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PubMed2002

Determination of the optimal amount of water in liquid-fill masses for hard gelatin capsules by means of texture analysis and experimental design.

The aim of this study is to use texture analysis as a non-destructive test for hard gelatin capsules filled with liquid formulations to investigate mechanical changes upon storage. A suitable amount of water in the formulations is determined to obtain the best possible compatibility with the gelatin shell. This quantity of water to be added to a formulation is called the balanced amount of water (BAW). Texture profiling was conducted on capsules filled with hydrophilic polymer mixtures and with formulations based on amphiphilic masses with high HLB value. The first model mixture consisted of polyethylene glycol 400 and polyvinylpyrrolidone K17 with water and the second type consisted of caprylocaproyl macrogol glycerides (Labrasol) with colloidal silica (Aerosil 200) and water. The liquid-fill capsules were investigated by measuring changes on mass and stiffness after storage under confined conditions in aluminium foils. Capsule stiffness was investigated also as a parameter in a response surface analysis to identify the BAW. Polyvinylpyrrolidone did not show a great influence on the BAW in the range of 10-12% (w/w) for the first model mixture. Capsules with the less hydrophilic Labrasol formulations, however, kept their initial stiffness after storage best with only half of that amount, i.e. 5-6% (w/w) of water in the compositions. From this study it can be concluded that texture profiling in the framework of an experimental design helps to find hydrophilic or amphiphilic formulations that are compatible with gelatin capsules. Short-term stability tests are meaningful if capsule embrittlement or softening is due to water equilibration or another migration process that takes place rapidly. Long-term stability tests will always be needed for a final statement of compatibility between a formulation and hard gelatin capsules.

Capsules↗

PubMed2001

Comparison of Scheimpflug images of posterior capsule opacification and histological findings in rabbits and humans.

PURPOSE: To compare the posterior capsule opacification in Scheimpflug photographic images produced by an electronic anterior eye segment analysis system with the histopathological findings in rabbits and humans. SETTING: Department of Ophthalmology, Wakayama Medical College, Japan. METHODS: Opacified posterior capsules were photographed using the EAS-1000 system (Nidek) and were then extracted during vitreous surgery for proliferative diabetic retinopathy or proliferative vitreoretinopathy in 2 patients. In rabbits, phacoemulsification and aspiration (PEA) with intraocular lens (IOL) implantation was performed. The IOL was implanted in the bag or in the sulcus. After intervals of healing, the posterior capsule was photographed with the EAS-1000 and the animals were then killed. In both clinical and experimental specimens, the posterior capsule was processed for light microscopic histology and immunohistochemistry. RESULTS: Opacified human capsules were well imaged by the EAS-1000. Histology showed that lens epithelial cells proliferated with and without an accumulation of extracellular matrix. Details such as rolling of the capsulotomy edge were seen well. Regenerated lens fibers of Soemmering's ring were seen as a mass within the capsule. In the rabbit model, Scheimpflug images accurately represented the capsules as they appeared histologically. CONCLUSION: The EAS-1000 system provided faithful, relatively high-resolution images that corresponded to the histologic findings in the posterior capsules after PEA-IOL surgery in humans and rabbits.

Aged↗

PubMed2001

Capsular bending ring to prevent posterior capsule opacification: 2 year follow-up.

