Chitosan-Tripoly Phosphate (CS-TPP) Synthesis Through Cross-linking Process: the Effect of Concentration Towards Membrane Mechanical Characteristic and Urea Permeation
Crosslinking reactions are required to modify the functional groups on chitosan and to increase the number of active groups of chitosan. In this study crosslinking reaction of tripolyphospate (TPP) groups on chitosan was conducted in order to produce membrane which functions as candidate of hemodialysis membrane. The mole ratio between chitosan and NaTPP was varied to obtain the best composition of modified materials. Study of TPP concentration effect towards membrane characteristics was conducte durea permeation ability. The resulting membrane was then characterized including tests of thickness, water uptake, tensile strength and membrane hydrophilicity. The results showed that the best composition of membrane occurred in the addition of 0.691 g of NaTPP proved byin creasing water uptake (150%), its highest mechanical strength and releasing the percentage of urea permeation by 44%.
Distribution and Assessment of Fe and Mn in the Coastal Sediments of Sendang Biru, East Java, Indonesia
The high presence of heavy metals in sediment can affect the ecological and biological systems in East Java Indonesia. To monitor the environmental status of Fe and Mn, we investigated geochemical fraction and distribution of these metals at 8 sites in the sediment of Sendang Biru. BCR and Tessier sequential leaching methods were applied to leach Fe and Mn, respectively, due to high precision and accuracy of these methods. The pattern of geochemical fractions in sediment samples showed the maximum leached levels of Fe and Mn (>50%) in residual fractions in Sendang Biru Beach, indicating the natural effects surrounding sites. The portions of Fe and Mn in non-residual fractions located at Sendang Biru Port were higher compared with the site in the adjacent sea, indicating these metals were derived possibly from anthropogenic effects. The assessment from CF and Igeo calculations of Fe and Mn in sediment samples showed that the sediment near the Sendang Biru Port was moderately contaminated by Fe and Mn.
Chitosan: a unique polysaccharide for drug delivery.
The aim of this review is to give an insight into the many potential applications of chitosan as a pharmaceutical drug carrier. The first part of this review concerns the principal uses of chitosan as an excipient in oral formulations (particularly as a direct tableting agent) and as a vehicle for parenteral drug delivery devices. The use of chitosan to manufacture sustained-release systems deliverable by other routes (nasal, ophthalmic, transdermal, and implantable devices) is discussed in the second part.