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PubMed2004

Clarithromycin suspension: bioequivalence studies on two different strengths.

Two studies were performed in different groups of volunteers, with the aim to prove the bioequivalence of test (Klaromin) and reference clarithromycin (CAS 81103-11-9) suspensions containing in 5 mL either 125 mg (study 1) or 250 mg (study 2) of the drug, administered as an oral dose of 10 mL. Each study was conducted according to an open, randomized, single-dose, two-period cross-over design in healthy volunteers with a wash-out period from 7 to 14 days. Blood samples were taken up to 24 h in both studies, and concentrations of clarithromycin and its principal active 14-hydroxy metabolite were determined by HPLC. In the first study, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of clarithromycin were between 0.84 and 1.03 (AUC0-t) and between 0.89 and 1.03 (Cmax). In the second study, i.e. after administration of clarithromycin suspension 250mg/5mL, the 90% confidence interval for intra-individual ratios of AUC0-inf and Cmax of clarithromycin were between 1.01 and 1.17 (AUC0-inf) and between 1.01 and 1.16 (Cmax). All these values were within the acceptance ranges for bioequivalence studies. In both studies, the 90% confidence interval for intra-individual ratios of AUC0-inf and Cmax of 14-hydroxy-clarithromycin were also within the acceptance ranges. In the light of the results of the studies reported here it can be concluded that the clarithromycin test formulations are bioequivalent to the respective reference formulations, i.e. suspensions containing 125 mg/5 mL and 250 mg/5 mL of the drug.

Adolescent↗
PubMed2004

Effect of the formulation on the bioequivalence of sultamicillin: tablets and suspension.

Sultamicillin (CAS 76497-13-7) is a pro-drug of a combination of ampicillin and sulbactam linked as a double ester. The aim of the present studies, performed in two different groups of volunteers, was to compare the bioavailability of 750 mg sultamicillin tablets (Duobaktam 750 mg tablets, study 1) and sultamicillin 250 mg/5mL suspensions (Duobaktam 250 mg/5mL, study 2). Each study was conducted according to an open, randomized, single-dose, two-period cross-over design in 24 healthy volunteers with a wash-out period from 7 to 14 days. Blood samples were taken up to 12 h post dosing, and concentrations of ampicillin and sulbactam were determined by a HPLC-UV method. In the first study, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of ampicillin and sulbactam were between 1.01-1.18 and 0.95-1.09 (AUC0-t) as well as between 0.87-1.04 and 0.80-0.96 (Cmax), respectively, and thus within the acceptance ranges. The 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of sultamicillin suspensions (2nd study) were between 0.94-1.16 (ampicillin) and 0.92-1.14 (sulbactam) for AUC0-t and between 0.96-1.23 (ampicillin) and 0.97-1.24 (sulbactam) for Cmax. These values were also within the acceptance range for bioequivalence studies. Concerning the secondary parameter tmax the 90%-confidence interval for the intra-individual differences for both ampicillin and sulbactam were between 0.00-0.50 in the first and between -0.17-0.00 in the second study, respectively. In the light of the present studies it can be concluded that the sultamicillin test formulations, i.e. tablet and suspension are bioequivalent to the respective reference formulations.

Adolescent↗
PubMedDate not supplied

Long-term stability of PBCA nanoparticle suspensions.

In this study, the stability of poly(butyl cyanoacrylate) (PBCA) nanoparticle suspensions was examined for up to 1 year by measuring the nanoparticle sizes. The nanoparticles were prepared with different stabilizers (dextran 70.000, poloxamer 188, or polysorbate 85), and the particle size was determined before and after purification by centrifugation and after dilution with different solutions (0.1 N HCl, 0.01 N HCl, H2O, and PBS). The most constant sizes were with the untreated acidic nanoparticle suspensions. In all other cases, agglomeration of the particles occurred: the extent of this agglomeration and the time at which the agglomeration occurred depended on the experimental conditions. Nanoparticle polymer degradation, as indicated by size decrease, was not observed. Thus, PBCA nanoparticles can be stored as suspensions, making the lyophilization and the sometimes problematic resuspension by ultrasonication, unnecessary, which is advantageous for clinical applications.

