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PubMed2003

Capsule thickness and amounts of a 39 kDa capsular protein of avian Pasteurella multocida type A strains correlate with their pathogenicity for chickens.

Capsule thickness of avian Pasteurella multocida type A strains was determined by transmission electron microscopy after labeling with polycationic ferritin and compared with their pathogenicity for chickens. The capsule thickness of P. multocida strains Pm-18 and X-73 was 81.4 and 50.1 nm on average, respectively. These strains were highly virulent for chicken, whereas the less virulent strains Pm-1 and Pm-3 had a thin and irregular capsule, 21.0 and 29.8 nm on average, respectively. However, the thickest capsule was observed in strain P-1059, 101.2 nm on average, and the strain revealed moderate virulence. The noncapsulated variant P-1059B, which was derived from strain P-1059, revealed low virulence. The six P. multocida strains were examined with regard to protein content on the capsule of organisms. Amounts of total proteins of crude capsular extract (CCE) from capsulated strains were approximately twice those of the noncapsulated strains. The amount of an antigenic 39 kDa protein in the CCE were found to correlate with the capsule thickness, since heavily capsulated strains exhibited the greatest amount, whereas noncapsulated strains including noncapsulated and low virulent variant P-1059B possessed little 39 kDa protein. The results demonstrated that the capsule thickness and the quantity of a 39 kDa capsular protein of avian P. multocida type A strains correlated with their pathogenicity for chickens.

Animals↗

PubMed2005

Feasibility and safety of string, wireless capsule endoscopy in the diagnosis of Barrett's esophagus.

BACKGROUND: Capsule endoscopy is a major technological advancement in the visualization of the small bowell. Its utility in the evaluation of the esophagus is mainly limited by its rapid and unpredictable transmission, thus limiting the number of pictures of the esophagus, in particular, the distal esophagus. METHODS: Strings were attached to the wireless capsule endoscopy device to allow its controlled movement up and down the esophagus. Microbiologic cultures of the capsule's surface after high-level disinfection were carried out after the procedure. At the time of recording, discomfort associated with the procedure was documented. Patient preference compared with conventional EGD was recorded. An independent endoscopist blinded to the EGD diagnoses assessed the diagnostic accuracy of pictures obtained. OBSERVATIONS: Fifty patients with Barrett's esophagus were enrolled: 28 with short-segment Barrett's and 22 with long-segment Barrett's. The procedure was safe (no strings were disrupted, and no capsule was lost), and it rendered negative microbiologic cultures after high-level disinfection. The mean recording time was 7.9 minutes; all patients with both short- and long-segment Barrett's esophagus were successfully identified. The difficulty/discomfort associated with swallowing the device, throat discomfort, gagging, moving the capsule (up and down and upon retrieval of the capsule) was none or minimal in 74%, 98%, 96%, 94%, and 76%, respectively. A single capsule was used in 24 studies, and the majority of patients (92%) preferred string-capsule endoscopy to EGD. CONCLUSIONS: String-capsule endoscopy was feasible, safe, and highly acceptable, and was preferred by patients and may prove to be more cost effective than screening EGD.

Adult↗

PubMed2002

The rate of absorption and relative bioavailability of caffeine administered in chewing gum versus capsules to normal healthy volunteers.

