An approach to prepare microparticles of uniform size.

Faculty of Pharmaceutical Sciences, Science University of Tokyo, Japan.
Journal of Microencapsulation (Impact Factor: 1.57). 01/1995; 12(2):129-36. DOI:10.3109/02652049509015283
Source: PubMed

ABSTRACT A novel emulsification method which employs a glass membrane of controlled pore size was adopted to prepare various types of microparticles. The microparticles thus obtained were uniform in size and the procedure proved applicable to a wide variety of microencapsulation processes. Furthermore, the particle size could be controlled by selecting preparative conditions.

0 0
  • [show abstract] [hide abstract]
    ABSTRACT: The aim of this study is to develop a duodenum-specific drug delivery system on the basis of a pH-sensitive coating and a mucoadhesive inner core for eradication of Helicobacter pylori (H. pylori) in the ulcer duodenum. Hydroxypropyl methylcellulose acetate maleate (HPMCAM) was used as the pH-sensitive material, which dissolves around pH 3.0. The mucoadhesive microspheres loaded with furazolidone (FZD-ad-MS) were prepared by the emulsification-solvent evaporation method using Carbopol 971NP as the mucoadhesive polymer. The prepared pH-sensitive coated mucoadhesive microspheres (AM-coated-MS) were characterized in regards to particle size, drug loading efficiency, morphological change, drug stability, drug release and in vitro anti-H. pylori activity. The particle size was 160.97 ± 47.24 μm and 336.44 ± 129.34 μm, and the drug content was 42.33 ± 3.43% and 10.96 ± 1.29% for FZD-ad-MS and AM-coated-MS, respectively. The morphological changes in different pH media were characterized by scanning electron microscopy (SEM). HPMCAM coating improved the stability of the FZD-ad-MS and these particles were expected to remain intact until their arrival in the duodenum. The drug release was extremely suppressed at pH 1.2 for AM-coated-MS, but increased at pH 4.0 after regeneration of FZD-ad-MS. In addition, FZD-ad-MS exhibited excellent anti-H. pylori activity in vitro. Thus, the HPMCAM-coated microspheres developed in this study hold great promise for use as a duodenum-specific drug delivery system for H. pylori clearance.
    Archives of Pharmacal Research 05/2012; 35(5):839-50. · 1.54 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Several methods and techniques are potentially useful for the preparation of polymeric microparticles in the broad field of microencapsulation. The preparation method determines the type and the size of microparticle and influence the ability of the interaction among the components used in microparticle formulations. This review is devoted to describe and allocate the recently awarded and pending patents regarding the technical and formulation innovations in microparticles involved in drug delivery that are based mainly on the emulsion solvent removal methods. The term microparticle designates systems larger than one micrometer in diameter and is used usually to describe both microcapsules and microspheres. Microparticle-containing drugs are employed for various purposes including--but not restricted to--controlled drug delivery, masking the taste and odor of drugs, protection of the drugs from degradation, and protection of the body from the toxic effects of the drugs. Polymeric carriers being essentially multidisciplinary are commonly utilized in microparticle fabrication and they can be of an erodible or a non-erodible type.
    Recent patents on drug delivery & formulation. 11/2009; 3(3):178-92.
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Particulate systems that could deliver drug specifically to duodenum have not yet been reported. The aim of this study was to develop a novel duodenum-specific drug delivery system based on thiolated chitosan and hydroxypropyl methylcellulose acetate maleate (HPMCAM) for the duodenal ulcer application. Berberine hydrochloride was used as model drug. Thiolated chitosan was synthesized and further used for the preparation of mucoadhesive microspheres. HPMCAM, which is insoluble below pH 3.0 was synthesized and used for the coating of thiolated chitosan microspheres (TCM). The resulting thiolated chitosan immobilized on chitosan was 268.21 ± 18 μmol/g. In vitro mucoadhesion study showed that the mucoadhesion property of TCM was better than that of chitosan microspheres. Morphological observation showed that the HPMCAM coating would maintain its integrity in simulated gastric fluid (SGF) for 2 h and dissolved quickly in simulated pathological duodenal fluid (SPDF; pH 3.3). In vitro drug release studies showed that only 4.75% of the drug was released in SGF for 2 h, while nearly 90% of the drug was released within 6 h after transferring into SPDF.
    Drug Development and Industrial Pharmacy 01/2011; 37(7):868-74. · 1.54 Impact Factor

N Muramatsu