Social Support and Academic Engagement Among Reconnected Youth: Adverse Life Experiences as a Moderator.

Using motivational theories of engagement and adopting a multidimensional perspective of academic engagement, the authors investigate the associations among teacher and parent support, students' academic self-efficacy, and academic engagement among a sample of reconnected youth who have returned to academic pursuit after dropping out (N = 938, mean age = 16.50, SD = 1.78). In addition, they examine how youth's adverse life experiences moderate the pathways in this model, an analysis notably missing from much of the academic engagement literature. They find that students' academic self-efficacy mediates parent and teacher support and youth academic engagement. Moreover, participants' adverse life experiences moderate the connections among perceived support from parents, academic self-efficacy, and academic engagement. Implications for practice and future directions are discussed.

Intradermal delivery of STAT3 siRNA to treat melanoma via dissolving microneedles.

Hyperactivity of signal transducer and activity of transcription 3 (STAT3) plays a crucial role in melanoma invasion and metastasis. Gene therapy applying siRNA targeting STAT3 is a potential therapeutic strategy for melanoma. In this article, we first fabricated safe and novel dissolving microneedles (MNs) for topical application of STAT3 siRNA to enhance the skin penetration of siRNA and used polyethylenimine (PEI, 25 kDa) as carrier to improve cellular uptake of siRNA. The results showed that MNs can effectively penetrate skin and rapidly dissolve in the skin. In vitro B16F10 cell experiments presented that STAT3 siRNA PEI complex can enhance cellular uptake and transfection of siRNA, correspondingly enhance gene silencing efficiency and inhibit tumor cells growth. In vivo experiments indicated that topical application of STAT3 siRNA PEI complex delivered by dissolving MNs into skin can effectively suppress the development of melanoma through silencing STAT3 gene, and the inhibition effect is dose-dependent. STAT3 siRNA delivery via dissolving MNs is a promising approach for skin melanoma treatment with targeting inhibition efficacy and minimal adverse effects.

Effects of nanoparticles with hydrotropic nicotinamide on tacrolimus: permeability through psoriatic skin and antipsoriatic and antiproliferative activities.

The hybrid system based on nanoparticles (NPs) self-assembled by the conjugations of hyaluronic acid with cholesterol (HA-Chol NPs) combined with nicotinamide (NIC) for tacrolimus (FK506), ie, FK506 NPs-NIC, has been confirmed to exhibit a significant synergistic effect on FK506 permeation through and into intact skin; thus, it may be a promising approach for FK506 to effectively treat skin diseases. The aim of this study was to evaluate its potential for the treatment of psoriasis. In vitro permeation through the psoriatic skin was carried out, and the results revealed that the combination of NPs with NIC exhibited a significant synergistic effect on FK506 deposition within the psoriatic skin (3.40±0.67 µg/cm2) and penetration through the psoriatic skin (30.86±9.66 µg/cm2). The antipsoriatic activity of FK506 NPs-NIC was evaluated through the treatment for imiquimod (IMQ)-induced psoriasis. The psoriasis area and severity index (PASI) score demonstrated that FK506 HA-Chol NPs-NIC exerted the effect on ameliorating the skin lesions comparable to clobetasol propionate (a positive drug for psoriasis) and superior to commercial FK506 ointment (Protopic®), and the histological study showed that it presented a synergistic effect on antipsoriasis after FK506 incorporation into NPs combined with NIC hydrotropic system, which might ultimately increase the therapeutic effect and minimize the systemic side effects by reducing the overall dose of FK506. RAW 264.7 cell uptake presented the enhancement of drugs delivered into cells by HA-Chol NPs-NIC. The antiproliferative activity on HaCaT cells identified that FK506 HA-Chol NPs-NIC exhibited significant inhibiting effects on HaCaT proliferation. The results support that the combination of HA-Chol NPs with NIC is a promising approach for FK506 for the treatment of psoriasis.

Dual roles of TPGS based microemulsion for tacrolimus: Enhancing the percutaneous delivery and anti-psoriatic efficacy.

In this study, we demonstrate for the first time the dual roles of Tocopheryl Polyethylene Glycol 1000 Succinate (TPGS) based microemulsion (ME) for tacrolimus (TAC) to enhance TAC percutaneous delivery and anti-psoriatic efficacy. The ME formulation was developed and optimized based on pseudo-ternary phase diagrams combined with in vitro permeation. The result of Fourier transform infrared spectroscopy (FTIR) demonstrated that TAC was completely solubilized in the TPGS-ME. In vitro permeation studies showed that TPGS-ME enhanced TAC permeation through and into the skin, and the enhanced deposition of TAC in the normal or psoriatic skin was further confirmed in vivo. The cellular uptake performed with HaCaT cells presented more pronounced uptake of TPGS-ME. Topical TAC-TPGS-ME treated imiquimod-induced psoriasis in mice more efficaciously than the commercial formulation of TAC (Protopic®), which is consistent with the enhanced TAC levels by TAC-TPGS-ME in the psoriatic skin. Haematoxylin and Eosin (HE) staining revealed that TAC-TPGS-ME significantly diminished the severity of the psoriasis-like skin inflammation. Moreover, TPGS-ME vehicle exhibited a moderate anti-inflammatory activity, which indicated that TPGS acted as a potential adjuvant in the TAC anti-psoriasis process, and the synergism was identified in anti-proliferation against HaCaT cells. The colloidal nano-carrier combined ME with TPGS is a potential approach for percutaneous delivery of TAC, which exploited both virtues of ME and TPGS to obtain the synergetic effects of enhanced permeability and anti-psoriatic efficacy.

Hyaluronic acid-coated niosomes facilitate tacrolimus ocular delivery: Mucoadhesion, precorneal retention, aqueous humor pharmacokinetics, and transcorneal permeability.