OBJECTIVE: The purpose of this study was to evaluate the rate of absorption and relative bioavailability of caffeine from a Stay Alert chewing gum and capsule formulation. METHODS: This was a double blind, parallel, randomized, seven treatment study. The treatment groups were: 50, 100, and 200 mg gum, 50, 100, and 200 mg capsule, and a placebo. Subjects consisted of 84 (n=12 per group); healthy, non-smoking, males who had abstained from caffeine ingestion for at least 20 h prior to dosing and were randomly assigned to the treatment groups. Blood samples were collected pre-dose and at 5, 15, 25, 35, 45, 55, 65, 90 min and 2, 3, 4, 6, 8, 12, 16 and 29 h post administration. Plasma caffeine levels were analyzed by a validated UV-HPLC method. RESULTS: Mean Tmax for the gum groups ranged from 44.2 to 80.4 min as compared with 84.0-120.0 min for the capsule groups. The Tmax, for the pooled data was significantly lower (P<0.05) for the gum groups as compared with the capsule groups. Differences in Tmax were significant for the 200 mg capsule versus 200 mg gum (P<0.05). The mean ka values for the gum group ranged from 3.21 to 3.96 h-1 and for the capsule groups ranged from 1.29 to 2.36 h-1. Relative bioavailability of the gum formulation after the 50, 100 and 200 mg dose was 64, 74 and 77%, respectively. When normalized to the total drug released from the gum (85%), the relative bioavailability of the 50, 100 and 200 mg dose were 75, 87, and 90%, respectively. No statistical differences were found for Cmax and AUCinf for comparisons of the gum and capsule formulations at each dose. Within each dose level, there were no significant formulation related differences in Cmax. No significant differences were observed in the elimination of caffeine after the gum or capsule. CONCLUSIONS: The results suggest that the rate of drug absorption from the gum formulation was significantly faster and may indicate absorption via the buccal mucosa. In addition, for the 100 and 200 mg groups, the gum and capsule formulations provide near comparable amounts of caffeine to the systemic circulation. These findings suggest that there may be an earlier onset of pharmacological effects of caffeine delivered as the gum formulation, which is advantageous in situations where the rapid reversal of alertness and performance deficits resulting from sleep loss is desirable.

Adolescent↗

PubMed2003

Pharmacologic prevention of posterior capsule opacification: in vitro effects of preservative-free lidocaine 1% on lens epithelial cells.

PURPOSE: To assess the in vitro effectiveness of preservative-free lidocaine 1% in removing lens epithelial cells (LECs) from the anterior capsule and to evaluate the effect of lidocaine on the LECs. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Eight rabbits (16 eyes) were used in the study. After the rabbits were killed, the eyes were enucleated and divided into 2 groups. In Group 1 (n = 8 eyes), LECs were exposed to preservative-free lidocaine 1% or balanced salt solution (BSS) for 1, 2, or 5 minutes. The anterior capsules were then stained with trypan blue and alizarin red. Photomicrographs of each capsule were taken and analyzed for LEC damage. In Group 2 (n = 8 eyes), hydrodissection was performed with 1 of the agents, followed by phacoemulsification and cortical cleanup. The LEC attachment to the anterior capsule was evaluated by histopathology. RESULTS: Anterior capsule fragments irrigated with BSS showed no LEC nuclear staining; ie, no direct toxic effect. In those irrigated with preservative-free lidocaine 1%, the LECs showed mild toxicity; some cells showed blue nuclear staining. After hydrodissection with lidocaine, the capsules were almost free of LECs; after hydrodissection with BSS, the capsules showed a normal layer of LECs attached to the anterior capsule. CONCLUSIONS: Preservative-free lidocaine 1% may help diminish the amount of live LECs by facilitating cortical cleanup, by loosening the desmosomal area of cell-cell adhesion with decreased cellular adherence, or by a direct toxic effect. The use of this agent may help prevent posterior capsule opacification.

Anesthetics, Local↗

PubMed1997

Light and scanning electron microscopy of rabbit lens capsules with intraocular lenses.

