N Udupa

Antitumor and Radiosensitizing Effects of Withaferin a on Mouse Ehrlich Ascites Carcinoma in vivo

The antitumor and radiosensitizing effects of withaferin A (WA), a steroidal lactone from Withania somnifera, was studied on Ehrlich ascites carcinoma in vivo. The acute LD50(14) for WA in Swiss mice was approximately 80 mg/kg. Twenty-four hours after i.p. inoculation of 10(6) tumor cells, WA was injected i.p. at different dose fractions (5 or 7.5 mg/kg x 8, 10 mg/kg x 5, 20 or 30 mg/kg x 2) with or without abdominal gamma irradiation (RT, 75. Gy) after the first drug dose. Increase in life span and tumor-free survival were studied up to 120 days. The drug inhibited tumor growth and increased survival, which was dependent on the WA dose per fraction rather than the total dose. Combination of RT with all the drug schedules increased tumor cure and tumor-free survival, the best effect seen after 2 fractions of 30 mg/kg each. In another experiment WA was given as 2 (40 mg/kg x 2), 3 (30 mg/kg x 3) or 4 (20 mg/kg x 4) fractions at 5, 7 or 10 days after tumor inoculation with or without RT after the first drug dose. At 7 and 10 days after inoculation the drug was effective only at 40 mg/kg x 2, but with RT 30 mg/kg x 3 produced an equal effect (20% survival) on 7 day old tumors.

Juglone, a naphthoquinone from walnut, exerts cytotoxic and genotoxic effects against cultured melanoma tumor cells.

This study demonstrates cytotoxic and genotoxic potential of juglone, a chief constituent of walnut, and its underlying mechanisms against melanoma cells. MTT assay and clonogenic assay were used to study cytotoxicity, micronucleus assay to assess genotoxicity, glutathione (GSH) assay and 2′,7′‐dicholorofluorescein diacetate (DCFH‐DA) assay to evaluate the oxidative stress induction. Apoptosis/necrosis induction was analysed by flow cytometry. We observed a concentration‐dependent decrease in cell survival with a corresponding increase in the lactate dehydrogenase levels. A dose‐dependent increase in the frequency of micronucleated binucleate cells indicated the potential of juglone to induce cytogenetic damage in melanoma tumor cells. Moreover, results of the micronuclei study indicated division delay in the proliferating cell population by showing decrease in the cytokinesis blocked proliferation index. Further, juglone‐induced apoptosis and necrosis could be demonstrated by oligonucleosomal ladder formation, microscopic analysis, increase in the hypodiploid fraction (sub Go peak in DNA histogram), as well as an increased percentage of AnnexinV(+)/PI(+) cells detected by flow cytometry. A significant concentration‐dependent decrease in the glutathione levels and increase in dichlorofluorescein (DCF) fluorescence after juglone treatment confirmed the ability of juglone to generate intracellular reactive oxygen species. The cytotoxic effect of juglone can be attributed to mechanisms including the induction of oxidative stress, cell membrane damage, and a clastogenic action leading to cell death by both apoptosis and necrosis.

In situ forming polymeric drug delivery systems.

In situ forming polymeric formulations are drug delivery systems that are in sol form before administration in the body, but once administered, undergo gelation in situ, to form a gel. The formation of gels depends on factors like temperature modulation, pH change, presence of ions and ultra violet irradiation, from which the drug gets released in a sustained and controlled manner. Various polymers that are used for the formulation of in situ gels include gellan gum, alginic acid, xyloglucan, pectin, chitosan, poly(DL-lactic acid), poly(DL-lactide-co-glycolide) and poly-caprolactone. The choice of solvents like water, dimethylsulphoxide, N-methyl pyrrolidone, triacetin and 2-pyrrolidone for these formulations depends on the solubility of polymer used. Mainly in situ gels are administered by oral, ocular, rectal, vaginal, injectable and intraperitoneal routes. The in situ gel forming polymeric formulations offer several advantages like sustained and prolonged action in comparison to conventional drug delivery systems. The article presents a detailed review of these types of polymeric systems, their evaluation, advancements and their commercial formulations. From a manufacturing point of view, the production of such devices is less complex and thus lowers the investment and manufacturing cost.

