucidate the type and extent of interactions established by INS within the hybrid nanoparticles and to get further knowledge on the nature of its release mechanism in vitro. Overall, INS release from the CS nanoparticles was thermodynamically driven, and when including HA a weaker INS binding to the nanoparticles, hence, a faster release rate in vitro were observed. As a negative polyelectrolyte, HA might have sterically blocked the activated sites of CS, such as the amino groups, through chain entanglement, thereby, attenuating the competitive binding interactions of INS. As a consequence, INS might have experienced a spatial exclusion onto the surface of the hybrid nanoparticles to a greater extent which, in turn, would explain its initial abrupt release. [ABSTRACT FROM AUTHOR]

In the present work, the intragastric structuring ability of o/w emulsions either stabilised (1–4%, w/w of sodium alginate (SA)) or structured with sheared ionic gel (1–3%, w/w of SA crosslinked with Ca 2+ ) in the absence (saliva and gastric phases constituted of deionised water) or presence of in vitro pre-absorptive conditions (physiological simulated saliva and gastric fluids) was investigated. Visualisation of the morphological aspects of the gastric chymes, in the absence of multivalent counterions, demonstrated that SA stabilised systems underwent a remarkable swelling in the pH range of 2–3, whilst at the same pH range, ionic SA gel structured systems maintained their major structure configuration. When the aforementioned systems were exposed to physiological intragastric fluids, a reduction of the length and the hydrodynamic volume of the alginate fibres was detected regardless the structuring approach. On their exposure to physiological intragastric conditions (pH = 2), SA stabilised emulsions underwent sol–gel transition achieving a ca. 3- to 4-order increase of storage modulus (at 1 Hz). In the case of ionic sheared gel structured emulsions, exposure to physiological intragastric fluids resulted in a 10-fold reduction ability of their acid structuring ability, most likely due to the dialysis of egg-box dimer conformations by monovalent cations and protons and the sterical hindering of hydrogen bonding of MM and GG sequences under acidic conditions. Using of non-physiological simulated intragastric fluids was associated with overestimated structuring performance of SA regardless its physical state. [ABSTRACT FROM AUTHOR]

In an earlier established gel-casting process, the biopolymer alginate is cross-linked with Ca 2+ -ions released through the temperature controlled dissolution of calcium iodate-particles (Ca(IO 3 ) 2 ). In this study, aluminum acetate (AlAc) is compared to Ca(IO 3 ) 2 as an alternative temperature controlled cross-linker for an alginate–alumina slurry. Both cross-linkers are characterized regarding gel-forming properties, resulting microstructure, impurities, mechanics of sintered parts and the ability of joining ceramic blocks in the green state via connecting gelation with and without adding slurry. Rheological measurements show that both cross-linker have a similar gelling behavior and lead to gelled blocks of high quality. AlAc-particle create a denser and more homogenous microstructure, while Ca(IO 3 ) 2 -particles induce pores, abnormal grain growth and lower mechanical values. Nevertheless Ca(IO 3 ) 2 shows excellent joining properties which makes it a suitable alternative to pressure joining. In summary, AlAc is an excellent alternative cross-linker but Ca(IO 3 ) 2 remains the method of choice for joining gelled bodies. [ABSTRACT FROM AUTHOR]

Propranolol hydrochloride is sympatholytic nonselective beta blocker. It is used to treat hypertension, anxiety and panic. Propranolol loaded hydrogel beads were prepared using chitosan, sodium bicarbonate and glyoxal by ionotropic gelation method. The preformulation study performed on combination of drug with polymer by FT-IR suggested that they were compatible with each other. The formulation ofhydrogel beads were done by applying 32 full factorial design. The surface morphology studied by scanning electron microscope revealed irregular shape hydrogel beads. All prepared hydrogel beads were evaluated for particle size, drug entrapment efficiency, in-vitro releases study and swelling ratio. Optimized formulation showed good swelling in 0.1 N HCl up to 24 h maintaining the integrity of formulation. The in-vitro release of propranolol hydrochloride from optimized hydrogel beads was more than 80% in controlled manner. Hence it could be concluded that propranolol hydrochloride loaded hydrogel beads prepared by using combination of chitosan with glyoxal (crosslinking agent) sustained the release of propranolol HCl more than 24 h in a predetermined manner for the effective management of hypertension. [ABSTRACT FROM AUTHOR]

