Starch nanocrystals based hydrogel: Construction, characterizations and transdermal application.

Bio-based nanocomposites were prepared using starch nanocrystals obtained by acid hydrolysis of native starches using different acid sources. In recent times, focuses on starch nanocrystals (SNCs) have been increasing in number of research works dedicated to the development of bio-nanocomposites by blending with different biopolymeric matrices. The work mainly deals with the preparation of starch nanocrystals using different native starches by acid hydrolysis using hydrochloric acid and trifluroacetic acid. The as-prepared starch nanocrystals are having high crystallinity and more platelet morphologies, and used as a drug carrying filler material in the hydrogel formulations with the care of different polymer matrices. The condensed work also concentrates on the dispersion of antiviral drug in the hydrogels, which are applied onto biocompatible bio-membrane to be formulating a complete transdermal patch. The acid hydrolysed starch nanocrystals were thoroughly characterized using TEM, SEM, particle size analysis and zeta potential. Their thermal stability and the crystalline properties were also characterized using TG-DSC and XRD respectively. The physiochemical interaction and compatibility between the drug and the SNCs filler in the polymeric hydrogels were evaluated using FT-IR analysis. The formulated hydrogels were subjected to evaluation of in vitro permeation studies using Franz diffusion studies. The in vitro study was indicated substantial guarantee for the fabrication of drug dispersed in polymeric hydrogels using SNCs as filler matrices for a successful transdermal drug delivery.

Crystal structure of 3'-(1H-indole-3-carbon-yl)-1'-methyl-2-oxo-4'-(4-oxo-4H-chromen-3-yl)spiro-[indoline-3,2'-pyrrolidine]-3'-carbo-nitrile.

In the title compound, C31H22N4O4, the pyrrolidine ring adopts a twist conformation on the N-CH2 bond. The indolin-2-one and the 1H-indole rings are nearly planar (r.m.s. deviations = 0.06 and 0.011 Å, respectively) and are inclined to one another by 34.19 (9)°. The chromene ring system is also nearly planar (r.m.s. deviation = 0.029 Å). It is almost normal to the 1H-indole ring system, with a dihedral angle of 88.71 (8)°, and is inclined to the indolin-2-one ring system by 72.76 (8)°. In the crystal, mol-ecules are linked via N-H⋯O hydrogen bonds, forming slabs parallel to (10-1). The slabs are linked by C-H⋯O hydrogen bonds, forming a three-dimensional structure.

Assessment of antifouling efficacy of polyhedral oligomeric silsesquioxane based poly (urea-urethane-imide) hybrid membranes.

UNLABELLED: A series of polyhedral oligomeric silsesquioxane (POSS) based poly(urea-urethane-imide) (PUUI-POSS) membranes were synthesized by varying the proportions of imide using 2,4-toluene diisocyanate (TDI) and bis(aminopropyl) terminated polydimethylsiloxane (PDMS). The molecular structures of poly(urea-urethane-imide)s were characterized by Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic technique. Incorporation of imide domain and its influence on surface roughness was investigated by atomic force microscopy (AFM). Hydrophobicity of polymeric membrane surfaces was determined by contact angle measurement. The thermal properties of the polymers were studied by thermogravimetric analysis. The antimicrobial activities and inhibition of bacterial attachment of these polymeric membranes were studied on Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) by the disc-diffusion method. SIGNIFICANCE AND IMPACT OF THE STUDY: The antifouling performance has been evaluated for the polymeric membranes against two bacteria (Staphylococcus aureus (ATCC 6538)) (Escherichia coli (ATCC 8739)). The polymeric membranes were incorporated with imide moiety to improve thermal stability of the polymeric materials. The synthesized polymeric membranes have shown good morphological properties for better antifouling activities. This study found that these membranes are capable of preventing micro-organisms besides offering excellent bio-fouling resistance.

Crystal structure of methyl 1-methyl-2-oxo-spiro-[indoline-3,2'-oxirane]-3'-carboxyl-ate.

