G. Krishna Mohan

pH-responsive interpenetrating network hydrogel beads of poly(acrylamide)-g-carrageenan and sodium alginate for intestinal targeted drug delivery: synthesis, in vitro and in vivo evaluation.

In the present work, we synthesized pH-responsive interpenetrating network (IPN) hydrogel beads of polyacrylamide grafted κ-carrageenan (PAAm-g-CG) and sodium alginate (SA) for targeting ketoprofen to the intestine. The PAAm-g-CG was synthesized by free radical polymerization followed by alkaline hydrolysis under nitrogen gas. The PAAm-g-CG was characterized by elemental analysis, FTIR spectroscopy and thermogravimetric analysis (TGA). The drug-loaded IPN hydrogel beads were prepared by simple ionotropic gelation/covalent crosslinking method. The amorphous nature of drug in the beads was confirmed by differential scanning calorimetry and X-ray diffraction studies. The spherical shape of the beads was confirmed by scanning electron microscopic analysis. The beads exhibited ample pH-responsive behavior in the pulsatile swelling study. The ketoprofen release was significantly increased when pH of the medium was changed from acidic to alkaline. The beads showed maximum of 10% drug release in acidic medium of pH 1.2, and about 90% drug release was recorded in alkaline medium of pH 7.4. Stomach histopathology of albino rats indicated that the prepared beads were able to retard the drug release in stomach leading to the reduced ulceration, hemorrhage and erosion of gastric mucosa.

Novel pH-sensitive IPNs of polyacrylamide-g-gum ghatti and sodium alginate for gastro-protective drug delivery

This article reports the development of pH-sensitive interpenetrating polymer network (IPN) microbeads using polyacrylamide-grafted-gum ghatti (PAAm-g-GG) and sodium alginate (SA) for gastro-protective controlled delivery of ketoprofen. We have synthesized PAAm-grafted-GG copolymer under microwave irradiation using cerric ammonium nitrate as reaction initiator; further, the PAAm-g-GG was converted to pH-sensitive copolymer through alkaline hydrolysis. Sophisticated instrumentation techniques were used to characterize PAAm-g-GG. The IPN microbeads of PAAm-g-GG and SA, pre-loaded with ketoprofen were prepared by dual crosslinking using Ca(2+) ions and glutaraldehyde (GA). The IPN microbeads demonstrated excellent pH-sensitive behavior as noted in the pulsatile swelling test and scanning electron microscopy. IPN microbeads also showed larger amount of drug release in buffer solution of pH 7.4 as compared to drug release in solution of pH 1.2. The in vivo pharmacokinetic, pharmacodynamic and stomach histopathology studies conducted on wistar rats confirmed the pH-sensitive controlled release of ketoprofen; IPN microbeads retarded the drug release in stomach resulting in reduced adverse effects of ketoprofen.

In vitro and in vivo assessment of novel pH-sensitive interpenetrating polymer networks of a graft copolymer for gastro-protective delivery of ketoprofen

The pH-sensitive polyacrylamide-grafted-tamarind seed polysaccharide (PAam-g-TSP) copolymer was synthesized under microwave irradiation in the presence of ceric ammonium nitrate in order to initiate the reaction. The reaction mixture was subjected to hydrolysis in alkaline medium. The copolymer was characterized with the help of FTIR, 1H-NMR and elemental analysis techniques. Furthermore, pH-sensitive IPN microbeads were prepared from these polymers in combination with sodium alginate through a dual crosslinking process and used for gastro-protective delivery of ketoprofen. The IPN microbeads were tested in vitro and in vivo and showed pH-dependent swelling/shrinking with the changing pH of the medium. Drug release was higher in 7.4 pH medium (about 83%), but it was lower in pH 1.2 medium (about 17%). The in vivo pharmacokinetics, anti-inflammatory activity and stomach histopathological evaluation performed on Wistar rats suggested that the microbeads are pH-sensitive and they were able to target ketoprofen to the intestine, resulting in diminished adverse effects in the stomach.

Analytical method development and validation of prasugrel in bulk and its pharmaceutical formulation using the RP-HPLC method

Purpose: This study was designed to develop and validate a simple, sensitive, precise, and specific reverse phase high-performance liquid chromatographic (HPLC) method for the determination of prasugrel in bulk and its tablet dosage forms. Materials and Methods: The HPLC separation was carried out by reverse phase chromatography on an inertsil ODS-3V column (5 μm; 250 × 4.6mm2) with a mobile phase composed of 0.02 M potassium dihydrogen orthophosphate, 0.02 M dipotassium hydrogen orthophosphate in water:acetonitrile (30:70 v/v) in isocratic mode at a flow rate of 1 ml/min. The detection was monitored at 210 nm. Results: The calibration curve for prasugrel was linear from 100 to 600 μg/ml. The inter-day and intra-day precision was found to be within limits. The proposed method has adequate sensitivity, reproducibility, and specificity for the determination of prasugrel in bulk and its tablet dosage forms. The limit of detection and limit of quantification for prasugrel were found to be 0.25 μg/ml and 0.75 μg /ml, respectively. Accuracy (recoveries: 99.8–101.2%) and reproducibility were found to be satisfactory. Conclusion: The proposed method is simple, fast, accurate, and precise for the simultaneous quantification of prasugrel in the dosage form, bulk drugs as well as for routine analysis in quality control.

