Tumor-targeted metabolic inhibitor prodrug labelled with cyanine dyes enhances immunoprevention of lung cancer

Recent progress in targeted metabolic therapy of cancer has been limited by the considerable toxicity associated with such drugs. To address this challenge, we developed a smart theranostic prodrug system that combines a fluorophore and an anticancer drug, specifically 6-diazo-5-oxo-l-norleucine (DON), using a thioketal linkage (TK). This system enables imaging, chemotherapy, photodynamic therapy, and on-demand drug release upon radiation exposure. The optimized prodrug, DON-TK-BM3, incorporating cyanine dyes as the fluorophore, displayed potent reactive oxygen species release and efficient tumor cell killing. Unlike the parent drug DON, DON-TK-BM3 exhibited no toxicity toward normal cells. Moreover, DON-TK-BM3 demonstrated high tumor accumulation and reduced side effects, including gastrointestinal toxicity, in mice. This study provides a practical strategy for designing prodrugs of metabolic inhibitors with significant toxicity stemming from their lack of tissue selectivity.

Targeting FAPα-positive lymph node metastatic tumor cells suppresses colorectal cancer metastasis

Lymphatic metastasis is the main metastatic route for colorectal cancer, which increases the risk of cancer recurrence and distant metastasis. The properties of the lymph node metastatic colorectal cancer (LNM-CRC) cells are poorly understood, and effective therapies are still lacking. Here, we found that hypoxia-induced fibroblast activation protein alpha (FAPα) expression in LNM-CRC cells. Gain- or loss-function experiments demonstrated that FAPα enhanced tumor cell migration, invasion, epithelial-mesenchymal transition, stemness, and lymphangiogenesis via activation of the STAT3 pathway. In addition, FAPα in tumor cells induced extracellular matrix remodeling and established an immunosuppressive environment via recruiting regulatory T cells, to promote colorectal cancer lymph node metastasis (CRCLNM). Z-GP-DAVLBH, a FAPα-activated prodrug, inhibited CRCLNM by targeting FAPα-positive LNM-CRC cells. Our study highlights the role of FAPα in tumor cells in CRCLNM and provides a potential therapeutic target and promising strategy for CRCLNM.

Efecto del compuesto N-2,6-dicloro-aralquil-2-Aminoindano en la conducta estereotipada de ratas. Acción dopaminérgica selectiva central sobre los ganglios basales más que en las estructuras límbicas / Effect of the compound N-2,6-dichloro-aralkyl-2-aminoindane on the stereotyped behavior of rats. Selective action on the central dopaminergic system in the basal ganglia over limbic structures

Resumen La dopamina 1, está implicada en trastornos neurodegenerativos que afectan al sistema nervioso central (SNC) tales como la enfermedad de Parkinson, entre otros. Aunque no se dispone aún de ningún fármaco capaz de prevenir, detener o curar la progresión de estas enfermedades, son numerosos los compuestos que han sido diseñados, sintetizados y evaluados farmacológicamente, que han aportado las generalizaciones farmacofóricas del receptor dopaminérgico, necesarias para la búsqueda de un fármaco capaz de mejorar o curar estas patologías. Los derivados 2-aminoindano-N-aralquílicos han mostrado tener actividad selectiva en el sistema dopaminérgico central, de modo tal que los compuestos clorhidratos de N-[(2,4-diclorofenil)-1-metil- etil]-2-aminoindano 2 y N-[(3,4-diclorofenil)-1-metil-etil]-2-aminoindano 3 demostraron tener actividad agonística mediada por mecanismos dopaminérgicos centrales. Con el propósito de contribuir en la búsqueda de nuevos fármacos que permitan restablecer la homeostasis de la transmisión dopaminérgica en la enfermedad de Parkinson, el compuesto N-2,6-dicloro-aralquil-2-aminoindano 4 fue diseñado a través de estrategias de la química medicinal, que contienen las aproximaciones farmacofóricas de los profármacos. La evaluación farmacológica del compuesto 4, en la conducta estereotipada en ratas macho de la cepa Sprague Dawley, demostró tener actividad agonística a través de la activación de los mecanismos dopaminérgicos centrales y mostró mayor selectividad en las respuestas de conductas estereotipadas propias de los ganglios basales sobre las respuestas conductuales propias de las estructuras límbicas.

