Showing papers in "Bollettino chimico farmaceutico in 2001"

Antioxidant activity of the microalga Chlorella vulgaris cultered on special conditions.

Abstract: The chemical composition of Chlorella vulgaris indicates that it has a high nutritional value to a wide range of essential nutrients, such as vitamins, minerals and proteins. Moreover, it contains other compounds such as n-3 and n-6 polynsaturated fatty acids, provitamins and phenolic compounds. In addition, this alga can be produced in large-scale systems. The objective of the present study was to evaluate the antioxidant capacity of a Chlorella cultured on three differents temperatures (15 degrees C, 20 degrees C and 30 degrees C) in 3 Klux. Chlorella cultured samples were submitted to sequential extration using as solvents: ether, methanol and water. The antioxidant activity in the extracts was measured by b-carotene/linoleic acid system, at 50 degrees C and absorbances reading at 470 nm. One control with BHT, 100 ppm was used in this determination. The total phenolic compounds was determined with Folin-Ciocalteu reagent using the spectrophotometric measured at 780 nm with catechin as standard. The phenolic acid analysis were carried out using gas chromatograph equipped with a capillary column and flame ionization detector. Non conjugated and total phenolic acids were identified on the basis of the relative retention time of their derivatives compared with the standard phenolic acids. The methanolic extract from Chlorella cultured at 30 degrees C showed higher antioxidant activity (85%) quite similar of BHT (86%). By the Rancimat test (lipidic medium) two fractions from methanolic extracts showed too higher antioxidant activity with induction times > 37.50 h at 60 degrees C and 11.5 h at 100 degrees C. The total phenolic compounds were 24.95 mg in 1 g of dry alga matter from methanolic extract and five phenolic acids were identified. The phenolic compounds salicylic, trans cinnamic, synaptic, chlorogenic, chimic and caffeic acids found in the methanolic Chlorella extract may be responsible for its higher antioxidant activity.

Synthesis and antimicrobial evaluation of chalcone and syndrome derivatives of 4(3H)-quinazolinone.

Abstract: The increasing clinical importance of drug-resistant bacterial pathogens has encouraged additional microbiological and antibacterial research. New chalcone and sydnone derivatives of 4(3H)-quinazolinone were synthesized and evaluated for their antibacterial and antifungal activity. The microorganisms used were Escherichia coli ATCC 25922 as Gram-negative bacteria, Staphylococcus aureus ATCC 19433 as Gram-Positive bacteria and Candida albicans as yeast like fungi. The most potent compound was the nitroso derivative 6b, which exhibits interesting antibacterial and antifungal activities.

Prediction of in vivo bioavailability of six brands of ciprofloxacin film coated tablets using the concept dissolution efficiency (DE).

Abstract: A comparative in vitro dissolution efficiencies (DE) of six commercial brands of ciprofloxacin tablets were evaluated in acetic acid and phosphate buffer (pH 7.4) and results obtained were used in ranking of their probable in vivo bioavailability. The dissolution efficiencies (DE) of the six brands varied widely in the two media. This was attributed to differences in solubility of the drug in the two media. The dissolution efficiencies of five out of the six brands (Citrovenot, Ciproxin, Cipoxin, Ciproflox, and Quflox), in 0.1 N acetic acid fell within 60-75% at 30 minutes, and therefore, could be considered bioequivalent. The dissolution efficiency of a brand, Cipro, fell below 40% in the same medium and at the same sampling time and it was considered to be most likely less bioavailable in vivo. There was absence of correlation between the hardness and disintegration time of the brands with their dissolution efficiencies.

A new type of tyrosinase inhibitors from natural products as potential treatments for hyperpigmentation.

Abstract: Selected flavonoids were evaluated for their effects on melanin biosynthesis by using mushroom-tyrosinase assay. Out of 27 tested flavonoids, only six showed a potential inhibitory activity on melanin biosynthesis. Flavonoids containing an alpha-keto group showed to be the active compounds in this assay. This may be explained in terms of similarity between the dihydroxyphenyl group in L-DOPA and the alpha-ketol group in flavonoids. The results of this study revealed a new type of tyrosinase inhibitor from natural origin. These compounds will be further examined for their application for treatment of hyperpigmentation problems e.g. melasma and ephelides.

Evaluation of the physico-chemical properties of a new polysaccharide gum from Prosopis africana.

