In order to develop a niosome-encapsulated ciprofloxacin (CPFX) HCl formulation for pulmonary delivery, the feasibility of encapsulation of CPFX in niosomes, its stability and nebulization capability was evaluated. Various combinations of nonionic surfactants with cholesterol were used to prepare the formulations. The in vitro deposition data of the niosomal formulations were examined using an Andersen cascade impactor. Formulations composed of Span 60 and Tween 60 in combination with 40 mol% of cholesterol exhibited high encapsulation efficacy and stability and also had fine particle fraction and nebulization efficiency of about 61.9% ± 1.0 and 77.9 ± 2.8, respectively. Minimal inhibitory concentration of the niosomal CPFX against some pulmonary pathogens were lower than free CPFX. Using the MTT assay in human lung carcinoma cell line (A549), niosome-entrapped CPFX showed significantly lower cytotoxicity in comparison to the free drug. These results indicate that niosome can be used as a carrier for pulmonary delivery of CPFX via nebulization.

This study details the process of coating theophylline with ethylcellulose using the coacervation technique of microencapsulation. Microencapsulation of theophylline not only renders it sustained-release, but also decreases its gastric irritation and masks the bitter taste (Lin and Yang 1987). The non-solvent addition method was chosen through a literature survey to ascertain various phases of the coacervate (Robinson 1989, Nixon and Wong 1990). A three-phase diagram was used to determine the optimum quantity of each component required. Steps were then carried out to optimize the production. Drug release rates of the prepared microcapsules were determined over 12-h cycles using the U.S.P. dissolution apparatus and the results obtained were compared with those of Knoll's (Germany) sustained-release theophylline capsules. Significant control over the rate of drug released from the developed dosage form was achieved during the experiment time (12 h). It is concluded that the method employed in this study could be effectively used in the preparation of sustained-release theophylline microcapsules capable of releasing their drug content for an extended period of time. Kinetic studies suggested that both the prepared microcapsules and Knoll's product followed Higuchi's model for drug release. Particle size and release data analysis from five consecutive batches prepared in the laboratory indicated suitable reproducibility of the coacervation process.