Abstract Dopamine 1 is involved in neurodegenerative disorders affecting the central nervous system (CNS), such as Parkinson's disease. Despite the absence of some available drugs capable of preventing, stopping or curing the progression of such diseases, there are numerous compounds designed, synthesized, and pharmacologically tested which give rise to pharmacophoric generalizations about the dopaminergic receptor required for the search of a drug able to improve or cure those pathologies. N-aralkyl-2-aminoindane derivatives have shown selective activity in the central dopaminergic system. Both the N-[(2,4-dichlorophenyl)-1-methyl-ethyl]-2-aminoindane hydrochloride 2 and N-[(3,4-dichlorophenyl)-1-methyl-ethyl]-2-aminoindane hydrochloride 3 showed an agonistic activity mediated by central dopaminergic mechanisms. To contribute to the search of new drugs able to re-establish homeostasis in the dopaminergic transmission in Parkinson's disease, the compound N-2,6- dichloro-aralkyl-2-aminoindane 4 was designed through medicinal chemistry strategies that contain pharmacophoric approximations of prodrugs. The pharmacological evaluation of compound 4 in the stereotyped behavior of male Sprague Dawley rats showed agonistic activity through the activation of central dopaminergic mechanisms and a higher selectivity in the responses of stereo- typed behavior characteristic of the basal ganglia over the typical responses from limbic structures.

Research advances in peptide‒drug conjugates

Peptide‒drug conjugates (PDCs) are drug delivery systems consisting of a drug covalently coupled to a multifunctional peptide via a cleavable linker. As an emerging prodrug strategy, PDCs not only preserve the function and bioactivity of the peptides but also release the drugs responsively with the cleavable property of the linkers. Given the ability to significantly improve the circulation stability and targeting of drugs in vivo and reduce the toxic side effects of drugs, PDCs have already been extensively applied in drug delivery. Herein, we review the types and mechanisms of peptides, linkers and drugs used to construct PDCs, and summarize the clinical applications and challenges of PDC drugs.

Full-profile pharmacokinetics, anticancer activity and toxicity of an extended release trivalent PEGylated irinotecan prodrug

Irinotecan is an anticancer topoisomerase I inhibitor that acts as a prodrug of the active metabolite, SN-38. Unfortunately, the limited utility of irinotecan is attributed to its pH-dependent stability, short half-life and dose-limiting toxicity. To address this problem, a novel trivalent PEGylated prodrug (PEG-[Irinotecan]3) has been synthesized and its full-profile pharmacokinetics, antitumor activity and toxicity compared with those of irinotecan. The results show that after intravenous administration to rats, PEG-[Irinotecan]3 undergoes stepwise loss of irinotecan to form PEG-[Irinotecan]3‒x (x = 1,2) and PEG-[linker] during which time the released irinotecan undergoes conversion to SN-38. As compared with conventional irinotecan, PEG-[Irinotecan]3 displays extended release of irinotecan and efficient formation of SN-38 with significantly improved AUC and half-life. In a colorectal cancer-bearing model in nude mice, the tumor concentrations of irinotecan and SN-38 produced by PEG-[Irinotecan]3 were respectively 86.2 and 2293 times higher at 48 h than produced by irinotecan. In summary, PEG-[Irinotecan]3 displays superior pharmacokinetic characteristics and antitumor activity with lower toxicity than irinotecan. This supports the view that PEG-[Irinotecan]3 is a superior anticancer drug to irinotecan and it has entered the phase II trial stage.

