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PubMed2000

Sustained release of recombinant human insulin-like growth factor-I for treatment of diabetes.

Recombinant human insulin-like growth factor-I (rhIGF-I) was found to improve glycemic control and enhance insulin sensitivity in patients with a syndrome of severe insulin resistance. Therefore, the protein may be considered as an alternative therapy in the treatment of diabetes when the patients become insensitive to insulin treatment. Because the protein was administered twice per day in the clinical trials, a sustained release polylactic-co-glycolic acid (PLGA) formulation for rhIGF-I with low initial burst (<20%), maximum possible protein loading (15-20%) and a continuous release of 1-2 weeks may provide greater patient convenience and compliance. The protein was encapsulated in PLGA for sustained release using a spray freeze-drying technique. Formulation parameters such as protein loading, polymer end group, and the presence of zinc carbonate were studied for their effects on in vitro release of rhIGF-I from PLGA microspheres. As the protein loading was increased, the initial burst increased. Due to the hydrophilic properties of the polymers, rhIGF-I encapsulated in unblocked PLGA (free acid end groups) gave a lower initial burst and a more steady-state release profile than the blocked PLGA (hydrocarbon end groups) with the same protein loading and PLGA molecular weight. At 15% w/w protein loading, the addition of 6% w/w zinc carbonate as a protein release modifier to the unblocked PLGA (12 kDa) decreased the initial burst of rhIGF-I. Therefore, a formulation consisting of 15% rhIGF-I and 6% zinc carbonate in 12 kDa, unblocked 50:50 PLGA can provide the required release characteristics in vitro. Rat studies revealed that rhIGF-I in this formulation was released in vivo at a rate which was comparable to that observed in vitro. These studies demonstrate the potential for a sustained release, 14-day formulation for rhIGF-I.

Animals↗

PubMed1992

Calcium alginate beads as core carriers of 5-aminosalicylic acid.

The utilization of calcium alginate beads as core carriers for delayed dissolution followed by burst release as a potential method of intestinal site specific drug delivery was investigated. 5-Aminosalicylic acid was spray-coated on dried calcium alginate beads and then coated with different percentages of enteric coating polymer and/or sustained-release polymer. Beads coated with more than 6% (w/w) methacrylic copolymer plastisized with dibutyl sebacate and triethyl citrate resisted release in 2-hr acid fluid challenge and allowed immediate dissolution upon transfer to simulated intestinal fluid. With 6% (w/w) methacrylic copolymer on top of 4% (w/w) ethylcellulose polymer, the major portion of drug did not release in 2 hr of acid treatment or the next 3 hr of simulated intestinal fluid treatment. This dosage form provides the possibility to deliver drug to the lower intestinal tract with minimal early release, followed by sustained release in the colon.

Alginates↗

PubMed2003

Optimization of an alum-adsorbed vaccine powder formulation for epidermal powder immunization.

PURPOSE: To develop stable and effective aluminum salt (alum)-adsorbed vaccine powder formulations for epidermal powder immunization (EPI) via a spray freeze-drying (SFD) process. METHODS: Powder properties were determined using particle size analysis, tap density, and scanning electron microscopy. Alum coagulation was monitored via optical microscopy and particle sedimentation. Protein analysis was determined by the BCA protein assay, SDS-PAGE, and an enzyme immunoassay. In vivo immunogenicity and skin reactogenicity were performed on hairless guinea pigs and pigs, respectively. RESULTS: SFD of hepatitis B surface antigen (HBsAg) adsorbed to aluminum hydroxide or aluminum phosphate using an excipient combination of trehalose/mannitol/dextran produced vaccine powders of dense particles and satisfactory powder flowability and hygroscopicity. This formulation also offered excellent long-term stability to the powder and the antigen. The two most important factors influencing alum particle coagulation are the freezing rate and the concentration of aluminum in the liquid formulation for SFD. The SFD vaccines, when delivered to hairless guinea pigs by EPI or injected intramuscularly after reconstitution, were as immunogenic as the original liquid vaccine. A further study showed that EPI with SFD alum-adsorbed diphtheria-tetanus toxoid vaccine was well tolerated, whereas needle injection of the liquid formulation caused persistent granuloma. CONCLUSIONS: Stabilization of alum-adsorbed vaccine by SFD has important implications in extending vaccination to areas lacking a cold chain for transportation and storage and may also accelerate the development of new immunization technologies such as EPI.

