Effect of diltiazem and methylene blue on human sperm motility,viability and cervical mucus penetration: potential use as vas irrigants at the time of vasectomy

The purpose of this study was to identify compounds that could potentially be useful for vas irrigation at the time of vasectomy. We studied the in vitro effects of a group of membrane-active and ion-channel blocking agents on human sperm motility, viability and cervical mucus penetration. Diltiazem, an anti-arrhythmic drug, and methylene blue, an agent commonly used in vasography, showed the most promising effects with marked reduction of sperm motility and cervical mucus penetration after incubation with sperm for a short period of 15 min. Diltiazem was more effective than methylene blue in inhibiting the motility and viability of sperm. Furthermore, unlike methylene blue, diltiazem significantly compromised sperm viability. Other compounds studied, such as lidocaine, nicardipine and Neosporin((R)), showed only partial inhibitory activity. Based on the data reported herein, both diltiazem and methylene blue appear to be suitable candidates to be developed for vas irrigation at the time of vasectomy.     

A Validated Stability-Indicating RP-UPLC Method for Simultaneous Determination of Desloratadine and Sodium Benzoate in Oral Liquid Pharmaceutical Formulations

A novel, sensitive and selective stability-indicating gradient reverse phase ultra performance liquid chromatographic method was developed and validated for the quantitative determination of desloratadine and sodium benzoate in pharmaceutical oral liquid formulation. The chromatographic separation was achieved on Acquity BEH C8 (100 mm × 2.1 mm) 1.7 μm column by using mobile phase containing a gradient mixture of solvent A (0.05 M KH(2)PO(4) and 0.07 M triethylamine, pH 3.0) and B (50:25:25 v/v/v mixture of acetonitrile, methanol and water) at flow rate of 0.4 mL/min. Column temperature was maintained at 40°C and detection was carried out at a wavelength of 272 nm. The described method shows excellent linearity over a range of 0.254 μg/mL to 76.194 μg/mL for desloratadine and 1.006 μg/mL to 301.67 μg/mL for sodium benzoate. The correlation coefficient for desloratadine and sodium benzoate was more than 0.999. To establish stability-indicating capability of the method, drug product was subjected to the stress conditions of acid, base, oxidative, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from desloratadine and sodium benzoate. The developed method was validated as per international ICH guidelines with respect to specificity, linearity, LOD, LOQ, accuracy, precision and robustness.     

A validated stability-indicating liquid-chromatographic method for ranitidine hydrochloride in liquid oral dosage form

A selective, specific and stability-indicating gradient reverse phase high-performance liquid chromatographic (HPLC) method was developed for the determination of Ranitidine in presence of its impurities, forced degradation products and placebo substances such as saccharide and parabens. Ultraviolet detection was performed at 230 nm. Separate portions of the drug product and ingredients were exposed to stress conditions to induce oxidative, acidic, basic, hydrolytic, thermal and photolytic degradation. Ranitidine was found to degrade significantly at acidic, basic and oxidative stress conditions but was stable at heat and humidity. The developed method was validated as per International Conference on Harmonization (ICH) guidelines. The method was validated over this range for (i) system suitability (ii) specificity, (iii) precision, (iv) limit of detection and limit of quantification, (v) linearity, (vi) accuracy, (vii) robustness. The method was found to be precise, accurate, linear and robust. The proposed method was successfully employed for estimation of Ranitidine impurities in pharmaceutical preparations.     

Bacterial lipopolysaccharide-induced oxidative stress in the impairment of steroidogenesis and spermatogenesis in rats

Microbial infections, localized as well as systemic, are known to cause transitive or permanent male infertility. However, the mechanisms of infection-induced infertility are largely unknown. Earlier reports showed that steroidogenesis and spermatogenesis are affected during bacterial lipopolysaccharide (LPS)-induced acute inflammation. The present study used an LPS rat model to investigate the role of oxidative stress in spermatogenesis. Intraperitoneal administration of bacterial LPS (5mg/kg body weight) to adult male albino rats elevated testicular malondialdehyde (MDA) and 4-hydroxy-2-nonenal (HNE), and decreased the activities of testicular antioxidant enzymes such as catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. The GSH/GSSG ratio also decreased significantly. Time series analysis revealed transitory oxidative stress and expression of inflammatory mediators such as interleukin-1beta (IL-1beta), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) from 3h to 12h after LPS. Testicular expression of steroidogenic acute regulatory (StAR) protein decreased to 24h, in correlation with damage to spermatogenesis. These data are consistent with oxidative stress as a major causal factor in altered steroidogenesis, spermatogenesis, and perhaps male infertility during endotoxin-induced acute inflammation.     

