Gemcitabine and rapamycin-loaded mixed polymeric thermogel for metastatic pancreatic cancer therapy.

Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer-related death and has a poor 5-year overall survival. The superior therapeutic benefits of combination or co-administration of drugs as intraperitoneal chemotherapy have increased interest in developing strategies to deliver chemotherapeutic agents to patients safely. In this study, we prepared a gel comprising the thermosensitive poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) polymer and gemcitabine (GEM), which is currently used as the primary chemotherapy for PDAC and rapamycin (RAPA), a mammalian TOR (mTOR) inhibitor, to deliver the drug through intraperitoneal injection. We performed in vitro cytotoxicity experiments to verify the synergistic effects of the two drugs at different molar ratios and characterized the physicochemical properties of the GEM, RAPA, and GEM/RAPA-loaded thermosensitive PLGA-PEG-PLGA gels, hereafter referred to as (g(G), g(R), and g(GR)), respectively. The g(GR) comprising PLGA-PEG-PLGA polymer (25% w/v) and GEM and RAPA at a molar ratio of 11:1 showed synergism and was optimized. An in vitro cytotoxicity assay was performed by treating Panc-1-luc2 tumor spheroids with g(G), g(R), or g(GR). The g(GR) treatment group showed a 2.75-fold higher inhibition rate than the non-treated (NT) and vehicle-treated groups. Furthermore, in vivo drug release assay in mice by intraperitoneal injection of g(G), g(R), or g(GR) showed a more rapid release rate of GEM than RAPA, similar to the in vitro release pattern. The drugs in the gel were released faster in vivo than in vitro and degraded in 48 h. In addition, g(GR) showed the highest anti-tumor efficacy with no toxicity to mice. These results provide evidence for the safety and efficacy of g(GR) for intraperitoneal drug delivery. This study will assist in developing and clinically administering topical anti-cancer formulations.

Validation of a HPLC method for the quantification and purity determination of SK3530 in drug substance and tablet.

SK3530.2HCl, (2-(5-(4-(2-hydroxyethyl)piperazin-1-ylsulfonyl)-2-n-propoxyphenyl)-5-ethyl-7-n-propyl-3,5-dihydro-4H-pyrrolo[3,2-d]pyrimidin-4-one dihydrochloride), is a novel a new phosphodiesterase type V (PDE V) inhibiting agents. The pharmaceutical development of SK3530 necessitated the availability of an assay for the quantification and purity determination of SK3530 active pharmaceutical ingredient (API) and its pharmaceutical dosage form. A reversed-phase high performance liquid chromatographic (HPLC) method with ultraviolet (UV) detection was developed, consisting of separation on a C18 column with a CapcellPack MG (4.6 mm x 150 mm, 5 microm) column with ammonium acetate buffer (pH 4.0, 20 mM)-acetonitrile (60:40, v/v) as the isocratic mobile phase and UV detection at 250 nm. The method has been shown good chromatographic separation for SK3530 and the other related substances. The method was found to be linear 200-300 microg/ml, precise and accurate. Stress testing showed degradation products, which were well separated from the parent compound, confirming its stability-indication capacity. Moreover, the use of LC-MS and on-line diode array detection enabled us to propose structures for degradation products.

Development of LC/MS/MS assay for the determination of 5-ethyl-2-{5-[4-(2-hydroxyethyl)piperazine-1-sulfonyl]-2-propoxyphenyl}-7-propyl-3,5-dihydropyrrolo[3,2-d]pyrimidin-4-one (SK3530) in human plasma: application to a clinical pharmacokinetic study.

5-Ethyl-2-{5-[4-(2-hydroxyethyl)piperazine-1-sulfonyl]-2-propoxyphenyl}-7-propyl-3,5-dihydropyrrolo[3,2-d]pyrimidin-4-one (SK3530) is a new phosphodiesterase type-5 inhibitor currently undergoing a Phase III investigation for the treatment of male erectile dysfunction. This study first describes a rapid and sensitive LC/MS/MS assay method for the quantification of SK3530 and its major metabolite, SK3541, in human plasma. The assay was validated to demonstrate the specificity, linearity, recovery, lower limit of quantification (LLOQ), accuracy, and precision. The multiple reaction monitoring was based on the transition of m/z=532.5-->99.1 for SK3530, 488.6-->295.5 for SK3541, and 520.3-->99.1 for SK3304 (internal standard). The assay utilized a single liquid-liquid extraction and isocratic elution, and the LLOQ was 1 ng/ml using 0.2 ml human plasma. The assay was linear over a range from 1 to 1000 ng/ml for both SK3530 and SK3541, with correlation coefficients >0.9999. The mean intra- and inter-day assay accuracy ranged from 94.7 to 101.6% and 96.8 to 101.1% for SK3530 and 92.6-105.7% and 97.4-107.8% for SK3541, respectively. The mean intra- and inter-day precision was between 7.2-12.1% and 5.7-7.4% for SK3530 and 4.6-13.2% and 5.0-14.1% for SK3541, respectively. The developed assay was applied to a clinical pharmacokinetic study after oral administration of SK3530 in healthy male volunteers (dose 100 mg).