Hydrogels are crosslinked polymers which has the ability to absorb water in aqueous media.Hydrogels are being prepared by different methods such as suspension polymerization, chemical or physical crosslinking, solution polymerization, radiation polymerization etc., and using different types of polymers. Hydrogels exhibiting swelling mechanism have been extensively used as drug carriers in the controlled drug delivery systems. The wide application of these biomaterials is due to its characteristics such as swelling in the aqueous environment, specific response to the pH, temperature, ion, electric stimuli sensitivity etc., Hydrogels of  biocompatible polymers have good loading capacity and so widely used for the encapsulation of drugs which can be targeted to the specific sites. Since the rate of drug diffusion from hydrogels can be controlled, these materials are potentially useful as drug delivery systems. Controlled release of many drugs including anticancer and antiviral agents has been efficiently done using hydrogels. Especially various anti-HIV drugs have been successfully formulated as hydrogel systems for the controlled release and prolonged action.  Bilayer and multilayer hydrogels have grown importance in recent days, wherein a burst release followed by controlled release could be achieved for superior therapeutic action at reduced dose and side effects. Also the efficiency of incorporating more than one drug in different layers of hydrogels is being investigated to improve combination therapy for various disorders.
Abstract Online: 21-Jan-2015

Microspheres as drug delivery systems have been used widely for oral delivery in the pharmaceuticals formulation. Alginates have received much attention as biodegradable polymer for controlled protein delivery. Ovalbumin was used as model antigen. The aim of the present research was to evaluate physical characteristics of unlyophilized and lyophilized ovalbumin-loaded alginate microspheres produced using aerosolisation technique. Crosslinking agent of BaCl₂ and CaCl₂ were studied. Physical characteristics of ovalbumin-loaded alginate microspheres were evaluated in terms of encapsulation efficiency, yield, particle size, surface morphology and protein integrity. In vivo immune response was studied using hemagglutination test by measuring antibody titre. High entrapment efficiency of unlyophilized ovalbumin-loaded alginate microspheres using crosslinker BaCl₂ and CaCl₂ of above 80% and loading of above 65% was produced. Entrapment efficiency of lyophilized ovalbumin-loaded alginate microspheres using 10% lactose lyoprotectant and maltodextrin were 46% and 54% respectively. For protein loading, ovalbumin-loaded alginate microspheres lyophilized using lactose was 28% and using maltodextrin was around 35% respectively. The microspheres size of less than 8μm of all formulas using BaCl₂ and CaCl₂ both lyophilized and unlyophilized were spherical in shapes and formed smooth surface. Ovalbumin maintained its integrity after release from alginate microspheres showing ovalbumin’s 45 kDa molecular weight indicated its stability has been protected by this delivery system after exposure to acid condition. In vivo immune response by hemaglutination test of lyophilized ovalbumin-loaded alginate microspheres with CaCl₂ crosslinker consist of 10% lactose or 10% maltodextrin and unlyophilized microspheres using CaCl₂ crosslinker showed higher antibody titres than ovalbumin control and blank microspheres. Whereas, unlyophilized ovalbumin-alginate microspheres using Ba²⁺ crosslinking agent resulted antibody titre as low as control and blank microspheres. However, No significant effect of immune response was found between microspheres lyophilized with lactose and maltodextrin. In conclusion, ovalbumin-loaded alginate microspheres crosslinked using CaCl₂ are potential as oral delivery systems and results indicated that lyoprotectants were involved in protecting ovalbumin entrapped in alginate microspheres therefore able to deliver antigen to the target site in order to induce antibody response.
Abstract Online: 22-Jan-2015

Dendrimers are the nano-sized structures which consist of tree-like branches with many functional terminal ends and are the monodisperse macromolecules which contain symmetric branching units built around a small core molecule. The properties and the applications of these structures depend on the functional terminals. One of the important properties of Dendrimers is its solubility which improves the bioavailability of the insoluble drugs and used as a carrier for drug delivery. Capsaicin can be used against many kinds of cancers. In the present study, the dendrimers were synthesized and capsaicin was bound to it. The successful binding of capsaicin onto the dendrimers was confirmed by the fourier transform infrared spectroscopy (FT-IR) and UV-Vis spectroscopy. The solubility was checked with various solvents and their biocompatibility was evaluated in zebra fish embryos. The results revealed that the prepared dendrimers were biologically compatible in the invivo conditions.
Abstract Online: 27-Jan-2015