Abstract: The gum obtained from the ripe seeds of Prosopis africana was processed to compendial standard for plant gums and characterised Toxicological studies of the polysaccharide on mice showed the material to be safe The material hydrates slowly in aqueous media to form a colloidal dispersion Swelling studies on the gum shows that the gum has a higher swelling capacity than methylcellulose Rheological studies showed that the material is more viscous than tragacanth gum at equivalent concentrations Acid hydrolysis and thin layer chromatography of the resulting hydrolysates showed that the gum contains glucose, fructose, galactose and xylose as the monosaccharide components Microbial tests showed the gum to contain 826 x 10(4) viable cells per gram when freshly prepared Other properties of the gum evaluated includes; melting or charring temperature, optical properties, true density, ash values, element content as well as its reactions with lead subacetate solution and 002 M iodine

Synthesis and calcium channel antagonist activity of nifedipine analogues containing 4(5)-chloro-2-methyl-5(4)-imidazolyl substituent.

Abstract: Dihydropyridine having substituted imidazole at 4-position in conjunction with various C3, C5 diesters have calcium channel antagonist activity. In this paper a group of dialkyl, dicycloalkyl and diaryl ester analogues of nifedipine, in which the ortho-nitro phenyl group at position 4 replaced by 2-methyl-4(5)-chloro-5(4)-imidazolyl substituent, were synthesized and evaluated as calcium channel antagonists using the high K+ contraction of guinea-pig ileal longitudinal smooth muscle (GPILSM). The results for the symmetrical ester series showed that increasing the length chain in C3 and C5 ester substituents increased activity. When increasing of the length or lipophilicity accompany with increasing the hindrance, the activity decreased. In asymmetrical diester series, the results showed when R1 is methyl or ethyl, increasing of the lipophilic property in R substituent increases the activity if this high lipophilicity don't accompany with steric hindrance. Our results demonstrate that in symmetrical and asymmetrical series aromatic compounds were more active than aliphatic compounds. In symmetrical diesters compounds, the most active compound was diphenylethyl ester derivative, that it was more active than the reference drug nifedipine. These structure activity data indicate that the 2-methyl-4(5)chloro-5(4)-imidazolyl moiety is bioisoester of 2-nitrophenyl and 2-chlorophenyl moieties.

Cis- and trans-platinum and palladium complexes: a comparative study review as antitumour agents.

Abstract: A large body of novel platinum and palladium complexes, in both the cis- and trans-forms, with various donor ligands, e.g. beta-carboline alkaloids, pyrazoles, DMSO, ferrocenylphosphines,...... have been tested for their antitumour activity against number of fluid suspension (P388, L1210, K562, and Raji) and solid tumour (KB, T47D, SW948, HeLa, A549, L929, Hep-2, RD,...) cell lines. Remarkable cytotoxic effects against these cell lines were observed by some of these complexes. The preliminary results indicated that most of the trans-palladium complexes showed a better activity than the cis-platinum isomers and superior activity than that of the cis-palladium isomers. More importantly they showed activities equal to (or superior than) those of cisplatin, carboplatin and oxaliplatin (the anti-cancer drugs) in vitro. Although these results are preliminary, however, encouraging since they are in a disagreement with the previous studies that cis-isomers are more active than trans-ones; the complexes which have not received the required attention from the vast number of researchers in this field.

Simple synthesis of condensed pyran containing compounds and their antimicrobial properties.

Abstract: Reaction of various fused pyran compounds with formic acid was studied. Thus, refluxing 6-aminopyrano[2,3-c]pyrazole-5-carbonitriles 3 with formic acid afforded the corresponding 3-aryl-3-(5-hydroxy-3-methyl-1H-pyrazole-4-yl)propanoic acids 4. Whereas, reaction of formic acid with 2-amino-4H-1-benzopyran-3-carbonitriles 6 gave the corresponding quinoline-2,5(1H,6H)-diones 7. The study was also extended towards many spiro compounds possessing pyran residue. The antimicrobial properties of the prepared compounds was screened.

Synthesis of some new triazoles as potential antifungal agents.

Abstract: The rise in the incidence of fungal infections over the past two decades, particularly those caused by opportunistic pathogens in immune-compromised patients, has strengthened the need for new antifungal drugs. New triazole derivatives were synthesized and evaluated for their in-vitro antifungal activities against three species of fungi. Most of the prepared compounds showed good antifungal activity. Three compounds exhibited pronounced activity against Cryptococcus neoformans with MIC less than 12.5 g/ml.