Capsules↗
PubMed2005

Alginate-based in situ gelling suspensions and emulsions comprising N4-alkyloxycarbonyl derivatives of cytosine: zero-order release and effect of physicochemical properties.

As an alternative to incorporation of various excipients, N(4)-alkyloxycarbonyl-cytosine derivatives possessing various physicochemical properties and cytosine regeneration rates have been examined to modify release rate and kinetics from in situ gelling alginate formulations, e.g., liquid formulations that gel in acidic gastric juice and release the entrapped derivative or parent cytosine. Linear relationships were obtained between the release rate constants and the square root of the solubility for suspension formulations. Calculated diffusion coefficients were observed to be similar for suspension and solution formulations; however, for in situ gelling emulsion formulations, diffusivity correlated linearly to log P. Zero-order release of parent cytosine was observed from in situ gelling suspensions of the poorly soluble acid-labile N(4)-adamantyloxycarbonyl-cytosine prodrug.

Acetamides↗
PubMed1993

A single-blind, randomised, comparative study of clarithromycin and amoxycillin suspensions in the treatment of children with lower respiratory tract infections.

One hundred and forty-five children with signs and symptoms of lower respiratory tract infections were entered into this multicentre, General Practice, investigator-blind study, designed to demonstrate equivalent efficacy between clarithromycin and amoxycillin suspensions. Seventy one children were randomised to treatment with clarithromycin suspension 7.5 mg/kg bodyweight twice daily and 74 to treatment with amoxycillin suspension 125 mg (bodyweight < 25 kg) or 250 mg (bodyweight > or = 25 kg) three times a day according to bodyweight. Duration of therapy was 5-10 days as determined by the investigator. Clinical evaluations were performed pretreatment, during treatment and post-treatment within 72 hours of cessation of therapy. Fifty two children in the clarithromycin group and 57 in the amoxycillin group were clinically evaluable. Both study medications were effective and there were no significant differences between the groups with respect to clinical cure rate (60% for clarithromycin and 63% for amoxycillin), clinical success rate (cure plus improvement, 96% for clarithromycin and 95% for amoxycillin) or rate of resolution of clinical signs and symptoms in clinically evaluable patients. The intention to treat analysis for all patients entered similarly showed no significant differences in efficacy. The two treatment groups did not differ significantly with respect to incidence or severity of adverse events which were generally mild and associated with the gastrointestinal system. Therapy was withdrawn because of adverse events in three children on clarithromycin and one on amoxycillin. Bacteriological cure rates could not be determined because of an insufficient number of evaluable pre-treatment sputum samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Amoxicillin↗
PubMed1992

Dermal absorption of chemicals: effect of application of chemicals as a solid, aqueous paste, suspension, or in volatile vehicle.

The purpose of this study was to investigate the dermal absorption of chemicals in different physical forms when applied to female F344 rats. Chemicals were applied either as a solid, aqueous paste, suspension, or dissolved in the volatile vehicle ethanol. The chemicals investigated were [14C]-2-sec-butyl-4,6-dinitrophenol (DNBP, 4.2 mumol), 2,4,5,2',4',5'-[14C]-hexachlorobiphenyl (HCB, 2.3 mumol), and 3,4,3',4'-[14C]-tetrachlorobiphenyl (TCB, 0.5 mumol). The chemicals were applied on the clipped mid-dorsal region of the rat over a 2.54-cm2 treatment area, which was then occluded. Urine and feces were collected and assayed for radioactivity. Twenty-four hours post-application, the treated skin was washed with a mixture (1:1) of soap and water, dried, and reoccluded. The animals were sacrificed at 120 h by exsanguination under ether anesthesia. Radioactivity in the blood, skin (treated and untreated), and carcass was assayed. Dermal absorption of DNBP-derived radioactivity was approximately 50% of the recovered dose after application in the four physical forms, and the major route of excretion was via the urine. Twelve percent of the absorbed dose of DNBP was retained in the body. Dermal penetration of HCB-derived radioactivity was 5-8% of the recovered dose after application in the four forms, and the major route of excretion was via the feces. Greater than 90% of the absorbed dose of HCB-derived radioactivity was retained in the body. Dermal penetration of TCB-derived radioactivity was 6-8% of the recovered dose in the four forms, and the major route of excretion was via the feces. Approximately 21% of the absorbed dose was retained in the body at 120 h. Absorption of each chemical applied either as solid, aqueous paste, or suspension was compared to the absorption of the same chemical in ethanol. Absorption of HCB applied as a solid was significantly higher (p less than or equal to .05) as compared to HCB applied in ethanol. There were no other significantly differences in the comparisons of absorption. The data indicate that the chemicals examined in this study can penetrate the skin as readily when applied either as a solid, aqueous paste, or suspension, as when applied in the volatile vehicle ethanol.

