Chitosan Used In Pharmaceutical Formulations : A Review

Tarun Kumar Satpathy

Excipient has been singing the key roles in all pharmaceutical formulation. From the time when polymer science has urbanized, polymer is one of the majority imperative groups among those excipients.

Attributable to having multitalented natures, polymers are being far and wide acknowledge in pharmaceutical grassland. Chitosan is one of the polymers, which is having countless characters to be a high-quality excipient. Chitosan has been used in the blueprint of may different types of drug carriers for various administration rules such as oral, bucal, nasal, transdermal, parenteral, vaginal, cervical, intrauterine and rectal. It has been proved by formerly completed investigate effort.

Introduction:-

Chitosan is a natural cationic biopolymer consequent commencing the hydrolysis of chitin. One perceptible improvement of this substance is that it can be obtained from ecologically sound natural sources, namely crab and shrimp shell wastes. Together with chitin, Chitosan is well thought-out the second most profuse polysaccharide subsequent to cellulose. However contrasting cellulose, the employ of Chitosan as an excipient in pharmaceutical formula is a pretty new development. But Chitosan has been widely premeditated in the biomedical field and has been found to be highly biocompatible. In addition to the good biocompatibility of Chitosan and the abundance of natural sources of the material, Chitosan has a number of enviable properties that put together study of it attention-grabbing.

Anticipation from a Polymer:-

The Polymer, which is generally, used in case of pharmaceutical formulation, having some general properties. Those properties should have reflected on the polymer to obtain a good place in polymer science for drug delivery.

In general, an ideal polymeric drug delivery system should have following characteristics. ^{1, 2, 3}

§It has to be biocompatible and degradable (i.e., it should degrade in vivo to smaller fragments which can then be excreted from the body)

§The degradation products should be nontoxic and should not create an inflammatory response.

§Degradation should occur within a reasonable periods of time as required by the application.

§Easy and cheap to manufacture

§Specific cellular interaction that can be used to target drugs to specific cell types.

§Capable of attachments with other molecules.

Times gone by Chitosan:-

Henri Braconnot, director of the botanical garden in Nancy, France, first discovered Chitosan in 1811. Bracannot pragmatic that a definite substance (chitin) set up in mushrooms did not dissolve in sulfuric acid. Some 20 years later, there was a man who authored an article on insects in which he renowned that analogous substance was present in the structure of insects as well as the structure of plants. He then called this amazing substance as “chitin”. Basically, the name chitin is derived from Greek, connotation “tunic” or “envelope”. The perception was further known in 1843 when Lassaigne demonstrated the presence of nitrogen in chitin.

After the discovery of chitin, the name “chitosan” emerged in the scene. Rouget while experimenting with chitin first discovered it. Accordingly, Rouget observed that the compound of chitin could be manipulated through chemical and temperature treatments for it to become soluble. Then, it was in 1878 when Ledderhose identified chitin to be made of glucosamine and acetic acid.

It was not actual by the early 20th century; quite a lot of researches took chitosan as their subject of study. They then involved sources of chitin, including crab shells and fungi. Over the last 200 years, the traveling around of chitosan has taken on many different forms. Several other researchers continue to build on the original finding of Bracannot, discovering new uses for chitin as they find different forms of it in nature. ^{4, 5}

Origin of Chitosan:-

Chemist always plays molecules. Chitin did not escape from it. Chemist did not spare chitin, the polymer either and made Chitosan. Chitin is the primary structural component of the outer skeletons of crustaceans, and of many other species such as molluscs, insects and fungi. Chitosan is most commonly obtaining from crustacean chitin, from crab and shrimp shells wastes. Chitin accounts for approximately 70% of the organic components in such shells. It is a reinforcing material, which occurs in three polymorphic forms, a-, b- and g-chitin. Where hardness in needed a-chitin is found, where flexibility is required b- and g-chitin occur. [25] Chitin is inert in aqueous environment. Chitosan is prepared from chitin to obtain a more reactive polymer. The term Chitosan is used when chitin could be dissolved in weak acid. When chitin is heated in a strong solution of sodium hydrochloride (>40%) at high temperature (90-120^o), ^{6, 7}

Figure1. Structural units of Chitosan and its parent substance chitin, Chitin consists mostly of N-acetyl-D-glucosamine-units (left). During the preparations of Chitosan, most units are deacetylated to D-glucosamine –units (right).