Self-assembled nanoformulations of paclitaxel for enhanced cancer theranostics

Chemotherapy has occupied the critical position in cancer therapy, especially towards the post-operative, advanced, recurrent, and metastatic tumors. Paclitaxel (PTX)-based formulations have been widely used in clinical practice, while the therapeutic effect is far from satisfied due to off-target toxicity and drug resistance. The caseless multi-components make the preparation technology complicated and aggravate the concerns with the excipients-associated toxicity. The self-assembled PTX nanoparticles possess a high drug content and could incorporate various functional molecules for enhancing the therapeutic index. In this work, we summarize the self-assembly strategy for diverse nanodrugs of PTX. Then, the advancement of nanodrugs for tumor therapy, especially emphasis on mono-chemotherapy, combinational therapy, and theranostics, have been outlined. Finally, the challenges and potential improvements have been briefly spotlighted.

Application of nanotechnology in local anesthetic drug sustained release and light-responsive controlled release / 药学学报

Local anesthetic drugs are commonly used to block the conduction function of patient's nerves temporarily for anesthesia during surgery or to provide targeted analgesia after trauma. Compared with general anesthetics, local anesthetics makes less impact on the physiological status and alleviates pain complications in the presence of clear consciousness. However, its clinical application is still limited by its systemic toxicity, as well as toxicity to nerves and muscles, duration of action and lack of penetration. Nanotechnology can help it penetrate the physiological barrier, prolong the time of nerve block, and reduce toxic side effects. In addition, by building a light-responsive release system, local anesthetics can be released on demand, enhancing drug effectiveness and safety. However, in addition to the problems of poor consistency and high production costs, the system of light response release is still limited in application due to the limitation of the depth of penetration of the tissue. According to the current research progress, this paper briefly introduces and analyzes the main dosage forms, hoping to provide new ideas for the responsive release of local anesthetic drugs.

Advance on small molecule self-assembled nano-drug delivery system / 药学学报

Since the application of biomedical nanotechnology in the field of drug delivery breathes new life into the research and development of high-end innovative agents, a substantial number of novel nano-drug delivery systems (nano-DDSs) have been successively developed and applied in the clinical practice. Among them, small molecule pure drug and prodrug-based nanoassemblies have grasped great attention, owing to the facile fabrication, ultrahigh drug loading and feasible industrial production. Herein, we provide an overview on the latest updates of small-molecule nanoassemblies. Firstly, the self-assembled prodrug-based nano-DDSs are introduced, including nanoassemblies formed by amphiphilic monomeric prodrugs, hydrophobic monomeric prodrugs and dimer monomeric prodrugs. Then, the recent advances on nanoassemblies of small molecule pure chemical drugs and biological drugs are presented. Furthermore, carrier-free small-molecule hybrid nanoassemblies of pure drugs and/or prodrugs are summarized and analyzed. Finally, the rational design, application prospects and clinical challenges of small-molecule self-assembled nano-DDSs are discussed and highlighted. This review aims to provide scientific reference for constructing the next generation of nanomedicines.

Research progress of ProTide technology and its application in the development of antiviral drugs / 药学学报

ProTide technology is a kind of prodrug design strategy invented by the team of Christopher McGuigan. ProTides are aryloxyphosphoramidates (or aryloxyphosphonamidates) which contain a phosphorus atom combined with an amino acid ester and an aryloxy group. These prodrugs can efficiently cross the cell membrane and escape from the first rate-limiting step of phosphorylation, which afford effective solutions to the drawbacks of current nucleoside analogues. At present, ProTide technology has been extensively applied in the field of antiviral research. It has been successful in providing a number of approved drugs and clinical candidates, such as sofosbuvir and so much more, highlighting the promising future in drug discovery. This review summarizes the brief history and characteristics of ProTide technology, as well as its application in the exploration of antiviral drugs.

