Tumor-targeted hyaluronic acid-mPEG modified nanostructured lipid carriers for cantharidin delivery: An in vivo and in vitro study.

AIM: Cantharidin (CTD), the major component of the anti-cancer medicine obtained from Mylabris cichorii, exerts good inhibitory effects on several cancers, such as liver and breast cancer. However, owing to its toxicity, its oral administration can cause various adverse effects, limiting its clinical applications. Therefore, the development of a novel nano-drug delivery system for CTD would be highly beneficial. METHODS: A nanostructured lipid carrier (NLC) was designed to actively target CTD to tumor cells using a hyaluronic acid (HA)-decorated copolymer (mPEG-NH2); the NLCs were called HA-mPEG-CTD-NLC. HA-mPEG was synthesized using amidation, and HA-mPEG-CTD-NLC was generated through ultrasonic emulsification in water. The mean hydrodynamic diameter of the particles was approximately 119.3 nm. RESULTS: Pharmacokinetic studies revealed that the half-life of HA-mPEG-CTD-NLC and its area under the curve were higher than those of a CTD solution. Further, the plasma clearance rate of HA-mPEG-CTD-NLC was 0.41 times that of the CTD solution, implying a significantly prolonged drug retention time in vivo. Fluorescence in vivo endo-microscopy and optical in vivo imaging revealed that HA-mPEG-CTD-NLC had superior cytotoxicity and targeting efficacy against SMMC-7721 cells. An evaluation of the in vivo anti-tumor activity showed that HA-mPEG-CTD-NLC significantly inhibited tumor growth and prolonged survival in tumor-bearing mice, with a tumor inhibition rate of 65.96%. CONCLUSIONS: Our results indicate that HA-mPEG-CTD-NLC may have great potential in liver cancer-targeted therapy.

Pharmacokinetics and tissue distribution of cantharidin after oral administration of aqueous extracts from Mylabris in rats.

A sensitive gas chromatography-mass spectroscopy method was established for the determination of cantharidin (CTD) in rat plasma and liver homogenates. During the experiment, rats were randomly divided into two groups (low, high) and were administered aqueous extract of Mylabris compound for 7 days. Then, plasma and tissue samples were taken at different time points to study the pharmacokinetics and tissue distribution of CTD in rats. The selected reaction monitoring transitions for CTD and clofibrate (internal standard) were m/z 128 → 85 and m/z 169 → 141, respectively. The calibration curve ranged from 10.26 to 3,078 ng/ml for plasma and from 10.26 to 246.24 ng/ml for liver homogenates. The lower limits of quantification were 10.26 ng/ml for both plasma and liver. The intra- and inter-day precision and accuracy were <20% for both plasma and liver homogenates. Extraction recovery ranged from 89.21 to 103.61% for CTD in rat plasma and liver and from 83.79 to 102.74% for IS in rat plasma and liver. Matrix effects ranged from 93.06 to 110.44% for CTD and from 91.65 to 110.80% for IS.

A Phase 2 Open-Label Study to Evaluate VP-102 for the Treatment of Molluscum Contagiosum.