Chemistry:-

Chitosan (Poly[-(1, 4)-2-amino-2-deoxy-D-glucopiranose]) has a structure as shown in figure –2.Chitin is isolated from shells of crustacean( for example shrimp, crab and lobster ) by treating the shells with 2.5 N NaOH at 75 ^oC and with 1.7 N HCl at room temperature for 6 hours. ⁸

Deacetylation can be done by alkaline treatment or by enzymatic reaction. The alkaline deacetylation is carried out by treating chitin with NaOH at high temperature. The degree of deacetylation increases with increasing temperature or NaOH concentration. Chang et.al. Determine the optimum deacetylation is done by mixing 23 ml of 60% NaOH per gram of chitin 170 ^oC. ⁹

Chitin deacetylation by enzymatic reaction is described by Martinou et.al. Chitin deacetylase isolated from Mucor rouxii has been used successfully to deacetylate chitin almost completely (98%). ¹⁰

The polymer differs from chitin in that a majority of the N-acetyl groups in Chitosan is hydrolyzed. The degree of hydrolysis has a significant effect on the solubility and rheological properties of the polymer. The amino group on the polymer has a pKa in the range of 5.5 to 6.5, depending on the source of the polymer. At low pH, the polymer is soluble, with the sol-gel transition occurring at approximate pH 7. The pH sensitivity coupled with the reactivity of the primary amino groups makes chitosan a unique polymer for and drug delivery applications. Chitosan is now available commercially in various molecular weights (50 kDa – 2,000 kDa) and different degree of deacetylation (40% to 90%). ¹¹

Figure2. Chemical structure of Chitosan, The polymer is obtained by the partial deacetylation of naturally occurring polymer, chitin.

Homework of chitosan:-

Production of chitosan was conducted using two Mucoralean strains, Mucor racemosus and Cunninghamella elegans. Chitosan was extracted from mycelia of M. racemosus and C. elegans at different growth phases on YPD medium. In both fungi, chitosan was rapidly produced, while highest yield of extractable chitosan was found in 24h of cultivation in submerged culture. The yield of chitosan isolated from dry mycelia of M. racemosus was about 40% higher than from C. elegans. The degree of N-acetylation of chitosan was 49% in M. racemosus and 20% in C. elegans, and the D-glucosamine contents were about 48% and 90%, respectively.

Disclosed is another process for producing particles of the modified carbohydrate polymer chitosan. Such chitosan particles are "activated" because of the specific steps used in the process. The process involves precipitation of dissolved chitosan from an acid solution thereof by the step-wise addition of neutralizing agent to the solution. A partial neutralization is carried out under shear agitation to form a continuous gel phase having a pH within the range of 5.0 to 6.9. This partially neutralized chitosan gel phase is then further subjected to shear agitation for at least 10 seconds to homogenize the gel phase. The homogenized gel phase is then further neutralized under shear agitation to a pH of above 6.9 to form a gel-like suspension of discrete chitosan particles. ^{12, 13}

Specification of Chitosan:- ¹⁴

General Pharmaceutical Application of Chitosan:-

Chitosan has received considerable attention as a possible pharmaceutical excipient in recent decades due to its good biocompatibility and low toxicity properties in both conventional excipient applications as well as in novel application. Some of the general applications of chitosan in pharmaceutical fields are: ¹⁵

• Diluents in direct compression of tablets.
• Binder in wet granulation
• Slow-release of drugs from tablets and granules
• Drug carrier in microparticle systems
• Films controlling drug release
• Preparation of hydrogels, agent for increasing viscosity in solutions.
• Wetting agent, and improvement of dissolution of poorly soluble drug substances
• Disintegrant
• Bioadhesive polymer
• Site-specific drug delivery (e.g. to the stomach or colon)
• Absorption enhancer (e.g. for nasal or oral drug delivery)
• Biodegradable polymer (implants, microparticles)
• Carrier in relation to vaccine delivery or gene therapy.