PURPOSE: To evaluate the preventive effect of a capsular bending ring on anterior and posterior capsule (PCO) opacification in a 2 year clinical study. SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: This study comprised 60 patients with senile cataract (35 women, 25 men) with a mean age of 69 years. An open poly(methyl methacrylate) capsular bending ring with a truncated edge profile designed to create a sharp bend in the equatorial capsule was implanted in 1 eye of patients with a hydroxyethyl methacrylate intraocular lens (IOL). The contralateral eye, which acted as a control, received an IOL but no ring. Patients were examined 6 months (n = 52), 1 year (n = 48), and 2 years (n = 42) postoperatively. Anterior capsule opacification was determined by slitlamp evaluation. Anterior capsule shrinkage (area within the capsulorhexis) and PCO were evaluated and scored using a computer software package for image analysis. Posterior capsule opacification was also measured by the rate of neodymium:YAG (Nd:YAG) capsulotomies. RESULTS: Anterior capsule opacification and shrinkage were significantly less in eyes with the ring. The mean PCO score was 0.235 +/- 0.215 (SD), 0.287 +/- 0.200, and 0.398 +/- 0.248 with the ring and 0.530 +/- 0.190, 0.670 +/- 0.225, and 1.111 +/- 0.298 without the ring at 6 months, 1 year, and 2 years, respectively (P <.01 at each follow-up). An Nd:YAG laser capsulotomy was performed in 4 eyes with and 17 eyes without the ring after 2 years (P <.01). CONCLUSIONS: The capsular bending ring significantly reduced anterior capsule fibrosis and shrinkage as well as PCO. The ring may be useful in patients who are at high risk of developing eye complications from capsule opacification that require Nd:YAG laser capsulotomy, in those expected to have vitreoretinal surgery and photocoagulation, and in cases of pediatric cataract.

Aged↗

PubMed2003

Thinning of the anterior capsule associated with congenital aniridia.

PURPOSE: To report the unusual finding of intraoperative fragility of the anterior capsule in some patients with congenital aniridia and determine the histopathologic etiology of this finding. SETTING: Cincinnati Eye Institute, Cincinnati, Ohio, USA. METHODS: Anterior lens capsule specimens were obtained from aniridic and nonaniridic patients during cataract surgery. The intraoperative behavior of each capsule was noted, after which the specimens were submitted for histopathologic evaluation. RESULTS: All anterior capsule specimens from the nonaniridic patients were of normal thickness. Some, but not all, anterior capsule specimens from the aniridic patients were remarkably thin. Thin capsules were associated with extreme intraoperative fragility. CONCLUSIONS: Greater awareness of anterior capsule fragility in some aniridic patients may reduce the risk of capsule complications and lead to safer surgical outcomes.

Adult↗

PubMed2003

Inhibition of lens epithelial cell migration at the intraocular lens optic edge: role of capsule bending and contact pressure.

PURPOSE: To evaluate the inhibitory effect of a sharp intraocular lens (IOL) optic edge, a sharp capsule bend, and contact pressure between the optic edge and posterior capsule on lens epithelial cell (LEC) migration. SETTING: Department of Ophthalmology, Kyorin University, Tokyo, Japan. METHODS: This in vitro laboratory study evaluated a tumble-polished convex-plano IOL (CP group), an AcrySof IOL (Alcon) with a sharp edge (AS group), a new IOL with a round ridge (RR group), and a new IOL with a sharp ridge (SR group). The 2 new IOLs have high ridges and high angled loops that create firm contact between the ridge and posterior capsule. After sham cataract surgery, an IOL and a capsular tension ring (CTR) were implanted in the capsular bag of rabbit eyes. The extracted capsular bags containing the CTR and IOL were cultured. The inhibitory effect of each IOL on cell migration was analyzed. Furthermore, LEC migration on the posterior capsule was compared in culture between capsules having a sharp right angle and those with gradually curving bends. RESULTS: The inhibitory effect on cell migration was statistically greatest in the SR group followed by the RR, AS, and CP groups. A sharp capsule bend did not inhibit cell migration. CONCLUSIONS: The results suggest that inhibition of cell migration at the optic edge is regulated by the degree of contact pressure between the optic edge and posterior capsule. A sharp capsule bend might indicate strong contact but does not in itself inhibit cell migration.

Animals↗

PubMed1999

Use of a polylysine-saporin conjugate to prevent posterior capsule opacification.

