Uttam Kumar Mandal

Simultaneous determination of metoprolol succinate and amlodipine besylate in human plasma by liquid chromatography-tandem mass spectrometry method and its application in bioequivalence study

A simple, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of metoprolol succinate (MPS) and amlodipine besylate (AM) using hydrochlorothiazide (HCTZ) as IS in human plasma. Both the drugs were extracted by simple liquid-liquid extraction with chloroform. The chromatographic separation was performed on a reversed-phase peerless basic C18 column with a mobile phase of methanol-water containing 0.5% formic acid (8:2, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The method was validated over the concentration range of 1-100 ng/ml for MPS and 1-15 ng/ml AM in human plasma. The MRM transition of m/z 268.10-103.10, m/z 409.10-334.20 and m/z 296.00-205.10 were used to measure MPS, AM and HCTZ (IS), respectively. This method was successfully applied to the pharmacokinetic study of fixed dose combination (FDC) of MPS and AM formulation product after an oral administration to Indian healthy human volunteers.

Experimental design and optimization of raloxifene hydrochloride loaded nanotransfersomes for transdermal application

Raloxifene hydrochloride, a highly effective drug for the treatment of invasive breast cancer and osteoporosis in post-menopausal women, shows poor oral bioavailability of 2%. The aim of this study was to develop, statistically optimize, and characterize raloxifene hydrochloride-loaded transfersomes for transdermal delivery, in order to overcome the poor bioavailability issue with the drug. A response surface methodology experimental design was applied for the optimization of transfersomes, using Box-Behnken experimental design. Phospholipon® 90G, sodium deoxycholate, and sonication time, each at three levels, were selected as independent variables, while entrapment efficiency, vesicle size, and transdermal flux were identified as dependent variables. The formulation was characterized by surface morphology and shape, particle size, and zeta potential. Ex vivo transdermal flux was determined using a Hanson diffusion cell assembly, with rat skin as a barrier medium. Transfersomes from the optimized formulation were found to have spherical, unilamellar structures, with a homogeneous distribution and low polydispersity index (0.08). They had a particle size of 134±9 nM, with an entrapment efficiency of 91.00%±4.90%, and transdermal flux of 6.5±1.1 μg/cm2/hour. Raloxifene hydrochloride-loaded transfersomes proved significantly superior in terms of amount of drug permeated and deposited in the skin, with enhancement ratios of 6.25±1.50 and 9.25±2.40, respectively, when compared with drug-loaded conventional liposomes, and an ethanolic phosphate buffer saline. Differential scanning calorimetry study revealed a greater change in skin structure, compared with a control sample, during the ex vivo drug diffusion study. Further, confocal laser scanning microscopy proved an enhanced permeation of coumarin-6-loaded transfersomes, to a depth of approximately160 μM, as compared with rigid liposomes. These ex vivo findings proved that a raloxifene hydrochloride-loaded transfersome formulation could be a superior alternative to oral delivery of the drug.

Formulation and In Vitro Studies of a Fixed-Dose Combination of a Bilayer Matrix Tablet Containing Metformin HCl as Sustained Release and Glipizide as Immediate Release

The emerging new fixed dose combination of metformin hydrocholride (HCl) as sustained release and glipizide as immediate release were formulated as a bilayer matrix tablet using hydroxy propyl methyl cellulose (HPMC) as the matrix-forming polymer, and the tablets were evaluated via in vitro studies. Three different grades of HPMC (HPMC K 4M, HPMC K 15M, and HPMC K 100M) were used. All tablet formulations yielded quality matrix preparations with satisfactory tableting properties. In vitro release studies were carried out at a phosphate buffer of pH 6.8 with 0.75% sodium lauryl sulphate w/v using the apparatus I (basket) as described in the . The release kinetics of metformin were evaluated using the regression coefficient analysis. There was no significant difference in drug release for different viscosity grade of HPMC with the same concentration. Tablet thus formulated provided sustained release of metformin HCl over a period of 8 hours and glipizide as immediate release.