Different studies on Chitosan and its derivatives:-

Ø Tozaki and coworkers utilized Chitosan capsules for colon-specific delivery to treat ulcerative colitis. A 5-amino salicylic acid was encapsulated into Chitosan capsules and delivered in vivo to Male Wistar rats after induction of colitis. It was observed that Chitosan capsules disintegrated specifically in the large intestines as compared to the control formulation (in absence of Chitosan), which demonstrated absorption of the drug in small intestines. This data is a representative example of utility of Chitosan for colon-specific delivery. ¹⁶

Ø A novel mucoadhesive polymer was prepared by template polymerization of acrylic acid in the presence of Chitosan for trans mucosal drug delivery system, where that polymer complex was formed between poly (acrylic acid) (PAA) and Chitosan through hydrogen bonding. ¹⁷

Ø Microcrystalline Chitosan (MCCh) may be particularly valuable as an excipient. As a highly crystalline grade of Chitosan base. One specific property of MCCh is its high capacity for retaining water. This property could be advantageous in relation to the development of slow-release formulations because it might facilitate the formation of gels that would control drug release. The pronounced ability of MCCh to form hydrogen bonds could theoretically result in efficient mucoadhesion by MCCh. The properties of MCCh mentioned made it particularly interesting for study as a hydrophilic excipient-controlling rate of drug release from formulations that were also intended to be mucoadhesive in the stomach. ¹⁵

Ø As study says, the mucoadhesive polymers carbomer 934P and Chitosan hydrochloride are able to enhance the intestinal absorption of buserelin in vivo in rats, and may therefore be promising excipients in peroral delivery systems for peptide drugs.¹⁸

Ø A simple carbohydrate polymer glycol Chitosan (degree of polymerization 800 approx) has been investigated fro its ability to form polymeric vesicles drug carries. Chitosan is used because the membrane penetration enhancement of Chitosan polymers offers the possibility of fabricating a drug delivery system suitable for the oral and intranasal administration of gut-labile molecules. Glycol Chitosan modified by attachment of a strategic number of fatty acid pendant groups (11-16 mols %) assembles into unilamellar polymeric vesicles in the presence of cholesterol. These polymeric vesicles are found to be biocompatible and haemocompatible and capable of entrapping water-soluble drugs like bleomycin where the drug polymer ratio was found to be 0.5 units mg. These polymeric vesicles efficiently entrap of water-soluble drugs. ¹⁹

Ø A new Chitosan-based polymer named N-palmitolyl Chitosan (PLCS), which can form micelles in water, has been prepared. Swollen Chitosan coupling with palmitic anhydride in dimethyl sulfoxide (DMSO) carried out the preparation of PLCs. The degree of substitution (DS) of PLCs was in the range of 1.2 – 14.2% and the critical aggregation concentration (CAC) of PLCs micelles was in the range of 2.0 ´ 10^-3 to 37.2 ´ 10^-3 mg/ml. The properties of PLCs micelles such as encapsulation capacity and controlled release ability of hydrophobic model drug ibuprofen (IBU) has evaluated. ²⁰

Ø Intratumoral and local drug delivery strategies have gained momentum recently as a promising modality in cancer therapy. In order to deliver paclitaxel at the tumor site in therapeutically relevant concentration, Chitosan films were fabricated. Paclitaxel could be loaded at 31% wt/wt in films, which were translucent and flexible. Chitosan films containing paclitaxels were obtained by casting method with high loading efficiencies and the chemical integrity of molecule was unaltered during preparation according to study. ²¹

Ø A quaternary derivative chitosan (N-trimethylene chloride Chitosan) was shown to demonstrate higher intestinal permeability than chitosan alone. The TMC derivative was used as a permeation enhancer for large molecules, such as octreotide, a cyclic peptide. Hamman and coworkers showed that the degree of quaternization of TMC influences its drug absorption-enhancing properties. ²²

Ø Chitosan esters, such as Chitosan succinate and Chitosan phthalate have been used successfully as potential matrices for the colon-specific oral delivery of sodium diclofenac. ²³

Ø During a study chitosan, nanoparticles including hydroxylpropylcyclodextrins prepared by the ionic cross linking of chitosan with sodium tripolyphosphate in the presence of cyclodextrins. Two hydrophobic drugs, triclosan and furosemide, were selected as models for complexation with the cyclodextrin and further entrapment in the chitasan nanocarrier. The resulting nanosystems were thoroughly characterized for their size and zeta potential and also for their ability to associate and deliver the complexed drugs. So this new nanosysrem with chitosan offers an interesting potential for the transmucosal delivery of hydrophobic compounds. ²⁴