Photosensitive pro-drug nanoassemblies harboring a chemotherapeutic dormancy function potentiates cancer immunotherapy

Immunotherapy combined with effective therapeutics such as chemotherapy and photodynamic therapy have been shown to be a successful strategy to activate anti-tumor immune responses for improved anticancer treatment. However, developing multifunctional biodegradable, biocompatible, low-toxic but highly efficient, and clinically available transformed nano-immunostimulants remains a challenge and is in great demand. Herein, we report and design of a novel carrier-free photo-chemotherapeutic nano-prodrug COS-BA/Ce6 NPs by combining three multifunctional components-a self-assembled natural small molecule betulinic acid (BA), a water-soluble chitosan oligosaccharide (COS), and a low toxic photosensitizer chlorin e6 (Ce6)-to augment the antitumor efficacy of the immune adjuvant anti-PD-L1-mediated cancer immunotherapy. We show that the designed nanodrugs harbored a smart and distinctive "dormancy" characteristic in chemotherapeutic effect with desired lower cytotoxicity, and multiple favorable therapeutic features including improved 1O2 generation induced by the reduced energy gap of Ce6, pH-responsiveness, good biodegradability, and biocompatibility, ensuring a highly efficient, synergistic photochemotherapy. Moreover, when combined with anti-PD-L1 therapy, both nano-coassembly based chemotherapy and chemotherapy/photodynamic therapy (PDT) could effectively activate antitumor immunity when treating primary or distant tumors, opening up potentially attractive possibilities for clinical immunotherapy.

A redox-responsive self-assembling COA-4-arm PEG prodrug nanosystem for dual drug delivery suppresses cancer metastasis and drug resistance by downregulating hsp90 expression

Metastasis and resistance are main causes to affect the outcome of the current anticancer therapies. Heat shock protein 90 (Hsp90) as an ATP-dependent molecular chaperone takes important role in the tumor metastasis and resistance. Targeting Hsp90 and downregulating its expression show promising in inhibiting tumor metastasis and resistance. In this study, a redox-responsive dual-drug nanocarrier was constructed for the effective delivery of a commonly used chemotherapeutic drug PTX, and a COA-modified 4-arm PEG polymer (4PSC) was synthesized. COA, an active component in oleanolic acid that exerts strong antitumor activity by downregulating Hsp90 expression, was used as a structural and functional element to endow 4PSC with redox responsiveness and Hsp90 inhibitory activity. Our results showed that 4PSC/PTX nanomicelles efficiently delivered PTX and COA to tumor locations without inducing systemic toxicity. By blocking the Hsp90 signaling pathway, 4PSC significantly enhanced the antitumor effect of PTX, inhibiting tumor proliferation and invasiveness as well as chemotherapy-induced resistance in vitro. Remarkable results were further confirmed in vivo with two preclinical tumor models. These findings demonstrate that the COA-modified 4PSC drug delivery nanosystem provides a potential platform for enhancing the efficacy of chemotherapies.

Time-course monitoring of in vitro biotransformation reaction via solid-phase microextraction-ambient mass spectrometry approaches / 药物分析学报

The solid-phase microextraction technique quantifies analytes without considerably affecting the sample composition.Herein,a proof-of-concept study was conducted to demonstrate the use of coated probe electrospray ionization(coated-PESI)and coated blade spray(CBS)as ambient mass spectrometry ap-proaches for monitoring drug biotransformation.The ability of these methods was investigated for monitoring the dephosphorylation of a prodrug,combretastatin A4 phosphate(CA4P),into its active form,combretastatin A4(CA4),in a cell culture medium supplemented with fetal bovine serum.The CBS spot analysis was modified to achieve the same extraction efficiency as protein precipitation and ob-tained results in 7 min.Because coated-PESI performs extraction without consuming any samples,it is the preferred technique in the case of a limited sample volume.Although coated-PESI only extracts small quantities of analytes,it uses the desorption solvent volume of 5-10 pL,resulting in high sensitivity,thus allowing the detection of compounds after only 1 min of extraction.The biotransformation of CA4P into CA4 via phosphatases occurs within the simple matrix,and the proposed sample preparation techniques are suitable for monitoring the biotransformation.