Adsorption↗

PubMed2003

Volatile substance and other drug abuse inhalation in Spain.

OBJECTIVE: Inhalant misuse is the intentional inhalation of volatile substances in order to obtain euphoric, disinhibiting, and exciting effects. Solvents, glues, adhesives, paints, varnishes, paint removers, dry cleaning agents, spray paints, nail polish removers, typewriter correction fluids, and aerosol propellants are common sources of volatile substance abuse. In recent years the abuse of inhalant substances, not only among those who abuse other drugs but also in teenagers and younger children, has been reported. We reviewed retrospectively the cases of inhalant misuse reported to the Spanish Poison Control Center. METHODS: Human intoxications from abuse of inhalant substances registered by our service from 1991 to 2000 were studied. Data analyzed were relative to age, gender, signs and symptoms, drug dependence antecedents, and severity of symptoms of the patients. The type of product and composition were also investigated. RESULTS: During the study period 109 cases of patients aged from 8 to 50 years were collected. A percentage of 36.6% was less or equal to 20 years old. Seventy percent corresponded to males. Of the patients, 11% presented dependence antecedents to other abuse drugs and 72.5% were symptomatic. In the symptomatic exposures clinical features affected the following systems: CNS (62.8%), gastrointestinal (8.1%), cardiovascular (8.1%), respiratory (2.9%), peripheral nervous system (1.1%), renal (1.1%), haematological (1.1%), hepatic (1.7%), and other (13.1%). The commercial products more frequently inhaled were solvents (34.9%) and glues/adhesives (22.9%). We noted the use of medicines with ethyl chloride-local anaesthetic (8.3%), three cases with aerosol bronchodilator (with fluorocarbons as propellants), and one case of xylazine inhalation. The composition most often involved was aromatic hydrocarbons (46.9%), halogenated hydrocarbons (16.5%), aliphatic hydrocarbons (11.4%), ketones (10.1%), local anaesthetic (ethyl chloride) (8.4%), ethers (2.5%), nitrous oxides (2.5%), and aliphatic nitrites (1.7%). The calls received were 59.6% from health care units and 22% from general public. Only 14% of cases were at home and 48% had moderate to severe clinical effects. Acute intoxications occurred in 82% of cases. CONCLUSIONS: Inhalation of volatile substance as abuse drugs has been detected in different age groups, including very young people. Although the principal source was industrial products, the use of drugs such as local anaesthetics and aerosol broncodilators was also detected. Based on epidemiological studies in the Spanish population (essentially adolescents and childhood) together with the ability of a Poison Center to detect sentinel-events, the community and authorities should develop strategies to prevent these exposures and the later use of other substances of abuse. In fact, recently a Law on Drug Dependences and Other Addictive Alterations has been approved in Madrid in order to take precautionary measures.

Administration, Inhalation↗

PubMed2000

The effects of epidermal debridement of partial-thickness burns on infection and reepithelialization in swine.