The aim of this work was to formulate chitosan (CS)-based nanoparticles (NPs) loaded with ketorolac tromethamine (KT) intended for topical ocular delivery. NPs were prepared using ionic gelation method incorporating tri-polyphosphate (TPP) as cross-linker. Following the preparation, the composition of the system was optimized in terms of their particle size, zeta potential, entrapment efficiency (EE) and morphology, as well as performing structural characterization studies using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The data suggested that the size of the NPs was affected by CS/TPP ratio where the diameter of the NPs ranged from 108.0 ± 2.4 nm to 257.2 ± 18.6 nm. A correlation between drug EE and the corresponding drug concentration added to the formulation was observed, where the EE of the NPs increased with increasing drug concentration, for up to 10 mg/mL. FT-IR and DSC revealed that KT was dispersed within the NPs where the phosphate groups of TPP were associated with the ammonium groups of CS. Thein vitrorelease profile of KT from CS NPs showed significant differences (p < 0.05) compared to KT solution. Furthermore, mucoadhesion studies revealed adhesive properties of the formulated NPs. The KT-loaded NPs were found to be stable when stored at different storage conditions for a period of 3 months. Theex vivocorneal permeation studies performed on excised porcine eye balls confirmed the ability of NPs in retaining the drug on the eye surface for a relatively longer time. These results demonstrate the potential of CS-based NPs for the ocular delivery of KT. [ABSTRACT FROM PUBLISHER]

The preparation of chitosan nanoparticles in combination with pectins, as additional mucoadhesive biopolymers, was investigated. Pectins from apple and from citrus fruit were considered; polygalacturonic acid was taken as a reference. Tripolyphosphate was used as an anionic cross-linker. Two different techniques were compared, namely the coating and the blending. Coated nanoparticles (NPs) in the ratio pectin:NPs from 2:1 to 5:1 evidenced that the size of NPs increased as the amount of pectin (both from apple and citrus fruit) was increased. In particular, for NPs coated with pectin from citrus fruit the size ranges from 200 to 260 nm; while for NPs coated with pectin from apple the size ranges from 330 to 450 nm. A minimum value of Z-potential around − 35 mV was obtained for the ratio pectin:NPs 4:1, while further addition of pectin did not decrease the Z-potential. Also blended NPs showed a dependence of the size on the ratio of the components: for a given ratio pectin:tripolyphosphate the size increases as the fraction of chitosan increases; for a low ratio chitosan:pectin a high amount of tripolyphosphate was needed to obtain a compact structure. The effect of the additional presence of loaded proteins in chitosan-pectin nanoparticles was also investigated, since proteins contribute to alter the electrostatic interactions among charged species. FT-IR and DSC characterization are presented to confirm the interactions between biopolymers. Finally, the biocompatibility of the used materials was assessed by the chorioallantoic membrane assay, confirming the safety of the materials. [ABSTRACT FROM AUTHOR]

