Preparation and pharmaceutical evaluation of glibenclamide slow release mucoadhesive buccal film

Buccal mucoadhesive systems among novel drug delivery systems have attracted great attention in recent years due to their ability to adhere and remain on the oral mucosa and to release their drug content gradually. Buccal mucoadhesive films can improve the drug therapeutic effect by enhancement of drug absorption through oral mucosa increasing the drug bioavailability via reducing the hepatic first pass effect. The aim of the current study was to formulate the drug as buccal bioadhesive film, which releases the drug at sufficient concentration with a sustain manner reducing the frequency of the dosage form administration. One of the advantagees of this formulation is better patient compliances due to the ease of administration with no water to swallow the product. The mucoadhesive films of glibenclamide were prepared using hydroxypropyl methylcellulose (HPMC) K4M, K15M and Eudragit RL100 polymers and propylene glycol as plasticizer and co-solvent. Films were prepared using solvent casting method, and were evaluated with regard to drug content, thickness, weight variations, swelling index, tensile strength, ex vivo adhesion force and percentage of in vitro drug release. Films with high concentrations of HPMC K4M and K15M did not have favorable appearance and uniformity. The formulations prepared from Eudragit were transparent, uniform, flexible, and without bubble. The highest and the lowest percentages of swelling were observed for the films containing HPMC K15M and Eudragit RL100, respectively. Films made of HPMC K15M had adhesion force higher than those containing Eudragit RL100. Formulations with Eudragit RL100 showed the highest mean dissolution time (MDT). Drug release kinetics of all formulations followed Higuchi's model and the mechanism of diffusion was considered non-Fickian type. It was concluded that formulations containing Eudragit RL100 were more favorable than others with regard to uniformity, flexibility, rate and percentage of drug release.

Immobilization of penicillin G acylase using permeabilized Escherichia coli whole cells within chitosan beads

Entrapment of permeabilized whole cells within a matrix is a common method for immobilization. Chitosan possesses distinct chemical and biological properties, which make it a suitable matrix for entrapment and immobilization of penicillin G acylase (PGA). In the first step, Escherichia coli (ATCC 11105) cells were permeabilized using N-cetyl-N,N,N-trimethyl ammonium bromide (CTAB) (0.1% w/v, 45 min, 45 rpm) which then immobilized using glutaraldehyde (5% w/v) as cross-linker and chitosan (3% w/v) as the matrix. These conditions were established after preliminary trials with CTAB and glutaraldehyde concentrations in the range of 0.05-0.25% w/v and 1-9% v/v, respectively. The hydrolytic activity was assayed using Ehrlich reagent. Permeabilization of cells caused 9% increase in Penicillin G Acylase (PGA) conversion after 15 min compared to the intact cells. Although, immobilization on chitosan decreased the conversion compared to un-immobilized treated cells (13%), the new biocatalyst showed acceptable operational stability, maintaining more than 90% of the initial activity after 20 cycles. Optimum conditions for immobilization of E. coli cells were: CTAB 0.1% w/v and glutaraldehyde 5% v/v. A new combination method was successfully developed and optimized for immobilization of treated whole cells on chitosan matrix.

Stability evaluation of freeze-dried Lactobacillus paracasei subsp. tolerance and Lactobacillus delbrueckii subsp. bulgaricus in oral capsules

Freeze-drying is a common preservation technology in the pharmaceutical industry. Various studies have investigated the effect of different cryoprotectants on probiotics during freeze-drying. However, information on the effect of cryoprotectants on the stability of some Lactobacillus strains during freeze-drying seems scarce. Therefore, the aim of the present study was to establish production methods for preparation of oral capsule probiotics containing Lactobacillus paracasei subsp. tolerance and Lactobacillus delbrueckii subsp. Bulgaricus. It was also of interest to examine the effect of various formulations of cryoprotectant media containing skim milk, trehalose and sodium ascorbate on the survival rate of probiotic bacteria during freeze-drying at various storage temperatures. Without any cryoprotectant, few numbers of microorganisms survived. However, microorganisms tested maintained higher viability after freeze-drying in media containing at least one of the cryoprotectants. Use of skim milk in water resulted in an increased viability after lyophilization. Media with a combination of trehalose and skim milk maintained a higher percentage of live microorganisms, up to 82%. In general, bacteria retained a higher number of viable cells in capsules containing freeze-dried bacteria with sodium ascorbate after three months of storage. After this period, a marked decline was observed in all samples stored at 23°C compared to those stored at 4°C. The maximum survival rate (about 72-76%) was observed with media containing 6% skim milk, 8% trehalose and 4% sodium ascorbate.

