جستجوی مقالات مرتبط با کلیدواژه « floating microspheres » در نشریات گروه « پزشکی »

Ciprofloxacin (CIP) is a broad-spectrum antibiotic, used to treat various bacterial infections. Administration of conventional oral dosage forms of CIP is associated with multiple challenges such as short residence time of the drug in the gastrointestinal tract which could reduce bioavailability and effectiveness of the drug. This study aimed to design and develop novel floating microspheres for the sustained release of CIP in the stomach over 24 hours after oral administration, besides evaluating the effect of different variables on the characteristics of developed microspheres.

Microspheres were developed by the solvent-evaporation method utilizing cellulose acetate and polyvinyl alcohol, then characterized for physicochemical properties including bulk density, buoyancy, and entrapment efficacy. The drug-excipient compatibility was evaluated by Fourier-transform infrared spectroscopy and the Scanning electron microscopy was used to observe the morphology of microspheres. The effects of the drug to polymer ratio, polymer concentration, and the pace of stirring through the preparation process, on the size and release rate were also evaluated.

Morphology analysis indicated round-shape microspheres with a mean particle size between 66-344 µm. The polydispersity index of prepared formulations was determined to be in the range of 0.129 to 0.230. It was observed that at higher polymer concentrations the drug release rate from microspheres decreased while the mean particle size increased. Increasing the drug to polymer ratio and decreasing the stirring speed increased the mean particle size. All formulations showed more than 70% cumulative drug release in the prolonged period of 24 h while remaining buoyant in the meantime. The formulations followed Higuchi and Korsmeyer-Peppas kinetics and release the drug by diffusion mechanism.

Based on the results obtained from in vitro release study besides floating properties, the prepared microspheres could be considered suitable for enhanced sustained-release of CIP following the oral administration.

Carvedilol (CVD) is an antihypertensive agent with a short half-life, pH-dependent solubility, and narrow absorption window. The purpose of this research was to prepare a floating-drug delivery-system of carvedilol to increase its half-life. The present study investigates the preparation of carvedilol-floating microspheres, evaluates the floating-drug delivery-system (FDDS) (by scanning electron microscope), it’s in vitro stability, and in vivo profile. Floating microspheres were prepared by solvent-evaporation (oil-in-water emulsion) technique using hydroxypropyl methylcellulose (HPMC) and ethyl cellulose (EC) as the rate controlling polymers. The surface morphology of the prepared microspheres w:as char:acterized by scanning electron microscopy. In this study, the particle size analysis, drug entrapment efficiency, surface morphology, buoyancy percentage, and release studies were performed. The microspheres were found to be spherical and porous. The results showed that the mean/mean (SD) values of tapped density, Carr's compressibility index, angle of repose, percentage yield, in vitro buoyancy, %entrapment efficiency of CVD-loaded floating microspheres were 0.42 (0.012), 12.5 (1.895), 23.5 (1.856), 80.2 %, 79.0 %, and 85.81(1.40), respectively. The developed floating-microsphere of CVD released the drug for 24 h and based on in vivo studies, the drug-loaded floating microspheres help in maintaining the mean (SD) systolic blood pressure within the range of 120 (0.32) to 120 (1.02) mmHg and diastolic pressure within 91 (0.71) to 92 (0.79) mmHg. Thus, floating microsphere of CVD offers a suitable and practical approach for prolonged release of the drug over an extended period, and thus improves the oral bioavailability and efficacy of the drug as well as the patient’s compliance.

The objective of the present study was to develop floating microspheres of cefpodoxime proxetil in order to achieve an extended retention in the upper GIT, which may result in enhanced absorption and thereby improved bioavailability. The microspheres were prepared by non-aqueous solvent evaporation method using polymers such as hydroxyl propyl methyl cellulose (HPMC K 15 M), ethyl cellulose in different ratios and cefpodoxime proxetil in each formulation. In vitro drug release were performed by USP apparatus type I and the microspheres were characterized by polymer compatibility by using FT-IR. The yield, particle size, Buoyancy percentage, drug entrapment efficiency, and in vitro drug release were studied. The result showed that microspheres yielded 50.5-72.2%. The particle size was distributed between75-600 μm, drug entrapment efficiency was 14.1-28.2%, and Buoyancy percentage was 70.1-88.3%. The best drug release profiles were seen with formulation 2 at the ratio of drug to polymer of 1:2.