How far did India drift during the Late Cretaceous?—Placenticeras kaffrarium Etheridge, 1904 (Ammonoidea) used as a measuring tape

Abstract India, once a member of the lost supercontinent Gondwana, broke away from it and made a solitary northward excursion and finally collided with Asia. During its long voyage, India remained isolated for 100 Ma and is expected to be characterized by stunning endemic biodiversity. But this is not recognized by the terrestrial faunal and floral content, and their distribution patterns paint no simple scenario. For example, the Inter-trappean vertebrate faunas of India, which lived during “India-in-exile”, do not show any made-in-India assemblages, but rather betray a mixed biota having both Gondwanan and Laurasian affinities. These differential distribution patterns of fauna and flora, and their affinities with those of other areas, prompted many workers to envisage an array of suggestions regarding the time of Indias final separation from Gondwana, the time of northward drifting and different palaeopositions during its long journey. But closer examination of the nature of the vertebrate fossil records reveals that the so-called elusive endemicity of Indian fauna during its sojourn is in fact a product of taxonomic artefact. The majority of the faunas have been described on the basis of poor fossil data, and comparisons for biogeographic correlations are made at higher taxonomic levels, which perhaps masked Indias faunal distinctiveness. Yet, the biological processes that constrain biogeographical distribution operate at the species level. In this paper, we present our own data to reconstruct the palaeoposition of India in the Late Cretaceous, and to estimate the time of its northward migration. The present study is based on a newly recorded ammonite species, Placenticeras kaffrarium Etheridge from the Coniacian horizons in Bagh, central India. The species abounds in Bagh and represents a complete population structure. It resembles significantly the populations described from the coeval horizons of Madagascar and Zululand, South Africa. P. kaffrarium has a stunning display of intraspecific variability represented by at least seven distinct morphotypes reported from Zululand and Madagascar. The Indian population, significantly matches the latter two populations, variant by variant and remarkably, also for the sexual dimorphs within each variant. Geographic range is a biological property of a species and ammonite species have differential distribution patterns depending on the length of larval longevity, oceanic circulation patterns and favourable environments. Placenticeras was a nektobenthic genus living in the shallowest depths of epicontinental seas, and could not cross a narrow strait wider than a few hundred kilometers. Palaeogeographic distribution patterns of all placenticeratid species during the Late Cretaceous support this view and show the wandering nature of the genus over time. However, they always exhibit a latitudinally limited distribution and are restricted mainly to the subtropics north and south of the equator. Thus, it appears that the P. kaffrarium population of Zululand, Madagascar and Bagh constitute a homogenous, single breeding population, implying geographical proximity of these areas, connected by exclusively shallow seas till the Coniacian. Other fossil records of ammonites and geophysical data also support this view. Shortly after this, India started its northward drift. By the Late Maastrichtian, India was completely isolated by a wide oceanic gap from the rest of the Gondwana fragments and the northern part of India crossed the equator. This is evident from strong endemicity of ammonite species assemblages of the northwest and southern Indian subcontinent, which constitute the most diverse communities known.

Controversies with self-emulsifying drug delivery system from pharmacokinetic point of view

Abstract Self-emulsifying drug delivery system (SEDDS) is an isotropic mixture of lipid, surfactant and co-surfactant, which forms a fine emulsion when comes in contact of an aqueous medium with mild agitation. SEDDS is considered as a potential platform for oral delivery of hydrophobic drug in order to overcome their poor and irregular bioavailability challenges. In spite of fewer advantages like improved solubility of drug, bypassing lymphatic transport etc., SEDDS faces different controversial issues such as the use of appropriate terminology (self-microemulsifying drug delivery system; SMEDDS or self-nanoemulsifying drug delivery system; SNEDDS), presence of high amount of surfactant, correlation of in vitro model to in vivo studies, lack of human volunteer study and effect of conversion of SEDDS to final administrable dosage form on pharmacokinetic behavior of the drug. In this review, potential issues or questions on SEDDS are identified and summarized from the pharmacokinetic point of view. Primarily this review includes the conflict between the influences of droplet size, variation in correlation between in vitro lipolysis or ex-vivo intestinal permeation and pharmacokinetic parameters, variation in in vivo results of solid and liquid SEDDS, and potential challenges or limitation of pharmacokinetic studies on human volunteers with orally administered SEDDS. In the past decades, hundreds of in vivo studies on SEDDS have been published. In the present study, only the relevant article on in vivo pharmacokinetic studies with orally administered SEDDS published in past 5–6 years are analyzed for an up to date compilation.

Pharmacokinetic and Pharmacodynamic Features of Nanoemulsion Following Oral, Intravenous, Topical and Nasal Route

BACKGROUND Most of the active pharmaceutical ingredients discovered recently in pharmaceutical field exhibits poor aqueous solubility that pose major problem in their oral administration. The oral administration of these drugs gets further complicated due to their short bioavailability, inconsistent absorption and inter/intra subject variability. METHODS Pharmaceutical emulsion holds a significant place as a primary choice of oral drug delivery system for lipophilic drugs used in pediatric and geriatric patients. Pharmacokinetic studies on nanoemulsion mediated drugs delivery approach indicates practical feasibility in regards to their clinical translation and commercialization. RESULTS This review article is to provide an updated understanding on pharmacokinetic and pharmacodynamic features of nanoemulsion delivered via oral, intravenous, topical and nasal route. CONCLUSION The article is of huge interest to formulation scientists working on range of lipophilic drug molecules intended to be administered through oral, intravenous, topical and nasal routes for vivid medical benefits.