BACKGROUND: This Phase 2, open-label study evaluated the safety, efficacy, systemic exposure, and impact on quality of life (QoL) with treatment using VP-102, a drug-device combination containing cantharidin (0.7% w/v) in subjects with molluscum contagiosum (MC). STUDY DESIGN: Pediatric subjects with MC (2–15 years of age) were eligible to enroll in this 12-week study. MC lesions were treated topically with VP-102 every 21 days until clearance (maximum of 4 treatments). Adverse events (AEs) and QoL outcomes (using the Children's Quality of Life Index, CDLQI) were documented at each visit. Rate of complete clearance and the percent reduction in lesions were measured at each visit on days 21, 42, 63, and 84 (end of study [EOS] visit). A group of 17 subjects with at least 21 MC lesions was evaluated for systemic cantharidin exposure via plasma samples obtained before the first application of VP-102, and at 2 hours, 6 hours, and 24 hours post-application. RESULTS: A total of 33 subjects enrolled in the study (n=17 systemic exposure group, n=16 standard group). There were an equal number of male and female subjects. Subject mean (SD, range) age was 6.7 (3.3, 2–15) years, with a mean lesion count of 30 (26.1, 3–113). Complete lesion clearance was achieved in 48.5% of subjects, with a 90.4% reduction in lesions from baseline to the EOS visit. Mean CDLQI score decreased from 2.6 at baseline to 0.38 at the EOS visit. AEs were mild to moderate in severity and expected due to the pharmacodynamic action of cantharidin. There were no serious treatment-related adverse events and no study discontinuations due to treatment. In the systemic exposure group plasma cantharidin levels were below the lower limit of quantitation (LLOQ, 2.5 ng/mL) in 65 of 66 samples. CONCLUSIONS: VP-102 treatment resulted in a reduction in lesion counts and improved QoL. Treated subjects had a 48.5% rate of complete clearance of molluscum lesions. Negligible systemic cantharidin exposure was observed in the systemic exposure group. This data demonstrates safety and efficacy of treatment with VP-102 in MC; a widespread viral infection that does not have any current FDA-approved treatments. Significant Finding: Treatment of subjects with MC using VP-102 resulted in negligible systemic cantharidin exposure, as well as a reduction in lesion counts, improved QoL, and a demonstrated efficacy in clearance of new and baseline MC lesions. Meaning: Results of this Phase 2 study demonstrate efficacy and safety outcomes in using VP-102 in MC subjects, and large randomized clinical trials are warranted to compare topical VP-102 with a vehicle control in order to fully evaluate the use of the medication. ClinicalTrials.gov identifier: NCT03186378 J Drugs Dermatol. 2021;20(1):70-75. doi:10.36849/JDD.5626.

Development of 11-DGA-3-O-Gal-Modified Cantharidin Liposomes for Treatment of Hepatocellular Carcinoma.

BACKGROUND: Liver cancer is a common malignant tumor worldwide, and its morbidity and mortality increase each year. The disease has a short course and high mortality, making it a serious threat to human health. PURPOSE: The objective of this study was to create novel liver-targeting nanoliposomes to encapsulate cantharidin (CTD) as a potential treatment for hepatic carcinoma. METHODS: 3-Galactosidase-30-stearyl deoxyglycyrrhetinic acid (11-DGA-3-O-Gal)-modified liposomes (11-DGA-3-O-Gal-CTD-lip) for the liver-targeted delivery of CTD were prepared via the film-dispersion method and characterized. In vitro analyses of the effects on cellular cytotoxicity, cell migration, cell cycle, and cell apoptosis were carried out and an in vivo pharmacokinetics study and tissue distribution analysis were performed. RESULTS: Compared with unmodified liposomes (CTD-lip), 11-DGA-3-O-Gal-CTD-lip showed higher cytotoxicity and increased the inhibition of HepG2 cell migration, but they did not increase the apoptotic rate of cells. The inhibition mechanism of 11-DGA-3-O-Gal-CTD-lip on hepatocellular carcinoma was partly through cell cycle arrest at the S phase. Analysis of pharmacokinetic parameters indicated that 11-DGA-3-O-Gal-CTD-lip were eliminated more rapidly than CTD-lip. Regarding tissue distribution, the targeting efficiency of 11-DGA-3-O-Gal-CTD-lip to the liver was (41.15 ± 3.28)%, relative targeting efficiency was (1.53 ± 0.31)%, relative uptake rate was( 1.69 ± 0.37)%, and peak concentration ratio was (2.68 ± 0.12)%. CONCLUSION: 11-DGA-3-O-Gal-CTD-lip represent a promising nanocarrier for the liver-targeted delivery of antitumor drugs to treat hepatocellular carcinoma.

Light-activatable dual prodrug polymer nanoparticle for precise synergistic chemotherapy guided by drug-mediated computed tomography imaging.