Quercetin reduced the formation of N‐acetyl‐p‐benzoquinoneimine,a toxic metabolite of paracetamol in rats and isolated rat hepatocytes

N‐acetyl‐p‐benzoquinoneimine (NAPQI) is toxic metabolite of paracetamol formed primarily by cytochrome P4502E1 (CYP2E1) metabolic pathway when administered at therapeutic doses or overdose. The influence of quercetin (flavonoid) on the bioactivation of paracetamol to NAPQI was investigated using rat liver microsomes and rats in vivo. Paracetamol (80 mg/kg) was administered orally without or with silymarin (100 mg/kg), a known inhibitor of CYP2E1, CYP3A4 and quercetin (10 and 20 mg/kg) to rats for 15 consecutive days. Area under the plasma concentration–time curve (AUC_0‐∞) and the peakplasma concentration (C_max) of paracetamol were dose‐dependently increased with quercetin (10 and 20 mg/kg) compared to paracetamol control group (p < 0.001). On the other hand, the AUC_0‐∞ and C_max of NAPQI were decreased significantly with quercetin. The same results were observed with silymarin also. The elevated liver and kidney functional enzymes/compounds were significantly reduced by quercetin and silymarin compared to paracetamol control group. The formation of NAPQI was reduced in the incubation samples in presence of quercetin in experiment using isolated rat hepatocytes. The presentstudy results revealed that quercetin might be inhibited the CYP2E1‐mediated metabolism of paracetamol; thereby decreased the formation of NAPQI and protected the liver and kidney.     

Development and Validation of a Stability-Indicating RP-UPLC Method for the Estimation of Impurities in Cinacalcet Hydrochloride API and its Formulation

A sensitive, stability-indicating, gradient reversed-phase ultra-performance liquid chromatography method has been developed for the quantitative estimation of cinacalcet hydrochloride impurities in active pharmaceutical ingredients and pharmaceutical formulations. Efficient chromatographic separation was achieved on an Acquity BEH Shield RP18, 100 × 2.1 mm, 1.7 µm column with the mobile phase containing pH 6.6 phosphate buffer and acetonitrile. The flow rate of the mobile phase was 0.3 mL min⁻¹ with a column temperature of 35°C and detection wavelength at 223 nm. The relative response factor values of (+)-R-1-(1-Naphthyl)ethylamine, regioisomer, diastereomer isomer-1, and diastereomer isomer-2 were 1.79, 0.99, 0.89, and 0.88, respectively. The cinacalcet hydrochloride formulation sample was subjected to the stress conditions of acid, base, oxidative, hydrolytic, thermal, humidity, and photolytic degradation. Cinacalcet hydrochloride was found to degrade significantly under the peroxide stress conditions. The degradation products were well-resolved from cinacalcet hydrochloride and its impurities. The peak purity test results confirmed that the cinacalcet hydrochloride peak was homogenous in all stress samples and the mass balance was found to be more than 96%, thus proving the stability-indicating power of the method. The developed method was validated according to ICH guidelines.     

Discovery of N-pyridoyl-Δ2-pyrazolines as Hsp90 inhibitors

Hsp90, as a key molecular chaperone, plays an important role in modulating the activity of many cell signaling proteins and is an attractive target for anticancer therapeutics. Herein, we report the discovery of N-pyridoyl-Δ²-pyrazoline analogs as novel Hsp90 inhibitors by integrated approaches of drug design, organic synthesis, cell biology, and qualitative proteomic analysis. Novel chemical compounds were designed and optimized in the adenosine triphosphate-binding site of Hsp90; lead optimized compounds were found to have significant interactions with Asp93 and other amino acids crucial for Hsp90 inhibition. The designed compounds were synthesized by a two-step procedure; different aromatic aldehydes were reacted with various acetophenones to form substituted 1,3-diphenyl-prop-2-enones ( Ic–Io ), which upon reaction with isonicotinic acid hydrazide in the presence of glacial acetic acid form N-pyridoyl-Δ²-pyrazoline compounds ( PY1–PY13 ). Compounds PY3 , PY2 , and PY1 were identified as potential leads amongst the series, with promising anticancer activity against human breast cancer and melanoma cells, and the ability to inhibit Hsp90 similar to radicicol by drug-affinity responsive target stability proteomic analysis in a whole-cell assay.     

Identification and synthesis of potential impurities of rabeprazole sodium

Rabeprazole sodium (1, Achiphex) is a gastric proton pump inhibitor. It causes dose-dependent inhibition of acid secretion and is useful as an anti-ulcer agent. In the process for the preparation of 1, two potential unknown impurities were identified in HPLC at levels ranging from 0.05-0.8%. Based on mass spectral data vide LC-MS, the two impurities were characterized as 2-{[(4-chloro-3-methyl-2-pyridinyl) methyl] sulfinyl}-1H-bezimidazole (2, chloro analogue of rabeprazole) and 2-[{(4-methoxy-3-methyl-2-pyridinyl)methyl}sulfinyl]-1H-benzimidazole (3, methoxy analogue of rabeprazole). The structures were unambiguously established by independently synthesizing them and co-injecting in HPLC. To our knowledge, the compounds 2 and 3 have not been reported as process impurities elsewhere.