Obtaining high efficiency room temperature phosphorescence (RTP) by employing non-noble metals poses two challenges: (1) strengthening spin-orbit coupling of excitons to improve the rate of intersystem crossing (ISC) by using non-noble metals with small-atomic-number; (2) employing structural confinement to enhance radiation relaxation because harsh conditions, including carefully selected matrices, rigid solid-state crystalline structure and low temperature, are commonly needed. Here, layered double hydroxides (LDHs) with orderly non-noble metal arrangements were used as an inorganic matrix to activate RTP of carbon dots (CDs). The Zn orderly arranged on the LDH layer contributes to the enhancement in spin-orbit coupling of excitons and the decrease in the energy gap for the singlet-triplet state. The structural confinements of the LDH layer and nano-interlayer testify that the phosphorescence of CDs-LDHs originates from the suppressed radiationless relaxation processes. Using the high tunability of metal species and ratios on the LDH layer, this method can be widely applied to optimize ISC and phosphorescence properties.

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The objective of this study is to compare two different dissolution-enhancing strategies, solid dispersion (SD) and micronized techniques, for improving oral absorption of poorly soluble glimepiride, and to decide which strategy is suitable for its solubilization. The formulation of glimepiride SD was prepared by a solvent-evaporation process with povidone k-30 (PVPk30) at a weight ratio of 1:9 (drug:carrier). The other was prepared via a modified micronization technique, where glimepiride was premilled together with lactose and Lutrol F68 until the milled material passes through a 500 mesh ASTM sieve (30 μm). The dissolution results indicated that the two techniques were both capable of enhancing the dissolution rate and extent of glimepiride. The release profiles of the two prepared products were similar to the marketed product (Amaryl®) in various types of dissolution media. Furthermore, the oral bioavailability was evaluated for the three formulations in fasted beagle dogs. Statistical analysis indicated that there were no significant differences in pharmacokinetic parameters among the two prepared formulations and a marketed product, especially for AUC₀₋₃₆, C(max), and T(max). The dissolution parameters (D₁₀ and AUC₀₋₂₀) in Tris buffer demonstrated the good in vitro/in vivo relationship with T(max) values for the three formulations. In conclusion, our studies confirmed that both SD and micronization techniques were capable of improving dissolution and oral absorption of glimepiride tablets to a similar extent as the marketed product, and the three glimepiride tablets were bioequivalent in the case of the rate and extent of absorption in dogs.

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