The synergistic efficacy and clinical application of light-responsive polymeric co-delivery systems are severely restricted by uncontrollable/imprecise drug loading, release, and adverse effects caused by the introduction of additional light-responsive molecules or contrast agents when diagnostic imaging is applied to guide therapy. Here, we report the design of a light-activatable dual prodrug polymer nanoparticle (DPP NP) for precise synergistic chemotherapy guided by drug-mediated computed tomography (DMCT) imaging without the introduction of any additional diagnostic imaging agent. DPP NP enables visible light-triggered prodrug polymer backbone cleavage and bioactive Pt(II) release in cancer cell/tumor site; the light-cleaved polymer fragments are further hydrolyzed to produce demethyl cantharidin (DMC). Notably, the drug loading ratio of Pt(IV) and DMC in DPP NP was fixed at an optimal value to achieve maximum synergistic cancer cell killing, which was kept even after cellular uptake, thereby resulting in enhanced synergistic antitumor efficacy both in vitro and in vivo. Because of the high content of the heavy metal Pt in the polymer chain, the spatial/temporal dynamic biodistribution as well as metabolism of DPP NP in vivo can be monitored by Pt DMCT imaging to guide the light irradiation parameters for optimized light-activatable synergistic chemotherapy. Guided by Pt DMCT imaging, DPP NP was able to achieve an improved light-activatable antitumor efficacy, with 75% tumors fully cured and low toxicity. The light-activatable DDP NP system exhibits tremendous potential as precise theranostic nanomedicine. STATEMENT OF SIGNIFICANCE: The synergistic efficacy and clinical application of light-responsive polymeric co-delivery systems are severely restricted by uncontrollable/imprecise drug loading, delivery, and release, as well as adverse effects caused by the introduction of additional light-responsive molecules or contrast agents when diagnostic imaging is applied to guide therapy. Herein, we report the design of a light-activatable dual prodrug polymer nanoparticle (DPP NP) for precise synergistic chemotherapy guided by drug-mediated computed tomography imaging without the introduction of any additional diagnostic imaging agents. Notably, the drug loading ratio of Pt(II) and DMC in DPP NP was fixed at an optimal value to achieve maximum synergistic cancer cell killing, which was kept even after cellular uptake, thereby resulting in enhanced synergistic antitumor efficacy both in vitro and in vivo. The light-activatable DDP NP system exhibits tremendous potential as precise theranostic nanomedicine.

Asialoglycoprotein receptor-targeted liposomes loaded with a norcantharimide derivative for hepatocyte-selective targeting.

In order to overcome the shortcomings associated with the clinical application of norcantharidin (NCTD), including intense irritation and a short half-life, and to obtain a hepatocyte-selective liposome system with high encapsulation efficiency (EE) and low leakage, we synthesized a C14 alkyl chain norcantharimide derivative of NCTD (2-tetradecylhexahydro-1H-4,7-epoxyisoindole-1,3(2H)-dione, N-14NCTDA). Asialoglycoprotein receptor-targeted, galactosylated liposomes loaded with N-14NCTDA (GAL-Lipo) were prepared by the lipid film hydration method. GAL-Lipo with a satisfactory particle size of approximately 120nm has a higher encapsulation efficiency of more than 98.0%, which is markedly increased compared with NCTD loaded liposomes (EE%=47.6%). In addition, GAL-Lipo remained stable for at least 1 month at 4°C. In cytotoxicity assays, GAL-Lipo demonstrated stronger cytotoxicity effects (IC50=24.58µmolL-1) on Hep G2 cells than free N-14NCTDA (100µmol/L) and conventional liposomes (Con-Lipo, 39.49µmol/L) without the GAL modification. GAL-Lipo can continuously accumulate in Hep G2 cells and be internalized into cells via two pathways, namely caveolin-dependent endocytosis and clathrin-dependent asialoglycoprotein receptors (ASGP-R) mediated endocytosis and produces considerably more significant cellular apoptosis. The results of vivo toxicity studies showed that GAL-Lipo dramatically reduced renal toxicity. In addition, GAL-Lipo has a markedly improved pharmacokinetic profile in vivo and a longer circulation time (AUC=6.700±2.964mgL-1h, t1/2z=1.347±0.519h) than Con-Lipo (AUC=2.319±0.121mgL-1h, t1/2z=0.413±0.238h). In conclusion, N-14NCTDA with an ideal logP is a better alternative for the treatment of primary hepatic carcinoma. GAL-Lipo offers an attractive strategy to specifically target hepatocytes via caveolin-dependent and clathrin-dependent asialoglycoprotein receptor-mediated endocytosis resulting in higher anticancer activity and fewer side-effects.