The properties of protein-containing micro- and nanoparticles that were produced from alginate and chitosan using the methods of layer-by-layer polyelectrolyte adsorption and ionotropic gelation have been compared. The encapsulation efficiency of proteins (aprotinin, interferon, and human insulin), the size and ζ-potential of the particles, the mucin binding, and the protein release under physiological conditions have been studied. The prospects for the possible mucosal application of the particles are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The GQDs@Bio-MOF(Cu) was prepared via an eco-friendly approach. • GQDs@Bio-MOF(Cu) showed high naproxen loading efficiency. • NAP@GQDs@Bio-MOF(Cu) was coated with CMS and CS to obtain controlled NAP release. • HT29 cells viability assay presented biocompatibility of CMS@CS/(GQDs@Bio-MOF(Cu)). In the present investigation, for the first time, bio metal–organic frameworks (Bio-MOFs) were synthesized with glutamic acid (Glu) as a biocompatible organic linker and copper as a metal node in presence of presynthesized citric acid-based graphene quantum dots (GQDs) (GQDs@Bio-MOF(Cu)). SEM analysis obtained a diameter of Bio-MOF(Cu) around 1 μm. Naproxen (NAP) as a model of a nonsteroidal anti-inflammatory drug was loaded on GQDs@Bio-MOF(Cu) at about 53.1 %. NAP@GQDs@Bio-MOF(Cu) showed fast drug release, hence, for achieving the system with controlled and delayed intestinal delivery the NAP@GQDs@Bio-MOF(Cu) was coated with carboxymethyl starch (CMS) and chitosan (CS). The physicochemical properties of the products were evaluated employing well-known characterization techniques. NAP release results displayed that the CMS@CS can afford gastric protection and is a more suitable drug carrier for colon targeting. Also, the CMS@CS/(NAP@GQDs@Bio-MOF(Cu)) showed biodegradability (68.7 %), biocompatibility (78.3 %), and antibacterial (75 µg·mL−1) features. Consequently, the finding displayed that the CMS@CS/(NAP@GQDs@Bio-MOF(Cu)) potentially could be employed for encapsulation, protection, and delivery of NAP in pharmaceutical applications without any concern about bacterial infections. [ABSTRACT FROM AUTHOR]

This study aims to develop hydrogels from apple pectin (AP) and hogweed pectin (HP) in multiple ratios (4:0; 3:1; 2:2; 1:3; and 0:4) using ionotropic gelling with calcium gluconate. Rheological and textural analyses, electromyography, a sensory analysis, and the digestibility of the hydrogels were determined. Increasing the HP content in the mixed hydrogel increased its strength. The Young's modulus and tangent after flow point values were higher for mixed hydrogels than for pure AP and HP hydrogels, suggesting a synergistic effect. The HP hydrogel increased the chewing duration, number of chews, and masticatory muscle activity. Pectin hydrogels received the same likeness scores and differed only in regard to perceived hardness and brittleness. The galacturonic acid was found predominantly in the incubation medium after the digestion of the pure AP hydrogel in simulated intestinal (SIF) and colonic (SCF) fluids. Galacturonic acid was slightly released from HP-containing hydrogels during chewing and treatment with simulated gastric fluid (SGF) and SIF, as well as in significant amounts during SCF treatment. Thus, new food hydrogels with new rheological, textural, and sensory properties can be obtained from a mixture of two low-methyl-esterified pectins (LMPs) with different structures.

Context:Polymers have been largely explored for the preparation of nanoparticles due to ease of preparation and modification, large gene/drug loading capacity, and biocompatibility. Various methods have been adapted for the preparation and characterization of chitosan nanoparticles.Objective:Focus on the different methods of preparation and characterization of chitosan nanoparticles.Methods:Detailed literature survey has been done for the studies reporting various methods of preparation and characterization of chitosan nanoparticles.Results and conclusion:Published database suggests of several methods which have been developed for the preparation and characterization of chitosan nanoparticles as per the application. [ABSTRACT FROM PUBLISHER]