OBJECTIVE: Early postburn debridement of burn blisters is controversial. This study was conducted to compare rates of infection and reepithelialization in debrided vs nondebrided second-degree burns in swine. METHODS: This was a prospective, blinded, controlled, experimental trial using isoflurane-anesthetized swine. Standardized partial-thickness burns were inflicted by applying an aluminum bar preheated to 80 degrees C to the backs and flanks of two young pigs for 20 seconds. In half of the burns the necrotic epidermis was manually debrided. All burns were randomly treated with octylcyanoacrylate spray (OCA) or dry gauze (C). Full-thickness biopsies were taken at 7, 10, and 14 days for blinded histopathologic evaluation. The primary outcomes were the proportions of infected burns at days 7 and 10 and the proportion of completely reepithelialized burns at day 14. Burns were considered infected in the presence of intradermal neutrophils containing bacteria (intraobserver agreement, K = 1.00). A secondary outcome was the proportion of burns with the presence of scar tissue (abnormal collagen under polarized light; intraobserver correlation, K = 0.93). Chi-square tests were used for group comparisons. This study had 90% power to detect a 40-percentage-point difference in infection rates (alpha = 0.05). RESULTS: A total of 126 biopsies from 42 burns were available for review. Infection rates were higher in the debrided burns both at day 7 (55% vs 4.5%, p < 0.001) and at day 10 (65% vs 9%, p < 0.001) after injury. The proportion of nondebrided burns that were completely reepithelialized was higher at days 10 (68% vs 0%, p < 0.001) and 14 (100% vs 65%, p = 0.003). The presence of scar tissue was more common in debrided burns (75% vs 4.5%, p < 0.001). Burns treated with OCA had fewer infections than controls (4% vs 55%, p < 0.001). Fewer OCA-treated debrided burns were reepithelialized at 14 days than those that were not debrided (30% vs 100%, p = 0.001). CONCLUSIONS: Under the current study conditions, early postburn epidermal debridement of second-degree burns resulted in more infections and slower reepithelialization rates in swine. The effects of early postburn epidermal debridement in humans should be explored.

Animals↗

PubMed1975

In vitro and in vivo effect of 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (ribavirin) on types 1 and 3 parainfulenza virus infections.

1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (ribavirin) had significant in vitro activity against type 1 parainfluenza (Sendai) and type 3 parainogenic (HA-1) viruses. Activity was manifested as inhibition of both viral cytopathogenic effect and of recoverable virus or viral hemagglutinin titer. The minimum Sendai virus inhibitory concentration was determined to be approximately 3.2 mug/ml. Previous studies had determined the minimum concentration inhibiting HA-1 virus was approximately 1-10 mug/ml. The effect of time of addition of ribavirin to virus-infected cells was determined; maximal activity was seen when the drug added just prior to either virus or within 4-8 h after each virus, although anti-Senadi viral effects were still apparent when ribavirin was added as late as 24 h after the virus. Ribavirin had no effect on adsorption of HA-1 or Sendai virus to cells. Lethal Sendai virus infections of mice were significantly inhibited by multiple intraperitoneal ribavirin treatment, starting either 4 h before or up to 24 h after virus inoculation. Therapy starting 48, 72 or 96 h after virus exposure had a moderate degree of efficacy. Treatment using an aerosol chamber also was of moderate effectiveness, although the procedure was considered traumatic to the animals. A nonlethal, principally upper respiratory tract infection of hamsters induced by the HA-1 virus was inhibited by ribavirin therapy. Treatment administered intraperitoneally, per os or by aerosol chamber resulted in reduced 23-day antibody titers to the virus, presumably because of reduction of virus in the animal. In a separate experiment, intraperitoneal ribavirin therapy resulted in a 1 log10 or less reduction in virus titer in nasal washings from HA-1 virus-infected hamsters, whereas, when the drug was administered intranasally in a dry powder aerosol spray, nasal virus titers were reduced up to 2 log10 and a moderate virus-induced lung consolidation was completely inhibited.

Adsorption↗

PubMed2006

Mathematical modeling of an aqueous film coating process in a Bohle Lab-Coater, part 1: development of the model.

The purpose of this study was to develop a model to predict (1) air and product temperatures, (2) product moisture, and (3) air humidity during an aqueous coating process using a Bohle Lab-Coater. Because of the geometrical properties and the airflow, the drum of the Bohle Lab-Coater can in principle be divided into 2 zones of equal size-the drying and the spraying zones. For each zone, 4 balance equations could be set up describing the change of the air humidity, the product moisture, the enthalpy of the air, and the enthalpy of the product in each zone. For this purpose, knowledge regarding heat and mass transfer and also the motion of the tablets in drums was used. Based on the considerations of the heat and mass transfer, a set of first-order coupled ordinary differential equations (ODEs) was developed. This set of ODEs can be solved numerically. In this part, the development of the model is described in detail, whereas the application of the model can be found in part 2.

Chemistry, Pharmaceutical↗

PubMed1992

Computer simulation of agglomeration in the Wurster process.

