Enhancement of Moisture Protective Properties and Stability of Pectin through Formation of a Composite Film: Effects of Shellac and Plasticizer.

The aim of this investigation was to develop the high moisture protective ability and stable pectin through the design of composite films based on varying shellac concentrations. A film casting method was applied to prepare a free film. The moisture protective properties and mechanical properties were investigated. The findings was the composite films exhibited the reductions in the hydrophilicity, water vapor permeability, and the moisture content compared with pectin films. The single and composite films were then study for their stability at 40 °C and 75% RH for 90 d. Among the concentrations of shellac, 50% (w/w) could improve stability in terms of moisture protection after 90 d of storage, whereas lower concentrations of shellac (10% to 40%) could not achieve this. However, the higher shellac content also contributed to weaker mechanical properties. The mechanical improvement and stability of composite films with the incorporation of plasticizers were further investigated. Polyethylene glycol 400 and diethyl phthalate at a concentration of 10% were used. The results indicated that both plasticizers could enhance the mechanical characteristics and had a slight effect on moisture protection. The stability of pectin in terms of moisture protective properties could, therefore, be modified through the fabrication of composite films with hydrophobic polymers, that is, shellac and the addition of proper plasticizers to enhance mechanical properties, which could offer wide applications for edible film in food, agro, and pharmaceutical industries. PRACTICAL APPLICATION: The composite film with 50% shellac could improve moisture protective properties of pectin film. Adding a plasticizer could build up the higher mechanical characteristics of composite film. Stability of pectin could be modified by fabrication of composite films with proper content of shellac and plasticizer.

Physicochemical and powder characteristics of various citrus pectins and their application for oral pharmaceutical tablets.

The physicochemical and powder properties of citrus pectins varying in molecular weight and degree of esterification (DE) were characterized. All the pectins were flake particles with average sizes of around 84-107µm in diameter. They were amorphous solids and classified as being from slightly to moderately hygroscopic. Pomelo pectin possessed passable to poor flowability while the others were classified as having fair flowability. Heckel's analysis indicated that all pectins underwent plastic deformation under compression. Pectin with a lower%DE and higher molecular weight produced higher tensile strength tablets. The swelling kinetics of all pectins during the first 4h demonstrated Fickian diffusion and the gel erosion in distilled water of higher%DE pectin was slower. Pectins, at 10% w/w in theophylline matrix tablets, provided fast drug release while those at 50% w/w, delayed drug release which reached 97-100% within 6-8h.

Pectin-based bioadhesive delivery of carbenoxolone sodium for aphthous ulcers in oral cavity.

The objective of this study was to prepare and evaluate the pectin-based dosage form for buccal adhesion. Carbenoxolone sodium, which is used for the treatment of aphthous ulcers in oral cavity, was used as a model drug. The pectin buccal discs were prepared by direct compression. The water uptake and erosion of pectin disc increased progressively with the swelling time. The bioadhesion of dried pectin discs decreased when either the discs were hydrated or the buccal tissue was wet with a small volume of medium. The influencing factors such as pectin type, pectin to lactose ratio, and sweetener type on the formulations were investigated. The results demonstrated that buccal discs prepared from pectin with a high degree of esterification (DE) showed a weaker and more friable characteristic than that with low DE. Decreasing pectin to lactose ratio resulted in the high dissolution rate with low bioadhesive properties. Addition of sweetener in the formulations also affected the hardness, friability, and bioadhesive properties of the discs. The pectin discs containing sweetening agent showed a higher drug release than those without sweetener. The results suggested that pectin-based bioadhesive discs could be used to deliver carbenoxolone sodium in oral cavity.

Wax-incorporated emulsion gel beads of calcium pectinate for intragastric floating drug delivery.

The purpose of this study was to prepare wax-incorporated pectin-based emulsion gel beads using a modified emulsion-gelation method. The waxes in pectin-olive oil mixtures containing a model drug, metronidazole, were hot-melted, homogenized and then extruded into calcium chloride solution. The beads formed were separated, washed with distilled water and dried for 12 h. The influence of various types and amounts of wax on floating and drug release behavior of emulsion gel beads of calcium pectinate was investigated. The drug-loaded gel beads were found to float on simulated gastric fluid if the sufficient amount of oil was used. Incorporation of wax into the emulsion gel beads affected the drug release. Water-soluble wax (i.e. polyethylene glycol) increased the drug release while other water-insoluble waxes (i.e. glyceryl monostearate, stearyl alcohol, carnauba wax, spermaceti wax and white wax) significantly retarded the drug release. Different waxes had a slight effect on the drug release. However, the increased amount of incorporated wax in the formulations significantly sustained the drug release while the beads remained floating. The results suggest that wax-incorporated emulsion gel beads could be used as a carrier for intragastric floating drug delivery.

Mucoadhesive properties of various pectins on gastrointestinal mucosa: an in vitro evaluation using texture analyzer.

Mucoadhesive performance of various pectins with different degrees of esterification and molecular weights was examined with porcine gastrointestinal (GI) mucosa, i.e. buccal, stomach, small intestine and large intestine, using a texture analyzer equipped with mucoadhesive platform. The instrumental parameters and test conditions such as pre-hydration time of pectin disc, contact time, contact force, test speed of probe withdrawal, GI tissue and test medium were also studied. Two parameters derived from texture analysis, namely maximum detachment force (F(max)) and work of adhesion (W(ad)), were used as parameters for comparison of mucoadhesive performance. The results indicated that degree of hydration of pectin disc affected the mucoadhesive properties. The mucoadhesion of pectin increased with the increased contact time and contact force, but not by the increased probe withdrawal speed. Tissue from different parts of GI tract and test medium also influenced the mucoadhesion. Pectins showed a stronger mucoadhesion on large intestinal mucosa than on small intestinal mucosa. The mucoadhesive properties of pectins on gastric mucosa depended on pH of the medium; a higher F(max) and W(ad) in a pH 4.8 medium than a pH 1.2 medium was revealed. Additionally, pectin showed a significantly higher mucoadhesion than carbomer934P in most of the GI mucosa tested. The results also demonstrated that the mucoadhesive performance of pectins largely depended on their characteristics, i.e. higher degree of esterification and molecular weight gave a stronger mucoadhesion. These findings suggest that pectin can be used as a mucoadhesive carrier for GI-mucoadhesive drug delivery systems.

Swelling and erosion of pectin matrix tablets and their impact on drug release behavior.

The aim of this study was to investigate swelling and erosion behaviors of hydrophilic matrix tablets using pectin and their impact on drug release. The matrix tablets were prepared by direct compression using different types of pectin. Swelling and erosion studies of pectin matrix tablets were carried out in various media. The pectin matrix tablets formed a continuous gel layer while in contact with the aqueous medium undergoing a combination of swelling and erosion. The swelling action of pectin matrices was controlled by the rate of its hydration in the medium. Release studies showed that the swelling and erosion of matrices influenced the drug release. The extent of matrix swelling, erosion and diffusion of drug determined the kinetics as well as mechanism of drug release from pectin-based matrix tablets. The release data showed a good fit into the power law or the Korsmeyer-Peppas equation indicating the combined effect of diffusion and erosion mechanisms of drug release.