Molecularly imprinted nanoparticles doped graphene oxide based electrochemical platform for highly sensitive and selective detection of L-tyrosine.

A highly sensitive and selective electrochemical sensor was developed using a surface modified glassy carbon electrode (GCE) through molecularly imprinted polymerization on the surface of vinyltrimethoxysilane (VTMS) coated magnetic nanoparticle (Fe3O4) decorated silver nanoparticles incorporated graphene oxide, GO (VTMS-Fe3O4/AgGO) for L- Tyrosine (Tyr) detection. A molecular imprinting technique based on free radical polymerization was applied to synthesize molecularly imprinted Methacrylic acid (MAA) and Acrylamide (AA) grafted VTMS-Fe3O4/AgGO polymer (MAA/AA-g- VTMS-Fe3O4/AgGO) designated as MIP and non-imprinted polymer (NIP). The structure and morphology of the prepared polymers were FTIR, XRD, FE-SEM and VSM. MIP and NIP were chosen for modifying the GCE surface by drop casting process to construct the sensors and their electrochemical properties were characterized via EIS and CV. Compared with NIP/GCE sensor, MIP /GCE sensor exhibits excellent sensing response towards Tyr with a wide linear range of 0.25 × 10-13 M to 0.10 × 10-3 M and the limit of detection and limit of quantification as 0.15 × 10-13 M and 0.50 × 10-13 M, respectively with R2 value of 0.9934 by DPV technique. Moreover, MIP/GCE sensor exhibits long-time storage, excellent selectivity and good stability in multiple cycle usage. The practical applicability of MIP/GCE sensor was tested in human blood serum sample. The recovery percentage was obtained between 98.8% and 106.0% with a relative standard deviation (RSD) between 1.01% and 1.59%. Results of the investigations revealed the clinical applicability of the MIP/GCE sensor.

Magnetic nanoparticle embedded chitosan-based polymeric network for the hydrophobic drug delivery of paclitaxel.

Safe delivery of hydrophobic drugs to the tumor site is a major problem for the scientific community. To improve the in vivo efficacy of hydrophobic drugs by avoiding solubility concerns and providing targeted delivery by nanoparticle, we have developed robust iron oxide nanoparticles coated chitosan with ([2- (methacryloyloxy) ethyl] trimethyl ammonium chloride) (METAC) [CS-IONPs-METAC-PTX] as a drug carrier for the delivery of hydrophobic drug, paclitaxel (PTX). Drug carrier was characterized using various techniques like FT-IR, XRD, FE-SEM, DLS and VSM. Maximum drug release of 93.50 ± 2.80 % from CS-IONPs-METAC-PTX occurs at pH 5.5 in 24 h. Significantly, the nanoparticles exhibited excellent therapeutic efficacy when appraised in L929 (Fibroblast) cell lines with a good cell viability profile. CS-IONPs-METAC-PTX shows excellent cytotoxic effect in MCF-7 cell lines. In 100 µg/mL concentration, CS-IONPs-METAC-PTX formulation shows 13.46 ± 0.40 % of cell viability. Selectivity index of 2.12 indicates the highly selective and safe performance of CS-IONPs-METAC-PTX. Admirable hemocompatibility of the developed polymer material demonstrating its applicability towards drug delivery. Results of the investigation substantiate that the prepared drug carrier is a potent material for the delivery of PTX.

Detection of chlorpyrifos based on molecular imprinting with a conducting polythiophene copolymer loaded on multi-walled carbon nanotubes.

Molecular imprinting technique (MIT) with electrochemical sensing provides an attractive tool for the fabrication of sensors. Incorporation of conducting copolymer and surface imprinting strategies in the sensing device improves the conducting properties and poor template accessibility, slow binding kinetics at the same time. Here, this technique was employed with conducting polymers with multi-walled carbon nanotubes (MWCNT) to build an electrochemical sensor for detecting Chlorpyrifos (CPF) in vegetable sample solutions. In this work, we aimed at synthesizing a copolymer of 3-thiophene acetic acid and 3,4-ethylene dioxythiophene on the surface of MWCNT. We further constructed a polymer drop-casted glassy carbon electrode sensor for ultrasensitive detection CPF. Under optimal conditions, the sensor exhibited a very low limit of detection (LOD) of 4.0 × 10-12 M for CPF. Due to the excellent repeatability and reusability of the materials, this study and findings have potential applications in the monitoring of pesticides from vegetable samples.

