Jagdish Singh

Effect of Penetration Enhancers on the in Vitro Transport of Ephedrine Through Rat Skin and Human Epidermis from Matrix Based Transdermal Formulations

AbstractThe potential of skin as a site for administration of systemically active Ephedrine HCl (EH) has been recognised. The effect of penetration enhancers, i.e., Dimethyl sulfoxide (DMSO), Dimethyl acetamide (DMA), Dimethyl formamide (DMF) and Azone on the in-vitro transport of EH from matrix based transdermal formulations through full thickness rat skin and human epidermis was investigated. The highest flux with minimum time lag through rat skin and human epidermis was observed from the batch containing Azone as penetration enhancer.

PREPARATION, CHARACTERIZATION AND IN-VITRO RELEASE KINETICS OF SALBUTAMOL SULPHATE LOADED ALBUMIN MICROSPHERES

AbstractSalbutamol sulphate loaded Bovine serum albumin microspheres were prepared by heat denaturation method. The effects of such preparation conditions as denaturation temperature, denaturation time, protein concentration and phase volume ratio on the extent of drug loading, size and size distribution and drug release were studied. An increase in protein concentration from 5% w/v to 15% w/v increased the mean particle size from 8.5 μm to 16.6 μm and decreased the drug loading from 46% w/w to 18% w/w. A decrease in the phase volume ratio substantially lowered mean particle size and size distribution. An increase in the severity of denaturaion conditions lowered both the drug incorporated and drug released. The kinetics of drug release from microspheres were compared to the theoretical models of Higuchi diffusional release and first order release. Both the models gave an adequate fit to the data. Scanning electron microscopy revealed that the dummy microspheres are spherical with smooth surfaces. As the ...

Effect of Sodium Lauryl Sulphate and TweenR80 on the Therapeutic Efficacy of Glibenclamide Tablet Formulations in Terms of BSL Lowering in Rabbits and Diabetic Human Volunteers

AbstractGlibenclamide has limited gastrointestinal absorption. Therefore, different concentrations of sodium lauryl sulphate and tweenR80 were included into the tablet formulations to increase the absorption of the drug and hence, to enhance the BSL lowering in rabbits and human volunteers suffering from maturity onset diabetes mellitus. It was found that the surfactants had enhanced both the rate and extent of BSL lowering in rabbits as well as in diabetic patients in higher concentrations present in the tablet formulations.

Sinigrin (2-Propenyl Glucosinolate) Content and Myrosinase Activity in BrassicaVegetables

Abstract Cruciferous vegetables can contribute to a healthy human diet. This may be due to the presence of the phytochemical glucosinolate. The sinigrin (2-propenyl glucosinolate) content and the myrosinase activity were estimated in edible portions of five broccoli (B. oleraceaL. var. italicaPlenck), three white cabbage (B. oleraceavar. capitataL. f. alba1 DC), two each of Chinese cabbage [B. rapaL. subsp. pekinensis(Lour.) Olsson], and cauliflower (B. oleraceaL. var. botrytisL.), and one each of Brussels sprouts (B. oleraceaL. var. gemmiferaDC.), kohlrabi (B. oleraceaL. var. gongylodesL.), red cabbage [B. oleraceavar. capitataL. f. rubra(L.) Jhell], and Savoy cabbage (B. oleraceavar. sabaudaL.). Significant differences for sinigrin (2-propenyl glucosino-late) content and myrosinase activity were recorded between Brassicasubspecies. Broccoli (3.23 mg/100 g) and Brussels sprouts (2.10 mg/ 100 g) had higher sinigrin content as compared with other Brassica vegetables. The highest myrosinase specific activity was recorded in Brussels sprouts (0.343 units/mg protein), and broccoli (0.324 units/mg protein), and the lowest myrosinase activity was for Savoy cabbage (0.036 units/mg protein) and Chinese cabbage (0.041 units/mg protein). Levels of sinigrin and myrosinase activity are dependent on the subspecies. Significant intraspecific variability for sinigrin and myrosinase activity in some of the Brassicavegetables can be utilized for selecting genotypes for the genetic improvement of such vegetables for phytochemical content through conventional breeding.

Formulation, in-vitro release and therapeutic effect of hydrogels based controlled release tablets of propranolol hydrochloride

AbstractMatrix based controlled release tablets of Propranolol Hydrochloride (PHCL) were formulated using hydroxy propyl methyl cellulose (HPMC), sodium carboxy methyl cellulose (sod. CMC) and their combinations. The in-vitro dissolution kinetics revealed a zero order release for selected drug, HPMC and sod. CMC combination. The selected formulation was evaluated in mongrel dog by recording the isoprenaline induced tachycardia and measuring the inhibition of tachycardia. The results showed the sustaining therapeutic effect of the formulation.