Chitosan cross-linked pentasodium tripolyphosphate particles were produced by ionotropic gelation. The aim of this study was to evaluate the influence of the molar mass and deacetylation degree of chitosan and of the concentration of pentasodium tripolyphosphate in the production of chitosan micro/nanoparticles. The obtained charge ratio (R±), mean particle size, surface electrical charge, polydispersity index, and tendency of particle aggregation were selected as dependent variables. Results demonstrated that stable particles exhibited a high zeta potential value, between +62 and +68 mV. Particles were produced in different size ranges controlling the R± between the positively charged chitosan and negatively charged pentasodium tripolyphosphate. Chitosan micro/nanoparticles were successfully prepared via the ionic gelation method controlling R±, therefore the association of an active ingredient to a micro/nanoparticle allows the molecule to intimately interact with specific structures, to overcome barriers and to prolong its residence time in the target. Chitosan cross-linked pentasodium tripolyphosphate particles are expected to be a good approach for active ingredients formulation in the agrofood sector and related industries. [ABSTRACT FROM AUTHOR]

Alginate solutions in the presence of bivalent ions can form ionic cross-linked gels. In particular gelation conditions the gel structure can be characterized by great anisotropy with the presence of straight capillaries along a preferential direction. These materials can find applications mainly in high-tech sectors, like tissue engineering, where the gel characteristics play a crucial role. Despite the need of mastering the capillary formation and properties, the process remains a poorly known problem, and its development is left to trial and error procedures. In this work a quantitative approach to the description of the capillary formation process has been developed. The theory proposed by Treml et al. (2003) has been implemented and extended to an alginate different from the one used in that study and two different ions (calcium and copper). Some of the model parameters have been derived through simple measurements; others have been scaled using proper scaling equations. Experiments have been performed in different gelation conditions, varying alginate and ionic solution concentrations, to highlight the effects of these parameters on the anisotropic structure and to validate the model. In all the analyses done, the model has performed nicely showing a good reliability in the prediction of gel characteristics like capillary formation, capillary length and process time. [ABSTRACT FROM AUTHOR]

Alginates form gels in the presence of various divalent ions, such as Ca 2+ that mediate lateral association of chain segments. Various procedures exist that introduce Ca 2+ to yield alginate hydrogels with overall homogeneous or controlled gradients in the concentration profiles. In the present study, the effect of adding oligomers of α- l -guluronic acid (oligoGs) to gelling solutions of alginate was investigated by determination of the cluster growth stimulated by in situ release of Ca 2+ . Three different alginate samples varying in fraction of α- l -guluronic acid and molecular weights were employed. The cluster growth was determined for both pure alginates and alginates with two different concentrations of the oligoGs employing dynamic light scattering. The results show that addition of oligoG slows down the cluster growth, the more efficient for the alginates with higher fraction of α- l -guluronic acid, and the higher molecular weight. The efficiency in delaying and slowing the cluster growth induced by added oligoG were discussed in view of the molecular parameters of the alginates. These results show that oligoG can be added to alginate solutions to control the cluster growth and eventually also transition to the gel state. Quantitative relation between the concentration of added oligoG, type and molecular weight of the alginate, and concentration, can be employed as guidelines in tuning alginate cluster growth with specific properties. [ABSTRACT FROM AUTHOR]

This work aims to investigate the effect of polyelectrolyte complexation (PEC) on the stability of protein–alginate hydrogels in simulated gastrointestinal fluids. The properties of two types of hydrogels based on pea protein isolates (PPI) and on canola protein isolates (CPI) were compared. The molecular structure of hydrogels was assessed by FTIR and their thermal stability was tested by DSC and TGA. The swelling capacity of hydrogels was tested in distilled water, simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) without enzymes. CPI beads showed higher swelling capacity than PPI beads in all swelling media. In SIF, relatively higher swelling, an increase in volume and partial degradation were observed for all hydrogel beads. In addition, the swelling of beads in SIF was found to be dependent on PEC with chitosan. Moreover, degradation tests in SGF and SIF media with enzymes were performed to assess the effect of PEC on the stability of hydrogels. The results indicated that PEC had no influence on the stability of hydrogels in SGF but significantly delayed the degradation of hydrogel under SIF conditions. These findings suggest that PEC could be utilized to modify protein–alginate hydrogels to create matrices for prolonged release applications. [ABSTRACT FROM AUTHOR]

