Potential applications of PLGA film-implants in modulating in vitro drugs release

ArticleinInternational Journal of Pharmaceutics 248(1-2):149-56 · December 2002with14 Reads
DOI: 10.1016/S0378-5173(02)00431-3 · Source: PubMed
In this work we evaluate poly(lactic/glycolic) acid (PLGA) film-implants as potential biodegradable devices for controlled release of two different drugs: 5-Fluorouridine (5-FUR), a conventional low molecular weight water-soluble compound and SPf66 malaria vaccine, a therapeutic synthetic polypeptide. Three types of devices were prepared by solvent-casting techniques alone or combined with compression method: simple monolithic discs (SMD), multilayer discs with a central monolithic layer (MLDM), and multilayer discs with a central drug-reservoir (MLDR). For the highly water-soluble drug, 5-FUR, in vitro release from SMD showed an initial burst (24% in 2 h) followed by prolonged release over 20 days. In contrast, from a MLDM (two drug-free PLGA discs were added to the SMD) showed an initial lag-time of 12 days followed by a very fast second release phase. Finally, when the load of this system was increased from 3 to 9%, an extended release over 20 days with a low burst effect was obtained. For SPf66, the central reservoir containing the synthetic polypeptide MLDR reduces the possibility of degradation due to peptide contact with polymer solution. When four layers were added, 10 days sustained-release was obtained without any burst effect. With six layers a moderate pulse was obtained, 18-22 days from the beginning of the release. The results show the suitability of the proposed devices to control release and avoid the burst effect with highly water-soluble drugs; as well as modulate in vitro peptide release.
    • "A biodegradable polymeric implant can function by releasing a drug in the correct amount of strength over a period of time following one or a combination of mechanisms viz., erosion of the matrix, diffusion through the matrix or combination of both diffusion and erosion mechanisms either enzymatically or non-enzymatically to produce biocompatible or nontoxic by-products [30]. The drug release rate from a polymeric matrix depends on interactions between the active ingredients and polymer [31]. In the literature, plenty of theoretical or empirical release models are described [32,33] . "
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    • "The type and molar ratio of individual monomer components (lactide and glycolide) in the copolymer chain partially determines the implant's degradation rate. Polyglycolic acid (PGA) is more hydrophilic than polylactic acid (PLA) (Dorta et al. 2002). Subsequently, higher glycolic acid molar ratio polymers degrade more quickly through hydrolysis by allowing more biological fluids to penetrate and swell the polymer matrix (Mundargi et al. 2008). "
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