Current Issue : January - March Volume : 2020 Issue Number : 1 Articles : 5 Articles
Tacrolimus is an immunosuppressive agent for acute rejection after allotransplantation.\nHowever, the low aqueous solubility of tacrolimus poses difficulties in formulating an injection\ndosage. Polypeptide thermosensitive hydrogels can maintain a sustained release depot to deliver\ntacrolimus. The copolymers, which consist of poloxamer and poly(l-alanine) with l-lysine segments\nat both ends (P-Lys-Ala-PLX), are able to carry tacrolimus in an in situ gelled form with acceptable\nbiocompatibility, biodegradability, and low gelling concentrations from 3 to 7 wt %. By adding\nPluronic F-127 to formulate a mixed hydrogel system, the drug release rate can be adjusted to maintain\nsuitable drug levels in animals with transplants. Under this formulation, the in vitro release of\ntacrolimus was stable for more than 100 days, while in vivo release of tacrolimus in mouse model\nshowed that rejection from skin allotransplantation was prevented for at least three weeks with one\nsingle administration. Using these mixed hydrogel systems for sustaining delivery of tacrolimus\ndemonstrates advancement in immunosuppressive therapy....
Nano anti-cancer drug carriers loaded with antineoplastic drugs can achieve targeted drug\ndelivery, which enriches drugs at tumor sites and reduces the toxic side effects in normal tissues.\nMesoporous silica nanoparticles (MSN) are good nano drug carriers, as they have large specific\nsurface areas, adjustable pore sizes, easily modifiable surfaces, and good biocompatibility. In this\nwork, polyethyleneimine (PEI) grafted MSN were modified with folic acid (FA) as an active target\nmolecule using chemical methods. The product was characterized by SEM, TEM, Zetasizer nano,\nFTIR, and an N2 adsorption and desorption test. MSN-PEI-FA are porous nano particles with an\naverage particle size of approximately 100 nm. In addition, the loading rate and release behavior\nof MSN-PEI-FA were studied with curcumin as a model drug. The results show that when loading\ncurcumin to MSN-PEI-FA at 7 mg and 0.1 g, respectively, the encapsulation efficiency was 90% and\nthe cumulative release rate reached more than 50% within 120 h at pH = 5. This drug delivery system\nis suitable for loading fat-soluble antineoplastic drugs for sustained release and pH sensitive delivery....
Calcium carbonate is an abundant mineral with several advantages to be a successful carrier\nto improve oral bioavailability of poorly water-soluble drugs, such as praziquantel. Praziquantel is an\nantiparasitic drug classified in group II of the Biopharmaceutical Classification System hence\ncharacterized by high-permeability and low-solubility. Therefore, the dissolution rate is the\nlimiting factor for the gastrointestinal absorption that contributes to the low bioavailability.\nConsequently, the therapeutic dose of the praziquantel must be high and big tablets and capsules are\nrequired, which are difficult to swallow, especially for pediatric and elderly patients. Mixtures of\npraziquantel and calcium carbonate using solid-solid physical mixtures and solid dispersions\nwere prepared and characterized using several techniques (X-ray diffraction differential scanning\ncalorimetry, thermogravimetric analysis, scanning electron microscopy, laser diffraction, Fourier\ntransform infrared and Raman spectroscopies). Solubility of these formulations evidenced that the\nsolubility of praziquantel-calcium carbonate interaction product increased in physiological media.\nIn vitro dissolution tests showed that the interaction product increased the dissolution rate of the\ndrug in acidic medium. Theoretical models were studied to understand this experimental behavior.\nCytotoxicity and cell cycle studies were performed, showing that praziquantel-calcium carbonate\nphysical mixture and interaction product were biocompatible with the HTC116 cells, because it did\nnot produce a decrease in cell viability or alterations in the cell cycle....
Natural antioxidants, such as astaxanthin (AX), resveratrol (RV) and curcumin (CU),\nare bioactive molecules that show a number of therapeutic effects. However, their applications are\nremarkably limited by their poor water solubility, physico-chemical instability and low bioavailability.\nIn the present work, it is shown that self-assembled hyaluronan (HA)-based nanohydrogels (NHs)\nare taken up by endothelial cells (Human Umbilical Vein Endothelial Cells, HUVECs), preferentially\naccumulating in the perinuclear area of oxidatively stressed HUVECs, as evidenced by flow cytometry\nand confocal microscopy analyses. Furthermore, NHs are able to physically entrap and to significantly\nenhance the apparent water solubility of AX, RV and CU in aqueous media. AX/NHs, RV/NHs and\nCU/NHs systems showed good hydrodynamic diameters (287, 214 and 267 nm, respectively), suitable����������...
Zein is an insoluble, yet swellable, biopolymer that has been extensively studied for its\napplications in drug delivery. Here, we screened the effect of co-excipients on the swelling and drug\nrelease of zein tablets. All throughout the study the behavior of zein was benchmarked against that\nof hydroxypropyl methylcellulose (HPMC) and ethylcellulose (EC). Tablets containing either zein,\nHPMC, or EC alone or in combination with co-excipients, namely lactose, dicalcium phosphate\n(DCP), microcrystalline cellulose (MCC), polyvinylpyrrolidone (PVP), or sodium lauryl sulfate\n(SLS) were prepared by direct compression. Matrix swelling was studied by taking continuous\npictures of the tablets over 20 h, using a USB microscope connected to a PC. The overall size change\nand the axial and radial expansion of the tablets were automatically extrapolated from the pictures\nby image analysis. Moreover, drug release from tablets containing ternary mixtures of zein, coexcipients\nand 10% propranolol HCl was also studied. Results showed that zein matrices swelled\nrapidly at first, but then a plateau was reached, resulting in an initial rapid drug burst followed by\nslow drug release. HPMC tablets swelled to a greater extent and more gradually, providing a more\nconstant drug release rate. EC did not practically swell, giving a nearly constant drug release\npattern. Among the additives studied, only MCC increased the swelling of zein up to nearly threefold,\nand thus suppressed drug burst from zein matrices and provided a nearly constant drug\nrelease over the test duration. Overall, the incorporation of co-excipients influenced the swelling\nbehavior of zein to a greater extent compared to that of HPMC and EC, indicating that the molecular\ninteractions of zein and additives are clearly more complex and distinct....
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