Chitosan is a linear aminopolysaccharide that has been widely used for the formation of chitosan-based nanoparticles by ionic gelation with sodium tripolyphosphate (TPP). Often, the experimental design used to obtain these systems does not take into consideration important variables, such as the degree of acetylation (DA) and the molecular weight ( M w ) of chitosan. In this work, we studied the formation of chitosan-TPP nanoparticles with chitosan samples of varying DA and M w (DA0 ∼ 0–47% and M w ∼ 2.5–282 kDa). We addressed the influence the degree of space occupancy and the degree of crosslinking on the physical properties of chitosan-TPP nanoparticles. Nanoparticles that comprised chitosan of DA ∼ 0–21.7% behaved differently than those made of chitosan of DA ∼ 34.7–47%. We attributed these differences to the polymer conformation and chain flexibility of the distinct chitosans in solution. Moreover, chitosan of high M w were found to have a stronger preference for incorporating into the formed nanoparticles than do low- M w ones, as determined by SEC-HPLC. These results open new perspectives to understand the formation of chitosan nanoparticles by the ionic gelation technique. [ABSTRACT FROM AUTHOR]

Metformin hydrochloride is oral antidiabetic drug belonging to the biguanide class of drugs. Metformin hydrochloride is used to treat non-insulin dependent diabetes mellitus (NIDDM-Type II diabetes), alone or in combination with other hypoglycaemic agents. It is also used in the treatment of polycystic ovary syndrome. The objective of the study was to prepare the sodium alginate beads of antidiabetic drug Metformin hydrochloride to provide sustained release effect. Five batches (F1-F5) were formulated by using varying concentration of drug and polymer. In this method drugs were blended with biopolymer and sodium alginate in different ratio (1:1, 1:2, 1:3, 1:4 and 1:5) and calcium chloride was used as a cross-linking agent. Metformin loaded Alginate beads were formulated by ionotropic gelation and prepared beads were evaluated with respect to its particle size, surface characteristics, entrapment effiency, swelling index, loss on drying, total moisture content and in-vitro release of drug. From the above investigation it was found that the biopolymer will serve as a better alternative to develop the alginate bead. [ABSTRACT FROM AUTHOR]

Resveratrol (Res), a polyphenolic phytoalexin, had shown a promising therapeutic efficacy towards treatment of periodontal disease in vitro . This work aims to develop Res microbeads with strong mucoadhesion using thiolated alginate (TA) for local treatment of periodontal pockets. TA was synthesized by conjugating sodium alginate (A) with thioglycolic acid. Product was evaluated by IR and DSC. Both A and A:TA Res microbeads with different ratios were prepared by ionotropic gelation method. Formulations were evaluated regarding their entrapment efficiency (%EE), swelling index (SI), in vitro drug release and kinetics. Selected formula was examined for its mucoadhesion by ex vivo wash-off method, surface morphology using scanning electron microscope (SEM) and stability against light. Clinical evaluation is running.Formation of TA was confirmed. %EE for all formulations ranged from 83.72 to 104.54%. Results revealed a significant lower SI for TA rich formulation (A/TA 1:1) along with slower release rate and zero-order kinetics, in addition to powerful mucoadhesion; 26% remaining of microbeads after 1 h, compared to 2% for A microbeads. SEM micrographs showed a rough surface with drug precipitation. The formula maintained its %EE after 5 h exposure to direct sunlight. A/TA 1:1 mucoadhesive Res microbeads could be exploited as a prolonged drug release devices for intrapocket application. [ABSTRACT FROM AUTHOR]