2,4-Dinitrophenol↗
PubMed2005

Effect of solid state transition on the physical stability of suspensions containing bupivacaine lipid microparticles.

Bupivacaine lipid microparticles were prepared and evaluated as a parenteral sustained-release dosage form for postoperative pain management. Bupivacaine free base was incorporated into a molten tristearin matrix and lipid micro-particles were subsequently formed from this molten mixture by a spray-congealing process. A 3% injectable bupivacaine lipid microparticle suspension was prepared by dispersing 30% bupivacaine lipid microparticles in an aqueous medium containing carboxymethylcellulose (CMC), mannitol, and Tween 80. Upon room temperature storage, the fluid suspension gradually changed into a nonflowing semisolid (gelation) as a result of crystal growth of bupivacaine. However, suspensions prepared with bupivacaine lipid microparticles that were previously annealed at an elevated temperature remained fluid upon long-term storage. Differential scanning calorimetry (DSC), x-ray powder diffraction (XRPD), and isoperibol solution calorimetry were used to investigate the changes in the solid-state properties of tristearin and bupivacaine in the lipid microparticles before and after the heat treatment. The DSC and XRPD results indicate that after 24 hours of heating at 40 degrees C, tristearin was completely converted from the unstable alpha form to the stable beta form. Using the isoperibol solution calorimetric method, bupivacaine was found to transform into a more stable form after the lipid microparticles were heated at 60 degrees C for 24 hours. The generation of the unstable solid forms of tristearin and bupivacaine was attributed to the resolidification of both components from the molten mixture during the spray-congealing process.

Anesthetics, Local↗
PubMed1998

The treatment of oropharyngeal candidiasis in HIV-infected patients with oral amphotericin B suspension.

Oropharyngeal candidiasis (OPC) is the most frequent opportunistic infection associated with HIV infection. Therapies such as topical clotrimazole and nystatin, as well as oral azoles, which had previously been effective prior to the advent of HIV, are increasingly only partially effective in OPC in HIV infection. The effectiveness of oral amphotericin B suspension for OPC is described in 17 HIV-infected patients whose response to other therapies had been unsatisfactory. Three patients yielded isolates of Candida albicans with a minimum inhibitory concentration (MIC) to fluconazole of >/=16 microg/mL. Eleven patients received amphotericin B suspension monotherapy. Of the 17 patients, the symptoms of six resolved entirely, seven patients partially responded, and four failed therapy. These data suggest that amphotericin B suspension may be a useful additional therapy for OPC in HIV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1999

The conventional ultrasonic nebulizer proved inefficient in nebulizing a suspension.

A study was undertaken to compare the amount of nebulized budesonide suspension and nebulized terbutaline sulphate solution inhaled by healthy adult subjects when conventional jet and ultrasonic nebulizers were used. Ten healthy subjects (5 male; age range, 16-52 years) used two conventional nebulizers: the Spira Elektro 4 jet nebulizer (Respiratory Care Center, Hämeenlinna, Finland) and the Spira Ultra ultrasonic nebulizer (Respiratory Care Center) in a breath-synchronized mode with each drug. The amount of drug inhaled, the inhaled mass, was defined as the amount of drug deposited on a filter between the inspiratory port of the nebulizer and the mouthpiece. The amount of budesonide and terbutaline sulphate was determined by reversed-phase high-performance liquid chromatography. Single-dose respules were used (0.5 mg of budesonide and 5.0 mg of terbutaline sulphate), and nebulization time up to the defined gravimetric output was recorded. The inhaled mass of budesonide varied depending on the nebulizer used, whereas the inhaled mass of terbutaline was unaffected by the choice of nebulizer. The median inhaled mass of budesonide was 31.4% of the nominal dose (i.e., dose of drug in the respule per label claim) with the Spira Elektro 4 and 9.9% with the Spira Ultra, whereas the median inhaled mass of terbutaline was 50% with the Spira Elektro 4 and 52% with the Spira Ultra. It appears that a suspension is generally more difficult to nebulize than a solution and that the budesonide suspension should not be used in conventional ultrasonic nebulizers.