PURPOSE: To examine postoperative changes in the lens capsules of rabbit eyes after phacoemulsification and aspiration of the crystalline lens and implantation of posterior chamber intraocular lenses (IOLs) using light and scanning electron microscopy. SETTING: Research Laboratory, Department of Ophthalmology, Wakayama Medical College, Japan. METHODS: The crystalline lens was emulsified and aspirated and an IOL implanted in the capsular bag or ciliary sulcus of each eye in adult albino rabbits under general anesthesia. Animals were killed after 4 weeks, and the lens capsules were removed. The specimens were observed under phase-contrast microscopy and processed for light and scanning electron microscopy. RESULTS: Phase-contrast microscopy revealed presumed lens epithelial cells (LECs) on the central posterior capsules in association with regenerating lenticular fibers and Elschnig pearls in the peripheral capsules. Scanning electron microscopy showed the accumulation of fibrous extracellular matrix on the surface of the posterior capsule in eyes in which the IOL was implanted in the ciliary sulcus. Deposition of packed material attached to the surface of IOLs and of Soemmering's ring were observed in eyes with in-the-bag IOL fixation. At a higher magnification, a parallel arrangement of lenticular fibers was seen in the regenerated lens structure on posterior capsules. An identical structure was observed under light microscopy. Outgrowth of presumed LECs from residual anterior lens capsules and adhesion of macrophages and giant cells were observed on the IOL surface. CONCLUSION: Two types of postoperative changes were observed in lens capsules after implantation of IOLs: accumulation of fibrous extracellular matrix and newly formed lenticular fibers. These changes are attributed to the proliferation of LECs and can induce posterior capsule opacification after IOL implantation.

Animals↗

PubMed2001

Magnetic marker monitoring of disintegrating capsules.

Magnetic marker monitoring was studied for its applicability to investigate the in vivo fate and behavior of disintegrating magnetically marked dosage forms. As a model, hard gelatin capsules were filled with an effervescent mixture of lactose, ascorbic acid and sodium hydrogen carbonate containing 1.3 mg black iron oxide as a magnetic label. The accuracy of the localization procedure whilst calculating all parameters of the dipole in one fitting procedure was checked in phantom experiments where the capsules were moved in well-defined paths with respect to the measurement device. The calculated position coordinates of the capsules deviated between less than 2 mm up to 8 mm from the expected position values depending on the distance between the sensor area and the capsule's path. Further experiments on the in vitro disintegration of the capsules showed that the value of the magnetic moment of the capsules can serve as a measure for their disintegration behavior. In vivo monitoring of the capsules was performed in eight experiments where a healthy volunteer swallowed each time one of the capsules. It was found that the in vivo disintegration behavior of the capsules corresponds well to their disintegration observed in water of about 37 degrees C.

Adult↗

PubMed2003

Cross-linking of hard gelatin carbamazepine capsules: effect of dissolution conditions on in vitro drug release.

The aim of this study was to determine if the use of both enzyme and surfactant in the dissolution medium changes the in vitro drug release from cross-linked hard gelatin capsules containing a water-insoluble drug. Hard gelatin capsules were cross-linked by a controlled exposure to formaldehyde resulting in different stressed capsules and carbamazepine (CBZ) was chosen as a drug model. In vitro dissolution studies were conducted using simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) with enzymes. Sodium lauryl sulfate (SLS) was added in the dissolution medium at a concentration of 2% m/v both in SGF and SIF with pepsin and pancreatin, respectively. The percentage of CBZ dissolved was reduced by increasing the degree of gelatin cross-linking. For unstressed hard gelatin capsules, 36% of the CBZ was released after 1 h, lowering to 5% for highly stressed hard gelatin capsules in the SGF. A similar effect was observed with SIF. In the case of moderately stressed hard gelatin capsules, addition of enzyme in the dissolution medium enhanced the percentage of CBZ dissolved. The dissolution level increased from 12% to 39% in SGF with pepsin for hard gelatin capsules cross-linked with 1500 ppm formaldehyde. On the contrary, the use of enzyme in the dissolution medium did not increase the dissolution of CBZ from highly stressed hard gelatin capsules. Surprisingly, the addition of SLS in the medium did not allow the release of the CBZ both in SGF and in SIF. The results of this study demonstrate that the use of enzyme in the dissolution medium is justified for moderately cross-linked hard gelatin capsules. However, the action of a surfactant added in the medium containing enzyme remains unclear.

Capsules↗

PubMed1998

Pulsatile drug release from an insoluble capsule body controlled by an erodible plug.

