Electrosprayed core-shell nanoparticles of PVP and shellac for furnishing biphasic controlled release of ferulic acid

Coaxial electrospraying was explored to organize polymer excipients in a core-shell manner for providing biphasic controlled release of active ingredient. With ferulic acid (FA) as a model drug, and shellac and polyvinylpyrrolidone (PVP) as the core and shell polymeric matrices, core-shell nanoparticles were successfully fabricated. A series of tests were carried out to characterize the prepared core-shell nanoparticles and also the nanoparticles prepared using a single fluid electrospraying of the shell or core fluids alone. The core-shell nanoparticles had an average diameter of 530 ± 80 nm with clear core-shell structure. The contained FA was converted to an amorphous state both in the core and the shell parts due to the favorable hydrogen bonding between the components. In vitro dissolution tests demonstrated that the core-shell nanoparticles were able to provide the desired biphasic drug-controlled release profiles. Coaxial electrospraying is a useful tool for the development of novel nanodrug delivery systems from polymers

Characterization of chitosan acetate as a binder for sustained release tablets

10.1016/j.jconrel.2004.06.008Journal of Controlled Release99115-26JCRE

Characterization of Chitosan Acetate as a Binder for Sustained Release Tablets

Abstract A chitosan derivative as an acetate salt was successfully prepared by using a spray drying technique. Physicochemical characteristics and micromeritic properties of spray-dried chitosan acetate (SD-CSA) were studied as well as drug-polymer and excipient-polymer interaction. SD-CSA was spherical agglomerates with rough surface and less than 75 Am in diameter. The salt was an amorphous solid with slight to moderate hygroscopicity. The results of Fourier transform infrared (FTIR) and solidstate 13 C NMR spectroscopy demonstrated the functional groups of an acetate salt in its molecular structure. DSC and TGA thermograms of SD-CSA as well as FTIR and NMR spectrum of the salt, heated at 120 8C for 12 h, revealed the evidence of the conversion of chitosan acetate molecular structure to N-acetylglucosamine at higher temperature. No interaction of SD-CSA with either drugs (salicylic acid and theophylline) or selected pharmaceutical excipients were observed in the study using DSC method. As a wet granulation binder, SD-CSA gave theophylline granules with good flowability (according to the value of angle of repose, Carr's index, and Hausner ratio) and an excellent compressibility profile comparable to a pharmaceutical binder, PVP K30. In vitro release study of theophylline from the tablets containing 3% w/w SD-CSA as a binder demonstrated sustained drug release in all media. Cumulative drug released in 0.1 N HCl, pH 6.8 phosphate buffer and distilled water was nearly 100% within 6, 16 and 24 h, respectively. It was suggested that the simple incorporation of spray-dried chitosan acetate as a tablet binder could give rise to controlled drug delivery systems exhibiting sustained drug release.

Chromium speciation analysis by separation of Cr(III) from Cr(VI) on a XAD sorbent derivatized with shellac: a natural polymer

A XAD-shellac sorbent, synthesized by the impregnation of the natural polymer shellac ( purified product of the hardened resinous secretion of the lac insect Kerria lacca) on Amberlite XAD-16 copolymer backbone, has been developed for the separation of Cr(III) from Cr( VI), and preconcentration of Cr( III) from synthetic solutions and real samples. The preconcentration factor for Cr( III) was 75. All chromium determinations were made using the diphenyl carbazide spectrophotometric method after oxidizing Cr to chromate( VI) where necessary, and simultaneously with flame-AAS for confirmation. The dynamic breakthrough and batch capacities of this sorbent for Cr( III) were 0.3 and 0.9 mg g(-1), respectively, indicating that the ion-exchange mechanism was prevalent in the dynamic mode, whereas in the batch mode, the surface sites were also capable of exerting their chelating effects. When XAD-shellac was thoroughly washed with ammonium acetate solution prior to use in chromium speciation, the cationic (RH+) surface sites were probably neutralized to yield free acetic acid, and the resulting resin did not retain CrO42-. Thus, complete separation and speciation of Cr( III) from CrO42- was possible using this sorbent. The shellac-coated sorbent decomposed in alkaline solution (i.e. over pH 7.5), and therefore the retained Cr( III) was eluted with dilute (0.025 - 0.050 M) HCl. Thus, Cr( III) in admixture with Cr( VI) could be separated and recovered, without interference from the hexavalent state. XAD-shellac was not successful for Cr preconcentration from seawater, but was efficiently used for synthetic and real electroplating wastewater and CRMs such as SO-2 soil, San Joaquin soil, BCR 145R sewage sludge, with a recovery ratio for Cr( III)/Cr(VI) extending up to <= 98%

Effect of chitosan salts and molecular weight on a nanoparticulate carrier for therapeutic protein

10.1081/PDT-200054388Pharmaceutical Development and Technology102189-196PDTE