155589-16-5

Upstream product

• 155589-15-4 rapamycin 42-hemisuccinate methyl ester 
• 143136-12-3 rapamycin 42-hemisuccinate benzyl ester 
• 108-30-5 succinic acid anhydride 
• 53123-88-9 sirolimus 

Relevant academic research and scientific papers

Lipase-catalyzed regioselective esterification of rapamycin: Synthesis of temsirolimus (CCI-779)

(Chemical Equation Presented) A lipase-catalyzed acylation of the immunosuppressant rapamycin with complete regioselectivity is described. The method was successfully applied to the synthesis of 42-hemiesters and temsirolimus (CCI-779), an investigational oncology drug.

Dendrimer-Mediated Targeted Delivery of Rapamycin to Tumor-Associated Macrophages Improves Systemic Treatment of Glioblastoma

Glioblastoma exhibits high mortality rates due to challenges with drug delivery to the brain and into solid tumors. This two-pronged barrier necessitates high doses of systemic therapies, resulting in significant off-target toxicities. Recently, dendrimer-nanomedicines (without ligands) have shown promise for targeting specific cells in brain tumors from systemic circulation, for improved efficacy and amelioration of systemic toxicities. A dendrimer-rapamycin conjugate (D-Rapa) is presented here that specifically targets tumor-associated macrophages (TAMs) in glioblastoma from systemic administration. D-Rapa improves suppression of pro-tumor expression in activated TAMs and antiproliferative properties of rapamycin in glioma cells in vitro. In vivo, D-Rapa localizes specifically within TAMs, acting as depots to release rapamycin into the tumor microenvironment. This targeted delivery strategy yields improved reduction in tumor burden and systemic toxicities in a challenging, clinically relevant orthotopic syngeneic model of glioblastoma, demonstrating the significant potential of dendrimers as targeted immunotherapies for improving glioblastoma treatment, still an unmet need.

Enhanced Cytotoxicity to Cancer Cells by Codelivery and Controlled Release of Paclitaxel-loaded Sirolimus-conjugated Albumin Nanoparticles

Recently, it is suggested that mTOR signaling pathway is an important mediator in many cancers especially breast cancer. Therefore, effects of sirolimus as a mTOR inhibitor in breast cancer have been studied in combination with paclitaxel with or without controlled release effect. In this work, we prepared a water-soluble formulation of sirolimus-conjugated albumin nanoparticles loaded with paclitaxel, to study the effects of sirolimus concentration when it releases more later than paclitaxel in comparison with sirolimus–paclitaxel-loaded albumin nanoparticles. Also effects of paclitaxel loading on cytotoxic properties of nanoparticles were studied. Sirolimus was succinylated at 42-OH with enzymatic reaction of Candida antarctica lipase B, and then its carboxylic group was activated with EDC/NHS and conjugated to the lysine residues of albumin. Paclitaxel was loaded on albumin surface by nab technique in concentration range of 0–10 μg/mL. Sirolimus-conjugated nanoparticles with 0.01 μg/mL paclitaxel showed lowest cell viability of 44% while it was 53% for non-conjugated nanoparticles in MDA-MB-468 cell lines after 48 h (p-value = 0.003). In MCF-7 cell lines, sirolimus-conjugated nanoparticles with 0.1 μg/mL paclitaxel showed lowest cell viability of 35.69% while it was 48% for non-conjugated nanoparticles after 48 h (p-value = 0.03). We guess that when cancer cell lines arrest in G2-M by anticancer drugs like paclitaxel, Akt activates mTOR to make cells continue living, then inhibiting mTOR can enhance anticancer effects.

Proactively Reducing Anti-Drug Antibodies via Immunomodulatory Bioconjugation

Although PEGylation reduces the immunogenicity of protein drugs to some extent, its limitations for highly immunogenic biotherapeutics have been demonstrated. Herein, a proactive strategy to alleviate the development of anti-drug antibodies (ADAs) against protein drugs by immunomodulatory bioconjugation is reported. Rapamycin was conjugated to a PEGylated protein therapeutic via a cleavable disulfide linker. The conjugated rapamycin can be released from the bioconjugate and prevent immune responses once the bioconjugate is uptaken by antigen-presenting cells. The immunomodulatory bioconjugate significantly reduced the titers of ADAs compared with a PEGylated protein. The inhibition of immune responses was specific to the conjugated antigen, avoiding systemic immune suppression and the risk of increased susceptibility to infections. The reported approach breaks the limitations of PEGylation by the proactive prevention of ADAs.

PROCESS FOR PREPARING RAPAMYCIN 42-ESTERS AND FK-506 32-ESTERS WITH DICARBOXYLIC ACID, PRECURSORS FOR RAPAMYCIN CONJUGATES AND ANTIBODIES

Methods for the synthesis of regiospecific rapamycin 42-hemiesters and regiospecific FK506 32-esters with dicarboxylic acids is described. The methods involve catalyzing the reaction between a rapamycin or a FK-506 and a dicarboxylic anhydride or a bifunc

Lipase mediated hydrolysis of rapamycin 42-hemisuccinate benzyl and methyl esters

Benzyl and methyl esters of rapamycin 42-hemisuccinate were hydrolyzed under very mild conditions to the rapamycin hemisuccinate using lipase from Pseudomonas sp. This selective deprotection was performed on a ≥100 mg scale for both esters resulting in 50% isolated yield from the methyl ester and 29% from the benzyl ester of the desired acid.