Background: Although Superabsorbent Polymer (SAP) microsphere has been useful in treatment of multiple and large hepatocellular carcinoma, efficient loading procedure of cisplatin onto SAP was not established. Loading efficiency of cisplatin was evaluated from the viewpoint of passive concentration gradient and ionic strength.Methods: To load cisplatin into SAP particle, 50mg of cisplatin powder was dissolved in three manners of aqueous solutions: (a) 50mg of cisplatin powder plus 35ml of warmed physiological saline solution (0.9%), (b) 5ml of physiological saline solution (0.9%) plus a half of solution (5ml) of the product made from 50mg of cisplatin powder in 10ml of iohexol 350mgI/ml, and (c) 10ml of iohexol 350mgI/ml plus 0.25ml of 10% NaCl solutionResults: Cisplatin dissolved sufficiently in all the three methods. Average amounts of loaded cisplatin into SAP particles were 1.7mg in solution (a), 6.6mg in solution (b), and 11.8mg in solution (c). Since alteration of ionic strength in the method (c) significantly affect the extent of SAP swelling, addition of 0.25ml of 10% NaCl was unquestionably necessary. Release of cisplatin from SAP was evidently gradual, showing 83.1% after 6 hours in static elution experiment and 68.6% after 1 hour in dynamic elution experiment. Conclusions: Cisplatin-loaded SAP may act as a drug delivery system for treatment of liver cancer, and loading of cisplatin should be consciously performed considering cisplatin concentration and ionic strength
Abstract Online: 27-Jan-2015

A first clicically-used, fully-bioabsorbable poly(L-lactic acid) (PLLA) stent was coated with microcrystals of paclitaxel (PTX), antiproliferative agent through seeding and/or crystal growing technique to investigate the drug properties on the stent surface and drug release behavior from the stent. PTX particles subject to only seeding process was peeled off after stent compression, while less PTX was coated on the stent subject to only crystal growth without seeding. PLLA stent with both processes could stably maintain an increased amount of PTX on its surface. The maximum amount of initial release (10 μg/cm2) was found in the sample only with seeding, which decreased to 3 μg/cm2 or below after one week. Also in the PLLA stent only with crystal growth, release amount decreased after one week. In the PLLA stent with seeding and crystal growth, formation of needle-like PTX crystals on the surface resulted in decreased initial release and lower solubility after hydration in phosphate buffered solution compared to other types of stent with different procedures. It is suggested that both seeding and crystal growth are required for stable application of PTX on fully-bioabsorbable PLLA stent and needle-like crystals containing water have lower aqueous solubility resulting in decreased PTX release
Abstract Online: 31-March-2015

Two simple, sensitive and specific gas and liquid chromatographic methods are developed and validated for quantification of articaine in human whole blood. Liquid-liquid extraction with n-hexane-isoamyl alcohol 90:10 (v/v) is used for sample preparation in both methods. GC-FID (gas chromatographic-flame ionization detection) analysis is performed with a gas chromatograph equipped with a split-splitless injector, flame-ionization detector and HP INNOwax capillary column. Reverse phase LC-PDA (liquid chromatographic-photo diode array detection) analysis is carried out using a C18 Hypersil GOLD column with two mobile phases: acetonitrile-water 10 mM ammonium acetate 50:50  (v/v), pH 7, and acetonitrile-buffer solution sodium acetate 10 mM and acetic acid 10 mM 50:50 (v/v), pH 4.7, respectively.  A comparison between GC-FID and LC-PDA is performed, as well as between internal  and external standard as quantification methods in LC. The best results in terms of accuracy (as recovery) and precision (as relative standard deviation) are obtained in GC (95-98% and 5.5-8.2%, respectively) with lidocaine internal standard and in LC (96-102% and 4.2-6.1%, respectively) with external standard and mobile phase pH 4.7. This method is applied in a preliminary pharmacokinetic study to three healthy volunteers to whom anesthesia with articaine is performed
Abstract Online: 31-March-2015