Synthesis and anti-HIV activity of some isatin derivatives.

Abstract: Isatin/5-substituted Isatin was reacted with 2-aminothiazole, 2-aminopyridine, 4-methoxyaniline to form Schiff bases and the N-Mannich bases of the above Schiff bases were synthesized by reacting with formaldehyde and piperidine. The chemical structures of the synthesized compounds were confirmed by means of IR, 1H-NMR data and elemental analysis. Investigation of Anti-HIV activity was done against replication of HIV-1 (III B) and HIV-2 (ROD) in MT-4 cells. Azidothymidine (AZT) was used as the reference standard. The most active compound of the series was 3-(2-thiazolylimino)-5-bromo-1,3-dihydro-indol-2-one (VI) which demonstrated 28% and 10% protection against HIV-1 and HIV-2 respectively.

Synthesis and antimicrobial activity of some imidazo-[1,2-a]pyridine-2- carboxylic acid arylidenehydrazide derivatives.

Abstract: Imidazo[1,2-a]pyridine-2-carboxylic acid, ethyl esters were reacted with hydrazine hydrate to furnish imidazo[1,2-a]pyridine-2-carboxylic acid hydrazide. The hydrazides formed were treated with various aldehydes to obtain 28 imidazo[1,2-a]pyridine-2-carboxylic acid arylidenehydrazides. Antimicrobial activity of the compounds were examined.

Synthesis and antimicrobial activity of novel pyrazole, pyrazoline, pyrazolinone and pyrazolidinedione derivatives of benzimidazole.

Abstract: Four novel series of pyrazolylbenzimidazole derivatives have been prepared, namely 2-[(1-substituted phenyl-3,5-dimethyl-4-pyrazolyl)methyl]benzimidazole 5a-d 2-[(1-substituted phenyl-3-methyl-5-oxo-4,5-dihydro-4-pyrazolyl-4-yl)methyl]benzimidazoles 6a-d; 2-[(1-substituted phenyl-3,5-dioxopyrazolidin-4-yl)methyl]benzimidazoles 7a-d and 2-[(4-(1-phenyl-5-aryl-4,5-dihydro-3-pyrazolyl)phenylaminoacetyl]thio- methyl)-benzimidazoles 12a-e. The antimicrobial testing of the prepared compounds was performed using Escherichia Coli (NCTC 5933) as Gram-negative bacteria, Staphylococcus aureus (NCTC 4163) as gram-positive bacteria and Candida albicans (NCTC 5310) as yeast like fungi. The most potent compound was the pyrazolone 6a which exhibits interesting antibacterial activity against the gram-negative bacteria E. coli.

Determination of amitriptyline in plasma samples by high-performance liquid chromatography.

Abstract: A simple and selective high-performance liquid chromatographic method for the determination of amitriptyline in human plasma has been developed. For plasma samples, the protein was removed with 1 M NaOH and 0.7 M ZnSO4. aqueous solutions. The chromatographic separation was performed on an analytical mbondapak C18 column (250 3.9 mm, i.d) with an isocratic mobile phase consisting of phosphate buffer-acetonitrile-triethylamine (65:35:0.1 v/v/v) adjusted to pH 5.1. Clomipramine was used as an internal standard. Using ultraviolet detection at 239 nm, the detection limit for amitriptyline in plasma was 5 ng/ml. No interferences were found with tricyclic antidepressant drugs, which allows this method to be used in clinical studies. The calibration curve was linear over the concentration range 5-200 ng/ml. The recovery was complete for plasma. The inter-day and intra-day assay coefficients of variation were found to be less than 10%.

Effect of Azadirachta indica extract on plasma lipid levels in human malaria.

Abstract: Plasma lipid levels (cholesterol, HDL-cholesterol, LDL-cholesterol, and triacylglycerol) were estimated in patients with different antimalarial drugs. The lipid levels especially cholesterol and LDL-cholesterol were found to be lower (p > 0.01) during therapy when compared to the control group (non-malaria patients), while triacylglycerol and HDL-cholesterol levels were higher (p < 0.01) in the malaria patients than the control group.

Chemoselective heterocyclization and pharmacological activities of new heterocycles--a review. Part V-Synthesis of biocidal 4-thiazolidinones derivatives.