Modified chitosan-hyaluronic acid based hydrogel for the pH-responsive Co-delivery of cisplatin and doxorubicin.

Combination chemotherapy has attracted more attention in the field of anticancer treatment due to the synergetic effects achieved in the targeted delivery of anticancer drugs. In the present work a hydrogel-based drug delivery system (CS-NSA/A-HA) was successfully developed from chitosan modified by nitrosalicylaldehyde and aldehyde hyaluronic acid. Anticancer drugs, Cisplatin (CDDP) and Doxorubicin (DOX) were incorporated into this hydrogel separately and a dual drug loaded system was synthesized and the potential of the single and dual drug loaded materials for lung cancer therapy was compared. The obtained hydrogel was characterized by various spectroscopic techniques. Morphological studies conducted by FE-SEM analysis. The loading and encapsulation efficiencies and percentage of drug release were determined by UV-Vis spectroscopy at different pHs. Cytotoxicity studies performed in A549 lung cancer cells confirmed the enhanced activity of the material as a dual drug carrier compared with the single loaded system. All the findings strongly suggest the applicability of the material for lung cancer therapy.

Hyaluronic acid coated Pluronic F127/Pluronic P123 mixed micelle for targeted delivery of Paclitaxel and Curcumin.

The hydrophobicity of most of the anticancer drugs offers a great challenge in selecting a system for their effective transport. Here comes the importance of micelles that offers a hydrophobic core for incorporating these drugs. In this study, Hyaluronic Acid coated Pluronic mixed micelle loaded with Paclitaxel and Curcumin was designed and evaluated its anticancer activity in MCF-7 cells. Pluronic F127 (PF127) and Pluronic P123 (PP123) were taken for preparing the mixed micelles. The targeting ligand folic acid (FA) was conjugated to one end of PP123 forming FA-PP. The end hydroxyl groups of PF127 were oxidized to aldehyde groups resulted in PF-CHO. Mixed micelles were prepared from PF-CHO and FA-PP and the end aldehyde groups were used for coating the micelles with hyaluronic acid. The material was characterized using FTIR, H1NMR, DLS, FE-SEM and TEM. The coated micelles showed spherical shape with drug loading efficiency of 50.15 and 65.05% for Paclitaxel and Curcumin, respectively. In vitro drug release was studied at pH 5.5 and 7.4. Dual drug-loaded material showed higher in-vitro anticancer activity than free Paclitaxel and Curcumin. The results suggested that synthesized mixed micelle with dual drugs showed great potential for targeted delivery to MCF-7 cells.

A new biodegradable nano cellulose-based drug delivery system for pH-controlled delivery of curcumin.

Targeted delivery and controlled release of drugs are attractive methods for avoiding the drug's leakage during blood circulation and burst release of the drug. We prepared a nano cellulose-based drug delivery system (DDS) for the effective delivery of curcumin (CUR). In the present scenario, the role of nanoparticles in fabricating the DDS is an important one and was characterized using various techniques. The drug loading capacity was high as 89.2% at pH = 8.0, and also the maximum drug release takes place at pH = 5.5. In vitro cell viability studies of DDS on MDA MB-231; breast cancer cells demonstrated its cytotoxicity towards cancer cells. The prepared DDS was also examined for apoptosis, hemocompatibility, and Chorioallantoic membrane (CAM) studies to assess its pharmaceutical field application and the investigation results recommended that it may serve as a potential device for targeted delivery and controlled release of CUR for cancer treatment.

Graphene oxide based functionalized chitosan polyelectrolyte nanocomposite for targeted and pH responsive drug delivery.