Determination of paclitaxel prodrug in SD rat plasma by LC-MS/MS and its application in preclinical pharmacokinetic studies / 药学学报

A fast and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of prodrug of paclitaxel (Pro-PTX) and paclitaxel (PTX) in rat plasma was developed. The plasma samples were subjected to protein precipitation with acetonitrile (0.1% formic acid), and then separated by LC with an Ultimate AQ-C18 column (50 mm × 3.0 mm, 3 μm) and acetonitrile-1 mmol·L-1 ammonium formate (containing 0.1% formic acid) as the mobile phase. Multiple reaction monitoring (MRM) scanning mode was used to detect the ion responses m/z 983.4→415.2 (Pro-PTX), m/z 854.4→286.1 (PTX) and m/z 808.3→527.2 (Docetaxel, internal standard) by using a triple quadrupole tandem mass spectrometer with electrospray ionization source and positive ion mode. The method validation results show that the linear ranges of Pro-PTX and PTX in plasma were 2.00-500 ng·mL-1 (r > 0.99) and 4.00-1 000 ng·mL-1 (r > 0.99), the lower limit of quantification was 2.00 ng·mL-1 and 4.00 ng·mL-1, respectively; the quality control samples with low, medium and high concentrations of Pro-PTX and PTX were within the batch, the relative standard deviation (RSD) between batches were all less than 9%; the relative deviation (RE) was within the range of ± 9%; In the stability test, both Pro-PTX and PTX in plasma were stable under various storage conditions. The method was sensitive, specific, and reproducible, and was suitable for the pharmacokinetic study of Pro-PTX in rats. Animal experiments were approved by the Ethics Committee of Laboratory Animal Management and Animal Welfare, Institute of Materia Medica, Chinese Academy of Medical Sciences (No.: 00003552).

Engineering prodrug nanomicelles as pyroptosis inducer for codelivery of PI3K/mTOR and CDK inhibitors to enhance antitumor immunity

Aberrant activation of oncogenic signaling pathways in tumors can promote resistance to the antitumor immune response. However, single blockade of these pathways is usually ineffective because of the complex crosstalk and feedback among oncogenic signaling pathways. The enhanced toxicity of free small molecule inhibitor combinations is considered an insurmountable barrier to their clinical applications. To circumvent this issue, we rationally designed an effective tumor microenvironment-activatable prodrug nanomicelle (PNM) for cancer therapy. PNM was engineered by integrating the PI3K/mTOR inhibitor PF-04691502 (PF) and the broad spectrum CDK inhibitor flavopiridol (Flav) into a single nanoplatform, which showed tumor-specific accumulation, activation and deep penetration in response to the high glutathione (GSH) tumoral microenvironment. The codelivery of PF and Flav could trigger gasdermin E (GSDME)-based immunogenic pyroptosis of tumor cells to elicit a robust antitumor immune response. Furthermore, the combination of PNM-induced immunogenic pyroptosis with anti-programmed cell death-1 (αPD-1) immunotherapy further boosted the antitumor effect and prolonged the survival time of mice. Collectively, these results indicated that the pyroptosis-induced nanoplatform codelivery of PI3K/mTOR and CDK inhibitors can reprogram the immunosuppressive tumor microenvironment and efficiently improve checkpoint blockade cancer immunotherapy.

YPD-30, a prodrug of YPD-29B, is an oral small-molecule inhibitor targeting PD-L1 for the treatment of human cancer

PD-1 and PD-L1 antibodies have brought about extraordinary clinical benefits for cancer patients, and their indications are expanding incessantly. Currently, most PD-1/PD-L1 agents are administered intravenously, which may be uncomfortable for some cancer patients. Herein, we develop a novel oral-delivered small molecular, YPD-29B, which specifically targets human PD-L1. Our data suggested that YPD-29B could potently and selectively block the interaction between PD-L1 and PD-1, but did not inhibit any other immune checkpoints. Mechanistically, YPD-29B induced human PD-L1 dimerization and internalization, which subsequently activated T lymphocytes and therefore overcomes immunity tolerance in vitro. YDP-29B was modified as the YPD-30 prodrug to improve druggability. Using humanized mice with human PD-1 xenografts of human PD-L1 knock-in mouse MC38 cancer cells, we demonstrated that YPD-30 exhibited significant antitumor activity and was well tolerated in vivo. Taken together, our results indicate that YPD-30 serves as a promising therapeutic candidate for anti-human PD-L1 cancer immunotherapy.