Study of the physicochemical properties and oral bioavailability of the solid dispersion of cantharidin with polyethylene glycol 4000.

Cantharidin (CA) is partially water-soluble. Solid dispersion of CA (CA-SD) in polyethylene glycol 4000 (PEG 4000) was carried out by a solvent-fusion method to increase its dissolution rate and oral bioavailability. The physicochemical properties of this solid dispersion (SD) were evaluated immediately after preparation by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM), and the oral in vivo bioavailability was studied. In in vitro experiments CA was analyzed by high-pressure liquid chromatography (HPLC) and by gas chromatography-mass spectrometry (GC-MS) in in vivo experiments. The solubility and dissolution rate of CA were improved by the SD technique. A comparison of the pharmacokinetics between CA-SD and free CA was performed in rats. The results showed that CA-SD had a higher bioavailability than free CA after oral dosing. By comparing the AUC(0-t) of CA and CA-SD, the relative bioavailability of CA-SD to free CA was 295.4%. From these observations it could be concluded that the CA-SD has a higher absorption than pure CA and this corresponds with the dissolution result in vitro.

[Pharmacokinetics and bioavailability of cantharidin in beagle dogs].

OBJECTIVE: To study the pharmacokinetics and bioavailability of cantharidin in beagle dogs to evaluate the pharmacokinetic parameters and bioavailability of cantharidin in beagle dogs by determining dose-time curve and by comparing with the pharmacokinetics of cantharidin injection. METHOD: Six beagle dogs, after protein precipitation by hydrochloric acid, ethyl acetate was applied to extract cantharidin from plasma The plasma concentration of cantharidin in beagle dogs was determined by GC-MS. The WinNonLin program was used to calculate the pharmacokinetic parameters and bioavailability. RESULT: The main pharmacokinetic parameters of cantharidin by iv in dogs (34 mL x h(-1) x kg(-1)) were AUC (203.5 +/- 23.8) h x microg x L(-1), CL (168.8 +/- 18.6) mL x h(-1) x kg(-1), t1/2 (0.69 +/- 0.03) h. The main pharmacokinetic parameters of cantharidin by op (102 microg x kg(-1)) were: AUC (160.4 +/- 26.9) h x microg x L(-1), CL (649.1 +/- 97.7) mL x h(-1) x kg(-1), t1/2 (0.38 +/- 0.1) h., F (bioavailability) = 26.7% comparing to injection. CONCLUSION: As compared with cantharidin injection, the absorption of catharidin by op is poor and the bioavailability is also low, indicating that enhancement of the bioavailability will be beneficial to the clinical application.

Determination of trace cantharidin in plasma and pharmacokinetic study in beagle dogs using gas chromatography-mass spectrometry.