Effect of fluoride dentifrices on the microhardness of deciduous enamel surfaces

PURPOSE

To evaluate the changes in the enamel surface microhardness following the application of various suspensions of Crest and Pooneh toothpastes with and without fluoride.

MATERIALS AND METHODS

Fifty-six enamel blocks of primary incisors were exposed to a pH-cycling regime consisting of demineralisation and remineralisation solution, then suspensions of the dentifrices Crest 1100, Crest 500, Pooneh 500, Pooneh without fluoride. Changes of the enamel surface microhardness in pre-demineralisation (initial), post-demineralisation (demineralised) and post-remineralisation (final) stages were measured for four groups and were analysed using the Student t test and one-way ANOVA.

RESULTS

The percentages of changes in surface microhardness for Crest 1100, Crest 500, Pooneh 500 and Pooneh without fluoride were 45.4, 35.4, 28.6 and 23.7, respectively.

CONCLUSION

Average changes of surface microhardness for Crest 1100 were significantly higher than Crest 500, Pooneh 500 and Pooneh without fluoride.

Development and validation of a rapid HPLC method for simultaneous analysis of budesonide and its novel synthesized hemiesters in colon specific formulations

A simple and reliable reversed-phase high performance liquid chromatographic (HPLC) method was developed, validated and applied for determination of budesonide and its novel synthesized hemiesters in colon specific formulations and dissolution media. The method was employed on a μ-Bondapak C(18) column (250 mm × 4.6 mm, 5 μm) at ambient temperature. The mobile phase consisted of acetonitrile: monobasic potassium phosphate containing orthophosphoric acid (55:45, pH 3.2) at a flow rate of 1 ml/min. The UV detection wavelength was set at 244 nm and 50 μL of sample was injected into the HPLC system. Dexamethasone was used as the internal standard. The retention times for internal standard and budesonide were 4.5 and 7.2 min, respectively. The method was linear in the concentration range of 1-20 μg/ml of budesonide (R(2)>0.999). Limit of detection and limit of quantitation were 0.05 and 0.5 μg/ml, respectively. The method presented the requisite accuracy, selectivity, sensitivity and precision and showed good resolution for separation of the drug and related derivatives in the presence of excipients. The proposed method was successfully used for analysis of the drug and its derivatives in dissolution media and oral colon specific formulations prepared in our laboratory with enough reproducibility.

Development of novel budesonide pellets based on CODES(TM) technology: In vitro/in vivo evaluation in induced colitis in rats

BACKGROUND AND THE PURPOSE OF THE STUDY

Budesonide is the drug of choice for treatment of active inflammatory bowel disease (IBD). The aim of this study was to develop budesonide pellets based on a novel colon drug delivery system (CODES).

METHODS

Pellet cores containing lactulose or mannitol were prepared by extrusion/spheronization and coated with an acid soluble polymer (Eudragit E100), hydroxypropylmethyl cellulose (HPMC) and an enteric coat (Eudragit FS 30D) sequentially. In vitro drug release of coated pellets was studied using USP dissolution apparatus type II in buffers of pH 1.2 (2 hrs), pH of 7.4 (4 hrs) and pH of 6.8 containing 8% rat cecal contents (RCC) (18 hrs). The efficacy of the optimized formulation (containing 50% lactulose coated with Eudragit E (30% w/w) and Eudragit FS 30D (12% w/w)) was evaluated against 2, 4, 6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats.

RESULTS

The results of the kind of bacteria in vitro dissolution tests indicated absence of drug release in pHs of 1.2 and 7.4 and controlled release in buffer of pH 6.8 containing RCC. It was found that release rate was controlled by the type and amount of polysaccharide and the thickness of the acid soluble layer. The prepared formulation showed promising results in alleviating the conditions of experimental model of colitis.

CONCLUSION

The results of this study suggest that pellets based on CODES technology could be useful for colonic delivery of budesonide.

Applying the Taguchi design for optimized formulation of sustained release gliclazide chitosan beads: an in vitro/in vivo study

Gliclazide is a second generation of hypoglycemic sulfonylurea and acts selectively on pancreatic beta cell to control diabetes mellitus. The objective of this study was to produce a controlled release system of gliclazide using chitosan beads. Chitosan beads were produced by dispersion technique using tripolyphosphate (TPP) as gelating agent. The effects of process variables including chitosan molecular weight, concentration of chitosan and TPP, pH of TPP, and cross-linking time after addition of chitosan were evaluated by Taguchi design on the rate of drug release, mean release time (MRT), release efficiency (RE(8)%), and particle size of the beads. The blood glucose lowering effect of the beads was studied in normal and streptozotocin-diabetic rats. The optimized formulation CL(2)T(5)P(2)t(10) with about 31% drug loading, 2.4 h MRT, and 69.16% RE(8)% decreased blood glucose level in normal rats for 24 h compared to pure powder of gliclazide that lasted for just 10 h.