Preliminary phytochemical and antioxidant study of hydroalcoholic extracts from selected genera of Indian Lamiaceae

Article history: Objective: To investigate the antioxidant activity and total phenolics content of the hydroalcoholic extracts of Salvia officinalis and Plectranthus mollis. Methods: The total antioxidant capacity and phenolic contents of hydroalcoholic extracts of the leaves of Salvia officinalis and Plectranthus mollis were evaluated using standard in-vitro methods. The total phenol and total flavonoid were determined spectrophotometrically. Quercetin and Gallic acid were used for these parameters. The antioxidant activity of the extracts were determined by phosphomolybdenum method. Results: Our results clearly demonstrate that both the extracts have antioxidant capacity. The inventions of antioxidant capacity harmonize with total flavonoid and phenol contents. Conclusions: A correlation between the antioxidant activity and the total phenolic contents of the extracts indicated that phenolic compounds were the dominant contributors to the antioxidant activity of both the plants. The results of the study show that Plectranthus mollis has the most flavonoid and phenol contents and the antioxidant capacity. Contents lists available at ScienceDirect

In vitro alpha-amylase inhibition and in vivo antioxidant potential of Momordica dioica seeds in streptozotocin-induced oxidative stress in diabetic rats

Momordica dioica Roxb. Commonly known as “Kakora” in Telugu, is used in the Indian traditional system of medicine for the treatment of diabetes. The aim of this study was to investigate the antidiabetic activity of methanolic extract of M. dioica seeds (MEMD) in streptozotocin (STZ) induced diabetic rats. The in vitro α-amylase inhibitory activity of the MEMD was done by spectrophotometric method. Diabetes was induced by STZ (45 mg/kg; i.p), MEMD (100 & 200 mg/kg; b.wt) and standard drug metformin (50 mg/kg; b.wt) were administered to the diabetic rats. Blood glucose was estimated on the 11th day and the level of MDA, SOD and CAT was estimated in the liver tissue homogenate after the 15 days of experimental period. MEMD showed significant inhibition of alpha amylase activity and the IC50 was found to be 48 μg/ml. Oral administration of MEMD significantly reduced blood glucose level (P < 0.05), diminished the MDA level and refurbished depleted antioxidant enzymes and Insulin level to normalcy. These findings revealed that M. dioica seeds possess antihyperglycemic, antioxidant and anti lipid peroxidative activity and thus mitigate STZ-induced oxidative damage.

A sub-acute oral toxicity analysis and comparative in vivo anti-diabetic activity of zinc oxide, cerium oxide, silver nanoparticles, and Momordica charantia in streptozotocin-induced diabetic Wistar rats

Type 2 diabetes mellitus (T2DM) is one of the most threatening, non-communicable ailments worldwide. The use of nanoparticles as a medicine in the treatment of T2DM is an attractive proposition. In the current study, zinc oxide nanoparticles (ZnO NPs), cerium oxide nanoparticles (CeO2 NPs), silver nanoparticles (Ag NPs), and Momordica charantia (MC) were evaluated for their in vivo anti-diabetic activity. The resulting ZnO, CeO2, and Ag NPs were characterized via various techniques such as XRD, FT-IR, PSA, and SEM. The synthesized NPs and MC extract were tested for toxicity using a sub-acute oral toxicity model by following the OECD 425 guidelines. The male Wistar rats with weights in the range of 180–200 g were grouped as follows: normal control: who did not receive any treatment; diabetic control: who received a single intraperitoneal dose of streptozotocin (40 mg kg−1); standard: who received a single daily oral dose of streptozotocin 50 mg per kg body weight; diabetic and ZnO NPs: who received a single daily oral dose of 100 mg kg−1 and 200 mg kg−1 of ZnO NPs; diabetic and CeO2 NPs: who received a single daily oral dose of 100 mg kg−1 and 200 mg kg−1 of CeO2 NPs; diabetic and Ag NPs: who received a single daily oral dose of 100 mg kg−1 and 200 mg kg−1 of Ag NPs; and diabetic and MC: who received a single daily oral dose of 100 mg kg−1 and 200 mg kg−1 of MC. In conclusion, the green-synthesized NPs showed no toxic effect and were considered safe. From the experimental results, it may be concluded that due to the extensive biological and pharmacological properties, the ZnO NPs and Ag NPs had more potent anti-hyperglycemic activity than MC and CeO2 NPs. Further pharmacokinetic studies are required to establish the exact mechanism of action (of NPs).

