In vitro 5-fluorouracil release properties investigation from pH sensitive sodium alginate coated and uncoated methyl cellulose/chitosan microspheres.

5-Fluorouracil (5-FU) has been in clinical practice for decades one of the oldest chemotherapy agents. However, intravenous administration of 5-FU requires the development of an oral controlled delivery system for improved patient compliances. For this purpose, 5-FU loaded and sodium alginate (NaAlg) coated and uncoated methyl cellulose (MC)/chitosan (CS) microspheres were prepared by emulsion crosslinking method using a mixture of water and oil. Firstly, MC/CS microspheres were prepared and then coated with NaAlg. The prepared microspheres were characterized by optical microscopy, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Microspheres were also characterized by equilibrium swelling values and drug release profiles. The in vitro drug release studies were carried out with three pH values 1.2, 6.8, and 7.4, respectively, each for 2 h. It was determined that coating the microspheres with NaAlg provides more controlled drug release, especially at pH 1.2. The effects of the preparation conditions, such as coating time, MC/CS ratio, NaAlg concentration, and crosslinker concentration on the 5-FU release were investigated.

Novel ionically crosslinked acrylamide-grafted poly(vinyl alcohol)/sodium alginate/sodium carboxymethyl cellulose pH-sensitive microspheres for delivery of Alzheimer's drug donepezil hydrochloride: Preparation and optimization of release conditions.

In this work, the graft copolymer, poly(vinyl alcohol)-grafted polyacrylamide (PVA-g-PAAm), was synthesized and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and elemental analysis. Microspheres of PVA-g-PAAm/sodium alginate (NaAlg)/sodium carboxymethyl cellulose (NaCMC) were prepared by the emulsion-crosslinking method and used for the delivery of an Alzheimer's drug, donepezil hydrochloride (DP). The release of DP increased with the increase in drug/polymer ratio (d/p) and PVA-g-PAAm/NaAlg/NaCMC ratio, while it decreased with the increase in the extent of crosslinking. The optimum DP release was obtained as 92.9% for a PVA-g-PAAm/NaAlg/NaCMC ratio of 1/2/1, d/p ratio of 1/8, and FeCl3 concentration of 7% (w/v).

Preparation of magnetite-chitosan/methylcellulose nanospheres by entrapment and adsorption techniques for targeting the anti-cancer drug 5-fluorouracil.

In this work, we have formulated novel nanospheres that could be used in the controlled release of the anticancer drug, 5-fluorouracil (5-FU). The nanospheres are composed of magnetite, containing chitosan (CS) and methylcellulose (MC). The drug entrapment was achieved through the encapsulation and adsorption processes. The effects of the preparation conditions, such as magnetite content, CS/MC ratio, crosslinking concentration, exposure time to glutaraldehyde (GA), and the drug/polymer ratio were investigated for both processes. The 5-FU release was found to follow the Fickian mechanism, and the Langmuir isotherm for the nanospheres was achieved through encapsulation and adsorption processes, respectively.

Preparation of ferric ion crosslinked acrylamide grafted poly (vinyl alcohol)/sodium alginate microspheres and application in controlled release of anticancer drug 5-fluorouracil.

Ionically crosslinked microspheres of acrylamide (AAm) grafted poly (vinyl alcohol) (PVA)/sodium alginate (NaAlg) were prepared by crosslinking with FeCl3 and 5-fluorouracil (5-FU), which is an anticancer drug and was successfully encapsulated into the microspheres. The graft copolymer (PVA-g-PAAm) was characterized by using Fourier transform infrared spectroscopy (FTIR) and elemental analysis. The prepared microspheres were characterized by FTIR and scanning electron microscopy (SEM). Microspheres were also characterized by particle diameter, equilibrium swelling values and release profiles. The release studies were carried out at three pH values 1.2, 6.8 and 7.4, respectively, each for 2 h. The effects of preparation conditions as PVA-g-PAAm/NaAlg ratio, drug/polymer ratio, crosslinker concentration and exposure time to FeCl3 on the release of 5-FU were investigated for 6 h at 37 °C. The highest 5-FU release was found to be as 99.57% (w/w) at the end of 6 h for PVA-g-PAAm/NaAlg ratio of 1:4 (w/w), drug/polymer ratio of 1:8 (w/w), crosslinker concentration of 0.05 M and exposure time of 10 min. The release results were also supported by the swelling measurements of the microspheres. Release kinetics was described by Fickian and non-Fickian approaches.

Release characteristics of diclofenac sodium from poly(vinyl alcohol)/sodium alginate and poly(vinyl alcohol)-grafted-poly(acrylamide)/sodium alginate blend beads.

In this study, acrylamide (AAm) was grafted onto poly(vinyl alcohol) (PVA) with UV radiation at ambient temperature. The graft copolymer (PVA-g-PAAm) was characterized by using Fourier transform infrared spectroscopy (FTIR), elemental analysis and differential scanning calorimetry (DSC). Polymeric blend beads of PVA-g-PAAm and PVA with sodium alginate (NaAlg) were prepared by cross-linking with glutaraldehyde (GA) and used to deliver a model anti-inflammatory drug, diclofenac sodium (DS). Preparation condition of the beads was optimized by considering the percentage entrapment efficiency, particle size, swelling capacity of beads and their release data. Effects of variables such as PVA/NaAlg ratio, acrylamide content, exposure time to GA and drug/polymer ratio on the release of DS were discussed at three different pH values (1.2, 6.8, 7.4). It was observed that, DS release from the beads decreased with increasing PVA/NaAlg (m/m) ratio, drug/polymer ratio (d/p) and extent of cross-linking. However, DS release increased with increasing acrylamide content of the PVA-g-PAAm polymer. The highest DS release was obtained to be 92% for 1/1 PVA-g-PAAm/NaAlg ratio beads. It was also observed from release results that DS release from the beads through the external medium is much higher at high pH (6.8 and 7.4) than that at low pH (1.2). The drug release from the beads mostly followed Case II transport.