Abstract: 4-Thiazolidinones have been reported to possess biological activity especially fungicidal activity. With an intention to prepare some more 4-thiazolidinones as drugs for anti HIV and anticancer activity, we have synthesized some more 4-thiazolidinones by the action of mercaptoacetic acid on Schiff's base and/or heterocyclization of N-substituted thioureas with monochloracetic acid. Characterization of 4-thiazolidinone was deduced upon elemental and spectral analysis.

Cissus stem gum as potential dispersant in pharmaceutical liquid systems: rheological characterization.

Abstract: A Co-axial viscometer, the Haake-Rotovisco, was used studying the rheological behaviour of aqueous dispersion of cissus stem gum. At concentrations of 4% w/v and above, the mucilage is both pseudoplastic and thixotropic. Two equations derived from a power law expression for apparent viscosity(h): h = ekc + b were solved simultaneously (c = 4 and 8% w/v) in the determination of material constants k and b for cissus gum. The apparent viscosity of the polymeric liquid system was affected by concentration of the gum, pH, temperature and aging.

Studies on the synthesis and biological activity of 3-arylaminomethyl-5-(3-pyridyl)-1,3,4-oxadiazole-2-thione derivatives.

Abstract: 3-arylaminomethyl-5-(3-pyridyl)-1,3,4-oxadiazole-2-thiones were prepared by reaction of 5-(3-pyridyl)-1,3,4-oxadiazole-2-thione with formaldehyde and appropriate alky and aryl amines in ethanol, as potential biological active agents. These new synthesized Mannich bases were screened for their antimicrobial, antifungal and antiinflammatory activities.

Synthesis of some 4-(alkylidene/arylidene)amino-2,4-dihydro-5- (2-thienyl)-3H-1,2,4-triazole-3-thiones tested for antimicrobial activity.

Abstract: A series of 4-(alkylidene/arylidene)amino-2,4-dihydro-5- (2-thienyl)-3H-1,2,4-triazole-3-thiones (2a-h) were synthesized. The structural elucidation of all the compounds was made on the basis of analytical and spectral data (IR, 1H-NMR and EIMS). All synthesized compounds were evaluated for in vitro antimicrobial activity against various bacteria and fungi. Some of the compounds demonstrated antimicrobial activity against Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Trichophyton rubrum, Trichophyton mentagrophytes var. erinacei NCPF-375 and Microsporum canis (MIC 50-6.25 mg/ml). The in vitro antimycobacterial activity of the new compounds was also investigated. Some of the compounds showed varying degrees of inhibition (2-40%) against Mycobacterium tuberculosis H37Rv in the primary screen that was conducted at 12.5 mg/ml using the BACTEC 460 radiometric system.

Rheological and mechanical properties of pharmaceutical gels. Part I: Non-medicated systems.

Abstract: Non-medicated gel systems based on polymers of different chemical nature and source have been characterized for rheological as well as for gel strength properties: a synthetic product, polyacrylic acid and a natural product, scleroglucan, both known to produce true gels, and two semi-synthetic materials, sodium carboxymethylcellulose and hydroxypropylmethylcellulose, both known to originate polymeric colloidal solutions, have been chosen. In particular, the rheological analysis involved the comparison of the different polymers on the basis either of viscosity (constant rate test) or of viscoelastic measurements (oscillation test). Subsequently the possible relationships between either viscosity or viscoelastic parameters (G', G", tg delta) and the gel strength parameter have been investigated. The mechanical resistance of the pharmaceutical gels examined didn't depend on the viscosity but rather on the viscoelasticity of the systems. In particular, low tg delta values were always accompanied by high gel strength values. A rank order correlation was found between the tg delta values obtained for the various samples at different frequency values and the relevant gel strength parameter: this suggests that mechanical resistance measurements, similarly to viscoelastic ones, give information on the structural properties of the samples and therefore represent a suitable tool in the optimization of gel formulations.

Rheological and mechanical properties of pharmaceutical gels. Part II: Medicated systems: relevance to hydration properties and drug release.