Administration, Inhalation↗
PubMed1996

The absence of an effect of food on the bioavailability of azithromycin administered as tablets, sachet or suspension.

Present product labelling indicates that azithromycin capsules should not be taken with food. However, three recent studies demonstrated that food does not significantly decrease the bioavilabilities of three new formulations of azithromycin (250 mg tablets, 1000 mg sachet, 500 mg paediatric suspension). With a 500 mg dosage, the mean relative bioavailability of azithromycin following ingestion of a standard high-fat breakfast was 96% when administered as two 250 mg tablets and 113% when administered as a suspension. The mean relative bioavailability of a 1000 mg sachet was 112%. The absolute bioavailability of the sachet formulation, relative to a 1 h iv infusion of 1000 mg, was 44%. Thus, azithromycin tablets, suspension and sachet may be given without regard to meals, further enhancing the convenience of once-daily, short-duration dosing regimens.

Adolescent↗
PubMed1997

An experimental study of embolic effect according to infusion rate and concentration of suspension in transarterial particulate embolization.

RATIONALE AND OBJECTIVES: The authors evaluate the embolic effect according to infusion rate and concentration of particulate suspension, focusing on arterial occlusion level. METHODS: The renal arteries of 14 rabbits were embolized with 150 to 250 microns polyvinyl alcohol (PVA) particles, divided into four groups according to two different infusion rates (1 mg/second and 0.1 mg/second) and two different concentrations of suspension (10 mg/mL and 2.5 mg/mL). Arteriograms obtained immediately and a week after embolization were assessed for occlusion level. For the nephrograms obtained a week after embolization, the opacifying areas were graded from 0 to 4. Median coronal sections of each kidney specimen were investigated for the presence of peripheral infarct grossly and for the presence of PVA particles in the small artery microscopically. RESULTS: Arteriograms showed various occlusion levels. Using a 0 to 4 grading system, the opacifying area of the nephrogram obtained 1 week after embolization was noted to be smaller in the low infusion rate group (P < 0.05). In gross and microscopic pathologic examination, the number of cases with peripheral infarct or PVA particles in the small artery (< 300 microns) was greater in the group with the low infusion rate and low concentration (P < 0.05). CONCLUSIONS: In transarterial particulate embolization, slower infusion of more diluted suspension provides for a more distal arterial occlusion.

Animals↗
PubMed1998

A prospective study of omeprazole suspension to prevent clinically significant gastrointestinal bleeding from stress ulcers in mechanically ventilated trauma patients.

OBJECTIVE: To prospectively evaluate the incidence of clinically significant bleeding, side effects, and cost of therapy in mechanically ventilated trauma patients at high risk for stress ulcers who received simplified omeprazole suspension (SOS). METHODS: Prospective, evaluative study in a Level I trauma center. Mechanically ventilated trauma patients admitted with at least one additional risk factor for stress ulcer development received SOS for stress ulcer prophylaxis. RESULTS: Sixty trauma patients were enrolled. The mean Injury Severity Score was 27.3. After starting SOS, there were no cases of clinically significant upper gastrointestinal bleeding related to stress ulceration. Baseline pH was 3.3, and mean gastric pH after SOS was increased to 6.7 (p < 0.005). There were no adverse effects thought to be related to omeprazole suspension. Incidence of nosocomial pneumonia after beginning SOS was 28.3%. The cost of acquisition plus administration of SOS was $13.13 per day, whereas the cost of drug acquisition alone was $3.83 per day. CONCLUSION: In a prospective, evaluative study of 60 trauma patients who required mechanical ventilation and had at least one additional risk factor for stress ulcer development, omeprazole suspension prevented clinically significant gastrointestinal bleeding, maintained excellent control of gastric pH, produced no toxicity, and was the least costly medication alternative.