Polymer nanoparticles (NPs) are promising systems for the delivery of protein drugs, as they enhance circulation half-life, reduce degradation, and increase selectivity of the encapsulated agent. Among the different methods for the preparation of protein-loaded NPs, ionotropic gelation-which exploits cross-linking between charged groups in the polymer and counterions in the protein solution-has been extensively investigated for chitosan NPs. The present study aims at exploring the possibility to apply the method to prepare BSA-loaded polyurethane NPs. A poly(ε-caprolactone)/poly(ethyleneglicol)-based polyurethane bearing tert-butyloxycarbonyl-protected amino groups was synthesized by a two-step synthesis procedure. Amino functionalities were exposed under acidic conditions, as confirmed by ninhydrin assay, and then exploited to obtain ionic cross-linking with sodium tripolyphosphate counterions. The effect of polymer and sodium tripolyphosphate concentration on particles size and BSA encapsulation has been investigated, showing that the PUR concentration plays a major role. Small particles, at 300 nm, with high BSA loading (90%) have been obtained. Sustained BSA release and low burst effect (20%) have been observed, indicating good interaction between the protein and the polymer matrix. The study highlights the possibility of introducing alternative polymers to improve loading and release of proteins from NPs obtained through the ionotropic gelation method. [ABSTRACT FROM AUTHOR]

Ionotropic gelation and density phase separation of high affinity salt ions and alginate gels have been investigated for the functional application of salt water desalination. Partial desalination has been demonstrated using ion chromatography, electron microscopy and electron dispersive X-ray spectroscopy. Despite being only a partial process, these findings show a less complex energy expenditure process compared with conventional desalination by the utilisation of alginate as a complete replacement for filter technology and pumping. This research has identified how this desalination process functions at a range of salinities between full strength seawater and freshwater and is simultaneously able to recycle alginate as a potential replacement sustainable chemical vector to filtration technology. [ABSTRACT FROM AUTHOR]

• Barium-alginate beads containing 1- dodecanol were formulated for chocolate temperature controlling. • PCM@Ba-Alg beads showed an excellent capacity for latent heat storage (∼149.15 J/g). • Exudation problems of EPCMs beads were overcome by applying a polyurea coating. • 60 g PCM@Ba-Alg@polyurea exhibited buffering of ̴ 86 min to the chocolate in the TCP box. Encapsulated phase change materials (EPCMs) are widely explored as potential materials for storing thermal energy as they can absorb and release large amounts of latent heat when they undergo a phase transition at a constant temperature. EPCMs comprise two components: (i) a core composed of organic, inorganic, or eutectic PCMs, and (ii) a shell made of organic or inorganic materials. In this context, the current study attempts to synthesize and characterize a novel 1-dodecanol embedded barium alginate (Ba-Alg) beads and utilized in a packaging box. 1-Dodecanol embedded barium alginate beads were synthesized via ionotropic gelation, and the obtained beads were subsequently coated with polyurea shell to stop phase change material exudation (leakage). Morphologies of the beads were analyzed using a field emission-scanning electron microscope, while attenuated total reflectance-infrared spectroscopy was used to explore the functional group nature and their interaction between PCM and porous Ba-Alg matrix. Phase change behavior and thermal stability of capsules were evaluated using a differential scanning calorimeter and thermogravimetric analyzer. The latent heat of beads (PCM embedded Barium alginate beads; PCM@Ba-Alg) without polyurea coating was ∼149.15 J/g, while with polyurea coating was of ∼76.67 J/g. Polyurea over PCM@Ba-Alg (PCM@Ba-Alg@polyurea) beads improved thermal stability and prevented PCM leakage. PCM@Ba-Alg@polyurea beads were used around the inner walls of the TCP (temperature controlled packaging) box to maintain the desired temperature (∼ 25 °C) and taste of the bubbly surface chocolate for a longer duration. 60 g of PCM@Ba-Alg@polyurea capsules could delay 86.28 min for 240 g of chocolate to attain 25 °C. 1-Dodecanol within Ba-Alginate beads through the inotropic gelation method which was further coated with polyurea through interfacial polymerization. [Display omitted] [ABSTRACT FROM AUTHOR]