Validated RP-HPLC-PDA method for simultaneous determination of Zidovudine, Lamivudine, and Nevirapine in pharmaceutical formulation

Aim and Objectives: A simple, rapid, and sensitive high performance liquid chromatographic method with ultraviolet detection has been developed and validated according to the International Conference on Harmonization (ICH) guidelines for the quantitation and qualification of zidovudine (ZID), lamivudine (LAM), and nevirapine (NEV) in pharmaceutical dosage forms. Materials and Methods: The proposed method was based on the separation of the drugs in reversed phase mode using Water′s C18 250 cm × 4.6 mm, 5 μ particle size column maintained at an ambient temperature. The optimum mobile phase consisted of Water: Methanol (70:30 v/v), pH adjusted to four with orthophosphoric acid (OPA). The flow rate of mobile phase was set 1.0 mL min -1 and photodiode array detection was performed at 275 nm with a total run time of 8 min which is very short for accurate analysis of simultaneous estimation of three analytes. The method was validated according to ICH guidelines. Results: The method was linear over the concentration range of 25-75 μg mL -1 with limit of quantifications (LOQ) of 13, 0.49, and 0.40 ng mL -1 for ZID, LAM and NEV respectively and limit of detection (LOD) of 4, 0.14, and 0.12 ng mL -1 for ZID, LAM and NEV respectively. Accuracy (% recovery studies) and precision values of both inter and intraday obtained from six different replicates for all the analytes ranged from 99.00% to 100.00% and % relative standard deviation of precision (assay) was between 0.64 and 1.28, respectively. All the three analytes and their combination drug product were exposed to thermal, photolytic, hydrolytic, reductive, oxidative and peroxide stress conditions and the stressed samples were analyzed by the proposed method. There were no interfering peaks from excipients, impurities or degradation products due to variable stress conditions and the proposed method is specific for the simultaneous estimation of ZID, LAM and NEV in the presence of their degradation products. Conclusion: The proposed method can be successfully applied in the quality control and stability samples of pharmaceutical dosage forms.

In vivo Therapeutic Potential of Biologically Synthesized Silver Nanoparticles

Abstract—Nowadays, nanoparticles are being used in pharmacological studies for their exclusive properties such as small size, more surface area, biocompatibility and enhanced solubility. In view of this, the present study aimed to evaluate the antihyperglycemic potential of biologically synthesized silver nanoparticles (BSSNPs) and Gymnema sylvestre (GS) extract. The SEM and SEM analysis divulges that the BSSNPs were spherical in shape. EDAX spectrum exhibits peaks for the presence of silver, carbon, and oxygen atoms in the range of 1.0-3.1 keV. FT-IR reveals the binding properties of active bio-constituents responsible for capping and stabilizing BSSNPs. The results showed increased blood glucose, huge loss in body weight and downturn in plasma insulin. The GS extract (200 mg/kg, 400 mg/kg), BSSNPs (100 mg/kg, 200 mg/kg) and metformin 50 mg/kg were administered to the diabetic rats. BSSNPs at a dose level of 200 mg/kg (b.wt.p.o.) showed significant inhibition of (p<0.001) blood glucose levels as compared with GS extract treated group. The results obtained from study indicate that the BSSNP shows potent anti-diabetic activity.Background: Verapamil hydrochloride is a commonly prescribed drug in the management of hypertension, angina and cluster headache prophylaxis. Verapamil hydrochloride has a disadvantage of low bioavailability because of extensive hepatic metabolism (only 10% to 20% becomes bioavailable) and short half-life (2 to 4 hours). As a result, it requires frequent dosing of the drug leading to the problem of noncompliance in patients and alternating over and under doses of the drug. A method of circumventing hepatic first pass effect is by making the drug particle microsized (<10 μm) and lipophilic.

Analytical Method Development and Validation for the Determination of Allopurinol and Alphalipoic Acid Using Reverse Phase HPLC Method in Bulk and Tablet Dosage Form

A new simple, accurate, precise and reproducible RP-HPLC method has been developed for the simultaneous estimation of Allopurinol and Alpha lipoic acid in bulk and pharmaceutical dosage form using C18 column (inertsil ODS, 250 x 4.6 mm, 5 μm) in isocratic mode. The mobile phase consisted of 0.1 M Dipotassium Phosphate buffer (pH 3.5) and acetonitrile in the ratio of 55:45v/v. The detection was carried out at 250 nm for Allopurinol and 212 nm for Alpha lipoic acid. The method was linear over the concentration range for Allopurinol 60–140 μg/ml and for Alpha lipoic acid 60–140μg/ml. The recoveries of Allopurinol and Alpha lipoic acid were found to be 98.9% and 98.7% respectively. The validation of method was carried out utilizing ICH-guidelines. The described HPLC method was successfully employed for the analysis of pharmaceutical formulations containing combined dosage form.