A simplified model for computer simulation of agglomeration in the Wurster coating process was constructed using droplet size distribution and the relation between the size of agglomerates and the number of primary particles composing them experimentally determined. Computer simulations were applied to the cases where a 2.5% aqueous solution of hydroxypropyl cellulose (containing sodium carboxymethyl cellulose of 10% on a dry basis) was sprayed on four kinds of sharply fractionized lactose powders between 32 and 75 microns. With cores larger than 53 microns, the agitation exerted on particles strongly suppressed the growth of agglomerates, but the fraction of produced agglomerates reached about 50%. The smallest droplet size that was contributable to agglomeration (critical droplet size) was estimated to be 37.1-49.0 microns, increasing with core size, and the weight fraction of droplets larger than this critical size was only 0.5-2.7%, decreasing with increase in core size. The production of even such a minor amount of coarse droplets could be responsible for significant agglomeration.

Chemistry, Pharmaceutical↗

PubMed1986

[A longitudinal entomologic survey on the transmission of malaria in Ouagadougou (Burkina Faso)].

A longitudinal entomological malaria survey was carried out in five zones of the town of Ouagadougou, Burkina Faso, and in three neighbouring villages. The main vector is Anopheles gambiae s.l. with An. funestus having a role in some localities during the dry season. Pyrethrum spray catches were carried out once or twice per month to determine variations in vector density. Inoculation rates were estimated from the number of blood-fed vectors per man and from the sporozoite rates. Larval sampling was routinely carried out all over the urban area in order to map the larval breeding sites. Widely different degrees of malaria transmission were documented in the urban area mainly related to the spatial and temporal distribution of An. gambiae larval breeding sites. Higher inoculation rates, depending both on higher vector densities and sporozoite rates, were documented in the villages.

Animals↗

PubMed1983

[Studies on iodine exchange in thermal therapy with salsobromoiodic water].

We have attempted a quantitative evaluation of the iodine taken in with the thermal waters from Salsomaggiore during therapeutic bathing, inhalation (dry and damp spray), or ingestion. For this purpose to 127I we have applied the metabolic parameters obtained through a 131I inhalation test and a 125I ingestion test. Of the iodine inhaled by aerosol 45% becomes exhaled; by 24 hours 2% is in the serum and in the extra-thyroid area of iodine distribution, 16% in the thyroid, 16% in the urine. By adding the amount of iodine exhaled to that found in the metabolic cycle of iodine, we find that about 21% of the inhaled iodine is still missing. This amount is trapped in the respiratory tract from where it disappears only very gradually. At the end of the 24 hours, therefore, in the metabolic cycle of the iodine we find 34% of that inhaled, whereas we find 87% of that ingested. The level of iodine in the serum reached in thermal therapeutic inhalation, never stays at a level which might alter the functioning of a normal thyroid. The amount of inhaled iodine which is excreted with the urine is usually eliminated during the first excretions. Experimental studies suggest that the iodine taken in during bathing in the thermal-pools mainly comes from iodine released from the water through the addition of hypochlorites, and is then inhaled through breathing the air just above the water.

Balneology↗

PubMed1996

Effect of wetting the mouth on aortic blood pressure just before taking sublingual nitrates.

The absorption of sublingual nitrate tablets is sometimes variable. We performed a randomized controlled trial to determine whether wetting the mouth improved the decrease in aortic systolic blood pressure (BP) from sublingual nitrate tablet or spray. The 100 patients undergoing routine diagnostic cardiac catheterization were allocated to control (no nitrate), 0.3 mg sublingual nitrate tablet, 0.4 mg sublingual nitrate spray, water + 0.3 mg sublingual nitrate tablet, or water + 0.4 mg sublingual nitrate spray. Aortic systolic and diastolic BP were recorded using a fluid-filled catheter and measured off-line blind to the treatment group. Compared with control subjects, there were significant decreases in aortic systolic BP with both nitrate preparations (tablet = -7.1 mm Hg, 95% confidence interval [CI] = -12.5 to -1.6 mm Hg; spray = -8.0 mm Hg, 95% CI = -13.4 to -2.5 mm Hg). On average, water significantly increased the fall in aortic systolic BP with nitrate tablets (-5.5 mm Hg, 95% CI = -10.9 to -0.1 mm Hg, p = 0.044) but did not significantly enhance the effect of nitrate spray (-2.8 mm Hg, 95% CI = -8.3 to 2.6 mm Hg). Water significantly increased the fall in aortic diastolic BP with tablets only (-2.9 mm Hg, 95% CI = -5.5 to -0.2), and had no significant effect on heart rate. Water had a consistently larger influence on the hemodynamic effects of nitrate tablets than on the effects of nitrate spray. Patients with a dry mouth will have an increased effect from sublingual nitrate tablets if they wet their mouth before using sublingual nitrate tablets. Water does not appear to assist in the action of sublingual spray.