In the title compound, C12H11NO4, the dihedral angle between the indole ring system (r.m.s. deviation = 0.019 Å) and the oxirane ring is 88.8 (2)°. The oxirane O atom and the bridging ester O atom are in an approximate syn conformation [O-C-C-O = -25.4 (3)°] In the crystal, inversion dimers linked by pair of C-H⋯O hydrogen bonds generate R 2 (2)(8) loops, where the C-H donor group forms part of the oxirane ring. A second C-H⋯O inter-action arising from one of the C-H groups of the benzene ring links the dimers into [001] double chains.

Crystal structure of methyl (E)-2-(1-methyl-2-oxoindolin-3-yl-idene)acetate.

The title compound, C12H11NO3, is essentially planar, with the mean plane of the acetate side chain [-C-C(=O)-O-C] being inclined to the mean plane of the indole ring system by 12.49 (7)°. The five- and six-membered rings of the indole group are almost coplanar, making a dihedral angle of 1.76 (8)°. The conformation about the C=C bond is E and there is an intra-molecular C-H⋯O hydrogen bond present. In the crystal, mol-ecules are linked by pairs of C-H⋯O hydrogen bonds forming inversion dimers, with an R 2 (2)(16) ring motif. The dimers are linked by a second pair of C-H⋯O hydrogen bonds, enclosing R 2 (2)(16) ring motifs, forming ribbons lying parallel to (-114). The ribbons are linked via C-H⋯π inter-actions, forming a three-dimensional structure.

Facile and diastereoselective synthesis of 3,2'-spiropyrrolidine-oxindoles derivatives, their molecular docking and antiproliferative activities.

In the present study, a series of novel highly functionalized spiropyrrolidine-oxindoles have been synthesized through 1,3-dipolar cycloaddition of an azomethine ylide formed from isatin and various amino acids such as sarcosine, proline and thioproline with the dipolarophile (E)-3-(1,3-diphenyl-1H-pyrazol-4-yl)-2-(1H-indole-3-carbonyl)acrylonitrile under optimized conditions. All the synthesized compounds were evaluated for their antimicrobial activity and shown significant activity.

(4S)-3-Methyl-5,6,7,8-tetra-hydro-4H-spiro-[[1,2]oxazolo[5,4-b]quinoline-4,3'-indole]-2',5-dione.

In the title compound, C18H15N3O3, the dihedral angle between the mean planes of the quinoline and indole ring systems [r.m.s. deviations = 0.189 (2) and 0.027 (2) Å, respectively] is 88.65 (5)°. The cyclo-hexene ring of the quinoline ring system adopts an envelope conformation with the central -CH2- C atom as the flap. In the crystal, mol-ecules are linked by two pairs of N-H⋯O hydrogen bonds, forming inversion dimers, and enclosing R 2 (2)(14) ring motifs. This arrangement results in the formation of chains propagating along [100].

1'-(1,3-Diphenyl-1H-pyrazol-4-yl)-1''-(prop-2-en-1-yl)-2',3',5',6',7',7a'-hexa-hydro-1'H-di-spiro-[1-benzo-pyran-3,2'-pyrrolizine-3',3''-indoline]-2'',4-dione 0.75-hydrate.

In the central aza-bi-cyclo-octane unit of the title compound, C40H34N4O3·0.75H2O, the peripheral pyrrolidine ring adopts an envelope conformation with the N atom deviating by 0.209 (2) Å, whereas the other pyrrolidine ring adopts a twisted conformation with the bridging N and C atoms deviating by -0.218 (2) and 0.236 (3) Å, respectively, from the rest of the ring. The pyrazole ring forms dihedral angles of 42.36 (7) and 24.07 (8)° with its C- and N-attached phenyl groups, respectively. The solvent water mol-ecule has a partial occupancy of 0.75. In the crystal, the water mol-ecules link the fused-ring mol-ecules into chains along the b axis via O-H⋯N and O-H⋯O hydrogen bonds. The crystal packing is further stabilized by C-H⋯π inter-actions involving a methyl-ene group of the pyran ring and the C-attached benzene ring on the pyrazole ring.

1'-(1,3-Diphenyl-1H-pyrazol-4-yl)-2',3',5',6',7',7a'-hexa-hydro-1'H-di-spiro-[ace-naphthyl-ene-1,3'-pyrrolizine-2',3''-chromane]-2,4''(1H)-dione.

