pH-responsive hydrogel microparticles as intelligent delivery carriers for α-MSH antagonists

Abstract

For a first step in the development of an intelligent delivery system for a nonapeptide as an a-MSH antagonist, pH-responsive P(MAA-co-EGMA) hydrogel microparticles were prepared and their feasibility as intelligent delivery carriers was evaluated. There was a drastic change in the swelling ratio of P(MAA-co-EGMA) microparticles at a pH of around 5 and as the MAA amount in the hydrogel increased, the swelling ratio increased at a pH above 5. The loading efficiency of the nonapeptide at pH 7 increased with the amount of Methacrylic acid (MAA) in the hydrogel and at pH 2, where the electrostatic attraction was greatest, a high loading efficiency was not obtained because of the low swelling ratio of the hydrogel. The P(MAA-co-EGMA) microparticles demonstrated a pH-sensitive release behavior for the nonapeptide. In addition, the P(MAA-co-EGMA) microparticles showed a protective ability for the nonapeptide and preserved the stability of the nonapeptide. V

Spin content ofΛin QCD sum rules

“…The upper limit is determined using a restrictive criterion such that the continuum-plus-excited-state contributions are less than about 30% of the phenomenological side, which is imposed so as to warrant the pole dominance. Using these criteria we have similarly found that the sum rule in (9) has a valid Borel window while those in (10) and (11) are seriously contaminated by continuum contributions. Therefore we choose to work with the sum rule at the structure iZ µ σ µν p ν γ 5 in (9).…”

“…Actually, this result is supported by some model-dependent approaches as well (see Appendix A). An investigation of this interesting issue has the potential to shed light on the "spin crisis" and therefore attracted considerable attention [7,8,9,10,11,12]. Experimentally, the polarization of Λ is of special interest because it can be easily measured from the nonleptonic decay Λ → p π [13,14,15,16,17].…”

“…One open question in this framework is how sensitive the Λ spin structure to SU(3) F breaking effects is. While it is claimed that the SU(3) F breaking may lead to a change in the sign of the u-and the d-quark polarizations in Λ [11], lattice [12] and some model-dependent works [10] find that Λ is insensitive to SU(3) F breaking. The isoscalar (g q A and g s A ), octet (g q 8 ) and singlet (g q 0 ) axial-vector coupling constants of Λ (shown gener- * Electronic address: guray.erkol@ozyegin.edu.tr † Electronic address: oka@th.phys.titech.ac.jp ically as g A ≡ g A (q 2 = 0) throughout the text) can be expressed in terms of the fractional contributions of the quark flavors, ∆q, to the Λ spin content as…”

Transdermal delivery of cosmetic ingredients using dissolving polymer microneedle arrays

“…To control microneedle properties, PEGDMA was copolymerized with VP. PEGDMA was used as a second monomer because it has a good biocompatibility, is liquid in monomeric form, can make a cross-linked network after polymerization, and has been used for pharmaceutical purpose for a long time [23][24][25]. The mechanical strength of the fabricated microneedles was tested by applying different loads onto the microneedles and calculating the remaining length ratio, defined as the ratio of the final length of the deformed needle to the length of the original needle.…”