Absorption↗

PubMed2005

Effect of antimicrobial monomer-containing adhesive on shear bond strength of orthodontic brackets.

A new antibacterial and fluoride-releasing bonding system consists of a self-etching primer that contains an antibacterial monomer and a bonding agent that contains sodium fluoride. This study was to determine the effect of using this new adhesive on the shear bond strength of orthodontic brackets. Forty molar teeth were randomly divided into two groups. Group 1 consisted of 20 teeth that were etched for 15 seconds with 35% phosphoric acid, washed with a water spray for 10 seconds, and dried to a chalky white appearance, and the sealant was applied to the etched surface. The precoated brackets were placed on the teeth and light cured. Group 2 consisted of 20 teeth that were etched with 35% phosphoric acid for 15 seconds as suggested by the manufacturer when bonding to intact enamel. The teeth were washed with a water spray for 10 seconds and dried to a chalky white appearance, and the primer containing antibacterial monomer was applied to the etched surface, left for 20 seconds, and sprayed with a mild airstream. The adhesive was applied to each tooth, and the precoated bracket was placed and light cured. There were no significant differences (P = .220) in the shear bond strengths of the two groups. The mean shear bond strength for the antibacterial fluoride-releasing adhesive was 11.7 +/- 5.6 MPa and for the control was 9.6 +/- 5.0 MPa. The use of an antibacterial fluoride-releasing adhesive system did not affect the shear bond strength of the orthodontic brackets within the first half hour after initial bonding.

Adhesives↗

PubMed2006

Heat transfer and thermographic analysis of catalyst surface during multiphase phenomena under spray-pulsed conditions for dehydrogenation of cyclohexane over Pt catalysts.

Dehydrogenation of cyclohexane over Pt/alumite and Pt/activated carbon catalysts has been carried out for hydrogen storage and supply to fuel cell applications. An unsteady state has been created using spray pulsed injection of cyclohexane over the catalyst surface to facilitate the endothermic reaction to occur efficiently. Higher temperature of the catalyst surface is more favorable for the reaction, thus the heat transfer phenomena and temperature profile under alternate wet and dry conditions created using spray pulsed injection becomes important. IR thermography has been used for monitoring of temperature profile of the catalyst surface simultaneously with product analysis. The heat flux from the plate-type heater to the catalyst has been estimated using a rapid temperature recording and thermocouple arrangement. The estimated heat flux under transient conditions was in the range of 10-15 kW/m(2), which equates the requirement for endothermic reactions to the injection frequency of 0.5 Hz, as used in this study. The analysis of temperature profiles, reaction products over two different supports namely activated carbon cloth and alumite, reveals that the more conductive support such as alumite is more suitable for dehydrogenation of cyclohexane.

Journal Article↗

PubMed2006

Preparation of polymeric submicron particle-containing microparticles using a 4-fluid nozzle spray drier.

