Preparation and evaluation of different polymers based dry adsorbed emulsions of chlorpheniramine maleate as a sustained drug delivery system

Dry adsorbed emulsions containing chlorpheniramine maleate and different polymers as adsorbent were chlorpheniramine Hydrophobic silica was used to cover the oil phase, while the aqueous phase was adsorbed by either pectin, Eudragit S, chitosan or hydrophilic silica. The physical properties of the prepared dry adsorbed emulsion, such as drug content, mean particle diameter, flowability and porosity, were evaluated. The release rate of the drug was investigated in dissolution media of varying pH. The stability of the hydrophilic silica based dry adsorbed emulsion was also studied. The results revealed that the physical properties of the prepared dry adsorbed emulsions were within the pharmaceutical working range. The release rate of chlorpheniramine maleate was affected by the properties of both the drug and the polymers. The highest sustained release rate was obtained from the silica based dry adsorbed emulsion. The temperature and relative humidity affected the physical properties and increased there release rate of the drug from the stored samples.