One-Pot Cascade Access to Ru(II)-Catalyzed Regioselective C(sp2)-H Activation/Alkenylation of Chromeno[4,3-c]pyrazol-4-ones and Their Emission Solvatochromic Studies.

Herein, one-pot cascade synthesis of chromeno[4,3-c]pyrazol-4-ones and their Ru(II)-catalyzed regioselective ortho-alkenylation using imine as a weak directing group are done with moderate to good yields. The reaction proceeds through a three-step domino process during which intermediates are also isolated in excellent yields. In addition, this methodology generates a number of interesting fluorophores with donor and acceptor groups, which show positive solvatochromism.

Ru(II)-Catalyzed Regioselective C(5)-H Functionalization of Quinazolinone-Coumarin Conjugates: Synthesis and Photophysical Studies.

The quinazolinone template offers an exciting potential for transforming molecules into useful bioactivity. Herein, we report the first regioselective C-5 alkenylation of quinazolinone-coumarin conjugates via ruthenium(II) catalyst using amide as a weak directing group. This methodology permits excellent regioselectivity, extensive substrate tolerance, and mild reaction conditions. In addition, it generates interesting fluorophores that show positive solvatochromism in the range from 404 nm (toluene) to 541 nm (methanol).

Assay and Dermatokinetics of Tetrahydrocurcumin Lipidic Nanostructures Using Reverse Phase-high Performance Liquid Chromatography.

BACKGROUND: Envisaging the poor solubility (56 ngml1) and permeability of tetrahydrocurcumin (THCC), it was formulated into lipidic nanostructures to enhance its bioavailability upon topical application to promote the healing process for skin inflammatory disorders. Lack of literature on a suitable method for determining THCC per se and nanoformulations prompted us to develop an RP-HPLC method to detect the drug in its nanostructures and in pig ear skin post dermatokinetics. OBJECTIVE: The present investigation aimed to develop a simple, precise and RP-HPLC method for the quantitative estimation of THCC in prepared lipidic nanostructures, its ointment, and in skin homogenate obtained post dermatokinetic study. METHODS: THCC encapsulated nanostructures and ointment were formulated using a modified emulsification method and embedded into an ointment base to enhance its spreadability and improve patient compliance. A fast and sensitive reverse-phase high-performance liquid chromatography method was developed using a Hypersil BDS reverse phase C18 column (4.6 mm × 250 mm, 5 µm) with mobile phase comprising tetrahydrofuran (THF) and 1 mgmL-1 citric acid (4:6), at a flow rate of 1.0 mLmin-1 with a run time of 20 min. RESULTS: THCC nanostructures were successfully prepared using the spontaneous microemulsification method. THCC was detected at 282 nm and revealed two peaks which were attributed to the keto-enol tautomerism in the molecule with retention times of 6.23 min and 11.06 min, respectively. The assay of THCC in nanostructures and ointment was found to be 98.30 % and 99.98 %, with an entrapment efficiency 77.00±2.74 %. The dermatokinetic studies revealed sufficient release of THCC from its ointment up to 24 hr with a concentration of 1382 µgcm-2, for causing a therapeutic effect. CONCLUSION: The method was found to be reproducible and robust, as shown by the low coefficient of variation and a constant analyte/IS ratio. It was successfully employed for the estimation of THCC assay in nanostructures and its ointment and dermatokinetic analysis in the skin.

Enhanced Oral Absorption of All-trans Retinoic Acid upon Encapsulation in Solid Lipid Nanoparticles.