PURPOSE: We studied a novel method for preparing polymeric submicron particle-containing microparticles using a 4-fluid nozzle spray drier. METHOD: Ethylcellulose (EC) and poly(lactic-co-glycolic acid) (PLGA), either alone or in combination with polyethylenimine (PEI), were used as polymers to produce submicron particles, and mannitol (MAN) was used as a water-soluble carrier for the microparticles. The polymer and MAN solutions were supplied through different liquid passages of a 4-fluid nozzle and then dried to obtain MAN microparticles containing EC or PLGA submicron particles. The polymer/MAN ratio was controlled by changing the concentration of the polymer and MAN solutions. EC or PLGA microparticles were observed via scanning electron microscopy, and the size of microparticles was determined by image analysis. The particle size distribution of EC or PLGA submicron particles was measured with a super dynamic light scattering spectrophotometer. RESULTS: The method generated submicron-sized (<1 microm) particles of EC and PLGA. The mean diameters of EC and PLGA particles at a polymer/MAN ratio of 1:10 were 631 and 490 nm, respectively. The mean diameter of PLGA particles decreased as the PLGA/MAN ratio was reduced, reaching approximately 200 nm at a PLGA/MAN ratio of 1:100. The mean diameter of PLGA/PEI particles at PLGA/PEI/MAN ratios of 1:0.5:10 and 1:0.5:100 were 525 and 223 nm, respectively, and their zeta potentials were +50.8 and +58.2 mV, respectively. The size of EC submicron particles could be controlled by varying the spray conditions. CONCLUSIONS: This study demonstrated that it is possible to prepare polymeric submicron particles dispersed in MAN microparticles in a single process using the 4-fluid nozzle spray drying method. Cationic PLGA particles with a diameter of approximately 200 nm could be prepared by adding PEI, suggesting the possibility of its use as a carrier for delivering DNA into cells. The precipitation of EC may occur by the mutual dispersion and mixing of solvents after collision of EC and MAN mists by antisolvent effect, thereby producing MAN microparticles containing EC submicron particles.

Aerosols↗

PubMed2000

Octylcyanoacrylate for the treatment of contaminated partial-thickness burns in swine: a randomized controlled experiment.

OBJECTIVE: To compare infection and reepithelialization rates of contaminated second-degree burns treated with octylcyanoacrylate (OCA), silver sulfadiazine (SSD), polyurethane (PU) film, and dry gauze (control; C) in swine. METHODS: Eighty standardized burns were created by applying an aluminum bar preheated to 80 degrees C to the backs and flanks of young pigs for 20 seconds. All burns were immediately contaminated with 0.1 mL of Staphylococcus aureus 10(5)/mL and randomly treated with OCA spray, SSD, PU, or dry gauze (C). Full-thickness biopsies were taken at 3, 7, and 14 days for blinded histopathologic evaluation using hematoxylin and eosin (H&E)-stained slides. Burns were considered infected in the presence of interstitial reticular dermal neutrophils containing bacteria (intraobserver agreement, kappa = 1.00). Quantitative wound cultures were performed on a second day-3 specimen. RESULTS: At day 3, wound infection rates were 30% (OCA), 50% (SSD), 55% (PU), and 50% (C); p = 0.40 (Kruskal-Wallis test). At day 7, infection rates were 35% (OCA), 85% (SSD), 70% (PU), and 65% (C); p = 0.01. Median bacterial counts at day 3 were 6,500 (OCA), 20,000 (SSD), 1,000,000 (PU), and 650,000 (C); p = 0.29. The proportion of completely reepithelialized wounds at day 14 were 75% (OCA), 90% (SSD), 85% (PU), and 90% (C); p = 0.50. CONCLUSIONS: Treatment of contaminated partial-thickness burns with OCA spray resulted in fewer infections at one week than with the other three treatments.

Animals↗

PubMed1978

Autoclaving of lubricated dental instruments.

Test organisms forced mechanically into lubricated, rotating dental instruments (handpieces) were all killed during autoclaving at 134 degrees C for 8 min, even when protected by serum and oil. The test organisms were: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and spores of Bacillus stearothermophilus. Also when testing the sterility of autoclaved simulated instrument surfaces (brass cylinders and pieces of a cotton fabric) which had been inoculated with bacteria and dried before they were sprayed with oil, there was no growth of the test organisms. In addition to the other test organisms, spores of Bacillus subtilis and Gram-positive, anaerobic bacteria isolated from used handpieces that had been exposed to several autoclavings were used. Some of the handpieces that had been left to dry after use in the dentist's office before they were autoclaved, were shown not to be sterile. Therefore, the authors suggest that autoclaving of the instruments should take place shortly after use and prescribed cleaning.

