PHARMACEUTICAL SCIENCES
Year:2006 | Volume:- | Issue:4|Papers Count:15

Objectives: Lactose is widely used as a filler or diluent in tablets and capsules and direct compresion grade of lactose can be used to carry small quantities of drug and this permits tablet to be made without granulation. The aim of the present study was to produce lactose agglomerates with high flow ability and compatibility using crystallization technique. Methods: The spherical crystal agglomeration of lactose was carried out by non-solvent method, the solvent was water and nonsolvent was ethanol. The operation parameters of the experiment were the flow rate of ethanol, the temperatures difference between solvent and nonsolvent and solvent/nonsolvent ratio. Results: The flowability as represented by the angle of repose (from 42°to 26°) and Carr index of the agglomerates (from 33 to 15), was much improved compared to original powder. The agglomerates were easily packed by tapping and the packability was described by Kawakita and Kuno's equations. Thus, the excellent flowability and packability of the agglomerates were attributed to the increase in particle size and spherical shape. Agglomerates were compressed to compacts which had considerable hardness without capping. Conclusion: In conclusion, the rnicromeritic properties of agglomerated crystals, such as flowability, pakability and compactibility were improved profoundly resulting in successful direct tableting without capping. The results from this study have identified many of the factors affecting the morphology of a-lactose monohydrate during the spherical crystallization process. Different a-lactose monohydrate crystals with precisely defined morphologies can be produced by careful control of the crystallization conditions.

Objectives: Multipotent mesenchymal stem cells (MSc) have been known for a long period of time. These cells are adherent, clonogenic and fibroblastic and can be isolated from bone marrow stroma of postnatal organisms. Under appropriate conditions, these cells can give rise to broad spectrum of fully differentiated connective tissues including cartilage, bone, adipose tissues and muscle cells. Upon the isolation of cells in vitro, these cells tend to differentiate and it is very difficult to direct these cells into self-renewal in order to get more Multipotent MSc for medical purposes. In this study, the effect of leukemia inhibitory factor (LIF) on MSc has been investigated. In the presence of LIF, embryonic stem cells proliferate without differentiation. However the effect of LIF on MSc has not been fully investigated. Methods: Bone marrow stroma cells were extracted from 2-month-old and 8-month-old mice. These cells were cultured in a medium containing LIF. After formation of colonies, cells were stained by methyl en blue. The activity of alkaline Phosphatase was also investigated. To study the effect of LIF on self-renewal ability of MSc, cells were cultured in a primary culture containing LIF. Colonies formed in the primary cultures, were harvested and recultured. The number and size of colonies compared with these cultured without LIF. Results: In the presence of LIF, cells tend to express alkaline phosphates enzyme more than control cells. However, in the presence of LIF in primary culture, there was no difference in the number of colonies. The size and number of colonies in secondary culture were significantly increased among those cells grown in the presence of LIF in primary culture. The number and quality of colonies did not show any significant difference among those cells extracted from 2-month-old and 8-month-old mice. Conclusion: The presence of LIF in primary culture does not affect the number of colonies formed. However, most of the cells in the primary culture express alkaline phosphatase. These cells tend to differentiate into bones. The presence of LIF in primary culture increases the self renewal ability of cells. Also these cells have more proliferation ability in comparison with control cells. The numbers of mesenchymal stem cells with aging do not decrease. Therefore, mesenchymal stem cells do not age and their number stays constant during the lifetime.