Chitosan (CHI) pentasodium tripolyphosphate (TPP) nanoparticles have been studied extensively for biomedical applications. However, these studies do not attempt to develop a scalable and reproducible process. In this study, we investigated the production of CHI/TPP nanoparticles using a high concentration (5 mg/mL) of chitosan at three different pHs (4, 5 and 5.5) in a scalable batch process using tank reactor with baffles and a cowles impeller. The smallest size was obtained when the pH was 4, but the polydispersity index (PDI) was the highest; the opposite behavior was observed at pH 5.5. CHI/TPP nanoparticles were also studied in terms of physico-chemical stability in two extreme situations: increasing the pH of the CHI/TPP nanoparticles to 7 and adding nanoparticles to PBS buffer (pH 7.4). In both cases, the buffer conditions modulated the nanoparticle properties and time was also an important parameter. Plasmid pVAX1Luc was used for incorporation into CHI/TPP nanoparticles (CHI:TPP 5.8:1 m/m) at 10 and 20% DNA/CHI w/w. The final DNA-loaded nanoparticles ranged in size from 142 to 248 nm and 190 to 254 nm for 10 and 20% DNA, respectively. The final physico-chemical properties and process differences in CHI/TPP nanoparticle production have a small influence on in vitro transfection studies. [ABSTRACT FROM AUTHOR]

The present work aimed at development of ranolazine loaded floating biomaterial gellan beads to enhance its site specific absorption. The beads obtained by ionotropic gelation method using sodium bicarbonate as gas-forming agent, calcium chloride and chitosan as a crosslinker were evaluated for physicochemical properties and in vitro performance. Yield and entrapment efficiency varied from 90 to 97% and 58 to 81% respectively. Surface topography revealed spherical microparticles with evenly distributed pores. Differential scanning calorimetry and powder X-ray diffraction pointed out amorphous nature of the drug. Effect of formulation variables on floating lag time and time required for 50% drug release was studied using Box-Behnken factorial design. The beads displayed good in vitro floatability in 0·1 N HCl with initial burst release followed by a controlled release up to 10 h whereas slow drug release was observed in phosphate buffer pH 6·8; probably due to decreased drug solubility and accelerated internal gelation through ionic crosslinking of gellan monomers. The beads, when studied in non-everted rat stomach and intestinal sac models, demonstrated twofold decrease in flux and apparent permeability coefficient as compared to pure ranolazine. Floating gellan beads proved advantageous for controlling the release and enhancing therapeutic activity of ranolazine. [ABSTRACT FROM AUTHOR]

This paper describes the production, purification, and immobilization of l-asparaginase II (ASNase II) in chitosan nanoparticles (CSNPs). ASNase II is an effective antineoplastic agent, used in the acute lymphoblastic leukemia chemotherapy. Cloned ASNase II gene ( ansB) in pAED4 plasmid was transformed into Escherichia coli BL21pLysS (DE3) competent cells and expressed under optimal conditions. The lyophilized enzyme was loaded into CSNPs by ionotropic gelation method. In order to get optimal entrapment efficiency, CSNP preparation, chitosan/tripolyphosphate (CS/TPP) ratio, and protein loading were investigated. ASNase II loading into CSNPs was confirmed by Fourier transform infrared (FTIR) spectroscopy, and morphological observation was carried out by transmission electron microscopy. Three absolute CS/TPP ratios were studied. Entrapment efficiency and loading capacity increased with increasing CS and TPP concentration. The best ratio was applied for obtaining optimal ASNase II-loaded CSNPs with the highest entrapment efficiency. Size, zeta potential, entrapment efficiency, and loading capacity of the optimal ASNase II-CSNPs were 340 ± 12 nm, 21.2 ± 3 mV, 76.2% and 47.6%, respectively. The immobilized enzyme showed an increased in vitro half-life in comparison with the free enzyme. The pH and thermostability of the immobilized enzyme was comparable with the free enzyme. This study leads to a better understanding of how to prepare CSNPs, how to achieve high encapsulation efficiency for a high molecular weight protein, and how to prolong the release of protein from CSNPs. A conceptual understanding of biological responses to ASNase II-loaded CSNPs is needed for the development of novel methods of drug delivery. [ABSTRACT FROM AUTHOR]