Graphene oxide (GO) was first modified to amine functionalized GO (AGO) and acts as a cationic polyelectrolyte. Chitosan (CS) was conjugated with folic acid (FA) through N, N´ -Dicyclohexylcarbodiimide coupling to form FA-CS. After this, itaconic acid and acrylic acid monomers are grafted to the hydroxyl group of CS using ethyleneglycol dimethacrylate as cross linker and potassium peroxydisulfate as an initiator to generate -COOH functional groups and forming chemically modified chitosan (CMCS). Further doxorubicin (DOX) loaded into the FA-CMCS/AGO through π-π stacking interactions. The resulting nanocomposite was characterized by FTIR, SEM, TEM, Raman, AFM, DLS and ZP. The drug loading capacity was as high as 95.0% and the drug release rate at pH 5.3 was significantly higher than that under physiological conditions of pH 7.4. Cell viability of L929, HeLa and MCF7 cells was studied. The studies suggest the drug carrier has potential clinical applications for anticancer drug delivery.

Development of voltage gated transdermal drug delivery platform to impose synergistic enhancement in skin permeation using electroporation and gold nanoparticle.

Owing to poor skin permeability, the transdermal (TRD) drug delivery at the required therapeutic rate still remains an arduous task. In the present investigation, a novel TRD enhancement strategy was introduced using the synergistic effect of gold nanoparticle (GNP) and skin electroporation. Diclofenac sodium (DS) was selected as a model drug. An electro-sensitive patch was constructed using skin adhesive matrix, polyvinyl alcohol/poly(dimethyl siloxane)-g-polyacrylate. GNP/carbon nanotube nanocomposite (GNP-CNT) was incorporated into the matrix with GNP and CNT to enhance skin permeability and electrical conductivity, respectively. Varying the concentration of GNP-CNT, alters the thermomechanical properties, water vapor permeability (WVP), drug encapsulation efficiency (DEE) and drug release profile, building a possibility to fine-tune the properties of the device. The membrane constructed with 1.5% GNP-CNT displayed the highest DEE and thermomechanical properties. The TRD DS release study was performed in rat skin at different GNP-CNT contents and variable conditions of applied voltage. Incorporating GNP-CNT enhanced the DS permeation profile with the best performance exhibited by device containing 1.5% nanofillers at an applied bias of 10.0 V. Electroporation in conjugation with GNP remarkably destroys the stratum corneum (SC) barrier by disparate mechanisms involving the breakdown of multilamellar lipid system, generation of new aqueous pathway and thermal effect. Furthermore, the dramatic disruption of lipid barriers generated by applied voltage was efficiently stabilized by GNP in addition to the transient and reversible openings created by them. Finally the safety of the device was confirmed by cell viability assay and environmental stability test. The developed skin permeation approach may open new avenues in TRD drug delivery.

Synthesis and characterization of amidoxime modified chitosan/bentonite composite for the adsorptive removal and recovery of uranium from seawater.

A novel amidoxime functionalized adsorbent, poly(amidoxime)-grafted-chitosan/bentonite composite [P(AO)-g-CTS/BT] was prepared by in situ intercalative polymerization of acrylonitrile (AN) and 3-hexenedinitrile (3-HDN) onto chitosan/bentonite composite using ethylene glycol dimethacrylate (EGDMA) as cross linking agent and potassium peroxy disulphate (K2S2O8) as free radical initiator. The adsorbent was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), BET surface area analyser and X-ray photoelectron spectroscopy (XPS). Nitrile groups from two monomers converted to amidoxime groups and therefore, increases the adsorption efficiency of uranium(VI) [U(VI)] from seawater. The optimum pH for U(VI) adsorption was found to be 8.0. The adsorbent dosage of 2.0 g/L was sufficient for the complete removal of U(VI) from seawater. The kinetic data fitted well with pseudo-second-order kinetic model which assumes the presence of chemisorption. The equilibrium attained within 60 min and well agreement of equilibrium data with Langmuir adsorption model confirms monolayer coverage of U(VI) onto P(AO)-g-CTS/BT. The maximum adsorption capacity was found to be 49.09 mg/g. Spent adsorbent was effectively regenerated using 0.1 N HCl. Six cycles of adsorption-desorption experiments were conducted to study the practical applicability and repeated use of the adsorbent. The feasibility of the adsorbent was also tested using natural seawater. The results show that P(AO)-g-CTS/BT is a promising adsorbent for the removal of U(VI) from seawater.

Electrochemical sensing of cholesterol by molecularly imprinted polymer of silylated graphene oxide and chemically modified nanocellulose polymer.