Bispecific prodrug nanoparticles circumventing multiple immune resistance mechanisms for promoting cancer immunotherapy

Cancer immunotherapy is impaired by the intrinsic and adaptive immune resistance. Herein, a bispecific prodrug nanoparticle was engineered for circumventing immune evasion of the tumor cells by targeting multiple immune resistance mechanisms. A disulfide bond-linked bispecific prodrug of NLG919 and JQ1 (namely NJ) was synthesized and self-assembled into a prodrug nanoparticle, which was subsequently coated with a photosensitizer-modified and tumor acidity-activatable diblock copolymer PHP for tumor-specific delivery of NJ. Upon tumor accumulation via passive tumor targeting, the polymeric shell was detached for facilitating intracellular uptake of the bispecific prodrug. NJ was then activated inside the tumor cells for releasing JQ1 and NLG919 via glutathione-mediated cleavage of the disulfide bond. JQ1 is a bromodomain-containing protein 4 inhibitor for abolishing interferon gamma-triggered expression of programmed death ligand 1. In contrast, NLG919 suppresses indoleamine-2,3-dioxygenase 1-mediated tryptophan consumption in the tumor microenvironment, which thus restores robust antitumor immune responses. Photodynamic therapy (PDT) was performed to elicit antitumor immunogenicity by triggering immunogenic cell death of the tumor cells. The combination of PDT and the bispecific prodrug nanoparticle might represent a novel strategy for blockading multiple immune evasion pathways and improving cancer immunotherapy.

GSH-sensitive polymeric prodrug: Synthesis and loading with photosensitizers as nanoscale chemo-photodynamic anti-cancer nanomedicine

Precisely delivering combinational therapeutic agents has become a crucial challenge for anti-tumor treatment. In this study, a novel redox-responsive polymeric prodrug (molecular weight, MW: 93.5 kDa) was produced by reversible addition-fragmentation chain transfer (RAFT) polymerization. The amphiphilic block polymer-doxorubicin (DOX) prodrug was employed to deliver a hydrophobic photosensitizer (PS), chlorin e6 (Ce6), and the as-prepared nanoscale system [NPs(Ce6)] was investigated as a chemo-photodynamic anti-cancer agent. The glutathione (GSH)-cleavable disulfide bond was inserted into the backbone of the polymer for biodegradation inside tumor cells, and DOX conjugated onto the polymer with a disulfide bond was successfully released intracellularly. NPs(Ce6) released DOX and Ce6 with their original molecular structures and degraded into segments with low MWs of 41.2 kDa in the presence of GSH. NPs(Ce6) showed a chemo-photodynamic therapeutic effect to kill 4T1 murine breast cancer cells, which was confirmed from a collapsed cell morphology, a lifted level in the intracellular reactive oxygen species, a reduced viability and induced apoptosis. Moreover, ex vivo fluorescence images indicated that NPs(Ce6) retained in the tumor, and exhibited a remarkable in vivo anticancer efficacy. The combinational therapy showed a significantly increased tumor growth inhibition (TGI, 58.53%). Therefore, the redox-responsive, amphiphilic block polymeric prodrug could have a great potential as a chemo-photodynamic anti-cancer agent.

Preparation and in vivo evaluation of a novel allicin pro-drug tablet / 中国药科大学学报

@#A novel allicin pro-drug tablet containing antacid pellets was developed to realize pH-regulated allicin release and to guarantee allicin yield in stomach environment.Firstly, allicin precursor pellets containing antacid pellet were prepared and artificial gastric juice was used as the medium to determine the yield of the allicin.Then, the total lipid cholesterol (TC), triglyceride cholesterol (TG), high density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) were used as indicators to study the hypolipidemic effect of allicin precursor pellets in rats.The dissolution test showed that in artificial gastric juice, the yield of allicin-containing antacid pellets exceeded 90%.In pharmacodynamic studies, it was found that antacid pellets showed the expected hypolipidemic effect on hyperlipidemia rats compared without antacid pellets.There was a very significant difference in blood lipid levels between the two test groups (P < 0.05).The allicin pro-drug tablets containing antacid pellets can effectively lower blood lipids.