Effect of transfusion on cerebral oxygenation, flow velocity in a patient with sickle cell anemia and Moyamoya disease: a case report

Vascular occlusive diseases affect brain blood flow, brain metabolism and are associated with arterial ischemic stroke. This study was designed to measure the brain blood flow velocity, brain oxygenation, hemoglobin concentrations, hematocrit, and cell free hemoglobin at pre- and post-exchange red cell transfusion in an 18 year old male patient with sickle cell disease and moyamoya syndrome (MMS). Exchange transfusion increased cerebral oxygen saturation 12%, total hemoglobin concentration 2%, hemoglobin AA 80%, and reduced sickle (SS) hemoglobin 12%, arterializations 33%, and cell free hemoglobin 33%. Brain blood flow velocity values were unaffected by transfusion. These observations suggest that exchange transfusion increases the hemoglobin carrying capacity and reduces sickle hemoglobin and shunting of blood, which may improve the peripheral and cerebral oxygenation. Transfusion did not affect the brain blood flow in this patient. Therefore the risk of transient ischemic attack and arterial ischemic stroke from mms still exist.

Formulation and in vitro characterization of ciprofloxacin floating and bioadhesive extended-release tablets

Ciprofloxacin is mainly absorbed in the proximal areas of the gastrointestinal tract. The purpose of our study was production of floating-bioadhesive tablets to lengthen the stay of drug in its absorption area. Effervescent tablets were made using sodium carboxymethyl cellulose (CMC), hydroxypropyl methylcellulose (HPMC), polyacrylic acid (AA), polymetacrylic acid (MAA), citric acid, and sodium bicarbonate. Tablets with 5% effervescent base had longer lag time than 10%. The type of polymer had no significant effect on the floating lag time. All tablets floated atop the medium for 23-24 hr. Increasing CMC caused higher mucoadhesion than AA (p < 0.05). All formulations showed a Higuchi, non-Fickian release mechanism. Tablets with 10% effervescent base, 80% CMC/20% HPMC, or 80% AA /20% MAA seemed desirable.

Risk factors for goiter in primary school girls in Qom city of Iran

OBJECTIVE

Goiter is endemic in Iran. The iodine deficiency disorders program was begun a few years ago in Iran, and the coverage of iodized salt is sufficient now. But, in a periodic yearly medical examination of primary school girls in Qom, the prevalence of goiter was above 30% in 2002. This survey was designed to study the risk factors of goiter in those students.

DESIGN

The study was a randomized (multistage, proportional simple random sampling) case-control study.

SUBJECTS AND INTERVENTIONS

We selected and performed thyroid examinations in 1050 girl students in primary schools in Qom city of Iran in 2002. We found 284 cases: girls in primary schools had goiter in accordance with the clinical exam of World Health Organization classification. Among students who did not present with goiter in the clinical exam, we randomly selected 288 students as the control group. We used a questionnaire to evaluate them for the risk factors of goiter.

RESULTS

The mean+/-s.d. ages of cases and controls were 8.7+/-1.3 and 8.9+/-1.3 years, respectively. There is no significant difference between the two groups regarding history of soya, kale, turnip, fish, daily iodized salt usage, education and job of mothers, monthly family income, nationality, immigration and residential situation. By using multinomial logistic regression, we found that storage of iodized salt in open containers, odds ratio (OR): 2.201 (1.412-3.428); P-value <0.0001, medium socioeconomic situation (SES) of family, OR: 2.099 (1.029-4.282), P-value=0.041, district 2 of Qom city, OR: 2.880 (1.376-6.027), P-value=0.005, and district 3 of Qom city, OR: 2.051(1.032-4.078), P-value=0.041, were the major risk factors for goiter in this population.

CONCLUSIONS

In this study, the main risk factors for goiter were storage of iodized salt in open containers, medium SES and also living in specific districts of Qom city. As the coverage of iodinized salt is over 95% in Iran, we advise the education of the family about storage of iodized salt in closed containers. We also recommend the study of the other risk factors of goiter in the different geographical areas of Iran, because of differences in the SES and nutritional habits.