PURPOSE: The objective of this study was to develop and evaluate a pulsatile drug delivery system based on an impermeable capsule body filled with drug and an erodible plug placed in the opening of the capsule body. METHODS: The erodible plugs were either prepared by direct compression followed by placing the tablets in the capsule opening or by congealing a meltable plug material directly within the capsule opening. The disintegration/erosion properties of these plugs were determined and optimized for the final delivery system. In order to assure rapid drug release of the capsule content after erosion of the plug, various excipients (fillers, effervescent agents) and drugs with different solubilities were evaluated. The lag time prior to drug release and the subsequent drug release were investigated as function of capsule content, plug composition, plug preparation technique, plug hardness, weight, and thickness. RESULTS: The erosion time of the compressed plugs increased with increasing molecular weight of the hydrophilic polymer (e.g. hydroxypropyl methylcellulose, polyethylene oxide), decreasing filler (lactose) content and decreased with congealable lipidic plugs with increasing HLB-value and inclusion on surfactants. For complete and rapid release of the drug from the capsule body, effervescent agents had to be included in the capsule content. The drug delivery system showed typical pulsatile release profiles with a lag time followed by a rapid release phase. The lag time prior to the pulsatile drug release correlated well with the erosion properties of the plugs and, besides the composition of the plug, could be controlled by the thickness (weight) of the plug. CONCLUSIONS: A single-unit, capsular-shaped pulsatile drug delivery system was developed wherein the pulsatile release was controlled by the erosion properties of a compressed or congealed plug placed within the opening of the capsule opening.

Capsules↗

PubMed2004

In vitro and in vivo pharmacoscintigraphic evaluation of ibuprofen hypromellose and gelatin capsules.

PURPOSE: To evaluate the in vitro and in vivo characteristics of hypromellose (HPMC) capsules prepared using a gellan gum and potassium gelling system compared to conventional hard gelatin capsules. METHODS: The in vitro dissolution of ibuprofen gelatin and HPMC capsules was determined using the USP and TRIS buffers at pH 7.2. The effect of pH and composition of the media was determined using a model drug that is soluble throughout the pH range 1.2 to 7.2. In an 11 subject four-way crossover study, the gastrointestinal performance of ibuprofen gelatin and HPMC capsule formulations was evaluated using scintigraphy and pharmacokinetics following fasted and fed dosing. RESULTS: Acid conditions and the presence of K+ cations hinder HPMC capsule opening, whereas in water, dissolution is identical to that of gelatin. These effects are related to the nature of the gel network that is formed in the presence of cations. No significant difference in esophageal transit was observed. Although the in vivo opening times of HPMC capsules were longer than for their gelatin counterparts, no significant difference in the regulatory important pharmacokinetic metrics of C(max) and AUC was found between ibuprofen, gelatin and HPMC capsules. CONCLUSIONS: The in vitro performance of HPMC capsules differ from gelatin, which will require modification to dissolution testing methodology for certain drugs. However, for the class II BCS drug ibuprofen, the two capsule types were not statistically different when comparing AUC and C(max) values, which suggests that the in vitro differences have reduced in vivo relevance.

Adult↗

PubMed2003

A histological analysis of lens capsules stained with trypan blue for capsulorrhexis in phacoemulsification cataract surgery.