Nanotechnology is currently employed as a tool to fight more efficiently against human pathogens. Nanoparticles can be prepared from a variety of materials such as protein, biodegradable polymers and synthetic polymers.Tamarindus indicaLinn. or tamarind is one of the most important biodegradable polymer. In the present study, chemically modified polymer of tamarind ‘carboxymethyl tamarind kernel polysaccharide’ (CMTKP) is used for the synthesis of nanoparticulate formulation. Antibacterial activity of CMTKP was analysed which was then enhanced by incorporating a flouroquinolone antibiotic, ciprofloxacin to it. Ciprofloxacin-loaded CMTKP nanoparticles were synthesised via ionotropic gelation technique. Nanosuspension so formed was lyophilised by addition of a cryoprotectant. Nanoparticles obtained were characterised for its particle size, morphology and stability. Interaction studies were confirmed by Fourier transform infrared spectroscopy (FT-IR). Antibacterial activities of ciprofloxacin, CMTKP and ciprofloxacin-loaded CMTKP nanoparticles were tested against two Gram negative and positive bacteria. The antibacterial assay results revealed greatest zone of inhibition by ciprofloxacin-loaded CMTKP nanoparticles inMicrococcus luteus. Toxicity analysis of the prepared formulation was carried out on vero cell lines via resazurin assay which revealed its minimum toxicity. [ABSTRACT FROM PUBLISHER]

Objective: This investigation aimed to synthesize amphiphilic hexyl amidic derivative of alginate to be used in the preparation of glibenclamide-loaded release system of improved dissolution rate. Materials and methods: Hexyl amine was associated to the activated carboxylic acid moieties of alginate to synthesize alginate hexyl amide polymer (AHAP). This polymer in comparison to alginate was used in different concentrations for preparing beads containing glibenclamide by an ionic gelation using Ca++ as gelling ion. The prepared beads were characterized by DSC, FTIR and scanning electron microscope. The swelling behavior, drug loading capacity and release behavior were studied. Results and discussion: The results showed that the prepared AHAP beads were smaller in size and more spherical. The surface was highly corrugated with much and wider pore size. The beads showed a high drug loading capacity and efficacy that was affected by the polymer concentration. The drug release rate from AHAP beads reached 100% after 4, 8 and 12 hours in comparison to 75.3%, 73.2% and 69.2% from alginate beads at 3%, 2% and 1% polymer concentrations, respectively. Conclusion: It can thus be concluded that the amphiphilic AHAP-based bead is a simple and efficient delivery system of promising industrial significance for the improvement of the dissolution rate. [ABSTRACT FROM AUTHOR]

Mucoadhesive microbeads of low methoxyl pectin were prepared, either alone or in combinations with hydroxypropyl methyl cellulose, sodium carboxymethyl cellulose, methyl cellulose and carbopol 934P, by ionotropic gelation. The influence of copolymers on mucoadhesivity, microbeads characteristics and in vitro drug release was investigated. Spherical microbeads with 78.69±0.59 to 85.84±0.78% drug entrapment and of a size of 791.90±4.58 to 960.88±4.61 µm were prepared. The concentration of cross linking agent affects the encapsulation efficiency of microbeads. Mucoadhesiveness of microbeads was dependent on the concentration of copolymers. The formulations exhibiteda pH-dependent release and followed diffusion-controlled first-order kinetics. [ABSTRACT FROM AUTHOR]