Development and Characterization of Drug Loaded PVA/PCL Fibres for Wound Dressing Applications.

Nowadays, synthetic polymers are used in medical applications due to their special biodegradable, biocompatible, hydrophilic, and non-toxic properties. The materials, which can be used for wound dressing fabrication with controlled drug release profile, are the need of the time. The main aim of this study was to develop and characterize polyvinyl alcohol/polycaprolactone (PVA/PCL) fibres containing a model drug. A dope solution comprising PVA/PCL with the drug was extruded into a coagulation bath and became solidified. The developed PVA/PCL fibres were then rinsed and dried. These fibres were tested for Fourier transform infrared spectroscopy, linear density, topographic analysis, tensile properties, liquid absorption, swelling behaviour, degradation, antimicrobial activity, and drug release profile for improved and better healing of the wound. From the results, it was concluded that PVA/PCL fibres containing a model drug can be produced by using the wet spinning technique and have respectable tensile properties; adequate liquid absorption, swelling %, and degradation %; and good antimicrobial activity with the controlled drug release profile of the model drug for wound dressing applications.

Silver-containing polysaccharide-based tricomponent antibacterial fibres for wound care applications.

OBJECTIVE: Polysaccharide-based biomaterials are extensively used in wound care healing due to their unique liquid absorption, gelling properties and biocompatibility properties. They play an important role in controlling infections of highly exuding hard-to-heal wounds. The main objective of this study was to develop silver-containing polysaccharide-based tricomponent antibacterial fibres for use in these complex wounds. METHOD: The fibres were developed by coating silver-containing alginate and psyllium fibres with hydrolysed chitosan. Dope solution containing alginate, psyllium and silver carbonate was extruded into a coagulation bath containing calcium chloride and hydrolysed chitosan. The developed fibres were tested for liquid absorption, swelling and antibacterial properties against a control fibre (of alginate and psyllium). RESULTS: The developed fibres showed comparatively better liquid absorption, gelling and antibacterial properties than the control fibres. CONCLUSION: The study concluded that developed fibres could be a preferred choice for application on hard-to-heal wounds with high levels of exudate, to support infection control and faster healing.

Development of tri-component antibacterial hybrid fibres for potential use in wound care.

OBJECTIVE: Tri-component antibacterial psyllium-alginate-chitosan fibres were developed and their properties were studied with reference to their application in health-care. METHOD: Psyllium was co-extruded with sodium alginate as a carrier into a coagulation bath containing calcium chloride and hydrolysed chitosan. Different concentrations of the hydrolysed chitosan were used and an in vitro assessment of antibacterial activity of the produced fibres was carried out against the known pathogens of Staphylococcus aureus and Escherichia coli. The effect of hydrolysed chitosan bath composition on physical and mechanical properties of produced fibres was also examined. RESULTS: Chitosan-containing fibres demonstrated a 70-130% thicker dry diameter than the control fibre (F1). The linear density of the fibre increased from 6.8 to 10 tex as the chitosan concentration increased from 10g/l to 30g/l (fibre type F1 to F4). With the addition of hydrolysed chitosan, distilled water absorption was increased while the saline and solution-A (0.83% w/v NaCl and 0.03% w/v CaCl2) absorption decreased. The percentage strain of hybrid fibres was lower than the control fibre due to the inclusion of hydrolysed chitosan. At lower viscosities of the hydrolysed chitosan bath, the fibres were much stiffer due to better penetration of the hydrolysed chitosan. Similarly, at lower viscosities, the tenacities of the hybrid fibres were higher than the control fibre. The hydrolysed chitosan-treated fibres were more effective against Staphylococcus aureus than the Escherichia coli, and the antibacterial activity increased with the decrease in viscosity of the hydrolysed chitosan bath. CONCLUSION: We developed novel PAC fibres. Antibacterial testing showed that hydrolysed chitosan was more effective against Gram-positive bacteria than Gram-negative bacteria.

