Progesterone release from biodegradable PLGA microspheres

IGNACIO M. HELBLING; CARLOS BUSATTO; DIANA ESTENOZ; JULIO A. LUNA

Dubai

Congreso; World Congress and Expo on Pharmaceutics & Drug Delivery Systems (Pharmaceutics-2016); 2016

Scientific Federation

Biodegradablemicrospheres have been studied extensively for drug delivery purposes. They provideseveral advantages compared to conventional pharmaceutical dosage forms, including:(i) the possibility to accurately control the drug release rates over extendedperiods of time, (ii) easy administration and (iii) complete biodegradation. Poly(lactic-co-glycolic acid) copolymer (PLGA) is widely used because of itsbiocompatibility, long clinical experience, controllable degradationcharacteristics and possibilities for sustained drug delivery. Inthe present contribution, PLGA-based microspheres loaded with progesterone wereprepared by the oil-in-water emulsion technique. Size exclusion chromatography(SEC), differential scanning calorimetry (DSC) and nuclear magnetic resonance(NMR) were used to evaluate polymer degradation during microspherespreparation. In addition, the effect of progesterone encapsulation on microspheressize was analysed. In vitro release studies were carried out in phosphatebuffer at 37ºC. The effect of particle size and hormone load on the releasekinetics were studied. Scanning electronmicroscopy (SEM) was employed to observe morphological changes of particlesafter delivery assays. Results showed that microspheres preparation conditionsdo not induce significant PLGA degradation. In addition, the hormone load(0-40% w/w) does not modify the initial particle size. Microspheres withsmaller size presented two release phases. Increasing the hormone load from 20to 40 % w/w, the release rate in the burst phase increase from 17 to 45 10-2mg mg-1 days -1/2. Microspheres withlarge size presented three release phases. The burst effect was low(approximately 8.7 10-2 mg mg-1days -1/2) and the hormone releasetakes place over a more extended period of time.