PURPOSE: Staining of anterior lens capsules with dye to facilitate completion of continuous curvilinear capsulorrhexis is now being used more frequently in phacoemulsification of white and mature cataracts with poor red reflexes. This study examined the histological characteristics of anterior lens capsules stained with trypan blue. The layer(s) of the lens capsule that stained with dye and the extent of accumulation of dye in these layers of the lens capsule were determined. To the best of our knowledge this has not been described before. METHODS: A series of 10 stained lens capsules were analysed histologically. The dye used in this study consisted of a standard sterile, noninflammatory, nonpyrogenic, 2 ml solution containing 0.6 mg/ml of trypan blue. Following capsulorrhexis, samples were sent to the laboratory for histological analysis. Frozen sections (8 microm) were prepared and examined with the light microscope. All 10 capsules were cut by frozen section to preserve trypan blue staining (which would be leached by processing) and then subjected to immunohistochemistry for collagen IV. Immunohistochemical analysis using markers for type IV collagen were done on formalin-fixed specimens for morphological comparison with the frozen sections. A counterstain highlighted the epithelium. RESULTS: Continuous curvilinear capsulorrhexis was successfully and easily completed in all cases without any complications. Frozen section analysis using light microscopy demonstrated accumulation of trypan blue dye in the basement membrane of the lens capsule. Staining was concentrated in the portion of the membrane adjacent to the lens epithelium. The lens epithelium could not be clearly identified on the frozen sections. Consequently, immunohistochemical analysis with markers for type IV collagen was performed. A counterstain highlighted the epithelium. This confirmed that the layer staining with trypan blue was the basement membrane, a consistent feature on all the specimens. CONCLUSION: Trypan blue selectively stains the basement membrane of the anterior lens capsule. There is a concentration of dye in the basement membrane adjacent to the lens epithelial cell layer. The lens cortex does not appear clinically to stain with trypan blue. This enables surgeons to distinguish the lens capsule from the cortex and provides sufficient contrast for successful completion of continuous curvilinear capsulorrhexis during cataract surgery.

Basement Membrane↗

PubMed1999

Structure, assembly and regulation of expression of capsules in Escherichia coli.

Many Escherichia coli strains are covered in a layer of surface-associated polysaccharide called the capsule. Capsular polysaccharides represent a major surface antigen, the K antigen, and more than 80 distinct K serotypes result from structural diversity in these polymers. However, not all capsules consist of K antigen. Some are due to production of an extensive layer of a polymer structurally identical to a lipopolysaccharide O antigen, but distinguished from lipopolysaccharide by the absence of terminal lipid A-core. Recent research has provided insight into the manner in which capsules are organized on the Gram-negative cell surface, the pathways used for their assembly, and the regulatory processes used to control their expression. A limited repertoire of capsule expression systems are available, despite the fact that the producing bacteria occupy a variety of ecological niches and possess diverse physiologies. All of the known capsule assembly systems seen in Gram-negative bacteria are represented in E. coli, as are the majority of the regulatory strategies. Escherichia coli therefore provides a variety of working models on which studies in other bacteria are (or can be) based. In this review, we present an overview of the current molecular and biochemical models for capsule expression in E. coli. By taking into account the organization of capsule gene clusters, details of the assembly pathway, and regulatory features that dictate capsule expression, we provide a new classification system that separates the known capsules of E. coli into four distinct groups.

ATP-Binding Cassette Transporters↗

PubMed2003

Capsule endoscopy versus push enteroscopy in patients with occult gastrointestinal bleeding.

BACKGROUND: Wireless capsule endoscopy is a new method enabling non-invasive diagnostic endoscopy of the entire small intestine. In this study we prospectively examined the diagnostic precision of capsule endoscopy compared with push enteroscopy in patients with occult gastrointestinal bleeding. METHODS: Between July 2001 and October 2002 we examined 48 patients with suspected disorders of the small intestine using capsule endoscopy. 33 patients with obscure bleeding (19 men, 14 women, mean age 58 +/- 23 years) were prospectively examined using capsule endoscopy and push enteroscopy. RESULTS: On average, the patients had been suffering from chronic gastrointestinal bleeding for 30 +/- 36 (1-120) months. The lowest haemoglobin level was 6.5 +/- 1.6 g/dl (2.3-9.6) and on average 9 +/- 10 (0-50) blood units were transfused. Each patient underwent 4 +/- 2 (1-10) hospitalisations, with a mean 9 +/- 4 (5-17) diagnostic procedures before capsule endoscopy was used. Definitive bleeding sites were diagnosed by push enteroscopy in 7 patients (angiodysplasia [n = 5], ulcers [n = 1], multiple jejunal diverticula [n = 1]). Capsule endoscopy showed a bleeding source in 25 cases (76 %) (angiodysplasias [n = 15], Meckel's diverticulum [n = 1], ulcers [n = 7], ileum diverticulosis [n = 1], B-cell lymphoma [n = 1]). Push enteroscopy localised an additional bleeding source in comparison with capsule endoscopy (multiple jejunal diverticula) in one patient. Both methods of examination were safe and showed no complications. DISCUSSION: The present study shows that capsule endoscopy had the highest diagnostic yield and was superior to push enteroscopy in patients with chronic gastrointestinal bleeding. By using the capsule at an early stage the subsequent therapeutic procedure could be considerably shortened and diagnostic processes could possibly be optimised.

