Properties Of Hydroxypropyl Cellulose Research Articles

Effect of Plasticizer Concentration on the Properties of Hydroxypropyl Cellulose (HPC) Film Enhanced with Sodium Dehydroacetate

Effect of Plasticizer Concentration on the Properties of Hydroxypropyl Cellulose (HPC) Film Enhanced with Sodium Dehydroacetate

Aqueous solutions of hydroxypropyl cellulose, Tween 80 and their binary mixtures: Colloid-chemical aspects

Tensiometry, dynamic light scattering, and rheology have been used to study the colloid-chemical properties of hydroxypropyl cellulose, Tween 80, and binary mixtures thereof in an aqueous medium and at water/decane and water/air interfaces. The efficiency of a reduction in the interfacial energy under dynamic and static conditions, the surface activity of the components, capability of self-organization in bulk and at interfaces, as well as emulsifying efficiency of the systems, have been analyzed. It has been found that, in a narrow concentration range and at a certain ratio of the components, they exhibit a synergetic effect with respect to a reduction in the interfacial energy, with this effect being due to the formation of a Tween 80–polymer bilayer via hydrogen bonding between hydroxyl groups of hydroxypropyl cellulose and ethoxy units of Tween 80.

Influence of Chlorpheniramine Maleate on Topical Hydroxypropylcellulose Films Produced by Hot-Melt Extrusion

The objective of this investigation is to study the influence of chlorpheniramine maleate (CPM) on the chemical and physical–mechanical properties of hydroxypropylcellulose (HPC) hot-melt extruded films without the use of a traditional plasticizer. HPC films containing CPM in concentrations of 1, 5, and 10 wt% were prepared by hot-melt extrusion utilizing a Randcastle Microtruder® (Model #RCP-0750) with a 6-in. flex-film die. The physical–mechanical properties including tensile strength and percent elongation were determined on an Instron according to the ASTM standards. Glass transition temperatures and thermal analysis of the extruded films were determined utilizing a DSC 2920 Modulated DSC and Thermal Analyst 2000 software. The crystalline properties of the drug, polymer, and extruded films were studied via wide angle X-ray diffraction (XRD) using a Philips Vertical Scanning Diffractometer (Type 42273, Philips Electronic Instrument, Mount Vernon, NY). Gel permeation chromatography was used to study the stability of the polymer matrix as a function of different concentrations of CPM and processing conditions. CPM functioned as an effective plasticizer, increasing percent elongation and decreasing tensile strength in a concentration dependent manner. All three concentrations of extruded films exhibited a 10- to 12-fold decrease in tensile strength in contrast to a fourfold increase in percent elongation when testing was performed perpendicular to flow vs. in the direction of flow. The drug was also shown by XRD and DSC data to be in solution in the HPC matrix within the films up to the 10% level. In addition, CPM functioned as a processing aid in the extrusion of hot-melt films, stabilizing the weight-average molecular weight of HPC and allowing for film processing at lower temperatures. CPM could potentially be a candidate antihistamine for transdermal or transmucosal applications in film devices prepared by hot-melt extrusion technology.

Rheological Characterization of Hydroxypropylcellulose Gels

The present paper describes the rheological properties of hydroxypropylcellulose (HPC) gels formulated in propylene glycol (PG), water, ethanol, and mixtures of these components. The effects of molecular weight, polymer concentration, and solvent composition on the apparent viscosity and flow characteristics have been studied by continuous shear rheometry. The HPC gels are shear thinning and do not exhibit significant yield or hysteresis in their rheograms. The apparent viscosity increases with increasing molecular weight and concentration of the polymer, as expected. Although not so pronounced at lower concentrations (≤ 1.5%), HPC gels tend to become increasingly non-Newtonian with increasing molecular weight at higher polymer concentrations (3%). A mathematical model has been proposed for the prediction of viscosities of HPC gels. There exists a high degree of dependence on molecular interactions between various solvent molecules in the prediction of mixture viscosities in ternary systems. The effects of solvent composition on the viscoelastic behavior of these gels have also been examined by dynamic mechanical analysis. The HPC gels are highly viscoelastic and exhibit greater degrees of elasticity with increased PG content in ternary solvent mixtures with water and ethanol. The study also suggests that dynamic mechanical analysis could prove to be a useful tool in the determination of zero-shear viscosities, viscosities that are representative of most realistic situations.