Improvement of Transdermal Delivery of Aciclovir Aliphatic Ester Prodrugs by Using Supersaturated System / 中国药房

OBJECTIVE：To prepare supersaturated system of lip ophilic aci clovir（ACV）prodrug，and to increase the cutaneous bioavailability of ACV. METHODS ：Three prodrugs of ACV were synthesized by anhydride acylation ，i.e. aciclovir acetate （ACV-Ace），butyrate（ACV-But）and hexanoate （ACV-Hex）. The structures of ACV and three ACV prodrugs were confirmed by 1H-NMR and HRESI-MS ；the concentrations of ACV and three ACV prodrugs were determined by UPLC-triple quadrupole tandem mass spectrometry ，and saturated solubility of them in different volume fractions of propylene glycol-water solution was calculated. The compound with the greatest potential of form supersaturated system was screened out. The supersaturated system of that compound was prepared by co-solvent method. The effect of hydroxypropyl methylcellulose E 3 （HPMC E 3） on its physical stability was observed by light microscope. Vertical Franz diffusion cells were used to study the effects of degree of supersaturation （DS）and HPMC E 3 on the deposited amount of drug in the excised porcine skin after using the supersaturated system for 1 h. The distribution of ACV in the excised porcine skin was determined by frozen slicing stratified quantitative method after using the supersaturated system and marketed aciclovir cream for 1 h. RESULTS ：Three ACV prodrugs were successfully synthesized. The established quantification methods met the requirements of biological sample analysis. Among all of the three ACV prodrugs ， ACV-Hex showed the lowest saturated solubility in water [ （0.5±0.0）mmol/L] a nd the highest saturated solubility in propylene glycol [（53.4 ± 14.2）mmol/L]，which made it potentially feasible to form supersaturated system with high DS. In 10％propylene glycol-water system ，the addition of HPMC E 3 163.com enabled ACV-Hex supersaturated systems ，with DS no morethan 4，to maintain physical stability within 1 h. The total deposited amount （ACV + ACV-Hex ） in skin after the application of ACV-Hex supersaturated system with DS of 4 for 1 h was higher than that after the application of ACV-Hex supersaturated system with DS less than 4 or without HPMC E 3. In addition ，the concentration of ACV in the basal epidermis （skin thickness was 100-160 mm）by supersaturated system was significantly higher than that of the marketed aciclovir cream （P＜0.05）. CONCLUSIONS：ACV-Hex，the lipophilic prodrug of ACV ，can form stable supersaturated system with DS of 4 in 10％ propylene glycol-water system in the presence of HPMC E 3. High concentration of ACV could be accumulated in the basal epidermis after the skin was exposed to supersaturated system for 1 h，which may be valuable for local treatment skin infection of herpes simplex virus .

Organic carbon monoxide prodrug, BW-CO-111, in protection against chemically-induced gastric mucosal damage

Metal-based carbon monoxide (CO)-releasing molecules have been shown to exert anti-inflammatory and anti-oxidative properties maintaining gastric mucosal integrity. We are interested in further development of metal-free CO-based therapeutics for oral administration. Thus, we examine the protective effect of representative CO prodrug, BW-CO-111, in rat models of gastric damage induced by necrotic ethanol or aspirin, a representative non-steroidal anti-inflammatory drug. Treatment effectiveness was assessed by measuring the microscopic/macroscopic gastric damage area and gastric blood flow by laser flowmetry. Gastric mucosal mRNA and/or protein expressions of HMOX1, HMOX2, nuclear factor erythroid 2-related factor 2, COX1, COX2,