Abstract: Aim of this work was to evaluate the influence of rheological and mechanical properties of medicated gels containing two viscosity grades of either sodium carboxymethylcellulose or polyacrylic acid on hydration properties and drug release. The two polymers were chosen since they produce different semi-solid systems: polymeric colloidal solutions in the case of sodium carboxymethylcellulose and true gels in the case of polyacrylic acid. Salicylic acid and sodium salicylate were used as model drugs for sodium carboxymethylcellulose solutions, benzoic acid and sodium benzoate were employed for polyacrylic acid gels. The relationship previously found (Part I of this study) between the viscoelastic (tg delta) and the gel strength parameters in non-medicated gelified vehicles also exists in medicated gels: the higher the tg delta, the lower the gel strength. The results obtained on isoviscous samples (either colloidal solutions or true gels), containing two viscosity grades of the same polymer, demonstrate that an increase in tg delta and the concomitant decrease in the mechanical resistance of the sample always accompany an improvement in hydration properties. The different rheo-mechanical and hydration properties entrain different release profiles only when drugs are suspended in the vehicle (i.e. in the case of the free acids here considered). In these cases, the limiting step for drug release is likely the preliminary drug dissolution, which is in turn affected by the hydration propensity of the vehicle.

Cholinergic mechanism in imipramine and morphine antinoception.

Abstract: Antinociceptive effect of imipramine and morphine was studied in rats using tail flick method. Morphine and imipramine both increased the latency of tail flick response. Pretreatment with naloxone (0.5 mg kg-1) decreased the antinociceptive effect of morphine (1 mg kg-1) and imipramine (10 mg kg-1). In order to see if antinociceptive effect of morphine or imipramine involve cholinergic mechanisms, mecamylamine (1 mg kg-1) or atropine (1 mg kg-1) were administered 30 minutes before morphine (1 mg kg-1) or imipramine (10 mg kg-1) administration. Mecamylamine decreased the antinociceptive effect of morphine and imipramine (P < 0.001), whereas atropine had no effect. Thus, opiodergic and nicotinic systems appear to be involved in morphine and imipramine induced antinociception.

Cytotoxic bicyclic diterpene from the brown alga Sargassum crispum.

Abstract: Study of the brown alga Sargassum crispum collected from Red Sea resulted in the isolation of new diterpene with hydroazulene skeleton, Sargassinone (6), some fatty acids ethyl ester andsome fatty acids. The identification of the isolated metabolites was established mainly by spectral methods and chemical transformation of sargassinone (6) to its acetate (7). The two diterpens (6, 7) exhibited substantial cytotoxic activities, as indicated by their IC50 values at the dose of 10 micrograms/ml or less.

Initial studies on the administration route of prolactin.

Abstract: The influence of administration route of prolactin on its biological availability in rats was determined. Prolactin was administered intraperitoneally, intramuscularly and intranasally (intranasal inhalation) in single doses of 2.5 mg/kg body weight. Within 5 hours after the administration, there were noticed evident differences in prolactin concentrations in blood dependening on the route of administration. The maximal prolactin concentration after its intraperitoneal administration was 1.5 times as high as the maximal concentration observed for intramuscular or intranasal administration. The area under the curves: concentration: intraperitoneal administration time and concentration: intramuscular administration time was 132.99 ng/cm3/h and 136.28 ng/cm3/h, respetively. The area under the curve (AUC0-&) for the intranasal administration of prolactin was not much different than for the intraperitoneal and intramuscular ones, and was 111.30 ng/cm3/h.

A comparative study of modified starches in direct compression of a poorly water soluble drug (hydrochlorothiazide).

Abstract: The direct compression properties of four modified starches in hydrochlorothiazide (HCTZ) tablets were studied. The starches were obtained locally from common plant sources and were modified through physicochemical treatment. Each modified starch was used as the only filler-binder-disintegrant in the formulation of hydrochlorothiazide tablets containing 25 mg of the drug. The tablets were produced by the direct compression technology. Sta-Rx 1500, a directly compressible starch, was used as basis for comparison. Evaluated tablet properties included weight and drug content uniformity, hardness and friability as well as disintegration time and dissolution profile. The modified starches exhibited species specificity in terms of the tablet properties. The weight, drug content and disintegration time for all batches of tablets were within acceptable limits. Proper ranking of the starches on the basis of specific tablet properties was used to highlight their differences.

Synthesis of some new derivatives of thiazolo-[3,2-a]pyrimidine-3,5,7(2H)-trione of potential biological activity.

Abstract: A number of 6-(m-tolylazo)-thiazolo[3,2-a]pyrimidine-3,5,7(2H)-trione (3), 2,6-di(m-tolylazo)thiazolo[3,2-a]pyrimidine-3,5,7(2H)-trione (4), thiazolo[3,2-a]pyrimidine-3,5,7-trione (5) and 2-(m-tolylazo)thiazolo[3,2-a]pyrimidine-3,5,7(2H)-trione (6) here been prepared. The structure of the new ring system have been confirmed by IR and 1H-NMR spectral data.