Bacteria↗

PubMed2002

Surface adsorption of recombinant human interferon-gamma in lyophilized and spray-lyophilized formulations.

Recombinant human interferon-gamma (rhIFN-gamma) was lyophilized or spray-lyophilized in 9.5% trehalose, +/- 0.12% polysorbate 20 in 10 mM potassium phosphate, pH 7.5. We measured recovery of soluble protein after spraying, freeze-thawing, and drying and reconstitution. Infrared spectroscopy showed rhIFN-gamma secondary structure to be native-like in all dried powders. Powders were characterized using electron spectroscopy for chemical analysis, time-of-flight secondary ion mass spectroscopy, X-ray diffraction, and gas adsorption isotherms. rhIFN-gamma adsorbed at air/liquid interfaces during spraying, and to ice/liquid interfaces during lyophilization. The concentration of rhIFN-gamma at ice/liquid interfaces was approximately one-fourth that adsorbed at air/liquid interfaces. Addition of 0.12% polysorbate 20 reduced the concentration of rhIFN-gamma at both interfaces. Time-of-flight secondary ion mass spectroscopy detected polysorbate 20 on surfaces of lyophilized powders. Lyophilized samples dried more slowly but reconstituted more quickly than spray-lyophilized samples. rhIFN-gamma aggregated after nebulization, but aggregation decreased in 0.12% polysorbate 20. Addition of 0.12% polysorbate 20 reduced protein surface adsorption and decreased but did not completely prevent aggregation. Insignificant aggregation occurred after exposure to ice/liquid interfaces, but subsequent drying and reconstitution caused aggregation. The majority of the aggregation is due to adsorption at air-liquid and solid-air interfaces formed during spray-lyophilization or lyophilization.

Chemistry, Pharmaceutical↗

PubMed2001

The effects of octylcyanoacrylate on scarring after burns.

OBJECTIVE: To compare the effects of octylcyanoacrylate (OCA), silver sulfadiazine (SSD), polyurethane film (PU), and dry gauze (G) on scarring three months after partial-thickness burns. METHODS: This was a prospective, blinded, controlled experimental trial using isoflurane-anesthetized swine. Standardized partial-thickness burns were inflicted by applying an aluminum bar preheated to 80 degrees C to the backs and flanks of a young pig for 20 seconds. Four equal sets of ten burns each were randomly treated with OCA spray, SSD, PU, or G. Dressing changes were performed on days 1, 2, 3, and 4 after injury. Digital images of the burns were obtained immediately and three months later for masked computerized determination of scar surface area. Full-thickness biopsies were taken at three months for masked histopathological evaluation. The primary outcome was the percent reduction in residual wound area (RWA) calculated by subtracting the area of each individual burn from the area of the largest burn and dividing this value by the area of the largest burn (intraobserver correlation, r = 0.99). Secondary outcomes were the proportion of burns with the presence of scar tissue (abnormal collagen under polarized light; intraobserver agreement, kappa = 0.93) and the cosmetic appearance on a 100-mm visual analog scale marked "best scar" at the high end (inter-observer correlation, r = 0.82). Analysis of variance (ANOVA) and chi(2) tests were used for group comparisons as appropriate. This study had 80% power to detect a 33-percentage-point difference in RWA among groups (alpha = 0.05). RESULTS: A total of 40 burns were inflicted on the pig. There was no difference in percent RWA across the groups (OCA = 25%, SSD = 40%, PU = 25%, G = 32%; p = 0.13). There was no difference in the proportion of wounds with scarring among the groups (OCA = 10%, SSD = 22%, PU = 2%, G = 30%; p = 0.89). There was also no difference in the cosmetic scores among the groups (OCA = 78 mm, SSD = 75 mm, PU = 74 mm, G = 74 mm; p = 0.96). CONCLUSIONS: The effects of OCA spray, SSD, PU, and dry gauze on scarring three months after burns in pigs are similar.

Animals↗