Current Issue : October - December Volume : 2019 Issue Number : 4 Articles : 5 Articles
The present study evaluates the in vitro release of diclofenac sodium (DFNa) from contact\nlenses based on poly-2-hydroxyethyl methacrylate (pHEMA) hydrogels containing an embedded\nmicroemulsion to extend release duration. The oil (ethyl butyrate)-in-water microemulsion systems are\nprepared with two non-ionic surfactants, Brij 97 or Tween 80, together with a long-alkyl chain cationic\nsurfactant, cetalkonium chloride (CKC).Without CKC, Brij 97 or Tween 80-based microemulsions\nshowed average droplet sizes of 12 nm and 18 nm, respectively. The addition of CKC decreased\nthe average droplet sizes to 2-5 nm for both non-ionic surfactants. Such significant reduction in\nthe average droplet size corresponds to an increase in the DFNa release duration as revealed by the\nin vitro experiments. Contact lens characterization showed that important properties such as optical\ntransparency and water content of Brij 97-based contact lenses with cationic microemulsions was\nexcellent. However, the optical transparency of the corresponding Tween 80 based contact lenses was\nunsatisfactory. The results indicate that cationic microemulsion-laden contact lenses can benefit from\ncombinatory effects of microemulsions and cationic surfactant at low CKC weight percentage, e.g.,\nwith the release of 70% of the drug in 45, 10, and 7 h for B97-CKC-0.45%, CKC-0.45%, and control\nlenses, respectively. However, the microemulsion effect on extending DFNa release became negligible\nat the highest CKC weight percentage (1.8%)....
Tobramycin is a potent antimicrobial aminoglycoside and its effective delivery by encapsulation\nwithin nanoparticle carriers could increase its activity against infections through a combination of\nsustained release and enhanced uptake. Effective antimicrobial therapy against a clinically relevant\nmodel bacteria (Pseudomonas aeruginosa) requires sufficient levels of therapeutic drug to maintain a drug\nconcentration above the microbial inhibitory concentration (MIC) of the bacteria. Previous studies have\nshown that loading of aminoglycoside drugs in poly(lactic-co-glycolic) acid (PLGA)-based delivery\nsystems is generally poor due to weak interactions between the drug and the polymer. The formation of\ncomplexes of tobramycin with dioctylsulfosuccinate (AOT) allows the effective loading of the drug in\nPLGA-nanoparticles and such nanoparticles can effectively deliver the antimicrobial aminoglycoside\nwith retention of tobramycin antibacterial function....
Vaccination faces many challenges nowadays, and among them the use of adjuvant\nmolecules and needle-free administration are some of the most demanding. The combination of\ntranscutaneous vaccination and nanomedicine through a rationally designed new-formulation could\nbe the solution to this problem. This study focuses on this rational design. For this purpose,\nnew hyaluronic acid nanocapsules (HA-NCs) have been developed. This new formulation has an oily\nnucleus with immunoadjuvant properties (due to alpha tocopherol) and a shell made of hyaluronic acid\n(HA) and decorated with ovalbumin (OVA) as the model antigen. The resulting nanocapsules are\nsmaller than 100 nm, have a negative superficial charge and have a population that is homogeneously\ndistributed. The systems show high colloidal stability in storage and physiological conditions and\nhigh OVA association without losing their integrity. The elevated interaction of the novel formulation\nwith the immune system was demonstrated through complement activation and macrophage viability\nstudies. Ex vivo studies using a pig skin model show the ability of these novel nanocapsules to\npenetrate and retain OVA in higher quantities in skin when compared to this antigen in the control\nsolution. Due to these findings, HA-NCs are an interesting platform for needle-free vaccination....
Micro-injection moulding (microIM) was used for the production of enteric tablets of plasticised\nand unplasticised solid dispersions of poly(vinylpyrrolidone-vinyl acetate) (PVPVA), and the eect\nof the mechanical and thermal treatment on the properties of the dispersions was investigated.\nThe physical state of the systems showed to be unaltered by the microIM step, maintaining the drug in\nthe amorphous state. The dissolution profile of the tablets showed a slower dissolution rate due to\nthe lower surface to volume ratio compared to the extruded strands. The lack of solubility of the\ndoses in the acidic medium as a consequence of the acidity of indomethacin (IND) was observed.\nHowever, in neutral pH the drug dissolution showed slower rates without affecting the dissolution\nextent, showing a potential application for the development of controlled release doses. Overall,\nthe production of tablets of amorphous solid dispersions (ASD), coupling hot-melt extrusion (HME)\nand microIM, proved to be a successful approach towards a continuous automated manufacturing process\nto improve the aqueous solubility of poorly water-soluble drugs....
The acid lability of rosuvastatin hinders the preparation of mixed combination formulations\nof rosuvastatin with acidic drugs such as clopidogrel. Therefore, the purpose of this study was to\ndevelop a multilayer-coated tablet that avoids physicochemical interactions between rosuvastatin\nand clopidogrel. Among the tested hydrophobic materials, glyceryl behenate was most effective\nat inhibiting the production of lactone, the acid degradation product of rosuvastatin. Therefore,\nthe multilayer-coated tablet included a hydrophobic separation layer consisting of glyceryl behenate\nbetween the clopidogrel core tablet and the rosuvastatin coating layer. In order to prevent delayed\ndissolution by the stable hydrophobic separation layer, crospovidone was added into the clopidogrel\ncore tablet as an effective disintegrant. Copovidone was also added to the coating layer of rosuvastatin,\nachieving a dissolution profile comparable to that of the reference drug, Crestor®. The resulting\nmultilayer-coated tablet exhibited similar pharmacokinetic profiles to those of reference drugs (Plavix®\nand Crestor®) in beagle dogs, and there was no statistically significant difference in the maximum\nplasma concentration (Cmax), the time to reach the maximum plasma concentration (Tmax), or the\narea under the plasma-concentration time curve (AUC) between the test and reference formulations.\nThe storage stability tests showed that the amounts of acid degradation products and total impurities\nwere comparable to that of the reference drug. In conclusion, the present study successfully developed\na stable multilayer-coated tablet containing both clopidogrel and rosuvastatin that may improve the\npatient compliance in combination therapy for cardiovascular diseases....
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