Silylated Graphene oxide-grafted-chemically modified nanocellulose (Si-GO-g-CMNC) is fabricated for selective sensing of Cholesterol. Zinc oxide (ZnO) incorporated in chemically modified nanocellulose (CMNC) for enhancing the conducting nature. The sensitivity of sensor was checked by modifying the glassy carbon electrode surface (GCE) with Si-GO-g-CMNC and the electro chemical studies were conducted with cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The physical and electrical properties of the sensor were analyzed by FTIR, Raman Spectroscopy, XRD, SEM, EDS and AFM techniques. CV analysis of [FeCN6]3-/4- showed a redox potential difference of 0.156 mV on the bare GCE, while for the electrode coated with MIP, redox peak current increased to 0.2319 mV. The values of limit of detection (LOD) obtained as 7.4 µmol/L for the detection range of 5.18-25.9 µmol/L. The optimum response time and optimum pH were found to be 10 min and 7.4, respectively. DPV analysis revealed good linearity in the cholesterol sensing range of 0.6475-10.360 × 103 µmol/L with LOD value 98.6 µmol/L.

Gold Nanoparticle and Hydrophobic Nanodiamond Based Synergistic System: A Way to Overcome Skin Barrier Function.

Gold nanoparticles (AuNP) have attracted ample attention as a transdermal (TND) drug delivery platform for improving the skin permeability of drug molecules. Herein a novel TND device formed from AuNP and oleylamine functionalized nanodiamond (AuD) has been developed successfully for the TND delivery of Ketoprofen (KP), a model drug. Poly(vinyl alcohol)/Polybutyl methacrylate (PVA/PBMA) film has been selected as the matrix of the TND device, as they furnish excellent skin adhesion properties. The PVA/PBMA membranes loaded with different concentrations of AuD have been characterized in terms of surface morphology, thermomechanical properties, water vapor permeability (WVP), optical transmittance, cosmetic attractiveness, skin adhesion behavior, and drug encapsulation efficiency (DEE). The matrix loaded with 3.0% AuD displayed enhanced thermomechanical and DEE due to the uniform distribution of nanofillers in the membrane. The in vitro skin permeation test proved that a higher amount of KP was delivered by AuD incorporated films, suggesting improved TND behavior. The synergistic management of AuNP and nanodiamonds (ND) has caused the enhanced skin permeation behavior of the device. The obtained results revealed that AuD may be employed as an effective carrier to substitute NDs for TND delivery. Additionally, while investigating the storage stability of the device we observed that the membrane kept at low temperature presented stability over time. More importantly, the results from cell viability assay and environmental fitness test revealed that the AuD based TND system is a high security device, as it is noncytotoxic and microbe-resistant. The developed device provides a novel and handy approach to the TND delivery of drug molecules.

The role of biopolymer matrix films derived from carboxymethyl cellulose, sodium alginate and polyvinyl alcohol on the sustained transdermal release of diltiazem.

Due to changing lifestyles of modern world, cardiac failures are increasing day by day. Drug delivery systems that can overcome the drawbacks of conventional drug administration are highly desired. Diltiazem hydrochloride (DTZ) is a common and effective drug used for cardiac failures. However, its efficient loading, high bio availability and sustained transdermal release from polymer matrix are of high demand. Herein, the main objective was to fabricate a transdermal drug delivery system (TDDS) capable of efficient DTZ loading with sustained release. Owing to the high hydrophilicity of DTZ, a hydrophilic matrix comprising of poly ethylene glycol coated vinyl trimethoxy silane-g-chitosan (PEG@VTMS-g-CS) was developed. DTZ encapsulated copolymer was dispersed in matrices like sodium alginate (ALG), carboxy methyl cellulose (CMC) and poly vinyl alcohol (PVA). Economic viability and cosmetic attractiveness of the films were evaluated and optimum results were obtained for PVA matrix. The in vitro skin penetration study of DTZ on rat skin further demonstrated the efficacy of PVA based film which yielded more than 40.0% cell viability on HaCaT and PBMC cell line with no histological changes on the skin which further confirmed the practical utility of the prepared film.

Temperature and ultrasound sensitive gatekeepers for the controlled release of chemotherapeutic drugs from mesoporous silica nanoparticles.

