Transdermal Delivery of Nicotine Using Pectin Isolated from Durian Fruit-Hulls-Based Polymer Blends as a Matrix Layer

Many natural polymers with various chemical structures are used to prepare transdermal patches. Pectin is a one interesting type of polymer because it can control drug release when used in transdermal patches. In Thailand, the waste from durian fruit-hulls is a major problem for the environment. However, the pectin from it can be isolated under acid conditions and used to prepare transdermal patches for nicotine delivery which has not yet been reported. As the isolated pectin is a natural polymer, the film made from isolated pectin is a brittle; therefore, adding a low protein natural rubber latex (LPNRL) polymer was needed to increase its flexibility. The transdermal patches were amorphous and had T_g values ranging from 81.0 to 93.3 °C. Moisture uptake, swelling ratio, and erosion values of the patches were significantly decreased after addition of LPNRL, which resulted in low hydrophilicity. The in vitro release and permeation of nicotine depends on the hydrophilicity of the patches. The kinetic models for in vitro release and permeation of nicotine were Higuchi model and zero order, respectively. In conclusion, pectin isolated from fruit-hulls of Mon Thong durians is an effective polymer to control the release of nicotine. It also is an option that could solve the environmental problems caused by durian fruit-hulls waste.     

Use of Isolated Pectin from a <Emphasis Type="Italic">Cissampelos pareira</Emphasis>-Based Polymer Blend Matrix for the Transdermal Delivery of Nicotine

Pectin is a natural biopolymer, and a major component of a complex heterogeneous polysaccharide found in the primary cell walls and middle lamella of plant tissues. This paper used pectin isolated from Cissampelos pareira (Krueo Ma Noy) leaves to prepare the matrix layer for nicotine transdermal patches. However, the patch was a brittle film, thus, deproteinized natural rubber latex (DNRL) was blended to improve flexibility of the patch. Here we present for the first time a preparation study exploring the suitability of isolated pectin blends to serve as drug carriers and the mechanism controlling the release patterns of nicotine. The hydrophilicity of the patches was found to decrease when increasing the DNRL ratio. Differential scanning calorimetry and X-ray diffraction experiments were used to characterize the interactions between the investigated drugs and the matrix polymers. In vitro studies showed that the isolated pectin blends were an effective matrix for controlled nicotine release. The release and permeation patterns of nicotine depend on the hydrophilicity of the patches. The kinetic models of nicotine were found to be a Higuchi model and zero order for in vitro release and skin permeation, respectively.     

Preferential flow path development and its influence on long-term PRB performance: column study

The operating life of an Fe(0)-based permeable reactive barrier (PRB) is limited due to chemical reactions of Fe(0) in groundwater. The relative contributions from mineral precipitation, gas production, and microbial activity to the degradation of PRB performance have been uncertain. In this controlled field study, nitrate-rich, site groundwater was treated by Fe(0) in large-volume, flow-through columns to monitor the changes in chemical and hydraulic parameters over time. Tracer tests showed a close relationship between hydraulic residence time and pH measurements. The ionic profiles suggest that mineral precipitation and accumulation is the primary mechanism for pore clogging around the inlet of the column. Accumulated N(2) gas generated by biotic processes also affected the hydraulics although the effects were secondary to that of mineral precipitation. Quantitative estimates indicate a porosity reduction of up to 45.3% near the column inlet over 72 days of operation under accelerated flow conditions. According to this study, preferential flow through a PRB at a site with similar groundwater chemistry should be detected over approximately 1 year of operation. During the early operation of a PRB, pH is a key indicator for monitoring the change in hydraulic residence time resulting from heterogeneity development. If the surrounding native material is more conductive than the clogged Fe-media, groundwater bypass may render the PRB ineffective for treating contaminated groundwater.     

Chromium steel from chromite ore processing residue — A valuable construction material from a waste

As species we humans generate excessive amounts of waste and hence for sustainability we should explore innovative ways to recover them. The primary objective of this study is to demonstrate an efficient and optimum way to recover chromium and iron from chromite ore processing residues (COPR) for the production of chrome steel and stainless steel. In Hudson County, New Jersey, there are more than two million tons of leftover COPR. Part of COPR was used as fill materials for construction sites, which spread the problem to a larger area. With high solubility along with their toxicity leached chromate from COPR is threatening the environment as well as human health. In this research, COPR was thermally treated to recover iron with chromium by applying techniques used in steel manufacturing. An extensive experimental program was performed using a Thermo-Gravimetric Analyzer (TGA) and bench scale tests to thermally treat the processed chromium contaminated soils with carbon and sand at varying temperatures and under reducing environment. The optimum chemical composition of COPR and additives to be used in the melts were evaluated based upon the thermodynamic properties of the mixture to ensure good phase separation, least amounts of iron and chromium oxides in the slag and minimum variability of final product (steel or iron with chromium). The impact of other oxides on the steel making process was evaluated to minimize the adverse impact on the process. The research demonstrated the feasibility of recovering a valuable construction material (chrome steel) from a waste (COPR).     

Formulation Design of Oral Strip-Films Based on PVA/PVP Polymer Blends for Nicotine Delivery

Journal of Polymers and the Environment - This work prepared oral strip-film for nicotine delivery using polyvinyl alcohol and polyvinylpyrrolidone as polymeric film and glycerin as a plasticizer....     

Investigation of gas production and entrapment in granular iron medium

A method for measuring gas entrapment in granular iron (Fe0) was developed and used to estimate the impact of gas production on porosity loss during the treatment of a high NO3- groundwater (up to approximately 10 mM). Over the 400-d study period the trapped gas in laboratory columns was small, with a maximum measured at 1.3% pore volume. Low levels of dissolved H2(g) were measured (up to 0.07+/-0.02 M). Free moving gas bubbles were not observed. Thus, porosity loss, which was determined by tracer tests to be 25-30%, is not accounted for by residual gas trapped in the iron. The removal of aqueous species (i.e., NO3-, Ca, and carbonate alkalinity) indicates that mineral precipitation contributed more significantly to porosity loss than did the trapped gases. Using the stoichiometric reactions between Fe0 and NO3-, an average corrosion rate of 1.7 mmol kg-1 d-1 was derived for the test granular iron. This rate is 10 times greater than Fe0 oxidation by H2O alone, based on H2 gas production. NO3- ion rather than H2O was the major oxidant in the groundwater in the absence of molecular O2. The N-mass balance [e.g., N2g and NH4+ and NO3-] suggests that abiotic reduction of NO3- dominated at the start of Fe0 treatment, whereas N2 production became more important once the microbial activity began. These laboratory results closely predict N2 gas production in a separated large column experiment that was operated for approximately 2 yr in the field, where a maximum of approximately 600 ml d-1 gas volumes was detected, of which 99.5% (v/v) was N2. We conclude that NO3- suppressed the production of H2(g) by competing with water for Fe0 oxidation, especially at the beginning of water treatment when Fe0 is highly reactive. Depends on the groundwater composition, gas venting may be necessary in maintaining PRB performance in the field.     

Polymer Blended Deproteinized Natural Rubber Reservoirs for Nicotine Transdermal Patches: In vitro Drug Release,Permeation Study,and Stability Test

Journal of Polymers and the Environment - The objective of this research was to prepare reservoir-type nicotine transdermal patches (R-NTPs) using deproteinized natural rubber latex (DNRL) blends...