BACKGROUND: All-trans retinoic acid (ATRA) is widely employed in the treatment of various proliferative and inflammatory diseases. However, its therapeutic efficacy is imperiled due to its poor solubility and stability. Latter was surmounted by its incorporation into a solid matrix of lipidic nanoparticles (SLNs). METHODS: ATRA loaded SLNs (ATRA-SLNs) were prepared using a novel microemulsification technique (USPTO 9907758) and an optimal composition and were characterized in terms of morphology, differential scanning calorimetry (DSC), and powder X-ray diffraction studies (PXRD). In vitro release, oral plasma pharmacokinetics (in rats) and stability studies were also done. RESULTS: Rod-shaped ATRA-SLNs could successfully incorporate 3.7 mg/mL of ATRA, increasing its solubility (from 4.7 µg/mL) by 787 times, having an average particle size of 131.30 ± 5.0 nm and polydispersibility of 0.283. PXRD, DSC, and FTIR studies confirmed the formation of SLNs. Assay/total drug content and entrapment efficiency of ATRA-SLNs was 92.50 ± 2.10% and 84.60 ± 3.20% (n=6), respectively, which was maintained even on storage for one year under refrigerated conditions as an aqueous dispersion. In vitro release in 0.01 M phosphate buffer (pH 7.4) with 3% tween 80 was extended 12 times from 2h for free ATRA to 24 h for ATRA-SLNs depicting Korsmeyer Peppas release. Oral administration in rats showed 35.03 times enhanced bioavailability for ATRA-SLNs. CONCLUSION: Present work reports preparation and evaluation of bioenhanced ATRA-SLNs containing a high concentration of ATRA (>15 times than that reported by others). Latter is attributed to the novel preparation process and intelligent selection of components. Lay Summary: All-trans retinoic acid (ATRA) shows an array of pharmacological activities but its efficacy is limited due to poor solubility, stability and side effects. In present study its solubility and efficacy is improved by 787 and 35.5 times, respectively upon incorporation into solid lipid nanoparticles (ATRA-SLNs). Latter extended its release by 12 times and provided stability for at least a year under refrigeration. A controlled and sustained release will reduce dose related side effects. ATRA-SLNs reported presently can thus be used in treatment /prophylaxis of disorders like cancers, tuberculosis, age related macular degeneration and acne and as an immune-booster.

Development of a validated UPLC method for simultaneous estimation of both free and entrapped (in solid lipid nanoparticles) all-trans retinoic acid and cholecalciferol (vitamin D3) and its pharmacokinetic applicability in rats.

A sensitive ultra-performance liquid chromatography (UPLC) method was developed for simultaneous estimation of all-trans retinoic acid (ATRA) and cholecalciferol (vitamin D3) in rat plasma. The method was validated over the linear range of 1.0-5000ng/ml (r(2)=0.999) for both vitamins with a limit of detection of 0.5ng/ml. Chromatographic separation was achieved using liquid-liquid extraction (LLE) on an Acquity BEH RP 18 column (2.1mm×50mm, I.D. 1.7µm), with mobile phase comprising of acetonitrile:methanol:water (90:8:2, v/v/v), at a flow rate of 0.20ml/min and a total run time of 5min. Intra and inter-day variability (RSD) was ≤3.1%, and the accuracy varied between 95.4-99.9% and 95.3-101.1% respectively, for ATRA and 98.5-100.8% and 99.3-101.7%, respectively for vitamin D3. High recovery of ≥96.0% for ATRA and ≥87.80% for vitamin D3 was achieved. ATRA and vitamin D3 were stable in plasma under different storage and processing conditions. The method was applied to estimate the total drug content and entrapment efficiency of ATRA and vitamin D3 loaded solid lipid nanoparticles (SLNs). Concentration of these two agents was determined in rat plasma after simultaneous subcutaneous administration in free form or when loaded into SLNs thus establishing pharmacokinetic application of the developed procedure. Results indicated an improvement in AUC0-∞ by 5.4 times and 29.4 times for ATRA and vitamin D3, respectively, upon their incorporation into SLNs. Simultaneous administration of these two vitamins and their improved and prolonged bioavailability has scope for their use in treatment and control of tuberculosis.

A randomized controlled trial to compare pregabalin with gabapentin for postoperative pain in abdominal hysterectomy.