Ø Guggi and Bernkop attached an enzyme inhibitor to Chitosan. The resulting polymer retained the mucoadhesivity of Chitosan and further prevented drug degradation by inhibiting enzymes, such as trypsin and chymotrypsin. This conjugated Chitosan demonstrated promise for delivery of sensitive peptide drugs, such as calcitonin. ²⁵

Ø Chitosan and randomly methylated b-cyclodextrin (RAMEB) were the most to be studied absorption enhancers for nasal administration recently. From where it has clear that Chitosan and randomly methylated b-cyclodextrin could combine to enhance the absorption and elevate the bioavailability of estradiol after nasal administration. ²⁶

Ø A cationic polymer like chitosan has potential for DNA complexation and may be useful as non-viral vectors for gene therapy application. Chitosan is a natural non-toxic polysaccharide, it is biodegradable and biocompatible, and protects DNA against DNase degradation and leads to its condensation. Hence chitosan can be use to improve the transfection efficiency in vivo and in vitro. ²⁷

Ø Solution formulations based on Chitosan salts having a molecular weight of greater than 100 kD and with a defined degree of deacetylation, have found utility in improving the bioavailability of nasally administrated polypeptides such as insulin, calcitonin, LHRH analogues, parathyroid hormone, growth hormone as well as non-peptide polar compounds useful in the treatment of pain (morphine). ²⁸

Ø Glipizide microspheres containing Chitosan were prepared by simple emulsification phase separation technique using glutaraldehyde as a cross-linking agent. Results of preliminary trials indicate that volume of cross-linking agent, time for cross-linking, polymer –to-drug ratio, and speed of rotation affected characteristics of microspheres. Microspheres were discrete, spherical, and free flowing. The microspheres exhibited good mucoadhesive property in the in vitro wash-off test and showed high percentage drug entrapment efficiency. ²⁹

Ø Some studies developed chitosan/tripolyphosphate nanoparticles that promote peptide absorption across mucosal surfaces. The aim of this work was to microencapsulate protein-loaded chitosan nanoparticles using typical aerosol excipients, such as mannitol and lactose, producing microspheres as carriers of protein-loaded nanoparticles to the lung. The results showed that the obtained microspheres are mostly spherical and possess appropriate aerodynamic properties for pulmonary delivery (aerodynamic diameters between 2 and 3 micron, apparent density lower than 0.45 g/cm3). Moreover, microspheres morphology was strongly affected by the content of chitosan nanoparticles. These nanoparticles show a good protein loading capacity (65-80%), providing the release of 75-80% insulin within 15 min, and can be easily recovered from microspheres after contact with an aqueous medium with no significant changes in their size and zeta potential values. ³⁰

Ø The positively charged polysaccharide chitosan is able to increase precorneal residence time of ophthalmic formulations containing active compounds when compared with simple aqueous solutions. The purpose of the study was to evaluate tear concentration of tobramycin and ofloxacin after topical application of chitosan-based formulations containing 0.3% wt/vol of antibiotic and to compare them with 2 commercial solutions: Tobrex® and Floxal®, respectively. ³¹

Ø In controlled released drug matrices cross linked chitosan sponges has been used as drug carrier system. Here Tramadol hydrochloride, a centrally acting analgesic, was used as a model drug. The sponges were prepared by freeze drying 1.25% and 2.5% (w/w) high and low molecular weight chitosan solution,respectively, using glutaraldehyde as a cross linking agent. The formulation made by this sponges has shown the release data followed the Higuchi model over 12 hours. ³²

Ø Insulin-chitosan nanoparticles were prepared by the ionotropic gelation of chitosan glutamate and tripolyphosphate pentasodium and by simple complexation of insulin and chitosan. The nasal absorption of insulin after administration in chitosan nanoparticle formulations and in chitosan solution and powder formulations was evaluated in anaesthetised rats and/or in conscious sheep. Insulin-chitosan nanoparticle formulations produced a pharmacological response in the two animal models, although in both cases the response in terms of lowering the blood glucose levels was less (to 52.9 or 59.7% of basal level in the rat, 72.6% in the sheep) than that of the nasal insulin chitosan solution formulation (40.1% in the rat, 53.0% in the sheep). The insulin-chitosan solution formulation was found to be significantly more effective than the complex and nanoparticle formulations. The hypoglycaemic response of the rat to the administration of post-loaded insulin-chitosan nanoparticles and insulin-loaded chitosan nanoparticles was comparable. As shown in the sheep model, the most effective chitosan formulation for nasal insulin absorption was a chitosan powder delivery system with a bioavailability of 17.0% as compared to 1.3% and 3.6% for the chitosan nanoparticles and chitosan solution formulations, respectively. ³³