Effect of sodium carboxymethylcelluloses on the disintegration, dissolution and bioavailability of lorazepam from tablets

AbstractA new range of soudium carboxymethylcelluloses (i.e. nymcelR types ZSB-10, ZSB-16 and ZSD-16) were included into lorazepam tablet formulations to improve the disintegration, dissolution and bioavailabiltiy of the drug. Tablets of the batch G containing 5% Nymcel ZSB-16 exhbibited quicker disintegration, faster dissolution, and higher rate and extent of bioavailability in mongrel dog in comparison to tablets of the other batches.

Dietary antioxidants and minerals in crucifers

Broccoli, Brussels sprouts, cabbage, cauliflower and kale are rich sources of antioxidant phytochemicals and significant amounts of dietary fiber. This study was conducted to estimate the variability of some important antioxidants and minerals between, and within, the crucifer accessions in edible portions of plants. Significant variations for protein, carbohydrate, fiber, β-carotene, ascorbic acid and mineral content were observed between, and within, the crucifers. Total carbohydrate content ranged between 2.54 to 4.03 g/100 g, whereas, protein content ranged from 0.41 to 3.57 g/100 g of fresh weight. Mean fiber content ranged from 0.60 to 3.62 g/100 g. Vitamin C content ranged from 22.16 to 82.14 mg/100 g and β-carotene ranged from 1.56 to 9.09 mg/100 g on fresh weight basis. In general kale, broccoli and Brussels sprouts contained significantly higher amounts of vitamin C and β-carotene as compared to cabbage and cauliflower. The total nitrogen ranged from 1.36 to 4.6% and phosphorous from 0.39 to 0.81% dry weight. Sodium and potassium contents ranged from 0.17 to 0.34% and 2.18 to 3.77% respectively. The copper content was 0.01 to 0.02 mg-g−1, iron, 0.14 to 0.31 mg-g−1, manganese, 0.01 to 0.07 mg-g−1 and zinc, 0.01 to 0.12 mg-g−1. The variability of each compound within accessions can be used to estimate the potential maximum concentration of each phytochemical that can be achieved through genetic manipulation

Role of histidine residues and mechanism of action of isocitrate lyase of castor seedling endosperm

Abstract Irradiation of isocitrate lyase of castor seedling endosperm with visible light in the presence of a small concentration of Rose Bengal at pH 6.8 brings about a time-dependent exponential decay of enzyme activity. The first-order rate constant of the inactivation reaction increases with pH in the range pH 6–8 and becomes constant at higher pH values. When the enzyme is treated with diethyl pyrocarbonate (DEPC), a time-dependent exponential decay of its activity is observed and the pseudo first-order rate constant is proportional to the reagent concentration. The loss of activity is accompanied by a parallel increase in absorbance at 240 nm. The latter corresponds to modification of two histidine residues per monomeric subunit of the enzyme for complete inactivation. An analysis of the kinetic data shows that only one of these histidine residues is involved in the catalytic activity. Control experiments ruled out the involvement of residues other than histidine in inactivation by photooxidation and DEPC. Succinate protects the enzyme strongly against inactivation by both procedures but glyoxylate does not. A probable mechanism of action of isocitrate lyase is proposed and discussed in the light of these and earlier results.

Communication: Physiologic Surfactants Affecting Permeation and Bsl Lowering in Rabbit from Glibenclamlde Tablets

AbstractThe physiologic surfactants (e.g. sodium taurocholate and sodium tauroglycocholate) were included in the tablet formulations to increase the solubility, permeability and absorption of glibenclamide. Sodium tauroglycocholate was found to increase the permeation, AUC, Cmaxl and % Frel with its increasing concentrations in tablets. Sodium taurocholate, at submicellar level, had increased the permeation, AUC, Cmaxl and % Frel and decreased the above parameters beyond critical micelle concentration.

Significance of sulphhydryl groups in the activity of isocitrate lyase of castor endosperm

Abstract Titration of isocitrate lyase of germinating castor endosperm, a tetrameric protein (mol. wt. 140 000; subunit mol. wt. 35 000), with 5,5′-dithio-bis-(2-nitrobenzoate) (DTNB) reveals the presence of 4.15 ‘accessible’ sulphhydryl (SH) groups. Denatured enzyme is found to titrate for 7.9 SH groups per molecule. Half of the ‘accessible’ groups react more readily with DTNB than the remaining half. The enzyme is inactivated at low concentrations of p- chloromercury benzoate (p-CMB) or N- ethylmaleimide (NEM). Under the conditions [p-CMB] ⪢ [enzyme], the inactivation reaction is found to be biphasic in which half of the activity is lost more rapidly than the remaining half. With NEM (reagent in excess over enzyme), the activity is destroyed in a single exponential decay (pseudo-first order kinetics). The loss of activity is found to be linearly related to the blocking of accessible SH groups. Glyoxylate protects the enzyme strongly against attack by NEM. Protection by succinate is very much weaker. Significance of these results is discussed.