BACKGROUND: Pregabalin is a potent ligand for alpha-2-delta subunit of voltage-gated calcium channels in the central nervous system, which exhibits potent anticonvulsant, analgesic and anxiolytic activity. The pharmacological activity of pregabalin is similar to that of gabapentin and shows possible advantages. Although it shows analgesic efficacy against neuropathic pain, very limited evidence supports its postoperative analgesic efficacy. We investigated its analgesic efficacy in patients experiencing acute pain after abdominal hysterectomy and compared it with gabapentin and placebo. METHODS: A randomized, double-blind, placebo-controlled study was conducted in 90 women undergoing abdominal hysterectomy who were anaesthetized in a standardized fashion. Patients received 300 mg pregabalin, 900 mg gabapentin or placebo, 1-2 hours prior to surgery. Postoperative analgesia was administered at visual analogue scale (VAS) ≥3. The primary outcome was analgesic consumption over 24 hours and patients were followed for pain scores, time to rescue analgesia and side effects as secondary outcomes. RESULTS: The diclofenac consumption was statistically significant between pregabalin and control groups, and gabapentin and control groups; however, pregabalin and gabapentin groups were comparable. Moreover, the consumption of tramadol was statistically significant among all the groups. Patients in pregabalin and gabapentin groups had lower pain scores in the initial hour of recovery. However, pain scores were subsequently similar in all the groups. Time to first request for analgesia was longer in pregabalin group followed by gabapentin and control groups. CONCLUSION: A single dose of 300 mg pregabalin given 1-2 hours prior to surgery is superior to 900 mg gabapentin and placebo after abdominal hysterectomy. Both the drugs are better than placebo.

Exploring solid lipid nanoparticles to enhance the oral bioavailability of curcumin.

SCOPE: Curcumin, a molecule with pluripharmacological properties, was loaded into solid lipid nanoparticles (SLNs) with a view to improve its oral bioavailability (BA). METHODS AND RESULTS: Curcumin-loaded solid lipid nanoparticles (C-SLNs) with an average particle size of 134.6 nm and a total drug content of 92.33±1.63% was produced using a microemulsification technique. The particles were spherical in shape, with high drug entrapment of 81.92±2.91% at 10% drug loading. The in vitro release was predominantly by diffusion phenomenon and was prolonged up to 7 days. No significant variation in particle size and curcumin content of C-SLNs was observed, upon storage, over a period of 12 months at 5±3°C. In vivo pharmacokinetics performed after oral administration of C-SLNs (50, 25, 12.5 and 1 mg/kg dose) and (free) solubilized curcumin (C-S; 50 mg/kg), using a validated LC-MS/MS method in rat plasma revealed significant improvement (at p<0.05) in BA (39 times at 50 mg/kg; 155 times at 1 mg/kg; and, 59 and 32 times at 12.5 and 25 mg/kg, respectively) after administration of C-SLNs at all the doses with respect to C-S. CONCLUSIONS: Enhanced and reliable BA will help in establishing its therapeutic usefulness especially for neurodegenerative and cancerous disorders in humans.

Pharmacokinetic applicability of a validated liquid chromatography tandem mass spectroscopy method for orally administered curcumin loaded solid lipid nanoparticles to rats.