Evaluation of adhesive properties of transdermal therapeutic systems containing nitroglycerin.

Abstract: The patch performances and the success of the transdermal drug delivery can be significantly affected by the quality of contact between the patch and the skin. Poor adhesion will dramatically reduce percutaneous delivery. In this study the adhesive properties (peel force and creep resistance) of three monolayer self-adhesive nitroglycerin (NTG) patches available on the market, Deponit, Minitran, and Triniplas, were compared. The patches were characterized also in terms of in vitro drug release and ex vivo skin permeation. The creep resistance values verified in the case of Deponit and Triniplas indicated a low cohesion of these matrices. The peel force values were in the accepted range, even if Triniplas and Deponit showed values double that shown by Minitran. The percentage of NTG released in vitro after two hours in all cases exceeded ninety percent. The ex vivo permeation profiles were similar, even if the three patches had different loaded amounts and surface areas. The measured permeated amount, 11 mg permeated in 24 h, was predictive of the claimed in vivo release (10 mg in 24 h).

Rapid high-performance liquid chromatographic method for determination of doxycycline in human plasma.

Abstract: A simple, rapid and precise analytical method for determination of doxycycline in human plasma is described. A high-performance liquid chromatography (HPLC) system based on a mbondapak C18 column (300 mm x 4.6 mm i.d., 10 microns) and a UV detector (lambda = 347 nm) were used. A mixture of actonitrile 0.1 M potassium dihydrogen phosphate buffer (35:65 v/v) adjusted to pH 3 was used as mobile phase. The proteins were precipitated with a 24% perchloric acid aqueous solution. The detection limit for doxycycline in plasma was 3 ng mL-1. The average recovery was about 96%. The method is simple, sensitive and suitable for pharmacokinetic studies of doxycycline. The inter-day and intra-day assay coefficients of variation were found to be less than 8%.

Quantitative determination of famotidine through charge-transfer complexation with chloranilic acid.

Abstract: Quantitative determination of famotidine and its dosage forms was carried out spectrophotometrically, analysing the coloured complex resulting from a charge-transfer interaction between the drug as an electron-donor and chloranilic acid as an electron-acceptor. Famotidine-Chloranilic acid complex displayed l-max at 5 25 nm. Conditions and time for complex formation have been optimized. The stoichiometry of the complex is 3:2 donor to acceptor mole ratio. Calibration graph of the complex was found to be linear at a working concentration range of 1.60-11.g% (w/v). Excellent quantitative recoveries (99.01-100.71%) was obtained for the drugs in both its pure and standard dosage forms.

Synthesis and antibacterial activity of some novel N-substituted piperazinyl-quinolones.

Abstract: A series of N-substituted-piperazinyl-quinolones were synthesized and evaluated for in vitro antibacterial activity. Compounds with a 2-(2,4-dichlorophenyl)-2-oxoethyl group attached to the piperazine ring (5a-c) had similar antibacterial activity to the reference drugs, ciprofloxacin, norfloxacin and enoxacin against both Gram-positive and Gram-negative bacteria. The oximes 6a-c and 6g-i were almost less active than corresponding ketones against the tested microorganisms, however the 2,4-difluorophenyl analogues (6g-i) were more active than 2,4-dichlorophenyl derivatives (6a-c). If the hydrogen of oxime is replaced with a benzyl group (6d-f & 6j-l), in-vitro antibacterial activity was decreased against both Gram-positive and Gram-negative bacteria. Generally ciprofloxacin derivatives were more active than norfloxacin and enoxacin derivatives.

Design and evaluation of microcapsules of diltiazem hydrochloride.

Abstract: Diltiazem Hydrochloride (DTZHCl), a potent calcium channel blocker was microencapsulated by emulsion/solvent evaporation technique using non-aqueous solution of Ethylcellulose (EC) polymer to achieve its release from microcapsules at a slower rate At the optimal conditions of process variables such as stirring speed, temperature of the medium, drug-polymer ratio, maximum encapsulation efficiency was obtained and the microcapsules produced were free flowing, discrete and spherical as evident from Scanning Electron Microscopy The in vitro release experiments were carried out in the simulated gastric fluid (pH 12) and simulated intestinal fluid (pH 72 phosphate buffer) using USP XXII apparatus II The data obtained from the dissolution profiles were compared in the light of different kinetic models and the regression coefficients were compared