A study of rivastigmine liposomes for delivery into the brain through intranasal route

A study of rivastigmine liposomes for delivery into the brain through intranasal route The present study is mainly aimed at delivering a drug into the brain via the intranasal route using a liposomal formulation. For this purpose, rivastigmine, which is used in the management of Alzheimers disease, was selected as a model drug. Conventional liposomes were formulated by the lipid layer hydration method using cholesterol and soya lecithin as lipid components. The concentration of rivastigmine in brain and plasma after intranasal liposomes, free drug and per oral administration was studied in rat models. A significantly higher level of drug was found in the brain with intranasal liposomes of rivastigmine compared to the intranasal free drug and the oral route. Intranasal liposomes had a longer half-life in the brain than intranasally or orally administered free drug. Delivering rivastigmine liposomes through the intranasal route for the treatment of Alzheimers disease might be a new approach to the management of this condition. Liposomi rivastigmina za isporuku u mozak intranazalnim putem Glavni cilj rada je razvoj liposoma za intranazalnu primjenu za isporuku lijeka u mozak. U tu svrhu izabran je rivastigmin kao modelni lijek koji se upotrebljava u terapiji Alzheimerove bolesti. Liposomi su pripravljeni metodom hidratacije lipidnog sloja koristeći kolesterol i lecitin iz soje kao lipidne komponente. Praćena je koncentracija rivastigmina u mozgu i plazmi nakon intranazalne i peroralne primjene liposoma i slobodnog lijeka. S intranazalnim liposomima rivastigmina postignuta je značajno veća koncentracija lijeka u mozgu. Osim toga intranazalni liposomi imaju dulje vrijeme poluživota u mozgu. Intranazalna primjena liposoma rivastigmina mogla bi predstavljati novi pristup terapiji Alzheimerove bolesti.

Niosomal plumbagin with reduced toxicity and improved anticancer activity in BALB/C mice

Plumbagin niosomes were prepared using a lipid layer hydration method, and drug entrapment was measured. The acute toxicity studies were conducted following treatment with free and niosomal plumbagin.

Glutaraldehyde cross-linked chitosan microspheres for controlled delivery of Zidovudine

Zidovudine-Chitosan microspheres were prepared by a suspension cross-linking method. The chitosan was dissolved in 2% acetic acid solution and this solution was dispersed in the light liquid paraffin. Span-80 was used as an emulsifier and glutaraldehyde as cross-linking agent. The prepared microspheres were slight yellow, free flowing and characterized by drug loading, infrared spectroscopy (IR), differential scanning colorimetry (DSC) and scanning electron microscopy (SEM). The in-vitro release studies are performed in pH 7.4 buffer solution. Microspheres produced are spherical and have smooth surfaces, with sizes ranging between 60–210 µm, as evidenced by SEM and particle size analysis. The drug loaded microspheres showed up to 60% of entrapment and release was extended up to 18–24 h. Among all the systems studied, the 35% Glutaraldehyde crosslinked, microspheres with 1 : 6 drug/chitosan ratio showed 75% release at 12 h. The infrared spectra and DSC thermograms showed stable character of zidovudine in the drug loaded microspheres and revealed the absence of drug–polymer interactions. Data obtained from in vitro release were fitted to various kinetic models and high correlation was obtained in the Higuchi model. The drug release was found to be diffusion controlled.

Nasal insulin gel as an alternate to parenteral insulin: Formulation, preclinical, and clinical studies

The objective of the present study was to formulate insulin gel for intranasal administration and to evaluate with respect to in vitro release studies and hypoglycemic activity in animal model and healthy human volunteers. The insulin gel was formulated using the combination of carbopol and hydroxypropyl methylcellulose as gelling agent. The in vivo efficacy of insulin gel administered intranasally was assessed by measuring the blood glucose levels and serum insulin levels at specified time intervals in rats and humans. The use of bioadhesive nasal gel containing insulin not only promoted the prolonged contact between the drug and the absorptive sites in the nasal cavity but also facilitated direct absorption of medicament through the nasal mucosa. Absorption of the drug through the nasal mucosa was high in the first 0.5 to 1.5 hours of the study with a sharp decline in blood sugar and rise in insulin values corresponding to that decline in blood sugar. This study further demonstrates that administration of insulin intranasally in gel form is a pleasant and painless alternative to injectable insulin.

