Photocontrolled targeted drug delivery: photocaged biologically active folic Acid as a light-responsive tumor-targeting molecule

Light-controlled: Biodegradable nanoparticles encapsulating an anticancer drug (red dots in picture) have been synthesized that carry photocaged folate groups on the surface. Upon irradiation the photocaging group (green) is removed and the free folate group, a tumor-homing agent, binds to folate receptors on cell surfaces, thus leading to specific targeting and cellular uptake.     

Computationally-designed phenylephrine prodrugs – a model for enhancing bioavailability

DFT calculations at B3LYP 6-31G (d,p) for intramolecular proton transfer in a number of Kirby's enzyme models demonstrated that the driving force for the proton transfer efficiency is the distance between the two reactive centres (r_GM) and the attack angle (α); and the rate of the reaction is linearly correlated with r_GM² and sin (180°- α). Based on these results three phenylephrine prodrugs were designed to provide phenylephrine with higher bioavailability than their parent drug. Using the experimental t_1/2 (the time needed for the conversion of 50% of the reactants to products) and EM (effective molarity) values for these processes the t_1/2 values for the conversion of the three prodrugs to the parent drug, phenylephrine were calculated. The calculated t_1/2 values for ProD 1 and ProD 2 were very high (145 days and several years, respectively) whereas that of ProD 3 was found to be about 35 hours. Therefore, the intra-conversion rates of the phenylephrine prodrugs to phenylephrine can be programmed according to the nature of the prodrug linker.     

Unsymmetric Cisplatin-Based Pt(IV) Conjugates Containing a PARP-1 Inhibitor Pharmacophore Tested on Malignant Pleural Mesothelioma Cell Lines

Cisplatin is widely employed as a first-line chemotherapeutic agent for many solid tumors, including malignant pleural mesothelioma (MPM). However, its clinical use is limited by heavy side effects and acquired resistance, the latter being mainly related to enhanced DNA repair. Many clinical trials using combinations of platinum drugs and PARP-1 inhibitors (PARPis) have been carried out, with the hope that such combinations might lead to improved therapeutic efficacy against tumors. Here, the synthesis and efficacy in reducing MPM cell viability of four cisplatin-based Pt(IV) prodrugs containing the PARPi 3-aminobenzamide (3-ABA) fragment are described. The most promising conjugate is more effective than cisplatin or cisplatin/3-ABA combination, administered in equimolar doses, in inhibiting PARP-1 activity and inducing apoptosis in BRCA1/2 wild type MPM cells, grown as monolayer or as multicellular spheroids.     

The Prodrug Platin‐A: Simultaneous Release of Cisplatin and Aspirin

Cancer‐associated inflammation induces tumor progression to the metastatic stage, thus indicating that a chemo‐anti‐inflammatory strategy is of interest for the management of aggressive cancers. The platinum(IV) prodrug Platin‐A was designed to release cisplatin and aspirin to ameliorate the nephrotoxicity and ototoxicity caused by cisplatin. Platin‐A exhibited anticancer and anti‐inflammatory properties which are better than a combination of cisplatin and aspirin. These findings highlight the advantages of combining anti‐inflammatory treatment with chemotherapy when both the drugs are delivered in the form of a single prodrug.     

Chemical adaptor systems

"Chemical adaptor systems" are molecules used to link different functionalities, based on unique reactivity that allows controlled fragmentation. Two different mechanistic reactivities were used to prepare chemical adaptor systems. The first is based on a spontaneous intra-cyclization reaction to form a stable ring molecule. Cleavage of the trigger generates a free nucleophile, for example, an amine group, which undergoes intra-cyclization to release the target molecule from the handle part (e.g., a targeting antibody or a solid support for synthesis). The second applied reactivity is an elimination reaction, which is usually based on a quinone-methide-type rearrangement. Similarly, cleavage of the trigger generates a free phenol functionality, which can undergo a self-elimination reaction through a quinone-methide rearrangement to release the target molecule. The adaptor molecules have been applied in the field of drug delivery to release a drug from a targeting device and in the field of solid-phase synthesis to release a synthetic molecule from the solid support. A chemical adaptor molecule has also been used as a building unit to construct dendrimers with a triggered fragmentation.     

Synthesis of α-Methyldopa Prodrugs Containing Dipeptide Moieties as Tools for Intestinal Delivery

Dipeptides containing D-phenylglycine or D-p-hydroxyphenylglycine were attached onto the antihypertensive agent α-methyldopa to form prodrugs 1a , 1b and 1c . The nonessential amino acids were introduced into the prodrug molecules as tools of chemical delivery to improve the intestinal absorption of the parent drug. Preliminary tests revealed that the prodrugs were stable in phosphate buffer solutions at pH 7.4 (t_1/2 > 10 h). These compounds also demonstrated satisfactory stability toward enzymatic degradation in a mucosa preparation isolated from rat intestine, indicating that they might be feasibly formulated as an oral prodrug of α-methyldopa.     

Aldolase antibody activation of prodrugs of potent aldehyde-containing cytotoxics for selective chemotherapy

Prodrugs of potent aldehyde analogues of the anticancer drug doxorubicin (Dox) were synthesized. These prodrugs were efficiently activated by antibody 93F3 and no drug formation was observed in the absence of 93F3 in either phosphate buffered saline or cell culture media. In the presence of antibody 93F3, these prodrugs were activated and decreased the proliferation of human cancer cells in in vitro proliferation assays.     

磷酰胺酯前药策略及ProTide技术在抗病毒药物研发中的应用

Antiviral drug is a powerful weapon for humans to defeat the virus. The spread of 2019 novel coronavirus pneumonia (COVID-19) outbreak has a serious impact on the world. At the same time, it also makes people aware of the importance of antiviral drug development. This article reviews the application of the phosphoramidate prodrug strategy and the application of ProTide technology in the development of antiviral drugs. The synthesis methods of nucleoside-phosphoramidate prodrugs are introduced. The application of nucleoside-phosphoramidate in different antiviral drugs is also summarized. This review can provide a reference for the development of new antiviral drugs in the future.     

Macromolecular Pt(IV) Prodrugs from Poly(organo)phosphazenes

The preparation of novel macromolecular prodrugs via the conjugation of two platinum(IV) complexes to suitably functionalized poly(organo)phosphazenes is presented. The inorganic/organic polymers provide carriers with controlled dimensions due to the use of living cationic polymerization and allow the preparation of conjugates with excellent aqueous solubility but long‐term hydrolytic degradability. The macromolecular Pt(IV) prodrugs are designed to undergo intracellular reduction and simultaneous release from the macromolecular carrier to present the active Pt(II) drug derivatives. In vitro investigations show a significantly enhanced intracellular uptake of Pt for the macromolecular prodrugs when compared to small molecule Pt complexes, which is also reflected in an increase in cytotoxicity. Interestingly, drug‐resistant sublines also show a significantly smaller resistance against the conjugates compared to clinically established platinum drugs, indicating that an alternative uptake route of the Pt(IV) conjugates might also be able to overcome acquired resistance against Pt(II) drugs. In vivo studies of a selected conjugate show improved tumor shrinkage compared to the respective Pt(IV) complex.