Tacrolimus (FK506) was used to prevent corneal allograft rejection in patients who were resistant to steroids and cyclosporine. However, the formulation for FK506 ocular delivery remained a challenge due to the drug's high hydrophobicity, high molecular weight, and eye's physiological and anatomical constraints. The aim of this project is to develop an ocular delivery system for FK506 based on a combined strategy of niosomes and mucoadhesive hyaluronic acid (HA), i.e., FK506HA-coated niosomes, which exploits virtues of both niosomes and HA to synergistically improve ophthalmic bioavailability. The FK506HA-coated niosomes were characterized with particle size, zeta potential, and rheology behavior. Mucoadhesion of FK506HA-coated niosomes to mucin was investigated through surface plasmon resonance in comparison with non-coated niosomes and HA solution. The results showed that niosomes possessed adhesion to mucin, and HA coating enhanced the adhesion. The in vivo precorneal retention was evaluated in rabbit, and the results showed that HA-coated niosomes prolonged the residence of FK506 significantly in comparison with non-coated niosomes or suspension. Aqueous humor pharmacokinetics test showed that area under curve of HA-coated niosomes was 2.3-fold and 1.2-fold as that of suspension and non-coated niosomes, respectively. Moreover, the synergetic corneal permeability enhancement of the hybrid delivery system on FK506 was visualized and confirmed by confocal laser scanning microscope. Overall, the results indicated that the hybrid system facilitated FK506 ocular delivery on mucoadhesion, precorneal retention, aqueous humor pharmacokinetics and transcorneal permeability. Therefore, HA-coated niosomes may be a promising approach for ocular targeting delivery of FK506.

Combination of hydrotropic nicotinamide with nanoparticles for enhancing tacrolimus percutaneous delivery.

Tacrolimus (FK506), an effective immunosuppressant for treating inflammatory skin diseases, hardly penetrates into and through the skin owing to its high hydrophobicity and molecular weight. The aim of this study was to develop a hybrid system based on nicotinamide (NIC) and nanoparticles (NPs) encapsulating FK506, such as FK506-NPs-NIC, for facilitating percutaneous delivery, which exploited virtues of both NIC and NPs to obtain the synergetic effect. Solubility and percutaneous permeation studies were carried out. The results showed that NIC could increase the solubility and permeability of FK506 and that 20% (w/v) NIC presented higher FK506 permeability and was thus chosen as the hydrotropic solution to solubilize FK506 and prepare FK506-NPs-NIC. Hyaluronic acid (HA) was chemically conjugated with cholesterol (Chol) to obtain amphiphilic conjugate of HA-Chol, which self-assembled NPs in 20% NIC solution containing FK506. The particle size, zeta potential, and morphology of NPs were characterized. The encapsulation efficiency and in vitro percutaneous permeation of NPs were evaluated in the presence and absence of NIC. The results demonstrated that hydrotropic solubilizing FK506 was readily encapsulated into NPs with a higher encapsulation efficiency of 79.2%±4.2%, and the combination of NPs with NIC exhibited a significantly synergistic effect on FK506 deposition within the skin (2.39±0.53 µg/cm(2)) and penetration through the skin (13.38±2.26 µg/cm(2)). The effect of the combination of NPs with NIC on drug permeation was further visualized by confocal laser scanning microscope through in vivo permeation studies, and the results confirmed that NPs-NIC synergistically enhanced the permeation of the drug into the skin. The cellular uptake performed in HaCaT cells presented a promoting effect of NPs on cellular uptake. These overall results demonstrated that HA-Chol-NPs-NIC can synergistically improve the percutaneous delivery of FK506, and it is a novel potential strategy based on a nano-sized carrier for FK506 to treat skin diseases.

Microemulsion based gel for topical dermal delivery of pseudolaric acid B: In vitro and in vivo evaluation.

Pseudolaric acid B (PAB) possesses comparable fungicidal activity against Candida albicans to amphotericin B and antifungal activity against azole-resistant Candida species. However, its poor water solubility makes the formulation a considerable challenge for dermal permeation of PAB. The aim of this project was to improve the solubility and eventually the dermal permeability and bioavailability by developing a microemulsion based gel for PAB (PAB ME-gel). PAB ME-gel was formulated using isopropyl myristate as oil phase, cremphor EL as surfactant, transcutol P as cosurfactant, and carbopol as gel matrix, and characterized by droplet size, morphology, pH, and rheology. The 3 month storage test showed that PAB ME-gel possessed good physicochemical stability. In vitro permeation of PAB through rat skin from ME-gel was investigated in comparison with PAB microemulsion (PAB ME) and PAB hydrogel (PAB gel), and results showed that ME significantly enhanced PAB retention in the skin and permeation through the skin whether it was incorporated into the gel or not. In vivo dermatopharmacokinetics study using microdialysis further confirmed that ME-gel significantly increased PAB dermal bioavailability compared with the gel (41.95 ± 8.89 µg/ml vs. 13.90 ± 2.22 µg/ml). In vitro sensitivity against C. albicans test indicated that the antifungal activity of PAB ME-gel increased with the increase of PAB loading, and 8 mg/g of PAB ME-gel exhibited a higher antifungal activity than that of 20mg/g miconazole nitrate cream. In vivo antifungal activity evaluation in C. albicans infected guinea pigs showed that 8 mg/g of PAB ME-gel exhibited a higher efficacy than that of 20mg/g miconazole nitrate cream after 7 day treatment. Overall, the results indicated that the ME enhanced in vitro permeability, in vivo dermal bioavailability, and antifungal activity of PAB. Therefore, ME-gel may be a promising approach for topical dermal delivery of PAB to treat skin fungal infection.