With the advent of smart biomaterials, environmental stimuli have always been the trigger for targeted drug delivery. Conventional routes of drug administration suffer from serious drawbacks like first pass metabolism, less patient compliance and the requirement of trained personnel. Of the many well-established non-conventional routes, transdermal drug delivery systems (TDDSs) seem to be promising as they do not enter directly into the bloodstream and hence, side effects can significantly be reduced. Researchers around the world are trying to incorporate environmental sensitivity into TDDSs. Herein, we report the design and fabrication of a dual sensitive TDDS: (tetrahydropyranyl methacrylate-co-amino ethyl methacrylate)-grafted-mesoporous silica nanoparticles, (THPMA-co-AEMA)-g-MSNs, that could simultaneously sense temperature and an external stimulus - ultrasound (US). Temperature sensitivity was imparted by the conformational changes adopted by the system above and below the lower critical solution temperature (LCST). Below the LCST (4 °C), the polymer would exist as linear chains allowing drug molecules to enter the mesopores of silica, and at physiological temperatures the copolymer collapses preventing premature drug leakage. This sensitivity could be complemented by the inclusion of mechanophores like tetrahydropyran (THP), which could cleave bonds on exposure to US. At physiological temperatures, the TDDS can be placed at malignant sites and on US exposure, the chemotherapeutic agents could be leached out, resulting in better targeting, efficient drug release and minimal side effects. US can act as a potential penetration enhancer making it ideal even for targeting internal organs. All reaction procedures were monitored with the aid of FTIR, XRD, 1H NMR and FE-SEM techniques. Temperature sensitivity was analysed by encapsulating 5-flurouracil (5-FU) and analysing with a UV-Visible spectrophotometer. US sensitivity was monitored as a function of scattering light intensity. Pore opening and closure was verified by nitrogen adsorption isotherms. The dual responsiveness of the material was confirmed by confocal images of the sample before and after exposure to US. The physiological acceptance and practical efficacy of the material in real life situations were confirmed by histological studies on rat skin, MTT assay in HeLa cell lines and in vivo CAM assay. The results suggest the potential applicability of the material in site selective transdermal delivery of chemotherapeutic drugs.

Methacrylate-Stitched ß-Cyclodextrin Embedded with Nanogold/Nanotitania: A Skin Adhesive Device for Enhanced Transdermal Drug Delivery.

Transdermal (TD) drug delivery is a more attractive technique for drug delivery compared to oral and intravenous injection. However, the permeation of drug molecules across the skin is difficult due to the presence of highly ordered lipid barrier. This study details the development of a novel TD system, which has the potential to simultaneously enhance the skin permeability and adhesion behavior. Ibuprofen (IP) was selected as model drug. The ability of gold nanoparticle (AuNP) and hydrophobic titanium nanotube (TNT) to enhance the skin permeability was explored. Additionally, ß-cyclodextrin (ßCD), which can exceptionally encapsulate poorly water-soluble drugs, is grafted with methacrylates to improve the skin adhesion property. Finally, Au-TNT nanocomposite was deposited onto methacrylate-grafted ßCD matrix. The developed material was characterized through NMR spectroscopy, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The characteristics of the film, including water vapor permeability (WVP), thermomechanical properties, etc., were examined in terms of Au-TNT content. The TD delivery of IP with different concentrations of Au-TNT was evaluated via an in vitro skin permeation study through rat skin. It is revealed that the prepared TD film exhibited an improved drug-delivery performance due to the synergistic action of AuNP and hydrophobic TNT. The cumulative percent of IP delivered across the skin is extremely depending on nanofiller content, lipophilicity, and thickness of the membrane, and the device incorporated with 4.0% Au-TNT displayed the best performance. In addition, a study on storage stability was performed by storing the films for 2 months at different temperatures. The study revealed that the device possessed excellent storage stability when stored at low temperature. The developed film offers excellent WVP, drug encapsulation efficiency, thermomechanical properties, and skin adhesion behavior. Moreover, the device was cosmetically attractive, noncytotoxic, and resistant to microbial growth and hence extremely reliable for skin application. The developed skin permeation strategy may open new avenues in TD drug delivery.

Nanoparticle assisted solvent selective transdermal combination therapy of curcumin and 5-flurouracil for efficient cancer treatment.

