Loading of 5-aminosalicylic in solid lipid microparticles

• Published in: Journal of thermal analysis and calorimetry 2020-01, Vol.139 (2), p.1151-1159
• Main Authors: Silveira, Elisânia F, Rannier, Lucas, Nalone, Luciana, da Silva, Classius F, Chaud, Marco V, de M. Barbosa, Raquel, Junior, Ricardo L. C. A
• Format: Article
• Language: English
• Subjects: Acetone; Alcohols; Bioavailability; Colon; Differential scanning calorimetry; Dimethyl sulfoxide; Fourier transforms; Gastrointestinal diseases; Infrared analysis; Lecithin; Lipids; Microparticles; Microscopy; Optical microscopy; Organic chemistry; Size distribution; Stability analysis; Surface active agents; Sustained release; Thermogravimetric analysis; Time dependence
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-019-08544-7

5-Aminosalicylic acid (5-ASA), the active moiety of sulphasalazine, is the most commonly used drug for treating patients with inflammatory bowel disease (IBD). Its bioavailability is low, i.e. 20-30% upon oral administration and 10-35% by rectal administration. As the extent of 5-ASA absorption is very much dependent on the time-length, the drug is retained in the colon, a way to increase drug retention is the use of orally administered sustained released formulations. Solid lipid microparticles (SLM) are a viable option for site-specific targeted delivery in compressed tablets produced by direct compaction. In this study, we describe the development and characterization of 5-ASA-loaded SLM for sustained release. The solubility of 5-ASA in different types of solid lipids (e.g. cetyl palmitate, cetyl alcohol, and cetearyl alcohol) was evaluated to select the best lipid as the inert matrix-forming agent to control the release of the drug. SLM dispersions were prepared using the hot emulsification method employing the selected solid lipid, lecithin (Lipoid.sup.®) as surfactant, dimethyl sulphoxide, and acetone stabilized with Arlacel.sup.®. The characterization was performed by differential scanning calorimetry, thermogravimetric analysis, wide-angle x-ray diffraction, Fourier transform infrared spectroscopy measurements, optical microscopy, and scanning electron microscopy. Results show that the best lipid for dissolving the 5-ASA was cetyl palmitate and that the melting process did not affect the chemical stability of the materials. The thermal analysis suggests that 5-ASA was successfully encapsulated with the microparticles, of spherical shape and uniform size distribution.