Development and evaluation of acyclovir loaded chitosan microspheres and cross linked with glutaraldehyde

The guanine derivative antiviral drug acyclovir (ACV) is one of the oldest molecules put downing triumphant market until date, being commercially accessible in a variety of dosage forms for oral, topical and parenteral administrations. Clinical purpose of this drug is better to new antiviral agents due to its potential values such as suppression of recurrence, security profile, negligible drug interactions and being inexpensive. ACV is slightly water soluble, less permeable and poorly bioavailable, yet further potential antiviral molecule, the physicochemical alterations and new dosage form approaches resulted with more than 100 research efforts within a decade. The current study endeavored at the formulation of chitosan microspheres loaded with ACV to conquer the poor bioavailability and recurrent dose administration. Chitosan microspheres were prepared by emulsification technique by glutaraldehyde cross-linking. A variety of formulation and process variables such as polymer, glutaraldehyde, drug, span 80 concentrations, effect of stirring speed and stirring time were optimized. Formulated microspheres were characterized for its drug loading, invitro drug release, entrapment efficiency, surface morphology (SEM), particle size analysis and FTIR spectroscopy. The characterization of the fabricated microspheres demonstrated smooth surface with thin particle size allocation and entrapment efficiency of 80.8% for stirring speed batch. The prepared microspheres showed a controlled drug release of 93.2% over a period of 8 hrs with initial burst release of 56.7 % in the first 2hrs. The FTIR showed that there was no possible drug interaction among the drug and polymer. From the data’s obtained it can be concluded that the chitosan microspheres could be believed as a possible carrier for controlled drug delivery of ACV. Keywords: Acyclovir, Antiviral drug, Microspheres, Chitosan, Glutaraldehyde.

Controlled Release Modeling of Urea from Chitosan Microspheres: Effect of Stirring Speed and Volume Ratio of Continuous to Dispersed Phase

The purpose of this study was to determine the release kinetics and diffusion coefficient of chitosan microspheres containing urea based on changes in the stirring speed and the volume ratio of the continuous to dispersed phase (CP/DP). Chitosan microspheres filled with urea were prepared using the emulsion cross-linking method. The initial stage of this method has formed an emulsion then slowly dripped with glutaraldehyde saturated toluene as a crosslinker. Urea-loaded chitosan microspheres were washed and dried and then tested for release in an aqueous medium. The calculated cumulative release was used to determine the release kinetics and diffusion coefficient of chitosan microspheres. The appropriate release kinetics model was Simple Power Law with the Burst Effect because it produces an R2 value of 0.99. The mechanism of urea release from chitosan microspheres is Case II the transport mechanism represents pure relaxation behavior. Determination of the diffusion coefficient values from 1,180 x 10-14 up to 1,433 x 10-14 cm2/sec.