Skin cancer is one among the many prominent diseases of the modern world and millions of people are suffering due to the lack of proper medication. Even though transdermal drug delivery systems (TDDS) provide an efficient route of drug administration, the advantages of combination chemotherapy have rarely been extended into TDDS. In the present work, a polymer capable of simultaneously encapsulating two anti-cancer drugs: 5-flurouracil (5-FU) and curcumin (CUR), and releasing them with varying kinetics as a function of the leaching solvent was developed. The prepared TDDS had two copolymers: alginate coated aminated nanodextran (ALG@AND) and chitosan coated folate decorated aminated ß-CD nano particles (CS@FA-g-AßCD). After inducing surface charges, both copolymers were coupled together by electrostatic forces. All the synthetic procedures for the preparation of TDDS were monitored using FTIR, DLS, Zeta Potential, SEM and TEM. The final TDDS was then evaluated for its solvent selectivity. Sustained release of 5-FU and CUR was observed with ethanol (EtOH) and 1-butanol (BuOH) respectively. However, these solvents could also release a small amount of the second drug which led to combinatorial therapy. The in vitro solvent selective drug permeation profiles were evaluated using Franz diffusion cell on rat skin. In order to evaluate the economic feasibility of the prepared TDDS, in vivo skin adhesion tests, skin irritation analysis, water vapour permeability and average visible transmittance were performed. Results proved that solvents could not only elute the drugs in a sustained manner, but could also act as penetration enhancers. Biological and histological studies carried out on skin and cancer cell lines suggested the potential usefulness of the prepared material in combinatorial chemotherapy.

Extraction of melamine from milk using a magnetic molecularly imprinted polymer.

A novel magnetic molecularly imprinted polymer (MMIP) for the preconcentration of melamine, a non-protein nitrogen food additive from complex matrices was synthesized and characterized using FT-IR, XRD, SEM and VSM techniques. Surface imprinting was done on vinyltrimethoxysilane coated Fe3O4 (Fe3O4-VTMS) using 2-acrylamido-2-methylpropane sulfonic acid (AMPS), N,N'-methylenebisacrylamide (MBA) and potassium persulfate (KPS) as functional monomer, crosslinker and initiator respectively. Saturation magnetization value obtained for MMIP was 1.72emug-1. Binding studies showed that MMIP exhibits good recognition to melamine compared to magnetic non imprinted polymer (MNIP). The optimum pH for the binding of melamine was found to be 4.5. Binding process was very fast and pseudo-second-order model fitted well with the kinetic data. Binding isotherm followed Langmuir isotherm model of monolayer adsorption with a maximum melamine binding efficiency of 62.25mgg-1. The HPLC-UV analysis results revealed the applicability of MMIP in solid phase extraction and determination of melamine from milk samples.

Nano-zinc oxide incorporated graphene oxide/nanocellulose composite for the adsorption and photo catalytic degradation of ciprofloxacin hydrochloride from aqueous solutions.

Purpose of this study is to report the synthetic procedure of a novel photo catalyst, nano zinc oxide incorporated graphene oxide/nanocellulose (ZnO-GO/NC) for the effective adsorption and subsequent photo degradation of ciprofloxacin (CF), an antibiotic widely used in the poultry. Self cleaning property in cellulose was achieved by introducing a nano zinc oxide incorporated graphene oxide into nanocellulose (NC) matrix. By incorporating nano zinc oxide (ZnO) in graphene oxide (GO), band gap could be tuned to 2.4eV and after the composite formation with NC, the band gap was enhanced to 2.8eV which is in the visible region. Thus the degradation of the CF was achieved under the visible light. Photo degradation was due to electron hole interaction. The step wise modification in the synthesis ZnO-GO/NC was characterized using FT-IR, XRD, SEM, EDS, AFM, DRS-UV and BET N2 adsorption isotherm techniques. The values of surface area, pore volume and pore radius were found to be 12.68m2/g, 0.026mL/g and 12.5nm, respectively. Efficiency in the adsorption process of CF onto ZnO-GO/NC was verified by batch adsorption technique. The optimum pH was found to be 5.5 and dose of the ZnO-GO/NC was optimized as 2.0g/L. Equilibrium was attained at 120min and the adsorption of drug followed second-order kinetics. Sips isotherm was the best fitted model and could explain the nature of interaction of CF with ZnO-GO/NC. The studies revealed that the degradation followed first-order kinetics and the optimum pH for the degradation process was found to be 6.0 and achieved a maximum degradation efficiency of 98.0%. The reusability of ZnO-GO/NC after five consecutive cycles indicated it to be a potential candidate for the removal and degradation of CF from aquatic environment.