SPONSORSHIP

This study was supported by issuing permission letters for our activities: (not funding support) Qom Health Network and Medical Services, Qom Medical University, Qom Primary School Education Office, Fathemieh Medical University.

A survey on the extent of medication storage and wastage in urban Iranian households

BACKGROUND

Prescription and nonprescription medications constitute a substantial proportion of the health care costs of countries. National drug policies and attitudes toward medication use may play a role in irrational prescribing and consumption of medicines, leading to drug wastage. The limited resources of developing countries warrant more careful assessments of current national drug policies.

OBJECTIVE

This study quantified the amounts and types of medications that are stored in a sample of urban Iranian households and estimated the extent of drug wastage in these families.

METHODS

A literature search was conducted using MEDLINE and International Pharmaceutical Abstracts for 1966 to 2004 to identify articles on drug utilization and wastage. Randomly selected households in a large city in Iran were visited to determine the amounts and types of medicines stored in these households. A questionnaire was used to collect information about medication use in these families.

RESULTS

A total of 512 households were assessed. The mean (SD) family size of household respondents was 4.3 (1.6) members. Mothers were responsible for managing medications in 58.1% (291/501) of families. Presence of chronic illness, insurance coverage, higher economic status, literacy among fathers, and siblings without medically related jobs were the variables that showed a significant relationship with the amount of medicines found in the households. The mean (SD) numbers of unit doses of medicines and of drug products found in these households were 238.5 (198.6) and 22.99 (20.1), respectively. The most common therapeutic classes of medications kept at home were central nervous system agents, anti-infectives, and gastrointestinal medications. The real and potential medication wastage was estimated to be 38.8% and 53.8%, respectively.

CONCLUSIONS

Medications were stored in large quantities in these urban Iranian households, and a large percentage was being wasted. Drug-use assessments and a comprehensive evaluation of the current national drug policies are warranted to curtail this problem.

Significance of the V-type ATPase for the adaptation to stressful growth conditions and its regulation on the molecular and biochemical level

Two electrogenic H(+)-pumps, the vacuolar type H(+)-ATPase (V-ATPase) and the vacuolar pyrophosphatase, coexist at membranes of the secretory pathway of plants. The V-ATPase is the dominant H(+)-pump at endomembranes of most plant cells, both in terms of protein amount and, frequently, also in activity. The V-ATPase is indispensable for plant growth under normal conditions due to its role in energizing secondary transport, maintenance of solute homeostasis and, possibly, in facilitating vesicle fusion. Under stress conditions such as salinity, drought, cold, acid stress, anoxia, and excess heavy metals in the soil, survival of the cells depends strongly on maintaining or adjusting the activity of the V-ATPase. Regulation of gene expression and activity are involved in adapting the V-ATPase on long- and short-term bases. The mechanisms known to regulate the V-ATPase are summarized in this paper with an emphasis on their implications for growth and development under stress.

Reversible redox control of plant vacuolar H+-ATPase activity is related to disulfide bridge formation in subunit E as well as subunit A

The plant vacuolar proton pump can be subjected to reversible redox regulation in vitro. The redox-dependent activity change involves disulfide bridge formation not only in Vatp A, as reported for bovine V-ATPase, but also in the stalk subunit Vatp E. Microsomal membranes isolated from barley leaves were analysed for their activity of bafilomycin-sensitive ATP hydrolysis and proton pumping using quinacrine fluorescence quenching in vesicle preparations. ATP hydrolysis and proton pumping activity were inhibited by H2O2. H2O2-deactivated ATPase was reactivated by cysteine and glutathione. The glutathione concentration needed for half maximal reactivation was 1 mmol l-1. The activity loss was accompanied by shifts in electrophoretic mobility of Vatp A and E which were reversed upon reductive reactivation. The redox-dependent shift was also seen with recombinant Vatp E, and was absent following site-directed mutagenesis of either of the two cys residues conserved throughout all plant Vatp E sequences. V-ATPase was also inhibited by oxidized thioredoxin. These results support the hypothesis that tuning of vacuolar ATPase activity can be mediated by redox control depending on the metabolic requirements.

pUB2380: characterization of a ColD-like resistance plasmid

A detailed analysis of the mobilizable, ColE1-like resistance plasmid, pUB2380, is reported. The 8.5-kb genome encodes six (possibly seven) major functions: (1) a ColD-like origin of replication, oriV, with associated replication functions, RNAI and RNAII; (2) a set of active mobilization functions highly homologous to that of ColE1, including the origin of transfer, oriT; (3) a ColE1-like multimer resolution site (cer); (4) a kanamycin-resistance determinant, aph, encoding an aminoglycoside-3'-phosphotransferase type 1; (5) an insertion sequence, IS1294; and (6) two genes, probably cotranscribed, of unknown function(s). The GC content of the various parts of the genome indicates that the plasmid is a hybrid structure assembled from DNA from at least three different sources, of which the replication region, the mobilization functions, and the resistance gene are likely to have originated in the enterobacteriaceae.