A simple and sensitive validated LC-MS/MS analytical method was used for determination of curcumin in rat plasma, using nimesulide as internal standard. Analyses were performed on an Agilent LC-MS/MS system using a Chromolith rod™ and isocratic elution with acetonitrile:10 mM ammonium acetate buffer (pH 3.5) (80:20, v/v) at a flow rate of 0.8 ml/min with a total run time of 3 min and an overall recovery of 77.15%. A triple quadrupole mass spectrometer, equipped with an electrospray ionization interface, operated in the negative mode was used. Calibration curve in plasma spiked with varying concentration of curcumin were linear over the concentration range of 10-2000 ng/ml with determination coefficient >0.99. The lower limit of quantification was 10 ng/ml. Intra and inter-day variability's (RSD) for extraction of curcumin from plasma were less than 10% and 15% respectively and accuracy was 102.43-108.5%. Multiple reaction monitoring was used to monitor the transition for curcumin (m/z; 367/217 [M-H](-)) and IS (m/z; 307/229). The method was applied for determining curcumin concentration in plasma after peroral administration of 50 mg/kg of free curcumin (C-S) or curcumin loaded solid lipid nanoparticles (C-SLNs) to rats. Results established selectivity and suitability of the method for pharmacokinetic studies of curcumin from C-SLNs.

Efficacy and safety of pegylated IFN alfa 2b alone or in combination with ribavirin in thalassemia major with chronic hepatitis C.

BACKGROUND: Treatment of HCV infection in patients with thalassemia major (TM) is limited by the lack of large clinical trials and concerns about ribavirin-induced hemolysis. METHODS: We conducted a prospective, randomized, open-label study to determine efficacy and tolerability of pegylated-interferon alfa 2b (1.5 microg/kg/week) alone (group A) or with ribavirin (12-15 mg/kg/day; group B) in patients with TM and chronic HCV infection. Patients with genotype 1 or 4 HCV were treated for 48 weeks and those with genotype 3 or 2 HCV for 24 weeks. Early viral response (EVR; after 12 weeks of treatment), end-of-treatment virological response (ETR) and sustained virological response (SVR; 6 months after stopping therapy) were assessed. RESULTS: Of 40 patients, 20 each were allocated to the two treatment groups. EVR rates in group A and B were 15 (75%) and 18 (90%), respectively. ETR occurred in 17/20 (85%) patients in each group. SVR occurred in 8 (40%) patients in group A and 14 (70%) in group B. Blood transfusion requirements increased in one patient in group A and four patients in group B. One patient in group A had severe sepsis and one in group B had nephrotic syndrome. Two patients in each group required reduction in drug dose. CONCLUSIONS: In patients with TM and chronic HCV infection, pegylated interferon alfa 2b and ribavirin combination therapy achieves a higher SVR rate than pegylated interferon alone, and is well tolerated except for an increase in blood transfusion requirement.

Barium meal follow through with pneumocolon: screening test for chronic bowel pain.

AIM: To study the sensitivity, specificity and cost effectiveness of barium meal follow through with pneumocolon (BMFTP) used as a screening modality for patients with chronic abdominal pain of luminal origin in developing countries. METHODS: Fifty patients attending the Gastroenterology Unit, SMS Hospital, whose clinical evaluation revealed chronic abdominal pain of bowel origin were included in the study. After routine testing, BMFT, BMFTP, contrast enhanced computed tomography (CECT) of the abdomen, barium enema and colonoscopy were performed. The sensitivity, specificity and cost effectiveness of these imaging modalities in the detection of small and/or large bowel lesions were compared. RESULTS: Out of fifty patients, structural pathology was found in ten. Nine out of these ten patients had small bowel involvement while seven had colonic involvement alone or in combination with small bowel involvement. The sensitivity of BMFTP was 100% compared to 88.89% with BMFT when detecting small bowel involvement (BMFTP detected one additional patient with ileocecal involvement). The sensitivity and specificity of BMFTP for the detection of colonic pathology were 85.71% and 95.35% (41/43), respectively. Screening a patient with chronic abdominal pain (bowel origin) using a combination of BMFT and barium enema cost significantly more than BMFTP while their sensitivity was almost comparable. CONCLUSION: BMFTP should be included in the investigative workup of patients with chronic abdominal pain of luminal origin, where either multiple sites (small and large intestine) of involvement are suspected or the site is unclear on clinical grounds. BMFTP is an economical, quick and comfortable procedure which obviates the need for colonoscopy in the majority of patients.