Ø Metronidazole was formulated in mucoadhesive vaginal tablets by directly compressing the natural cationic polymer chitosan, loosely cross-linked with glutaraldehyde, together with sodium alginate with or without microcrystalline cellulose (MCC). Sodium carboxymethylcellulose (CMC) was added to some of the formulations. The drug content in tablets was 20%. Drug dissolution rate studies from tablets were carried out in buffer pH 4.8 and distilled water. Swelling indices and adhesion forces were also measured for all formulations. The formula containing 6% chitosan, 24% sodium alginate, 30% sodium CMC, and 20% MCC showed adequate release properties in both media and gave lower values of swelling index compared with the other examined formulations. This also proved to have good adhesion properties with minimum applied weights. Moreover, its release properties (percentage dissolution efficiency, DE) in buffer pH 4.8, as well as release mechanism (n values), were negligibly affected by aging. Thus, this formula may be considered a good candidate for vaginal mucoadhesive dosage forms. ³⁴

Ø Bring into play of differential stirring speed during the preparation of chitosan microspheres by the chemical cross-linking method may help to obtain chitosan microspheres using a chitosan solution of less than 1% wt/vol concentration. The pharmaceutical attributes of microspheres thus obtained are significantly affected by stirring speed and chitosan concentration as well as their interaction. Effect of change in drug concentration on the pharmaceutical characteristics of drug-loaded chitosan microspheres is more prominent for water-soluble drug. ³⁵

Ø Spray-dried chitosan particles, displaying an irregular surface morphology and diameter of less than two µm, readily adsorbed to lactose-LPD particles following mixing. In contrast with the smooth spherical surface of lactose-LPD particles, spray-dried trimethyl chitosan-lactose-LPD particles demonstrated increased surface roughness and a unimodal particle size distribution (mean diameter 3.4 µm), compared with the multimodal distribution for unmodified lactose-LPD powders (mean diameter 23.7 µm). The emitted dose and in vitro deposition of chitosan-modified powders was significantly greater than that of unmodified powders. ³⁶

Ø The solubilizing and absorption enhancer properties towards naproxen of chitosan and polyvinylpyrrolidone (PVP) have been investigated. Both carriers improved drug dissolution and their performance depended on the drug polymer ratio and the system preparation method. Chitosan was more effective than PVP, despite the greater amorphizing power of PVP as revealed by solid-state analyses. After different studies it found to be that the direct compression properties and antiulcerogenic activity, combined with the demonstrated solubilizing power and analgesic effect enhancer ability towards the drugs, make chitosan particularly suitable for developing a reduced-dose fast-release solid oral dosage form of naproxen. ³⁷

Ø Chitosan microspheres were evaluated for sustained-release of recombinant human interleukin-2 (rIL-2). Subsequent to study, it establish to be that, rIL-2 was released from chitosan microspheres in a sustained manner. The efficacy of rIL-2 loaded chitosan microspheres was studied using two model cells, HeLa and L-strain cell lines. Chitosan microspheres were added to the cells at different concentrations, and the amount of rIL-2 was assayed using the ELISA kit. Cell culture studies indicated that microspheres were uptaken by cells, and rIL-2 was released from the microspheres. Cellular uptake of rIL-2-loaded microspheres was dose dependent. It can be said that chitosan microsphere is a suitable carrier for rIL-2 delivery. ³⁸

Ø Graft copolymerization of methyl methacrylate (MMA) onto Chitosan using cerium (IV) as the initiator was deliberate with changeable concentrations of MMA. Under controlled environment, 49 % grafting (calculated from Thermogravimetric analysis, TGA) with a grafting yield of 92 % was achieved. FTIR, thermal and XRD techniques were used to confirm the formation of the grafted copolymer. Grafting caused a significant decrease in the mechanical strength of the polymer. The grafted products demonstrated improved swelling at pH 7.4 and pH 1.98 compared to the original Chitosan. The glass transition temperature (Tg) and the initial decomposition temperature were enhanced for the grafted copolymers. The grafting did not affect the hydrophilicity of chitosan, as evident from the contact angle studies. The grafted polymers were found to be non-cytotoxic and blood compatible. The properties of chitosan could be tailored by the concentration of the graft. The graft copolymer could be made into microspheres for possible drug release applications. ³⁹