Objectives: The purpose of this study was to investigate the effect of thermal-treating on the release of theophylline HCl from the granules which have been prepared using aqueous dispersions of Eudragit. Methods: To accomplish this goal, different granules were prepared using wet granulation method containing three different types of Eudragit aqueous dispersions, NE40D, RS30D, RL30D and dicalcium phosphate. The drug release studies were conducted using USP dissolution apparatus. The concentration of released drug was analyzed using DV spectrophotometer at 271.4 nm. Since the drug release from granules was nearly completed at the first hour, for thermal-treating studies, tablets were prepared using direct compression method. The prepared tablets were thermally treated at 50 and 70°C for 24 hours. Release of drug was assessed before and after thermal-treating. Results: The results of release study showed that, thermally-treating the tablets at the temperatures higher than Tg of the polymer can decrease the drug release from matrices. For mechanistic evaluation of the effect of thermal-treating, XRD, SEM, DSC and FT-IR have been employed. SEM micrographs showed that the tablets have smoother surface with less porosity after thermal-treating. XRD difractograms showed that during granulation, monohydrate theophylline has been formed but there was no obvious crystal change between control and thermal-treated tablets. FT-IR spectra showed a hydrogen bonding between Eudragit and drug but there was no change in the spectrum of thermally-treated tablet compared to control. In DSC thermograrns, endothermic peak of the melting point of theophylline has been disappeared which it can be likely due to the solvation of the drug in polymer during the recording of DSC spectrum. Conclusion: Heat treating of Eudrag it over the Tg can rotard the drug release from its matrices.

Objectives: The recommended doses of aprotinin [3 or 6 million Kallikrein inhibitor units (Kill)] reduce the rate at bleeding after an open heart surgery and the need for the transfusion of the blood products. But due to the expensiveness of aprotinin and some side effects of its, low doses have been noticed. Various studies have demonstrated the effectiveness of two million Kill doses, but about one million Kill there is controversy. The purpose of this study is to assess the effects of one million KIU aprotinin on the bleeding and the need for the transfusion after cardiac surgery. Methods: This double blined randomized clinical trial has been done on 162 patients in Shahid Madani Heart Hospital of Tabriz in 2004. The patients were randomly divided into two groups of 81 individuals. In the aprotinin group (group I) 0.5 million Kill infused before and during cardiopulmonary bypass (CPB) and, in the placebo group (group II) 100 NS infused before and during CPB. The need for the use of FFP and blood transfusion during and after operation and the rate of chest tubes drainage in 6,12 and 24 hours after surgery were measured in two group. The collected data were analyzed by using, chi square and t-test as appropriate. Results: The rate of mediastanal and pleural drainage in 6 hours after surgery was 190±24 ml in Group I and 266±33 ml in Group II (P=0.066). The rate of bleeding in 12 and 24 hours was significant in two groups and (p=0.048 and P=0.009 respectively). The need for the transfusion of blood and FFP in two groups in ICU was not significant but it was significant in intra-operative period (P=0.002). The frequency of the use of blood products in group I was 68% and its rate in group II was 75% (P=0.02). The total amount of transfusion in group I was 2.56±0.27 unit and in group II it was 4.37±0.27 units (P=0.0001). Conclusion: The results indicate that the routine use of one million Kill of aprotinin in open heart surgery is effective in reducing post operative bleeding and transfusion requirements.

Objectives: Oxazepam is a practically water-insoluble drug which its oral absorption is limited by dissolution rate in gastrointestinal fluids therefore enhancement of dissolution rate can increase the rate and extent of its oral absorption. In this study, the effect of anionic (SLS), cationic (CTAB) and nonionic (Myrj 52) surfactants as carriers with different drug-carrier ratios (1:0.25, 1:0.5, I: 1 and 1:2) on dissolution rate of oxazepam from solid dispersions was evaluated. Methods: Solid dispersions were made by using co-evaporation method with 85% hydroalcoholic mixture as solvent. Dissolution rate of samples was measured by USP standard dissolution tester apparatus (USP No: II) and UV spectrophotometer. XRD and FT-IR spectroscopy were taken for the determination of probable crystalline changes in drug and drug-carrier interaction during process respectively. Results: The results showed significant higher dissolution rates for solid dispersions with all ratios compared with physical mixtures, treated physical mixtures, treated and intact drug powder. Physical mixtures also had a significant higher dissolution rates over intact drug and treated drug powders. 1:0.25 was selected as optimum ratio for oxazepam-SLS and oxazepam-CTAB solid dispersions. 1:0.5 oxazepam-Myrj52 ratios were also selected as optimum drug-carrier ratio for these solid dispersions. Solubility test results showed solubility enhancement ability of all surfactants. XRD and FT-IR spectra rejected any polymorphic changes or drug-carrier interaction during co-evaporation process. Conclusion: Solid dispersion is very effective technique for improving dissolution rate of practically insoluble drugs such as benzodiuazepines. Surfactants are suitable carriers for low-dose and very low water-soluble drugs.  

