Composite bi-layered erodible films for potential ocular drug delivery.

Bi-layered hydroxypropylmethylcellulose and Eudragit based films were formulated as potential ocular drug delivery systems using chloramphenicol as a model antibiotic. Films were plasticized with polyethylene glycol 400 present in the Eudragit layer or both Eudragit and hydroxypropylmethylcellulose layers, and loaded with chloramphenicol (0.5% w/v in solution) in the hydroxypropylmethylcellulose layer. The weight, thickness and folding endurance of the optimized formulations were measured and further characterised for transparency, tensile, mucoadhesive, swelling and in vitro drug dissolution properties. The physical form of chloramphenicol within the films was evaluated using differential scanning calorimetry (DSC), and X-ray diffraction (XRD), complimented with scanning electron microscopy and energy dispersive X-ray spectroscopy. Fourier transform infrared spectroscopy was used to assess the interactions between the drug and the film components and confirm chloramphenicol's presence within the sample. Optimum films showed high transparency (≥80% transmittance), ease of peeling from Petri dish and folding endurance above 250. Average thickness was lower than contact lenses (0.4-1mm), confirming them as thin ocular films. The tensile properties showed a good balance between toughness and flexibility, and mucoadhesivity showed that they could potentially adhere to the ocular surface for prolonged periods. The drug loaded films showed swelling capacity that was greater than 300% of their original weight. The physical form of chloramphenicol within the films was amorphous (DSC and XRD) whilst in vitro drug dissolution showed sustained drug release from the films for four hours, before complete erosion. The chloramphenicol loaded films represent a potential means of treating common eye infections.

Preparation, optimisation and characterisation of novel wound healing film dressings loaded with streptomycin and diclofenac.

Streptomycin (STP) and diclofenac (DLF) loaded film dressings were prepared by blending Polyox(®) (POL) with four hydrophilic polymers [hydroxypropylmethylcellulose (HPMC), carrageenan (CAR), sodium alginate (SA) or chitosan (CS)] using glycerol (GLY) as plasticiser. The films were characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, texture analysis (tensile and swelling characteristics) and in vitro dissolution profiles using Franz diffusion cell. SEM showed homogeneous morphology for both blank (BLK) and drug loaded (DL) films. Films prepared by blending of POL with the other polymers showed a reduction in the crystallisation of POL in descending order of SA>CS>HPMC>CAR respectively. DSC and XRD showed no crystalline peaks of STP and DLF suggesting molecular dispersion of both drugs as well as possible drug interaction with negatively charged sulphate ions present in CAR. The DL films did not show any IR bands of both drugs, confirming the DSC and XRD results. POL-CAR-BLK films showed higher tensile strength (12.32±1.40 MPa) than the POL-CAR-DL films (9.52±1.12 MPa). DL films plasticised with 25%w/w GLY revealed soft and tough (tensile strength 1.02±0.28 MPa, % elongation 1031.33±16.23) formulations. The swelling capacities of POL-CAR-BLK and POL-CAR-DL films were (733.17±25.78%) and (646.39±40.39%), increasing to (1072.71±80.30%) and (1051±86.68%) for POL-CAR-BLK-25% GLY and POL-CAR-DL-25% GLY respectively. POL-CAR-DL films showed significantly (n=3, p<0.0318) lower cumulative release of STP and DLF (52.11±1.34, 55.26±2.25) compared to POL-CAR-DL-25% GLY films (60.07±1.56, 63.39±1.92) respectively.

Dissolution enhancement of poorly water-soluble APIs processed by hot-melt extrusion using hydrophilic polymers.

The aim of this study was to investigate the efficiency of hydrophilic polymers to enhance the dissolution rate of poorly water-soluble active pharmaceutical ingredients (APIs) processed by hot-melt extrusion (HME). Indomethacin (INM) and famotidine (FMT) were selected as model active substances while polyvinyl caprolactam graft copolymer, soluplus (SOL) and vinylpyrrolidone-vinyl acetate copolymer grades, Kollidon VA64 (VA64) and Plasdone S630 (S630) were used as hydrophilic polymeric carriers. For the purpose of the study, drug-polymer binary blends at various ratios were processed by a Randcastle single screw extruder. The physicochemical properties and the morphology of the extrudates were evaluated through X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Increased drug loadings of up to 40% were achieved in the extruded formulations for both drugs. INM and FMT exhibited strong plasticization effects with increasing concentrations and were found to be molecularly dispersed within the polymer blends. The in vitro dissolution studies showed increased INM/FMT release rates for all formulations compared to that of pure APIs alone.