In the title compound, C41H31N3O3, the pyrazole and pyrrolidine rings adopt twisted conformations. The mean plane of the pyrazole ring forms dihedral angles of 9.11 (12) and 39.65 (11)° with the phenyl rings. The O atoms deviate from the mean planes of the chromene and ace-naphthyl-ene ring systems by 0.194 (15) and 0.079 (15) Å, respectively. In the crystal, molecules are linked via pairs of C-H⋯O inter-actions,forming inversion dimers with an R 2 (2)(12) ring motif.

(6'R*,7'R*)-7'-(1,3,-Diphenyl-1H-pyrazol-4-yl)-1,2,5',6',7',7a',3'',4''-octa-hydro-1'H,2''H-dispiro-[acenaphthyl-ene-1,5'-pyrrolo-[1,2-c][1,3]thia-zole-6',3''-[1]benzopyran]-2,4''-dione.

In the title compound, C40H29N3O3S, the pyran ring adopts a sofa conformation, the thia-zolidine ring adopts a twisted conformation and the pyrrolidine ring adopts an envelope conformation with the N atom as the flap. The pyrazole ring is essentially planar [maximum deviation = 0.002 (2) Å] and forms dihedral angles of 4.8 (1) and 39.0 (1)°, respectively, with the benzene rings attached to the N and C atoms. The acenapthylene ring system is approximately planar [maximum deviation = 0.058 (2) Å] and forms dihedral angles of 85.9 (1) and 48.5 (1)°, respectively, with the pyrollothia-zole and chromene ring systems. The mol-ecular conformation is stabilized by three weak intra-molecular C-H⋯O hydrogen bonds, which generate one S(8) and two S(6) ring motifs. In the crystal, pairs of C-H⋯O hydrogen bonds link centrosymmetrically related mol-ecules into dimers, generating R 2 (2)(14) ring motifs. The crystal packing also features pairs of C-H⋯π inter-actions, which link the dimers into a supra-molecular chain along the b axis.

1'-(1,3-Diphenyl-1H-pyrazol-4-yl)-1''-methyl-2',3',5',6',7',7a'-octa-hydro-1'H-dispiro-[1-benzopyran-3,2'-pyrrolizine-3',3''-indoline]-2'',4-dione.

In the title compound C38H32N4O3, one pyrrolidine ring adopts an envelope conformation with the N atom as the flap while other pyrrolidine ring adopts an twisted conformation. The pyrrolizine ring forms dihedral angles of 79.24 (5) and 77.57 (5)° with the chromene and indole rings, respectively. The carbonyl O atoms deviate from the least-square planes through the chromene and indole rings by 0.0113 (12) and 0.0247 (12) Å, respectively. In the crystal, non-classical C-H⋯O inter-actions link the mol-ecules, generating an C(9) chain along the b-axis direction.

Adsorption and emulsification properties of amphiphilic poly(styrene-co-octadecyl maleamic acid salt) with comb-like architecture.

Amphiphilic poly(styrene-co-octadecyl maleamic acid salt) (PS-co-ODMAS) with a comb-like architecture was synthesized employing a heterophase aqueous polymerization reaction. The side-chain comonomer from octadecyl maleamic acid salt exhibited hydrogelation characteristics and provided conditions for a controlled polymerization reaction. PS-co-ODMAS polymers consisting of 5 and 10 mol% side-chain monomer showed a high molecular weight on the order of 10(6) and narrow polydispersity index at 1.33+0.02. The polymer consisting of 10 mol% side-chain monomer was shown to exhibit properties that are significantly different from those with 5 mol%, and the control poly(styrene) synthesized using sodium dodecyl sulfate surfactant. The polymer consisting of 10 mol% side-chain monomer formed hollow spherical spheres of 30 nm size. It also showed close-packed structures of the side-chain monomer on the polymer surface. Detailed adsorption studies at the liquid/liquid interface were carried out to evaluate and understand the scope for modification in surface energy characteristics of polymers in the presence of additives drawn from simple surfactants. Triton X-100 was shown to undergo effective adsorption on the polymer consisting of 10 mol% side-chain monomer and thus could generate stable emulsions with different volume fractions of heptadecane. The results from electron microscopy studies and viscosity of emulsions are discussed.

