Controlled release of anticholinesterase drug pyridostigmine bromide from chitosan/sodium alginate and emulsion crosslinked chitosan/methyl cellulose interpenetrating polymer network microspheres

In this study, microspheres of chitosan/sodium alginate (CS/NaAlg) and chitosan/methylcellulose (CS/MC) were prepared to capsulate pyridostigmine bromide which is an anticholinesterase drug. Microspheres were prepared by jelation and emulsion crosslinking methods using CaCl2-CS and glutaraldehyde solutions. The prepared microspheres were characterized by fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and optic microscopy. 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 and it was observed that as the pH of the medium increased cumulative drug release increased. Increase in drug/polymer ratio increased the release of pyridostigmine bromide from the CS/NaAlg and CS/MC interpenetrating network (IPN) microspheres however has not changed the entrappment efficiency significantley.Optimum conditions for the preparation and release of the microspheres were determined as CS/NaAlg (w/w): 2/1, crosslinker concentration: 0,025M, drug/polymer ratio (w/w): 1/8 crosslinking time: 5 minutes and pH: 7,4; CS/MC structured IPN microspheres (w/w) : 4/1, crosslinker concentration: 3,25 M, drug/polymer ratio (w/w): 1/6, crosslinking time: 5 minutes and pH: 7,4. The cumulative release at these conditions was found to be 81,60 % at the end of 6 hours for CS/NaAlg microspheres and found 100,00% for CS/MC structured IPN microspheres.