Adolescent↗

PubMed1998

Thermal and mechanical stability of the lens capsule.

PURPOSE: Several procedures in cataract surgery carry the risk of high temperature increases in the capsular bag. The present study was undertaken to determine the shrinkage temperature of the human lens capsule and to investigate the effect of temperature on the mechanical behavior of the lens capsule. METHOD: Thermal-shrinkage characteristics of the lens capsule were determined during gradual heating of circular specimens (2 mm in diameter) prepared from anterior lens capsules from 25 human donors, ranging in age from 20 to 98 years. Uniaxial mechanical testing was carried out at 22 degrees C, 36 degrees C and 61 degrees C on ring-shaped test specimens prepared from anterior lens capsules from 5- to 6-month-old pigs. RESULTS: The mean shrinkage temperature (Ts) for the human lens capsule was 51.5 degrees C (range 49.3-54.3) and the mean shrinkage area in percent of the original area (AST) was 49% (36-66). Ts was significantly associated with the age of the donors and decreased 0.1 degree C per year until age 65 after which Ts was found to increase. AST showed no association with age. The mechanical effect of temperatures below the shrinkage temperature was modest. The capsule became slightly more extensible with increasing temperature. The effect of temperatures above the shrinkage temperature was an increased ultimate strain, a reduced ultimate stiffness and a slightly reduced ultimate stress. CONCLUSION: Thermal stability of the human lens capsule (type IV collagen) seems to be considerably lower than that of fibrous connective tissue (type I collagen). A potential risk of capsular shrinking has to be taken into account when the capsule is exposed to thermal stress during cataract surgery.

Adult↗

PubMed2002

Effect of bioadhesive polymers, sodium salicylate, polyoxyethylene-9-lauryl ether, and method of preparation on the relative hypoglycemia produced by insulin enteric-coated capsules in diabetic beagle dogs.

The hypoglycemic effect of oral insulin capsules coated with pH-dependent Eudragit S100 and containing various absorption promoters was studied in hyperglycemic beagle dogs. The absorption enhancers used were bioadhesive polymers, sodium salicylate, and non-ionic surfactants. A comparative study of the bioadhesive polymers, polycarbophil (PC), hydroxypropyl methylcellulose (HPMC), and carbopol 934 in insulin-coated capsules revealed no significant difference between the insulin capsules containing these polymers, giving relative hypoglycemia (RH) values ranging from 4.3 +/- 2.3% to 6.5 +/- 5.1%. It was also found that the method of preparation of the mixture of the bioadhesive polymer with insulin either by physical mixing or freeze-drying did not affect the RH values obtained. Sodium salicylate, when used in insulin enteric-coated capsules (50 mg) mixed with insulin as a physical mixture, or prepared by wet granulation using 10% polyvinyl pyrollidone (PVP), or by freeze-drying, produced RH values ranging from 7.3 +/- 2.9% to 9.4 +/- 3.7%. When sodium salicylate (100 mg) was used with insulin in freeze-dried granules an RH value of 10 +/- 2.6% was produced. As the dose of insulin increased from 6 to 9 U/kg, the area under curve (AUC) of the enteric-coated capsules containing 50 mg sodium salicylate increased from 73.2 +/- 27.8% to 121.4 +/- 102.7% reduction, but the RH did not change significantly. Insulin capsules containing polyoxyethylene-9-lauryl ether (POELE) used in its optimum concentration (2%), found in these experiments, produced RH of 9.5 +/- 6.8% when prepared as granules by wetting with a few drops of absolute alcohol in the presence of PC (50 mg). Insulin capsules containing lower (1%) or higher (3%) concentrations of POELE and prepared with PC, 50 mg by wet granulation produced lower RH of about 6%. The enteric-coated oral insulin capsules containing insulin (6 or 9 U/kg) and sodium salicylate (50 mg) as an absorption promoter, together with the bioadhesive polymer polycarbophil (50 mg), and prepared either by wet granulation using ethanol or by freeze-drying, are the best formulations to be used. They achieved a reduction in plasma glucose levels of about 25-30% and RH of about 10%. Also insulin (9 U/kg) capsules containing 2% POELE produced a 28% reduction in plasma glucose levels and RH of 9.6 +/- 6.8%.

