Synthesis and Crystal Structure of Anhydrous Analog of 1,25-Dihydroxyvitamin D3

Calcipotriol Nanosuspension-Loaded Trilayer Dissolving Microneedle Patches for the Treatment of Psoriasis: In Vitro Delivery and In Vivo Antipsoriatic Activity Studies

Psoriasis, affecting 2-3% of the global population, is a chronic inflammatory skin condition without a definitive cure. Current treatments focus on managing symptoms. Recognizing the need for innovative drug delivery methods to enhance patient adherence, this study explores a new approach using calcipotriol monohydrate (CPM), a primary topical treatment for psoriasis. Despite its effectiveness, CPM's therapeutic potential is often limited by factors like the greasiness of topical applications, poor skin permeability, low skin retention, and lack of controlled delivery. To overcome these challenges, the study introduces CPM in the form of nanosuspensions (NSs), characterized by an average particle size of 211 ± 2 nm. These CPM NSs are then incorporated into a trilayer dissolving microneedle patch (MAP) made from poly(vinylpyrrolidone) and w poly(vinyl alcohol) as needle arrays and prefrom 3D printed polylactic acid backing layer. This MAP features rapidly dissolving tips and exhibits good mechanical properties and insertion capability with delivery efficiency compared to the conventional Daivonex ointment. The effectiveness of this novel MAP was tested on Sprague-Dawley rats with imiquimod-induced psoriasis, demonstrating efficacy comparable to the marketed ointment. This innovative trilayer dissolving MAP represents a promising new local delivery system for calcipotriol, potentially revolutionizing psoriasis treatment by enhancing drug delivery and patient compliance.

First Experimental Quantitative Charge Density Studies of Advanced Intermediate of Vitamin D Analogues

Vitamins D are a group of fat-soluble secosteroids which play a regulatory role in the functioning of most cells. Rational design of new vitamin D analogs, of increased therapeutic potency and lowered calcemic side effects, requires high-resolution initial structures and a deep understanding of interactions with the molecular targets. In this paper, using quantum crystallography, we present the first determination of the experimental quantitative charge density of an advanced intermediate of vitamin D analogues as well as a reconstruction of the theoretical electron density of final vitamin D analogues. Application of these methods allows for topological and electrostatic interaction energy analysis. We showed that the A-ring chair conformation has a significant influence on the topological properties of vitamin D compounds. Moreover, the interactions between the CD-ring and side-chain additionally stabilize the crystal structure. These results are supported by our theoretical calculations and previous biological studies.

Predicted structures of new Vitamin D Receptor agonists based on available X-ray structures

Current efforts in the field of vitamin D are to develop 1,25(OH)2D3 analogs that exhibit equal or even increased anti-proliferative activity while possessing a reduced tendency to cause hypercalcemia. The study proposes a new, rational design of vitamin D analogs based on data available in the Protein Data Bank. Undertaken approach was to minimize the electrostatic interaction energies available after the reconstruction of charge density with the aid of the pseudoatom databank, namely the University at Buffalo Pseudoatom Databank (UBDB). Analysis of 24 vitamin D analogs, bearing similar molecular structures complexed with Vitamin D Receptor enabled the design of new agonists forming all advantageous interaction to the receptor, coded TB1, TB2, TB3 and TB4.

Synthesis and biological activity of two C-7 methyl analogues of vitamin D

Two novel vitamin D analogues of the hormone 1α,25-(OH)2D3 modified at C-7, namely, 7-methyl-1α,25-(OH)2D3 (12) and 7-methyl-1α,25-(OH)2-19-nor-D3 (26), were synthesized and biologically evaluated to gain further insights into the structure-function relationships of vitamin D. Key steps in the synthesis of 12 include the functionalization at C-7 by an efficient regioselective hydrostannylation of an allene precursor, and the construction of the triene framework by a palladium-catalyzed intramolecular cyclization-Suzuki-Miyaura coupling cascade. Since the calcitriol analogue 12 was prone to conversion into its previtamin D form by thermal equilibration, the corresponding 19-nor-compound 26 was also synthesized. The diene moiety of compound 26 was constructed by a modified Julia coupling. UV data as well as X-ray analysis indicate that introduction of the methyl group at C-7 results in a significant deviation from planarity of the 5,7-diene moiety. The new vitamin D analogues 12 and 26 retained good VDR binding ability.

Synthesis and Biological Activity of Diastereomeric and Geometric Analogs of Calcipotriol, PRI-2202 and PRI-2205, Against Human HL-60 Leukemia and MCF-7 Breast Cancer Cells

Diastereomeric and geometric analogs of calcipotriol, PRI-2202 and PRI-2205, were synthesized as advanced intermediates from vitamin D C-22 benzothiazoyl sulfones and side-chain aldehydes using our convergent strategy. Calcitriol, calcipotriol (PRI-2201) and tacalcitol (PRI-2191) were used as the reference compounds. Among a series of tested analogs the diastereomeric analog PRI-2202 showed the strongest antiproliferative activity on the human breast cancer cell line MCF-7, whereas the geometric analog PRI-2205 was the weakest. Both analogs were less potent in antiproliferative activity against HL-60 cells compared to the reference compounds. The ability to potentiate antiproliferative effect of cisplatin or doxorubicin against HL-60 cells or that of tamoxifen against the MCF-7 cell line was observed at higher doses of PRI-2202 or PRI-2205 than those of the reference compounds. The proapoptotic activity of tamoxifen, expressed as the diminished mitochondrial membrane potential, as well as the increased phosphatidylserine expression, was partially attenuated by calcitriol, PRI-2191, PRI-2201 and PRI-2205. The treatment of the MCF-7 cells with tamoxifen alone resulted in an increase in VDR expression. Moreover, a further increase in VDR expression was observed when the analogs PRI-2201 or PRI-2205, but not PRI-2191, were used in combination with tamoxifen. This observation could partially explain the potentiation of the antiproliferative effect of tamoxifen by vitamin D analogs.