Alginate-poloxamer beads for clotrimazole delivery: Molecular interactions, mechanical properties, and anticandidal activity.

Calcium alginate (CA) beads loaded with clotrimazole (CZ) were modified by adding poloxamer (PLX) in this study. Blends of PLX188 or PLX407 into sodium alginate (SA) dispersions caused a decrease in the SA zeta potential and led to viscosity synergism. SA with carboxyl and hydroxyl groups can interact with the hydroxyl groups of PLX via hydrogen bonding. A stronger interaction of SA with PLX407 was found when compared to the interaction between SA and PLX188. The PLX-CA beads gave a higher CZ entrapment efficiency than the CA beads. The highest PLX content used created an amorphous form of CZ in the beads because of the CZ solubilization by the PLX micelles. The addition of 0.5 or 1% w/v PLX can strengthen the CZ-loaded CA beads. Furthermore, the PLX-CA beads display a lower water uptake than the CA beads. PLX micellization can enhance CZ release and enhance the efficacy of CZ against Candida albicans. This study indicates that the molecular interaction of SA with PLX and the PLX micellization of CZ can improve the characteristics of CZ-loaded CA beads, which offer good potential for use as drug delivery systems or drug reservoirs in tablets for oral candidiasis.

Modification of alginate beads using gelatinized and ungelatinized arrowroot (Tacca leontopetaloides L. Kuntze) starch for drug delivery.

Arrowroot (Tacca leontopetaloides L. Kuntze) starch in gelatinized and ungelatinized forms was used to modify the characteristics of calcium alginate (CA) beads containing diclofenac sodium (DS). Sodium alginate (SA) was able to molecularly interact with ungelatinized starch (UGS) granules and gelatinized starch (GS) gel via hydrogen bonding mechanisms in the dispersions, leading to viscosity synergism before cross-linking. The GS-CA beads provided a significantly higher DS entrapment efficiency than the UGS-CA beads. The added UGS retarded the water uptake of the CA beads, resulting in slower DS release profiles in purified water and a longer lag time of DS release in pH 6.8 phosphate buffer. On the other hand, GS enhanced water uptake and accelerated the DS release of the beads in both media. Moreover, the 1%GS-CA beads displayed slower DS release than the CA and 1%UGS-CA beads in pH 6.8 phosphate buffer when simulated gastro-intestinal (GI) condition was used. This study shows that UGS and GS obtained from Tacca leontopetaloides L. Kuntze have good potential to improve drug entrapment efficiency of the CA beads, and the DS-loaded GS-CA beads can be used as multiunit dosage forms for sustaining drug release in simulated GI condition.

Alginate-caseinate composites: Molecular interactions and characterization of cross-linked beads for the delivery of anticandidals.

Polysaccharide-protein composites offer potential utility for the delivery of drugs. The objectives of this work were to investigate the molecular interactions between sodium alginate (SA) and sodium caseinate (SC) in dispersions and films and to characterize calcium alginate (CA) beads mixed with SC for the delivery of fluconazole (FZ) and clotrimazole (CZ). The results demonstrated that SA could interact with SC, which caused a viscosity synergism in the dispersions. Hydrogen bonding between the carboxyl or hydroxyl groups of SA and the amide groups of SC led to the formation of soluble complexes that could reinforce the CA beads prepared by calcium cross-linking. The SC-CA beads provided higher drug entrapment efficiency, lower water uptake and erosion, and slower drug release than for the CA beads. The loaded FZ was an amorphous form, but CZ crystals were embedded in the bead matrix due to the low water solubility of this drug. However, SC micellization could enhance the water solubility and efficacy of CZ against Candida albicans. This finding indicates that SA can interact with SC via hydrogen bonding to form complexes and that the anticandidal-loaded SC-CA beads can be used as drug delivery systems and drug reservoirs in tablets for oral candidiasis.

Particle agglomeration of chitosan-magnesium aluminum silicate nanocomposites for direct compression tablets.

Exfoliated nanocomposites of chitosan-magnesium aluminum silicate (CS-MAS) particles are characterized by good compressibility but poor flowability. Thus, the aims of this study were to investigate agglomerates of CS-MAS nanocomposites prepared using the agglomerating agents water, ethanol, or polyvinylpyrrolidone (PVP) for flowability enhancement and to evaluate the agglomerates obtained as direct compression fillers for tablets. The results showed that the addition of agglomerating agents did not affect crystallinity, but slightly influenced thermal behavior of the CS-MAS nanocomposites. The agglomerates prepared using water were larger than those prepared using 95% ethanol because high swelling of the layer of chitosonium acetate occurred, allowing formation of solid bridges and capillary force between particles, leading to higher flowability and particle strength. Incorporation of PVP resulted in larger agglomerates with good flowability and high strength due to the binder hardening mechanism. The tablets prepared from agglomerates using water showed lower hardness, shorter disintegration times and faster drug release than those using 95% ethanol. In contrast, greater hardness and more prolonged drug release were obtained from the tablets prepared from agglomerates using PVP. Additionally, the agglomerates of CS-MAS nanocomposites showed good carrying capacity and provided desirable characteristics of direct compression tablets.