Acrylates↗

PubMed2004

Process and formulation variables affecting the performance of a rupturable capsule-based drug delivery system with pulsatile drug release.

The objective of this study was to optimize several process and formulation parameters, which influence the performance of a rupturable, pulsatile drug delivery system. The system consisted of a drug-containing hard gelatin capsule, a swelling layer of croscarmellose (Ac-Di-Sol) and a binder, and an outer ethylcellulose coating. Polyvinyl pyrrolidone (Kollidon 90F) was superior to HPMC and HPC as a binder for the swelling layer with regard to binding (adherence to capsule) and disintegration properties of the swelling layer. The capsule-to-capsule uniformity in the amount of swelling layer and outer ethylcellulose coating, which significantly affected the lag time prior to rupture of the capsule, was optimized by decreasing the batch size, and by increasing the rotational pan speed and the distance between the spray nozzle and the product bed. The type of baffles used in the coating pan also affected the layering uniformity. Fully-filled hard gelatin capsules had a shorter lag time with a higher reproducibility compared to only half-filled capsules, because the swelling pressure was directed primarily to the outer ethylcellulose coating and not to the inner capsule core. Stability studies revealed that the lag time of the capsules was stable over a 240-day period when the moisture content was kept unchanged.

Capsules↗

PubMed2005

Erosion characteristics of an erodible tablet incorporated in a time-delayed capsule device.

A time-delayed oral drug delivery device was investigated in which an erodible tablet (ET), sealing the mouth of an insoluble capsule, controlled the lag-time prior to drug release. The time-delayed capsule (TDC) lag-time may be altered by manipulation of the excipients used in the preparation of the ET. Erosion rates and drug release profiles from TDCs were investigated with four different excipient admixtures with lactose: calcium sulphate dihydrate (CSD), dicalcium phosphate (DCP), hydroxypropylmethyl cellulose (HPMC; Methocel K100LV grade) and silicified microcrystalline cellulose (SMCC; Prosolv 90 grade). Additionally, the compressibility of different insoluble coated capsules was tested at different moisture levels to determine their overall integrity and suitability for oral delivery. Erosion rates of CSD, DCP, and SMCC displayed a nonlinear relationship to their concentration, while HPMC indicated rapid first-order erosion followed by zero-order erosion, the onset of which was dependent on the HPMC concentration. Capsule integrity was confirmed to be most suitable for oral delivery when the insoluble ethyl cellulose coat was applied to a hard gelatin capsule using an organic spray coating process. T50% drug release times varied between 245 (+/-33.4) and 393 (+/-40.8) minutes for 8% and 20% DCP, respectively, T50% release times of 91 (+/-22.1) and 167 (+/-34.6) were observed for 8% and 20% CSD; both formulations showed incidence of premature drug release. The SMCC formulations showed high variability due to lamination effects. The HPMC formulations had T50% release times of 69 (+/-13.9), 213 (+/-25.4), and 325 (+/-30.3) minutes for 15%, 24%, and 30% HPMC concentrations respectively, with no premature drug release. In conclusion, HPMC showed the highest reproducibility for a range of time-delayed drug release from the assembled capsule formulation. The method of capsule coating was confirmed to be important by investigation of the overall capsule integrity at elevated humidity levels. The erosion characteristics of ETs containing HPMC may be described by gravimetric loss. The novel time-delayed capsule device presented in this study may be assembled to include an erodible tablet with a known concentration of HPMC. A variety of suitable drugs for targeted chronopharmaceutical therapy can be incorporated into such a device, ultimately improving drug efficacy and patient compliance, and reducing harmful side effects.