Extended wear therapeutic contact lens fabricated from timolol imprinted carboxymethyl chitosan-g-hydroxy ethyl methacrylate-g-poly acrylamide as a onetime medication for glaucoma.

An extended wear therapeutic contact lens (TCL) for the sustained delivery of timolol maleate (TML) was fabricated based on molecular imprinting technique. The designed TCL comprised of a TML imprinted copolymer of carboxymethyl chitosan-g-hydroxy ethyl methacrylate-g-polyacrylamide (CmCS-g-HEMA-g-pAAm) embedded onto a poly HEMA matrix (pHEMA). Successful reloading of TML onto the lens was monitored using a simple and novel UV-Visible spectrophotometric method which showed an excellent reloading capacity of 6.53µgTML/TCL. The in vitro drug release profile in lacrimal fluid after each cycle was fitted onto Higuchi model of drug release suggesting diffusion release mechanism with no polymer degradation. Also, the TML release kinetics indicated a sustained drug delivery which can effectively achieve the therapeutic index of TML leading to a onetime medication for glaucoma. Biological activity of eluted drug after each cycle and cell viability of the TCL were verified using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,3-bis(2-methoxynitro-5-sulfophenyl)-5-(phenylaminocarbonyl)-2H-tetrazolium hydroxide (XTT) assay, respectively.

Fabrication of a bioadhesive transdermal device from chitosan and hyaluronic acid for the controlled release of lidocaine.

A novel efficient transdermal (TD) lidocaine (LD) delivery device based on chitosan (CS) and hyaluronic acid (HA) was successfully developed in the present investigation. CS was grafted with glycidyl methacrylate (GMA) and butyl methacrylate (BMA) to fabricate a versatile material with improved adhesion and mechanical properties. HA was hydrophobically modified by covalently conjugating 3-(dimethylamino)-1-propylamine (DMPA) to encapsulate poorly water soluble LD and was uniformly dispersed in modified CS matrix. The prepared materials were characterized through FTIR, NMR, XRD, SEM, TEM and tensile assay. The dispersion of amine functionalized HA (AHA) on modified CS matrix offered strong matrix - filler interaction, which improved the mechanical properties and drug retention behavior of the device. In vitro skin permeation study of LD was performed with modified Franz diffusion cell using rat skin and exhibited controlled release. The influence of storage time on release profile was investigated and demonstrated that after the initial burst, LD release profile of the device after 30 and 60days storage was identical to that of a device which was not stored. In vivo skin adhesion test and skin irritation assay in human subjects, water vapor permeability and environmental fitness test was performed to judge its application in biomedical field. All results displayed that the fabricated device is a potential candidate for TD LD administration to the systemic circulation.

Enzyme coated beta-cyclodextrin for effective adsorption and glucose-responsive closed-loop insulin delivery.

Inconsistent dosage of insulin (INS) for type 2 diabetes patients lead to severe adverse effects like limb amputation, blindness and fatal hypo or hyper glycaemia. Hence, a drug delivery system (DDS) capable of consistent INS release by sensing changes in blood glucose level is essential. Herein, we report a glucose responsive DDS comprised of oleic acid-grafted-aminated beta cyclodextrin (OA-g-ACD) copolymer, coated with a dispersion of glucose oxidase (GOx) and catalase (CAT). The prepared DDS was characterised using FTIR, Optical Microscopy, H(1) NMR, DLS and SEM. Hydrophobicity and drug loading capacity was ascertained using contact angle measurements and confocal laser scanning microscopy (CLSM) respectively. Extent of swelling was observed to be a function of glucose concentration. INS release profile showed a cumulative release of 78.0 % after 240min. Flow cytometry studies revealed greater population of INS on HeLa cells indicating application of DDS as potential candidate for the intravenous administration of INS.