A combined approach of chemical enhancers and sonophoresis for the transdermal delivery of tizanidine hydrochloride

The effects of chemical enhancers and sonophoresis on the transdermal permeation of tizanidine hydrochloride (TIZ) across mouse skin were investigated. Parameters including drug solubility, apparent partition coefficient (APC), drug permeation, and degradation in skin were determined. Low frequency ultrasound was also applied in the presence and absence of chemical enhancers to assess whether drug permeation improved. APC values indicated that TIZ preferentially partitions into intercellular spaces and does not form a reservoir, with the drug also exhibiting good enzymatic stability in skin. Most of the enhancers studied significantly increased the permeation rate of TIZ through full thickness mouse skin in comparison with TIZ formulated in phosphate buffer. Maximum enhancement was observed for TIZ formulated as a suspension in 50% v/v aqueous ethanol containing 5% v/v citral. Sonophoresis significantly (p < 0.05) increased the cumulative amount of TIZ permeating through the skin at 15 and 30 min in comparison to passive diffusion. A synergistic effect was noted when sonophoresis was applied in the presence of chemical enhancers. The results suggest that the formulation of TIZ with an appropriate penetration enhancer may be useful in the development of a therapeutic system to deliver TIZ across the skin for a prolonged period, i.e. 24 hr. The application of ultrasound in association with chemical enhancers, such as the combination of 5% v/v citral in 50% v/v aqueous ethanol, could further serve as a non-oral and non-invasive drug delivery modality for the immediate therapeutic effect of muscle relaxants such as TIZ.

Preparation and, in vitro, preclinical and clinical studies of aceclofenac spherical agglomerates

Aceclofenac agglomerates were prepared by spherical crystallization technique using a three solvent system comprising acetone: dichloromethane (DCM): water (bridging liquid, good solvent and bad solvent, respectively). Hydroxypropyl methylcellulose-50cps (HPMC) in different concentrations was used as hydrophilic polymer. The effect of speed of rotation and amount of bridging liquid on spherical agglomeration were studied. The agglomerates were subjected to various physicochemical evaluations such as practical yield, drug content, particle size, loss on drying, porosity, IR spectroscopy, differential scanning calorimetry, X-ray diffraction studies, relative crystallinity, scanning electron microscopy, micromeritic properties, solubility and dissolution studies. The agglomerates showed improved micromeritic properties as well as dissolution behaviour in comparison to conventional drug crystals. The optimized agglomerates (F-9) showed good sphericity as well as high drug release, and hence they were compressed into tablets by direct compression. The tablets were found within the limits with respect to various physicochemical parameters. The dissolution rate of prepared tablets was better than that of marketed tablet and pure drug. The optimized agglomerates and tablet formulations were found to be stable for 6 months under accelerated conditions. The in vivo studies (preclinical pharmacokinetics, pharmacodynamics and toxicity studies, and clinical pharmacokinetics) of optimized agglomerates were carried out. The results of preclinical studies revealed that the agglomerates provided improved pharmacodynamic and pharmacokinetic profiles of drug besides being nontoxic. The results of pharmacokinetic studies of optimized tablet in human subjects indicated improved pharmacokinetic parameters of drug in comparison with that of marketed tablet.

Enhanced oral absorption of saquinavir with Methyl-Beta-Cyclodextrin-Preparation and in vitro and in vivo evaluation.

Saquinavir (SQV) is a weak base compound, whose solubility is strongly influenced by pH variations. Thus, in the present work, we thought it worthy of interest to investigate in-depth the combined effect of pH control and cyclodextrin (CyD) complexation on SQV solubilization. Phase-solubility studies were performed by adding excess drug to buffered (pH from 1.1 to 7.4) aqueous solutions containing increasing concentrations of Methyl-Beta-CyD (M-β-CyD) in order to evaluate the role of the unionized species of SQV in improving solubility by CyD complexation and to be able to select the most suitable conditions for optimizing drug solubilization. Our study reveals that the integrated approach of pH adjustment and CyD complexation can be successfully used for improving the CyD solubilizing power towards an ionizable drug such as SQV, thus allowing a smaller quantity of CyD to solubilize a given amount of drug, offering clear economic and technologic advantages as well. When biopharmaceutics of the optimized cyclodextrin-based formulation of SQV was studied in Wistar rats after intravenous and oral administrations, we found that inclusion of SQV into M-β-CyD could dramatically improve its oral bioavailability and decrease the variation of its oral pharmacokinetics. Compared to the control, the presence of M-β-CyD significantly increased the area under the plasma concentration-time curve (439.7±161.35 to 2312.03±159.53, p<0.01) and the peak plasma concentration (117.24±35.77 to 1347.88±276.76, p<0.01) of orally administered SQV. The modulating effect of M-β-CyD on the bidirectional transport of SQV was also investigated using a modified Ussing chamber system. The results demonstrated that the enhancing effect of M-β-CyD on the oral bioavailability of SQV is due not only to its solubilizing effect on SQV but also, at least in part, to the inhibitory effect of M-β-CyD on the P-glycoprotein (P-gp) mediated efflux of SQV in the gastrointestinal tract. The present results suggest that M-β-CyD is particularly useful in designing oral preparations of SQV with an enhanced bioavailability and a reduced variability in absorption.