Adrenergic beta-Antagonists↗

PubMed1999

Thyroid uptake of liquid versus capsule 131I tracers in hyperthyroid patients treated with liquid 131I.

The amount of 131I used to treat hyperthyroid patients is based in part on the 24-hour thyroid uptake of a diagnostic amount of radioiodine (tracer). We compared the 24-hour uptake of an 131I tracer administered in liquid or capsule form to the 24-hour uptake of 131I therapy administered as liquid. Sixty-five hyperthyroid patients with Graves' disease were evaluated and subsequently treated with radioiodine. The liquid group (45 patients) received a liquid 131I tracer (1.85 MBq [0.05 mCi]) and the capsule group (20 patients) received a capsule 131I tracer (1.63 MBq [0.044 mCi]). Probe calibration factors were the same for the liquid and capsule 131I standards. All patients received therapeutic amounts of 131I [114.7-1106.3 MBq [3.1-29.9 mCi]) in liquid form. Therapy uptakes were obtained using the same collimated uptake probe modified with a calibrated lead shield to attenuate the high photon flux. The mean therapeutic uptake was the same for both groups (58%). The mean diagnostic uptake for the capsule group, however, was less than the mean diagnostic uptake for the liquid group (44% vs. 63%). The mean diagnostic uptake for the capsule group was significantly lower than the mean therapeutic uptake for this group (44% vs. 58%), whereas the mean diagnostic and therapeutic uptakes were similar for the group receiving a liquid tracer (63% vs. 58%). In conclusion, diagnostic uptakes performed with a liquid tracer more accurately predicted liquid therapy uptakes than diagnostic uptakes performed with a capsule tracer. This raises concern about the bioavailability of 131I in capsule form and has implications for determining the amount of 131I to administer for therapy. Patients whose 131I therapy was based on the uptake of a capsule tracer received a higher than intended amount of radiation to the thyroid gland.

Administration, Oral↗

PubMed2001

An immunohistochemical study of the dorsal capsule of the lumbar and thoracic facet joints.

STUDY DESIGN: The molecular composition of the extracellular matrix in the dorsal capsules of lumbar and thoracic facet joints was analyzed immunohistochemically. OBJECTIVES: To determine whether the immunohistochemical profile of the lumbar joint capsule suggests a role of the capsule in limiting axial rotation of the lumbar motion segment. SUMMARY OF BACKGROUND DATA: During axial rotation of the lumbar vertebrae, the axis of rotation shifts toward the facet joints in the direction of rotation. Thus, the capsule of the opposing joint should become tensed and wrap around the inferior articular process. Previous studies suggest that wrap-around ligaments are fibrocartilaginous. However, thoracic joint capsules are largely shielded from such loading and should be purely fibrous. METHODS: Dorsal capsules were removed from lumbar and thoracic facet joints of six adult cadavers. Specimens were immunolabeled with monoclonal antibodies for collagens, chondroitin, dermatan and keratan sulfates, versican, tenascin, aggrecan and link protein. Antibody binding was detected using the Vectastain ABC 'Elite' peroxidase kit (Vector Laboratories, Inc., Burlingame, CA). RESULTS: Both lumbar and thoracic joint capsules immunolabelled for most glycosaminoglycans and for Type I, III and VI collagens. However, labeling for Type II collagen, chondroitin-6-sulfate, aggrecan, and link protein was restricted to lumbar capsules. Such labeling was constantly seen at entheses and occasionally in the midsubstance. CONCLUSIONS: The molecular composition of the lumbar joint capsule suggests that it acts as a fibrocartilaginous, 'wrap-around' ligament that withstands compression in addition to tension during torsional movements of the lumbar spine. It wraps around the inferior articular process as rotation occurs and limits further movement.

Adult↗