Anti-Ulcer Agents↗
PubMed1993

Clarithromycin vs. amoxicillin suspensions in the treatment of pediatric patients with acute otitis media.

Clarithromycin is a new macrolide antibiotic that is active in vitro against a variety of organisms that are responsible for acute otitis media in children. The parent compound is metabolized to microbiologically active 14-hydroxy clarithromycin, which is especially active against Haemophilus influenzae. The safety and efficacy of clarithromycin and amoxicillin suspensions were compared in the treatment of acute otitis media in children 1 to 12 years of age inclusive. This was a Phase III, single blind (investigator-blind), randomized, multicenter clinical trial. Clarithromycin oral suspension was given in a dose of 7.5 mg/kg (maximum, 500 mg) twice daily, and amoxicillin suspension in a dose of 20 mg/kg (maximum, 750 mg) was given twice daily for 7 to 10 days in a 1:1 ratio. Clinical evaluations were performed pretreatment, within 48 hours posttreatment and 10 to 14 days posttreatment. Myringotomy was performed in every child to obtain a microbiologic sample pretreatment and at subsequent visits as clinically indicated. A total of 79 children were enrolled, 39 in the clarithromycin and 40 in the amoxicillin treatment group. Thirty-two children were excluded from the efficacy analysis for various reasons. Clinical success (cure and improvement) rates at 0 to 4 days posttreatment were 93% for clarithromycin and 90% for amoxicillin (P > 0.999). Altogether 17 children (10 receiving clarithromycin, 7 receiving amoxicillin) experienced some adverse event, with gastrointestinal disorders being the most common complaint. No clinically significant differences in laboratory tests were found between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1995

Worldwide safety experience with ceftibuten pediatric suspension.

Ceftibuten suspension was administered to 1312 pediatric patients in clinical trials at a dosage of 9 mg/kg once daily, with a maximal daily dose of 400 mg. Adverse experiences were collected by voluntary reports by physicians from direct observations, parental and/or patient complaints in 1152 patients. In 160 patients gastrointestinal adverse experiences were elicited at each visit in addition to voluntary reports. Patients had a mean age of 4.9 years, the male: female ratio was 1:1 and 72% were white. Fifty-five percent (719 of 1312) of patients were treated in otitis media studies, 33% (438 of 1312) were treated in a pharyngitis study and 12% (155 of 1312) were treated in other studies. Adverse experiences occurred in 10% (138 of 1312) of all patients receiving ceftibuten suspension. The most common voluntarily reported treatment-related adverse events were diarrhea 3% (34 of 1152) and vomiting 2% (22 of 1152). For elicited adverse events related to treatment, the most common were also diarrhea 9% (14 of 160) and vomiting 3% (5 of 160). There were no deaths and only 0.9% (12 of 1312) patients discontinued treatment because of adverse events. Abnormal laboratory values related to therapy were uncommon and no patient discontinued treatment because of abnormal laboratory values. No cases of Stevens-Johnson syndrome, toxic epidermal necrolysis, serum sickness-like reactions or pseudomembranous colitis have been observed with ceftibuten suspension in research studies to date.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2005

Pediatric carbamazepine suspension overdose-clinical manifestations and toxicokinetics.

Two toddlers ingested unknown quantities of their older sibling's carbamazepine suspension and rapidly manifested central nervous depression requiring intubation in 1 patient. Coma was the primary clinical finding throughout their care with no anticholinergic syndrome, seizures, or dysrhythmia. Both patients recovered without sequelae within 24 hours. Initial carbamazepine concentrations were 36.6 and 22.7 mg/L. The elimination rates (zero-order kinetic) were approximately 1.4 and 0.75 mg/L per hour. We provide the first toxicokinetic data for carbamazepine suspension overdose in children. We confirm that the oral absorption of suspension carbamazepine is rapid necessitating prompt referral to a health care facility for this exposure.

