Lakshmi Kanta Ghosh

Multiunit Floating Drug Delivery System of Rosiglitazone Maleate: Development, Characterization, Statistical Optimization of Drug Release and In Vivo Evaluation

A multiunit floating drug delivery system of rosiglitazone maleate has been developed by encapsulating the drug into Eudragit® RS100 through nonaqueous emulsification/solvent evaporation method. The in vitro performances of microspheres were evaluated by yield (%), particle size analysis, drug entrapment efficiency, in vitro floating behavior, surface topography, drug–polymer compatibility, crystallinity of the drug in the microspheres, and drug release studies. In vitro release was optimized by a {3, 3} simplex lattice mixture design to achieve predetermined target release. The in vivo performance of the optimized formulation was evaluated in streptozotocin-induced diabetic rats. The results showed that floating microspheres could be successfully prepared with good yields (69–75%), high entrapment (78-97%), narrow size distribution, and desired target release with the help of statistical design of experiments from very small number of formulations. In vivo evaluation in albino rats suggested that floating microspheres of rosiglitazone could be a promising approach for better glycemic control.

Effect of salts on gelation and drug release profiles of methylcellulose-based ophthalmic thermo-reversible in situ gels.

The poor bioavailability and therapeutic response exhibited by conventional ophthalmic solutions may be overcome by the use of thermo-reversible in situ gel. The purpose of this study was to examine the influence of different salts on the gelation, rheology and drug release of in situ gel based on methylcellulose. The gel temperature of 1% w/v methylcellulose (MC) was 60?C. It was found that 5?7% w/v sodium chloride (NaCl), 8?9% w/v potassium chloride (KCl), or 5% w/v sodium bicarbonate (NaHCO(3)) was capable of decreasing the gel temperature below physiological temperature, i.e. 37?C. Rheological studies indicated a large increase in viscosity at 37?C with the addition of salts in MC solutions. The duration of drug release from MC solution was 1.5?h. The significant observation was that the duration of drug release increased from 1.5?h to 3?5?h from salted MC solutions depending on the concentration and the type of salt. So, it can be concluded that the salted MC solutions were a better alternative than the MC solution to enhance the ocular bioavailability of the drug.

Development and in vitro evaluation of Letrozole loaded biodegradable nanoparticles for breast cancer therapy

The objectives of our study were to prepare and evaluate a biodegradable nanoparticulate system of Letrozole (LTZ) intended for breast cancer therapy. LTZ loaded poly(lactide-co-glycolide) nanoparticles (LTZ-PLGA-NPs) were prepared by emulsion-solvent evaporation method using methylene chloride and polyvinyl alcohol. Percentage of drug (with respect to polymer) was selected as formulation variable. LTZ-PLGA-NPs were characterized by particle size, zeta potential, infrared spectra, drug entrapment efficiency and in vitro release. Sonication was done with an ultrasound pulse sonicator at 70 W, 30 kHz for 90 sec to produce stable NPs of mean size range from 64 nm to 255 nm with high entrapment efficiency (68% to 82%). Percentage of drug significantly influenced particle size, entrapment efficiency and release (p <0.05). The system sustained release of LTZ significantly and further investigation could exhibit its potential usefulness in breast cancer therapy.

Gastroretentive extended release of metformin from methacrylamide-g-gellan and tamarind seed gum composite matrix

Formulation of a gastroretentive extended release tablet of metformin based on polymethacrylamide-g-gellan (Pmaa-g-GG)-tamarind seed gum (TSG) composite matrix is the main purpose of this study. Tablets were prepared employing wet granulation method taking amount of Pmaa-g-GG, TSG and NaHCO3 (SBC, buoyancy contributor) as independent formulation variables. The tablets were then evaluated for in vitro drug release, buoyancy, ex vivo mucoadhesion, swelling and surface morphology. Compatibility between drug and excipients was checked by DSC, FTIR and XRD analysis. Buoyancy-lag-time, mucoadhesive strength, % drug release and release-rate constant were statistically analyzed using Design-Expert software (version 9.0.4.1) and the formulation was then numerically optimized to obtain USP-reference release profile. The optimized formulation showed excellent buoyancy over a 10h period with buoyancy lag time of 2.76min, significant mucoadhesion and drug release over a period of 10h with f2=71.58. Kinetic modeling unveiled anomalous non-Fickian transport based drug release mechanism.

Sustained release gastroretentive tablet of metformin hydrochloride based on poly (acrylic acid)-grafted-gellan

Development of a gastroretentive sustained release tablet of metformin based on poly (acrylic acid)-grafted-gellan (PAAc-g-GG) is the main purpose of this study. At first, PAAc-g-GG was synthesized by microwave-promoted free radical initiation method using cerric (IV) ammonium nitrate (CAN) as redox initiator and characterized by elemental analysis, FTIR, DSC-TGA, 13C NMR, biodegradation and viscosity study. The synthetic parameters were optimized by 23 full factorial design using Design Expert software. Acute oral toxicity and histological studies were also performed as per OECD guideline. Tablets were then prepared employing wet granulation method using PAAc-g-GG and evaluated for various physical characters, in vitro drug release, ex-vivo mucoadhesion and swelling. Compatibility between drug and excipients was checked by DSC and FTIR analysis. The F3 batch showed excellent mucoadhesion and sustained drug release over a period of 10h with dissolution similarity factor, f2=77.43. Kinetic modeling unveiled Case-1 Fickian diffusion based drug release mechanism.

Attenuation of reactive nitrogen species by different flavonoids enriched fractions of Schima Wallichii

Abstract Objective To investigate Schima wallichii (S. wallichii) Choisy (Ternstroemiaceae) which is a well known plant of Sikkim in the Himalayan region, India. Methods Therefore three major flavonoid enriched fractions (FPet.Ether, FChloroform and FEthylacetate) were isolated by petroleum ether chloroform and ethyl acetate successively. The reactive nitrogen species scavenging activity of the flavonoid fractions was established using biochemical assay to measure scavenging of 2, 2 diphenyl picrylhydrazyl (DPPH), nitric oxide (NO) and peroxinitrite. Results FEthylacetate showed maximum scavenging activity: their IC50 being (7.33 ± 3.32), (7.11 ± 2.21), and (6.67 ± 2.23) μg/mL in DPPH, NO, peroxinitrite radical respectively. Presence of (57.32 ± 2.31) and (163.4 ± 2.22) μg of flavonoids and phenolic compound in 1 mg of extract is assumed to be responsible for free radical scavenging activity. Conclusion Taken together S. wallichii has potent free radical scavenging property indicating its importance in food supplement as a rich source of active flavonoid and phenolic compounds in ethyl acetate fraction which is responsible for its free radical scavenging as well as antioxidant activity.