The blister beetle is traditional Chinese medicine that was first discovered and used as anticancer drug in China, and cantharidin proved to be its principal active ingredient. Cantharidin-based pharmaceutical preparations are now widely used in clinics in China with good therapeutic efficacy. As a toxic anticancer drug, the therapeutic dose of cantharidin is low, and no method to determine the blood cantharidin concentration under the therapeutic dose has so far been reported. Here, we present a simple, sensitive, and reliable gas chromatography-mass spectrometry (GC-MS) method to monitor the plasma cantharidin and perform the pharmacokinetic study of cantharidin in beagle dogs. After protein precipitation by hydrochloric acid, a liquid-liquid extraction procedure using ethyl acetate was applied to extract cantharidin from plasma. An elastic quartz capillary GC column DB-5MS was used in GC-MS, the temperature was kept at 60 degrees C for 1 min, then increased to 220 degrees C at the rate of 6 degrees C/min, held there for 1 min, and then to 280 degrees C at the rate of 20 degrees C/min, held for 3 min. The extraction recovery was over 80% for all the tested specimens. The linearity ranged from 2.14 to 314.2 ng/mL, the intra- and interday precisions were both below 20%, the limit of detection was 0.5 ng/mL, and the limit of quantification was 2.14 ng/mL. Cantharidin in plasma proved to be stable during the whole period of storage, treatment, and analysis. Cantharidin demonstrated as one-compartment model after i.v. administration with an elimination half-life of 0.69 +/- 0.03 h and area under curve of 204 +/- 24 h.ng/mL. This GC-MS assay proved to have high precision, accuracy, reliability, and sensitivity, and it was suitable for determination of trace cantharidin in plasma.

Determination of the release of hydrolyzed demethylcantharidin from novel traditional chinese medicine-platinum compounds with anticancer activity by gas chromatography.

The present paper describes the development of a simple, accurate and reproducible gas chromatographic method for the determination of hydrolyzed demethylcantharidin release from a novel series of traditional Chinese medicine (TCM)-platinum compounds possessing potent anticancer and protein phosphatase 2A (PP2A)-inhibition properties. The salient features of the validated assay were a limit of detection (LOD) of 2 microg/mL, a limit of quantitation (LOQ) of 6 microg/mL, an intra- and inter-day precision of less than 11%, and an accuracy of more than 92%. The developed GC-flame ionization detection (FID) method was successfully utilized for the analysis of hydrolyzed demethylcantharidin, the TCM component that is slowly released from the novel compounds over 24 h, leading to PP2A inhibition. Further structural confirmation was achieved by GC-MS. The GC method is suitable for further mechanistic, pharmacokinetic and metabolic studies of the TCM-Pt compounds that might prove to be new anticancer agents with novel mechanisms of cytotoxic action.

Clinical features of blister beetle poisoning in equids: 70 cases (1983-1996).

OBJECTIVE: To document clinical signs and gross pathologic changes associated with naturally acquired cantharidiasis (blister beetle poisoning) in equids. DESIGN: Retrospective study. ANIMALS: 70 equids with laboratory-confirmed blister beetle poisoning. PROCEDURE: Medical records were reviewed to obtain history, physical examination findings, feeding practices, and diagnostic test and necropsy results. RESULTS: 32 horses and 2 donkeys died from exposure to cantharidin, whereas 36 horses survived. Diet content varied, but alfalfa hay was the common component. Onset of signs of disease was rapid. Most equids had signs of gastrointestinal tract distress. Six horses had nonspecific neurologic signs. All equids dying from cantharidiasis were in shock terminally, with duration of clinical signs ranging from 3 to 18 hours. Six horses that died had no gross lesions, whereas 14 had mild to moderate erythema of gastric, small intestinal, or colonic mucosa. Only 2 horses had gastric or duodenal ulceration, and 2 had hemorrhage of the urinary bladder mucosa. One horse had cardiac muscle necrosis. Clinicopathologic data available on 10 horses included hypocalcemia, hypomagnesemia, and azotemia. Cantharidin concentrations in urine or pooled gastric-cecal contents did not always correlate with severity of disease. CLINICAL IMPLICATIONS: Blister beetle poisoning is not universally fatal in equids. Clinical signs are related to the amount of cantharidin ingested. Every horse that survived was treated aggressively. In fatal poisonings, gross lesions may be minimal or inapparent, and diagnosis must be confirmed by chemical detection of cantharidin in urine, blood, or stomach or cecal contents.