Linear and crosslinked Polyurethanes based catalysts for reduction of methylene blue.

The large amount of synthetic dyes in effluents is a serious concern to be addressed. The chemical reduction is one of the potential way to resolve this problem. In this study, linear and crosslinked polyurethanes i.e. LPUR & CLPUR were synthesized from toluene diisocyanate (TDI), polyethylene glycol (PEG;1000g/mole) and tetraethylenepentamine (TEPA). The structure and morphology of synthesized materials were examined by FTIR, SEM and BET. The CLPUR was found stable in aqueous system with 0.80g/cm3 density and 16.4998m2g-1 surface area. These materials were applied for the reduction of methylene blue in presence of NaBH4. Both, polymers catalyzed the process and showed 100% reduction in 16 and 28mins., respectively, while, the reduction rate was significantly low in absence of these materials, even after 120mins. Furthermore, negligible adsorption was observed with only 7% removal of dye. The best reduction rates were observed at low concentration of dye, increasing concentration of NaBH4 and with more dosage of polymeric catalyst. The kinetic study of process followed zero order kinetics. It was hence concluded that both synthesized polymers played a catalytic role in reduction process. However, stability in aqueous system and better efficiency in reduction process endorsed CLPUR as an optimal choice for further studies.

Production of rhamnolipid surfactant and its application in bioscouring of cotton fabric.

In the present study, a biosurfactant was synthesized by using a bacterial strain of Pseudomonas aeruginosa in minimal media provided with n-heptadecane as sole carbon source under shake-flask conditions. The biosurfactant was isolated (by acid precipitation, solvent extraction, and rotary evaporation), purified (by column chromatography and TLC), identified (by FAB-MS, FTIR, and 1D-(1)H NMR), and chemo-physical characterized (by tensiometry). Two principal rhamnolipid congeners were identified as dirhamnolipid RRC10C10 and monorhamnolipid RC10C10 with a CMC of 50mg/L. The biosurfactant, hence produced, was applied in sole and in combination with pectinase in scouring of cotton fabric in contrast to conventional scouring agents of NaOH and anionic surfactant SDS. The scoured cotton fabric was investigated for its weight loss, residual oil and grease, wettability, whiteness, and tensile strength. The results were compared both for conventional and biological approaches. The scouring with biosurfactant plus pectinase was equivalent to or better in efficiency than conventional alkaline scouring. The former process is additionally environmentally friendly and bio-compatible. Scanning electron microscopy of cotton fabric showed that the alkaline scouring deteriorates the fabric texture whereas bioscouring with biosurfactant plus pectinase gently removes hydrophobic impurities from the cotton fabric.

Early complications following pancreatico-duodenectomy.

OBJECTIVE: To determine the mortality and morbidity in patients after Whipple's pancreaticoduodenectomy. DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Department of General Surgery (Ward-2), Jinnah Postgraduate Medical Centre, Karachi. PATIENTS AND METHODS: All the patients who underwent standard Whipple's procedure were followed up during their hospital stay for early postoperative complication. The indicators for the development of complications included daily nasogastric (NG) tube output for delayed gastric emptying, ultrasound abdomen for intra-abdominal collections, presence of blood in drains and NG tubes for haemorrhage and measuring serum amylase for pancreatitis. RESULTS: Out of 30 patients, 3 patients died in early postoperative period with 10% mortality while 26.67% had wound infection, 16.67% had chest complications, 13.34% developed intra-abdominal collections, 10% had haemorrhage, 3.34% had delayed gastric emptying, 3.34% had pancreatic fistula and 3.34% had organ failure. CONCLUSION: In this series the procedure was associated with decreased mortality due to increased experience and skills but morbidity was still high due to lack of facilities for the detection and management of postoperative complications. It should only be performed in tertiary care centres with expert surgical teams and facilities for adequate management of postoperative complications.