Ø Topical formulations containing 5-FU loaded liposome embedded into a structured vehicle of chitosan have been prepared and evaluated. The release rate of 5-FU from topical liposome gels was affected by the formulation variables. Comparing the liposome gels with hydrogel formulations, the release rate of liposome-entrapped drug was prolonged, while a steady-state release rate, established after 1.5 hours, suggests that with chitosan liposome function as a reservoir system for continuous delivery of the encapsulated drug substance. ⁴⁰

Ø The antimicrobial activity of chitosan in lipid emulsions as well as in aqueous solution was investigated. It was originate that lipid emulsions containing 0.5% chitosan conformed to the requirements of the preservation efficacy test for topical formulations according to the European Pharmacopoeia while the emulsion without chitosan and a lactic acid solution with and without the biopolymer did not conform. In hemolysis studies on human erythrocytes, the hemolytic activity of the lipid emulsions with chitosan was assessed. These emulsions showed a negligible hemolytic behavior. The results point toward a use of chitosan as antimicrobial preservative in emulsion formulations for mucosal as well intended for parenteral applications. ⁴¹

Ø Study has been done and develop of mucoadhesive vaginal tablets designed for the local controlled release of acriflavine, an antimicrobial drugs used as a model. The tablets were prepared using drug-loaded Chitosan microscopheres and additional excipients (methyl cellulose, sodium alginate, sodium carboxy methyl cellulose or carbopol 974) by using spray-drying method. The formulation has done with carbopol 974 was studied with in vitro mucoadhesion tests showing good mucoadhesive properties. ⁴²

Ø Effects of chitosan oligomers on pulmonary absorption of interferon-alpha (IFN) were examined by means of an in vivo pulmonary absorption experiment. Chitosan oligomers used in this study were chitosan dimer, tetramer, hexamer, and water-soluble (WS) chitosan. A significant increase in serum IFN concentrations was observed after intratracheal administration of IFN with these oligomers. Of these chitosan oligomers 0.5% w/v chitosan hexamer appeared to be more effective in enhancing the pulmonary absorption of IFN than other oligomers at the same concentration, and the AUC value of IFN with chitosan hexamer increased 2.6 –fold as compared with the control. Therefore these findings indicated that the use of chitosan oligomers would be a promising approach for improving of the pulmonary absorption of biologically active peptides including IFN. ⁴³

Conclusion:-

Biologically degradable polymers can be loosely distinct as a class of polymers, which degrade to smaller fragments due to chemical present inside the body. Natural polymers are always biodegradable because they undergo enzymatically promoted degradation. Chitosan is one of them, which exhibits biodegradability, scrawny antigeneity and better-quality biocompatibility compared with supplementary natural polymer. Chitin in fact, is one of the most abundant polysaccharides bring into being in nature, assembly Chitosan a plentiful and moderately inexpensive product. Chitosan has recently sparked significance in the tissue-engineering field. Chitosan has been used in the blueprint of may different types of drug carriers for various administration rules such as oral, bucal, nasal, transdermal, parenteral, vaginal, cervical, intrauterine and rectal. It can be engineered into poles apart shapes and geometrics such as nanoparticles, micro spheres, membrane, sponge and rods. On drug delivery special preparation techniques are used to put in order chitosan drug carriers by cultering such parameters as cross linker concentration, Chitosan molecular weight, drug / polymer ratio and processing conditions all of which impinge on the morphology of Chitosan drug carriers and release rate of the loaded drugs. Accessibility of different chemical side groups for add-on to other molecules in Chitosan would however be most wanted to further endorse the exploit of the polymer as development of a new Chitosan derivatives.

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About Authors:

Tarun Kumar Satpathy
Zydus Cadila, (Quality Assurance), Sarkej-Bavla N.H. No. 8A, Moraiya, Tal: Sanand, Ahmedabad, 382 210,
Ph: 91-2717-250331/32/36/37; Tel: +91-9998597144
E-mail: tarun.satpathy@yahoo.co.in