The use of gelatin microparticles to delay the release of readily water-soluble materials.
The adsorption of D-arabinose onto gelatin microparticles demonstrated a Langmuirian adsorption pattern. Evaluation of the dissolution behaviour of D-arabinose-loaded gelatin microparticles suggested that the saccharide, loaded at a level below the adsorption saturation level, was released uniformly over a 14-h period after the loaded gelatin microparticles had been lyophilized for a second time. When dissolution curves were corrected for the initial burst effect seen after the gelatin microparticles had been loaded at higher levels of D-arabinose and lyophilized, steady-state release rates were also evident over prolonged periods. In addition, it was evident that the D-arabinose was adsorbed onto internal surfaces of the hydrated gelatin matrix. Calculation of this internal surface demonstrated the influence of the concentration of the glutaraldehyde used as a cross-linking agent and this parameter, in turn, influenced both the adsorption maxima and the subsequent equilibrium release rates. Application of this data base to a highly water-soluble complex polysaccharide antineoplastic agent, which has a higher molecular weight (22.4 kDa vs 150 Da), demonstrated similar behaviour in that a near zero-order release pattern over at least 16 h could be obtained by attention to the conditions under which the gelatin microparticles were made and subsequently loaded before lyophilization.
Lou
Y
Y
Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago 60607-7019, USA.
Groves
M J
MJ
D000327:Adsorption; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000378:metabolism; D001089:Arabinose / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000592:standards*; D005612:Freeze Drying; D005780:Gelatin / Q000737:chemistry / Q000378:metabolism*; D005976:Glutaral / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D010316:Particle Size; D011134:Polysaccharides / Q000008:administration & dosage* / Q000378:metabolism; D012015:Reference Standards; D012995:Solubility; D013696:Temperature; D014867:Water
D000970:Antineoplastic Agents; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D011134:Polysaccharides; D014867:Water; D005780:Gelatin; D001089:Arabinose; D005976:Glutaral