Taste Masking and Characterization of Chlorpheniramine Maleate by Using Enteric Polymers Carrier System

Chlorpheniramine maleate is a widely used antihistaminic drug but it is very bitter and as yet no mouth dissolving/disintegrating taste-masked preparation that might be useful in pediatric and geriatric patients is available in the market. The aim of this study was to prepare a microsphere formulation in order to mask the bitter taste of chlorpheniramine. Microspheres of chlorpheniramine with pH-dependent polymers (such as Eudragits S100, L100 and L100-55) were prepared by the double emulsion solvent diffusion method. The effect of different polymers and drug–polymer ratios on the taste masking and the characteristics of the microspheres were investigated. At first, the drug dissolved in water and polymer dissolved in an organic solvent that was composed of ethanol (good solvent) and dichloromethane (bridging liquid) with 2:1 ratio. Silica is a good anti-adhesion agent against the viscous characteristic of polymers and disperses into dichloromethane. In the current study formulations with different drug/polymer ratio were prepared and were characterized by drug loading, loading efficiency, yield, particle size, x-ray diffraction (XRD), Fourier transform spectroscopy (FTIR) and differential scanning calorimetry (DSC). The in vitro release studies were performed in pH 1.2 and 7.4. The best polymer to drug ratio in microparticles Eudragit L100 and L100-55 were F'3 and F"3 (7:1) which showed 9.67% and 7.88% of entrapment, loading efficiency 77.34% and 63.08% and mean particle size of 12.484 μm and 10.675 μm, respectively. The drug loading microparticle Eudragit S100 (5:1) showed 9.65% of entrapment, loading efficiency 57.92% and mean particle size of 6.807 μm. The FTIR, XRD and DSC showed the stable character of clorpheniramine in the drug-loaded microspheres and revealed an amorphous form. The results showed that microparticles prepared with pHdependent polymers were slower release than the commercial tablet (p< 0.05). The results demonstrated that Eudragit S100 was the best for masking the unpleasant taste of chlorpheniramine among the three polymers investigated. The results indicated that the microsphere formulation could be a promising drug carrier for masking the bitter taste of chlorpheniramine.