Evaluation of The Dip-Coating of Ibuprofen on Poly(Lactic-Co-Glycolic Acid) Microneedles

Background: Dip-coating method is one of the popular meth-ods for loading drugs on microneedles. A rapid drug delivery can be achieved by drug coated microneedles through forma-tion of pores in the stratum corneum of the skin. Since pain relief drugs usually need to be absorbed quickly, microneedles coated with these types of drugs seems to be an attractive sys-tem for delivery of them to the body. The purpose of this study is to evaluate the loading of ibuprofen (as a model of analgesic drugs) on a poly (lactic-co-glycolic acid) (PLGA) microneedle patch through dip-coating technique.Materials and Methods: PLGA powder (molecular ratio of D, L-Lactide/glycolide 50:50, Mw 20000 Da) was provided by IPPI; ibuprofen was donated by Aryapharm Company (Tehran, Iran) and methanol was bought from Merck (Germany). Spe-cific amounts of ibuprofen were dissolved in methanol to give a clear solution. Then the PLGA microneedle that was prepared through a melt-molding technique was dipped into the solution such that the needles were in direct contact with the solution. FTIR and DSC were used to confirm the loading of the drug on microneedles. Finally SEM was used to monitor the morphol-ogy of the needles before and after the drug loading process.Results: FTIR analysis confirmed the loading of ibuprofen on PLGA microneedles and the results showed that the drug was loaded mainly through physical absorption. The results were also confirmed by Differential scanning calorimetry (DSC) through showing characteristic transitions of PLGA and the drug. Morphology investigations through SEM before and after coating process as well as penetration of microneedles into pa-ra-film (as a skin model) showed that the shape and morphology of the microneedles after the drug coating is preserved while after penetrating into the film the sharpness of a few number of microneedles were lost.Conclusion: The results showed that the process of ibuprofen loading on PLGA microneedles was successfully performed through dip-coating without any sign of deformation in the morphology of needles. Some minor changes in the tip of the needles were observed after penetrating into para-film.

Keywords:

Microneedle Patch , PLGA , Dip-Coatong , Ibuprofen , Loading