Biopolymer from microbial assisted in situ hydrolysis of triglycerides and dimerization of fatty acids.

The present study demonstrates biopolymer production by in situ bio-based dimerization of fatty acids by microorganism isolated from marine sediments. Microbial isolate grown in Zobell medium in the presence of triglycerides for the period of 24-240 h at 37 degrees C, hydrolyze the applied triglycerides and sequentially dimerized the hydrolyzed products and subsequently polymerized and transformed to a biopolymer having appreciable adhesive properties. Physical (nature, odour, stickyness and tensile strength), chemical (instrumentation) and biochemical (cell free broth) methods of analyses carried out provided the hypotheses involved in the formation of the product as well as the nature of the product formed. Results revealed, lipolytic enzymes released during initial period of growth and the biosurfactant production during later period, respectively, hydrolyze the applied triglycerides and initiate the dimerization and further accelerated when the incubation period extended. The existence and the non-existence of in situ hydrolysis of various triglycerides followed by dimerization and polymerization and the mechanism of transformation of triglycerides to biopolymer are discussed in detail.

Polymeric drug based on sulfanilamide: synthesis, antimicrobial and drug releasing studies.

N-((4-amino sulfonyl)phenyl)acrylamide (APA) was synthesized using sulfanilamide and acryloyl chloride in the presence of triethyl amine at 0-5 degrees C. Homo- and co-polymerization of 2-hydroxyethyl acrylate (HEA) and acrylic acid (AA) were done by adopting a solution polymerization technique using methyl ethyl ketone (MEK) as a solvent and benzoyl peroxide (BPO) as a free radical initiator at 70 +/- 1 degrees C. All the monomers and polymers were characterized by IR and NMR techniques. These monomers and polymers were tested for their antimicrobial activity against five different ATCC strain microorganisms (Escherichia coli (25922), Pseudomonas aeruginosa (27853), Klebsiella (70063), Salmonella typhi (6539) and Staphylococcus aureus (25923)). The effect of co-monomer, other than the active drug moiety present in the polymeric drug, is discussed. The antimicrobial activity of APA on Gram-positive bacteria was enhanced when copolymerized with AA and HEA. The polymer was made into a film form and that film was used for drug releasing study. The drug releasing rate was monitored by the absorption at 268 nm using a UV spectrophotometer. The effect of pH and the temperature on the drug releasing rate was monitored and found that the releasing rate was dependent on the co-monomer, pH and temperature of the medium.

Sustained release of protein from poly(ethylene glycol) incorporated amphiphilic comb like polymers.

Amphiphilic comb like macromonomer containing hydrophilic poly(ethylene glycol) groups covalently linked to poly(hydromethyl siloxane) (PHMS) were prepared by hydrosilylation reaction. The epoxy reacting sites were introduced to this amphiphilic system by the reaction with allyl epoxy propyl ether (AEPE). Bovine serum albumin (BSA), a model protein drug was loaded to the PEG-PDMS system and very thin membranes were made from this macromonomer adopting solution casting technique. The in vitro protein release studies at various pH conditions showed a controlled release profile without exhibiting any initial burst. The control of the initial burst might be due to the strong linkages of the protein with the membrane and the aggregation of the protein at the surface. The morphology of the membrane before and after the protein release, and the mechanical strength were evaluated. The surface properties of the membrane were studied using the contact angle measurements.

In vitro drug release studies of 2-hydroxyethyl acrylate or 2-hydroxypropyl methacrylate-4-{(1E,4E)-5-[4-(acryloyloxy)phenyl]-3-oxopenta-1,4-dienyl}phenyl acrylate copolymer beads.