Administration, Oral↗
PubMed2003

Film flow of a suspension down an inclined plane.

A method is developed for simulating the film flow of a suspension of rigid particles with arbitrary shapes down an inclined plane in the limit of vanishing Reynolds number. The problem is formulated in terms of a system of integral equations of the first and second kind for the free-surface velocity and the traction distribution along the particle surfaces involving the a priori unknown particle linear velocity of translation and angular velocity of rotation about designated centres. The problem statement is completed by introducing scalar constraints that specify the force and torque exerted on the individual particles. A boundary-element method is implemented for solving the governing equations for the case of a two-dimensional periodic suspension. The system of linear equations arising from numerical discretization is solved using a preconditioner based on a particle-cluster iterative method recently developed by Pozrikidis (2000 Engng Analysis Bound. Elem. 25, 19-30). Numerical investigations show that the generalized minimal residual (GMRES) method with this preconditioner is significantly more efficient than the plain GMRES method used routinely in boundary-element implementations. Extensive numerical simulations for solitary particles and random suspensions illustrate the effect of the particle shape, size and aspect ratio in semi-finite shear flow, and the effect of free-surface deformability in film flow.

Computer Simulation↗
PubMed2003

Film depth and concentration banding in free-surface Couette flow of a suspension.

The film depth of a free-surface suspension flowing in a partially filled horizontal concentric-cylinder, or Couette, device has been studied in order to assess its role in the axial concentration banding observed in this flow. The flow is driven by rotation of the inner cylinder. The banding phenomenon is characterized by particle-rich bands which under flow appear as elevated regions at the free surface separated axially by regions dilute relative to the mean concentration. The concentric cylinders studied had outer radius R(o) = 2.22 cm and inner radii R(i) = 0.64, 0.95 and 1.27 cm; the suspension, of bulk particle volume fraction phi = 0.2 in all experiments described, was composed of particles of either 250-300 microm diameter or less than 106 microm diameter, with the suspending fluid an equal density liquid of viscosity 160 P. The ratio of the maximum to the minimum particle volume fraction along the axis in the segregated condition varies from O(1) to infinite. The latter case implies complete segregation, with bands of clear fluid separating the concentrated bands. The film depth has been varied through variation of the filled fraction, f, of the annular gap between the cylinders and through the rotation rate. Film depth was analysed by edge detection of video images of the free surface under flow, and the time required for band formation was determined for all conditions at which film depth was studied. The film depth increases roughly as the square root of rotation speed for f = 0.5. Band formation is more rapid for thicker films associated with more rapid rotation rates at f = 0.5, whereas slower formation rates are observed with thicker films caused by large f, f > 0.65. It is observed that the film depth over the inner cylinder grows prior to onset of banding, for as yet unknown reasons. A mechanism for segregation of particles and liquid in film flows based upon 'differential drainage' of the particle and liquid phase in the gravity-driven flow within the film over the inner cylinder is formulated to describe the onset of concentration fluctuations. This model predicts that suspension drainage flows lead to growth of fluctuations in phi under regions of negative surface curvature.

Computer Simulation↗
PubMed2003

Microstructure evolution in magnetorheological suspensions governed by Mason number.

The spatiotemporal evolution of field-induced structures in very dilute polarizable colloidal suspensions subject to rotating magnetic fields has been experimentally studied using video microscopy. We found that there is a crossover Mason number (ratio of viscous to magnetic forces) above which the rotation of the field prevents the particle aggregation to form chains. Therefore, at these high Mason numbers, more isotropic clusters and isolated particles appear. The same behavior was also found in recent scattering dichroism experiments developed in more concentrated suspensions, which seems to indicate that the dynamics does not depend on the volume fraction. Scattering dichroism experiments have been used to study the role played by the volume fraction in suspensions with low concentration. As expected, we found that the crossover Mason number does not depend on the volume fraction. Brownian particle dynamics simulations are also reported, showing good agreement with the experiments.

Anisotropy↗