IS1294, a DNA element that transposes by RC transposition

IS1294, found on the ColD-like resistance plasmid pUB2380, is IS91-like. It is an active 1.7-kb insertion sequence that lacks terminal inverted repeats, displays insertion-site specificity, and does not generate direct repeats of the target site. The element has one large open reading frame, tnp(1294), encoding a transposase of 351 amino acids, related to members of the REP family of replication proteins used by RC-plasmids of gram-positive bacteria. IS1294 transposes using rolling-circle replication, initiated at one end of the element, oriIS, and terminated at the other, terIS. oriIS and terIS are highly conserved among like IS elements. oriIS resembles the leading strand replication origins of RC-plasmids; terIS resembles a rho-independent transcription terminator. IS1294 mediates not only its own transposition, but also sequences adjacent to terIS. A transposition model for IS1294 and related elements, involving rolling-circle replication and single-strand DNA intermediates, is presented.

Subunit C of the vacuolar H+-ATPase of Hordeum vulgare

The molecular cloning of the first subunit C of the plant vacuolar H+-ATPase is reported. Tonoplast vesicles were purified from barley leaves by sucrose gradient centrifugation, and the tonoplast polypeptides were separated by two-dimensional (2-D) gel electrophoresis. Using an anti-ATPase holoenzyme antibody, a polypeptide was recognized in the molecular mass range of 40 kDa with an isoelectric point of about 6.0, and tentatively identified as subunit C. The polypeptide spot was excised from about 50 2-D gels and subjected to endo Lys C proteolysis. Two proteolytic peptides were sequenced and the amino acid sequences were used to design degenerated oligonucleotides, followed by PCR amplification with cDNA template and screening of a cDNA library synthesized from Hordeum vulgare poly A mRNA of epidermis strips. The full length clone of 1.5 kbp contains an open reading frame of 1062 bp encoding a polypeptide of 354 amino acids with a molecular mass of 39,982 Da and an isoelectric point of 6.04. Amino acid identity with sequences of SUC from animals and fungi is in the range of 36.7 to 38.5%. Expression of the cloned gene was demonstrated by Northern blotting and RT-PCR.

Comparison of the efficacy and safety of fenofibrate and lovastatin in patients with primary type IIa or IIb hyperlipidaemia

OBJECTIVES

To evaluate and compare the efficacy and safety of fenofibrate and lovastatin in patients with type IIa or IIb hyperlipidaemia.

METHODS

One hundred patients entered this single-centre, open, comparative trial. After 2 months of diet therapy, 33 patients (16 with type IIa and 17 with type IIb hyperlipidaemia) were randomized to treatment for 3 months with a single daily 300 mg dose of fenofibrate or 20 mg of lovastatin.

RESULTS

After 3 months of drug therapy, fenofibrate and lovastatin produced significant reductions in levels of total cholesterol and low-density lipoprotein cholesterol in type IIa hyperlipidaemia. In type IIb, the levels of total cholesterol were significantly decreased by both drugs, but only lovastatin significantly reduced low-density lipoprotein cholesterol in these patients. High-density lipoprotein cholesterol levels were significantly increased by lovastatin in type IIa and fenofibrate in type IIb. Fenofibrate decreased total triglyceride levels in both types of hyperlipidaemia significantly more effectively than lovastatin. The most important and commonly observed adverse effects in the fenofibrate group were dermatological events (three patients), myalgia (two patients) and asymptomatic increase in aminotransferase values (nine patients), while in the lovastatin group cardiovascular events (five patients) were the most common. All five patients had coronary heart disease at baseline. In general terms, both drugs were well tolerated.

CONCLUSIONS

Comparison between fenofibrate and lovastatin after 3 months of drug therapy in both types IIa and IIb hyperlipidaemia demonstrated that both drugs produced similar reductions in levels of total cholesterol and low-density lipoprotein cholesterol. However, fenofibrate decreased total triglyceride levels in both types of hyperlipidaemia, more effectively than lovastatin. Thus, fenofibrate is suitable for both primary hypercholesterolaemia and combined hyperlipidaemia.