Evaluation of bioequivalence of two formulations containing 100 milligrams of aceclofenac

ABSTRACT The bioequivalence of two oral formulations containing aceclofenac 100 mg was determined in 24 healthy Indian male volunteers. The study was designed as a single dose, fasting, two-period two-sequence crossover study with a washout period of 1 week. The content of aceclofenac in plasma was determined by a validated HPLC method with UV detection. The preparations were compared using the parameters area under the plasma concentration–time curve (AUC0–t), area under the plasma concentration–time curve from zero to infinity (AUC0–∞), peak plasma concentration (Cmax), and time to reach peak plasma concentration (tmax). No statistically significant difference was observed between the logarithmic transformed AUC0–∞ and Cmax values of the two preparations. The 90% confidence interval for the ratio of the logarithmic transformed AUC0–t, AUC0–∞, and Cmax were within the bioequivalence limit of 0.80–1.25.

PVA-PEG physically cross-linked hydrogel film as a wound dressing: Experimental design and optimization

Abstract The development of hydrogel films as wound healing dressings is of a great interest owing to their biological tissue-like nature. Polyvinyl alcohol/polyethylene glycol (PVA/PEG) hydrogels loaded with asiaticoside, a standardized rich fraction of Centella asiatica, were successfully developed using the freeze–thaw method. Response surface methodology with Box–Behnken experimental design was employed to optimize the hydrogels. The hydrogels were characterized and optimized by gel fraction, swelling behavior, water vapor transmission rate and mechanical strength. The formulation with 8% PVA, 5% PEG 400 and five consecutive freeze–thaw cycles was selected as the optimized formulation and was further characterized by its drug release, rheological study, morphology, cytotoxicity and microbial studies. The optimized formulation showed more than 90% drug release at 12 hours. The rheological properties exhibited that the formulation has viscoelastic behavior and remains stable upon storage. Cell culture studies confirmed the biocompatible nature of the optimized hydrogel formulation. In the microbial limit tests, the optimized hydrogel showed no microbial growth. The developed optimized PVA/PEG hydrogel using freeze–thaw method was swellable, elastic, safe, and it can be considered as a promising new wound dressing formulation.

Development and validation of a high throughput LC–MS/MS method for simultaneous quantitation of pioglitazone and telmisartan in rat plasma and its application to a pharmacokinetic study

Management of cardiovascular risk factors in diabetes demands special attention due to their co-existence. Pioglitazone (PIO) and telmisartan (TLM) combination can be beneficial in effective control of cardiovascular complication in diabetes. In this research, we developed and validated a high throughput LC–MS/MS method for simultaneous quantitation of PIO and TLM in rat plasma. This developed method is more sensitive and can quantitate the analytes in relatively shorter period of time compared to the previously reported methods for their individual quantification. Moreover, till date, there is no bioanalytical method available to simultaneously quantitate PIO and TLM in a single run. The method was validated according to the USFDA guidelines for bioanalytical method validation. A linear response of the analytes was observed over the range of 0.005–10 µg/mL with satisfactory precision and accuracy. Accuracy at four quality control levels was within 94.27%–106.10%. The intra- and inter-day precision ranged from 2.32%–10.14 and 5.02%–8.12%, respectively. The method was reproducible and sensitive enough to quantitate PIO and TLM in rat plasma samples of a preclinical pharmacokinetic study. Due to the potential of PIO-TLM combination to be therapeutically explored, this method is expected to have significant usefulness in future.

Development of RP-HPLC for analysis of human insulin

The objective of the present work is to develop a simple and sensitive method for analysis of human insulin injection by using reverse-phase high performance liquid chromatography technique. A reverse-phase high performance liquid chromatography method with UV-detection at room temperature has been developed for the analysis of insulin from formulation. Hypersil BDS C-18 was used as stationary phase, and mobile phase consisted of 60 volume of 1 mmol sodium sulphate and 0.2% triethylamine in water, pH 3.2 adjusted by phosphoric acid, and 40 volume of acetonitrile. The eluent was monitored with a UV detector set at 214 nm with a flow rate of 1 ml/min, and sample size of 20 µl were carried out at room temperature all over the study. The method produced linear response over the concentration range of 10-100 µg/ml, with a mean recovery of 97 ± 0.31% as well as average intra- and inter-day variations of 1.35 and 5.13% respectively. The limits of detection and quantitation of the method were 0.25 and 0.75 µg/ml respectively. Considering the analysis specifications, the system is suitable for direct analysis of routine formulations and stability studies.