Cross-linked starch microspheres: effect of cross-linking condition on the microsphere characteristics.
Cross-linked starch microspheres were prepared using different kinds of cross-linking agents. The influence of several parameters on morphology, size, swelling ratio and drug release rate from these microspheres were evaluated. These parameters included cross-linker type, concentration and the duration of cross-linking reaction. Microspheres cross-linked with glutaraldehyde had smooth surface compared with those prepared with epichlorhydrine or formaldehyde. The particle size increased with increasing the cross-linking time and increasing the drug loading. Swelling ratio of the particles was a function of cross-linker type but not the concentration or time of cross-linking. Drug release from starch microspheres was measured in phosphate buffer and also in phosphate buffer containing alpha-amylase. Results showed that microspheres cross-linked with epichlorhydrine released all their drug content in the first 30 minutes. However, cross-linking of the starch microspheres with glutaraldehyde or formaldehyde decreased drug release rate. SEM and drug release studies showed that cross-linked starch microspheres were susceptible to the enzymatic degradation under the influence of alpha-amylase. Changing the enzyme concentration from 5000 to 10,000 IU/L, increased drug release rate but higher concentration of enzyme (20,000 IU/L) caused no more acceleration.
Atyabi
Fatemeh
F
Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, PO Box 14155-6451, Iran. atyabifa@tums.ac.ir
Manoochehri
Saeed
S
Moghadam
Shadi H
SH
Dinarvand
Rassoul
R
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000737:chemistry; D003106:Colon / Q000187:drug effects; D003432:Cross-Linking Reagents; D004008:Diclofenac / Q000008:administration & dosage / Q000737:chemistry; D004339:Drug Compounding; D016503:Drug Delivery Systems; D005557:Formaldehyde; D005976:Glutaral / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D013213:Starch / Q000737:chemistry*; D000516:alpha-Amylases / Q000737:chemistry
D000894:Anti-Inflammatory Agents, Non-Steroidal; D003432:Cross-Linking Reagents; D004008:Diclofenac; D005557:Formaldehyde; D013213:Starch; D000516:alpha-Amylases; D005976:Glutaral