4-{(1E,4E)-5-[4-(Acryloyloxy)phenyl]-3-oxopenta-1,4-dienyl}phenyl acrylate (APPA) was synthesized by reacting (1E,4E)-1,5-bis(4-hydroxyphenyl)penta-1,4-dien-3-one (HPD) and acryloyl chloride using triethylamine as a base. 2',4-Dichloro-5'-fluoro-1-ene-2-(4-hydroxyphenyl)phenone (EHP) (Arun A, Reddy BSR, Rajkumar M. Polymeric drug for antimicrobial activity studies: Synthesis and characterization. J Bioact Compat Polym 2003;18:219) was used for the controlled release studies. Two types of porous hydrogels were prepared by copolymerizing 2-hydroxyethyl acrylate (HEA) or 2-hydroxypropyl methacrylate (HPMA) with APPA (as a crosslinker) by employing the suspension polymerization technique. The morphology of the hydrogels were characterized by the optical microscopy (OM) and scanning electron microscopy (SEM). Different variations were employed in the preparation of hydrogels to study the effect of crosslinker percentage and drug the loading percentage. Totally 18 types of hydrogels were prepared. The drug-releasing pattern was monitored over a period of 4 weeks using the UV spectroscopic technique by measuring the absorptions at 330.5 nm. In vitro release experiments were carried out at pH 7.4 and pH 9.2. In total, 36 releasing experiments were conducted. The results showed that the controlled release of the drug was dependent on the monomer (HEA or HPMA), crosslinker percentage (CLP), drug-loading percentage (DLP), and pH. The release rate was higher for HEA-based hydrogels when compared with HPMA-based hydrogels in all compositions. The release rate was noticeably higher in pH 9.2 than pH 7.4.

In vitro drug release studies from the polymeric hydrogels based on HEA and HPMA using 4-[(E)-[(3Z)-3-(4-(acryloyloxy)benzylidene)-2-hexylidene]methyl]phenyl acrylate as a crosslinker.

Novel crosslinker, 4-[(E)-[(3Z)-3-(4-(acryloyloxy)benzylidene)-2-hexylidene]methyl]phenyl acrylate (AMA) was synthesized using (2Z, 6E)-2,6-bis(4-hydroxybenzylidene)cyclohexanone (HBC) and acryloyl chloride. Two types of crosslinked polymeric hydrogels were prepared from 2-hydroxyethyl acrylate (HEA) and 2-hydroxypropyl methacrylate (HPMA) monomers using AMA as a crosslinking agent. 2',4-dichloro-5'-fluoro-1-ene-2-(4-hydroxyphenyl)phenone (EHP) (J. Bio Active Compat. Polym. 18 (2003) 219) was used as a drug molecule for monitoring the releasing behaviour of the hydrogels. Morphology of the hydrogels was characterized using optical microscopy (OM) and Scanning Electron Microscopy (SEM) techniques. Several modifications were made in the experimental sections to study the effect of crosslinking percentage (CLP), drug loading percentage (DLP), monomer type (HEA and HPMA) and the pH. Totally 18 experiments were carried out to study the desired parameters in the hydrogels. The drug-releasing rate was monitored by the absorption appeared at 330.5 nm using UV spectrometer. It was found that the releasing rate of the drug from the polymeric hydrogels was dependent on the crosslinking density, drug loading percentage, monomer type and pH of the medium.

Effect of N-glycinylmaleamic acid on microstructural characteristics and solubilization properties of sodium dodecyl sulfate micellar assemblies.

The cosurfactant activity of N-glycinylmaleamic acid (NGMA) in sodium dodecyl sulfate (SDS) micelles has been demonstrated. The complementary techniques of electron spin resonance (ESR) and fluorescence spectroscopy have been used to draw information on hydration index (H), microviscosity (eta), and aggregation number (N) of micellar assemblies. The estimate of the critical micelle concentration of SDS in the presence of NGMA suggests a synergistic effect of NGMA. The enhanced solubilization of butyl propionate in the presence of NGMA in SDS micelles is explained on the basis of availability of larger interfacial area calculated from a simple spherical geometric model, combined with a low hydrophilicity index as estimated from ESR. Thus, addition of NGMA contributes to an increase of about 50% in ratio of area of polar shell (AP)/volume of hydration (Vh) ratio. The decrease in H accompanied by a decrease in eta with the incorporation of butyl propionate probably arises from solubilization of a butyl component inside the core with the adsorption of propionate ester on the interface.