Objectives: The evaluation of effectiveness of second line agents against mycobacterial isolates has become more important in the past few years predominantly due to the appearance of multi drug - resistant tuberculosis. The aim of this study was to investigate the in vitro susceptibility of resistant M. tuberculosis (MT) and nontuberculous mycobacteria (NTM) to some second line anti - mycobacterial agents. Methods: In this study, in-vitro activity of kanamycin and amikacin against 90 MT and 10 NTM strains were investigated by proportional method. Results: Of 90 MT strains, 40 isolates were found to be resistant and 50 isolates were susceptible to first line drugs. All of 10 NTM strains were found to be resistant to first line drugs. H37RV MT (susceptible to all drugs) was used as a control. Of 90 M. tuberculosis isolates, %13 of strains was found to be resistant to kanamycin and %5 of strains was resistant to amikacin. Of 90 MT isolates, 29 strains were resistant to streptomycin, 8 strains to kanamycin and 3 strains were found to be resistant to amikacin. Of 10 NTM isolates, 8 strains were resistant to kanamycin and amikacin. Conclusion: These findings show the usefulness of amikacin and kanamycin in the treatment of resistant tuberculosis in MT strains. Studies such as this investigation should be conducted regularly in order to help effectively TB control efforts.

Objectives: The use of slow release formulations will reduce the number of doses per day that is administered by patients. This study reports formulation and dissolution performance of alginate and carboxy methylcellulose based sustained release beads of nitroglycerin. Methods: The beads were obtained by an emulsion/ionic cross-linking technique. Effects of polymer and ion concentration on the dissolution performance of drug were also evaluated. In vitro drug release from the beads was determined by means of USP dissolution apparatus I, using distilled water as a medium and HPLC analytical technique. To compare the dissolution profiles, several release models were tested such as Higuchi, zero order, first order, Weibull and Korsmeyer-Peppas. A model-independent dissolution efficiency (DE) at t8 was used as well. The similarity between two in vitro dissolution profiles was assessed by similarity factor (f2) as a pair-wise independent-model procedure. Results: Most of f2 values indicated the similarity between the dissolution profiles of the test and the reference product. The results obtained from fitting dissolution profile s to mathematical release models show that the rate constants (K) are significantly smaller in the case of formulations containing Al3+ with respect to formulations containing Ca2+ as cross-linker. When Al3+ was used as cross-linker the dissolution rate constant was remarkably smaller (slow release) when the Al3+ concentration was increased. Conclusion: Generally, it can be concluded that the cross-linking technique is a potential technique to prepare alginate beads containing liquid drug with slow release capability.

Objectives: In order to determine whether the three heterozygous CYP3A4 gene mutations (a 9 bp insertion at -845, an A→G transition at -392 and a G→ A transition at +14269) found in genomic DNA amplification from one subject were in the same allele, linkage analysis was performed. Methods: An initial amplification and cloning (using pSEAP-Basic plasmid, Clontech) of the 5'-proximal promoter region (-1201/-61) was used to separate the alleles and determine if the two mutations in this region are linked. Using the recombinant plasmid DNAs as template, PCR amplification of 592 bp (to cover both mutations) of the CYP3A4 promoter (-929/-337) was performed and sent directly for sequencing. Following this, "long-range (-858/+14536) allele-specific PCR" was performed using specific primers discriminating the two alleles. Resulting PCR products were then used as templates after gel extraction and purification to amplify each corresponding exon 6. The exon 6 PCR products were then sequenced to identify on which allele the exon 6 mutation was present. Results: The results of cloning and sequencing experiments on promoter region revealed that both mutations are in the same allele. The results obtained from "long-range allele specific PCR" again showed that all three mutations found in CYP3A4 gene are in fact present on the same allele introducing a novel CYP3A4 allele "CYP3A4*15B". Conclusion: This work has revealed successful application of carefully designed cloning and "long-range allele-specific PCR" experiments to linkage analysis of mutations found in different locations of a gene.

Objectives: The purpose of the study was to predict the human intestinal permeability and the fraction of oral dose absorbed using Caco-2 system. METHODS: Permeability coefficients were determined for nine passively absorbed compounds in Caco-2 system. Caco-2 monolayers were grown on porous filters in multi-well plates as monolayers. Drug solution in HBSS was added to top inserts (apical sides) and then the inserts with plate were incubated at 37° C for 60 min with shaking (-70 rpm). Samples were collected at 60 min from basolateral sides. Lucifer yellow was applied as marker for monolayer integrity in Caco-2 minelayers. Drug concentrations in samples were determined using HPLC equipment and permeability coefficients were calculated. Finally the obtained values were compared with published data for human intestinal permeability and fraction of dose absorbed in human. RESULTS: The relationship between penneabilities was found to be 10gPeff(human)= 0.65 logP app(Caco-2) - 0.37 (R2= 0.79, P= 0.001). The fraction of dose absorbed in vivo in human (Fa) after oral dosing can also be estimated from Fa (human) = 100 (1-e 1917852 Papp(Caco-2) (R2= 0.91, P= 0.0002). CONCLUSION: Therefore we conclude that the Caco-2 system has the potential for the prediction of human intestinal permeability and fraction of oral dose absorbed in human (Fa) as well.

Objectives: Cardiovascular disease is a major cause of morbidity and mortality in the world. Compared to men of similar age, pre-menopausal women have significantly lower incidence of adverse cardiovascular event including coronary heart disease, essential hypertension and stroke. The incidence of these disorders increases in women with absence of functional ovaries. Estrogen therapy of post menopausal women reduces the incidence of these diseases. This beneficial effect of estrogen may have several mechanisms. The vas ore lax ant effect of estrogens on vasculature is one f the important cardio protective effects. The exact underlying molecular mechanism of this estrogen-induced vasodilatation has not yet been determined. Considering the important roles of veins in preload and heart failure and coronary artery diseases, in this study the acute relaxant effect of 17 b-estradiol and role of endothelium and cyclic guanosin mono phosphate (cGMP) on this effect has been investigated on human saphenous vein. Methods: Rings of human saphenous vein with 3-5 mm length were prepared and equilibrated in Krebs solution under 3 g tension (37°C; 95% O2 ; 5% CO2) for 60 min. In the various experiments, the vascular rings were contracted with prostaglandin F2a(PGF2a, 1.5µM) or potassium chloride (KCl, 60 mM). When contraction was stable 17 b-estradiol was applied for 40 minutes in the presence or absence of endothelium and different inhibitors. Relaxation was expressed as % reversal of contraction induced by vasoactive agents. Results: 17 b-estradiol (5-40 µM) elicited a concentration-dependent relaxation of KCI- and PGF2a -induced active tone in human saphenous vein rings. Incubation of veins for 20 min with methylen blue or N-nitro-L-arginine methyl ester (L-NAME) reduced the relaxant effect of estrogen, significantly (p<0.05). This reduction was disappeared by denuding endothelium. However, when intact tissues were incubated with 10 µM indomethacin, cycloxygenase inhibitor or 1µM KT5823, a protein kinase G inhibitor or cyclohexamide (100 µM) or puromycin (10µM) protein synthetase inhibitors, the vasorelaxant effect of 17 b-estradiol on PGF2a -induced contraction was not modified significantly (p>0.05). Conclusion: These results suggest that 17 b-estradiol induces dose dependent vasorelaxant effect in human saphenous vein, at least partially, by nitric oxide production and this relaxant effect is independent of cGMP, cycloxygenase or genomic pathways.