PURPOSE: To determine the feasibility of applying a polylysine-saporin (PLS) conjugate to the lens capsule at surgery to prevent lens epithelial cell (LEC) proliferation and posterior capsule opacification (PCO). SETTING: Department of Research & Development, Bausch & Lomb Surgical, and Department of Ophthalmology, Saint Louis University, St. Louis, Missouri, USA. METHODS: Fluorescein-labeled polylysine was applied to the lens capsule of rabbits after phacoemulsification and analyzed histologically to determine the extent of binding to the lens capsule and surrounding tissues. The cytotoxin saporin was conjugated to polylysine using bifunctional cross-linkers. This PLS conjugate was applied to LECs in culture and to the lens capsules of rabbits. These eyes were monitored for PCO. RESULTS: Polylysine primarily bound to the lens capsule membranes, with little or no binding to surrounding tissues. When PLS was added to LECs in culture, it was internalized and destroyed the cells. Of 9 rabbit eyes treated with PLS during surgery, 1 remained free of PCO for the life of the animal (40 weeks), while 6 showed a delay of cortical regrowth approximately 2 to 3 times that of control eyes. CONCLUSIONS: Polylysine bound selectively to the lens capsule membrane. The PLS conjugation resulted in a toxic agent that targeted the lens capsule and destroyed proliferating LECs. The application of a PLS conjugate during surgery may prevent PCO.

Animals↗

PubMed2000

Effect of surgical technique on in vitro posterior capsule opacification.

PURPOSE: To compare the effect of different cataract extraction surgical techniques on residual lens epithelial cell (LEC) density and cell regrowth rates using an in vitro model of posterior capsule opacification (PCO). SETTING: Comparative Ophthalmology Research Laboratories, North Carolina State University, Raleigh, North Carolina, USA. METHODS: Lens capsule explants were prepared from freshly enucleated canine globes after extracapsular cataract extraction (ECCE), phacoemulsification, or phacoemulsification followed by capsule vacuuming. Initial cell density on the capsule and cell proliferation were determined by phase contrast microscopy. The effects of the surgical technique on time to confluent growth of the cells across the posterior lens capsule were determined. RESULTS: Residual cell density on the remaining anterior capsule immediately after lens removal was 31.6% +/- 19.3%, 16.1% +/- 8.9%, and 7.7% +/- 5.7% in the ECCE, phacoemulsification, and phacoemulsification/capsule-vacuuming groups, respectively. Time to confluence (range 5.0 to 6.3 days) was not significantly different among the 3 groups when the lens capsules were cultured in serum-supplemented media. The confluence rate was significantly longer (by approximately 5 to 7 days) in the phacoemulsification/capsule-vacuuming group than in the other 2 groups when the capsules were cultured in serum-free media. CONCLUSIONS: Phacoemulsification with and without anterior and equatorial capsular vacuuming led to less initial LEC density in the capsular bag than ECCE. However, because cell proliferation rates among the 3 groups were only marginally affected, near 100% removal of LEC at the time of cataract extraction may be necessary to prevent PCO.

Animals↗

PubMed2004

Permeability and conductivity of red blood cell templated polyelectrolyte capsules coated with supplementary layers.

The permeability of ions and small polar molecules through polyelectrolyte multilayer capsules templated on red blood cells was studied by means of confocal microscopy and electrorotation. Capsules were obtained by removing the cell after polyelectrolyte multilayer formation by means of NaOCl treatment. This procedure results in cross-linking of poly(allylamine hydrochloride) (PAH) molecules and destroying poly(styrene sulfonate) (PSS) within the multilayer. Capsules are obtained being remarkably different from layer-by-layer (LbL) capsules. These capsules are rather permeable for low as well as for high molecular weight species. However, upon adsorption of extra polyelectrolyte layers the permeability decreased remarkably. The assembly of six supplementary layers of PAH and PSS rendered the capsule almost impermeable for fluorescein. Resealing by supplementary layers is a potential means for filling and release control. By means of electrorotation measurements, it was shown that the capsule walls obtained isolating properties in electrolyte solutions. Conclusions are drawn concerning the mechanism of permeability through cell templated polyelectrolyte multilayer capsules.

Capsules↗

PubMed1999

Uneven distribution and size of rabbit lens capsule proteoglycans.

To document the ultrastructural distribution of lens capsule proteoglycans, rabbit lens capsules were fixed and stained overnight in 50 mM sodium acetate, pH 5.6, containing 2.5% glutaraldehyde, 0.2% Cuprolinic Blue and 0.2 M MgCl2. They were rinsed, stained with 1% aqueous sodium tungstate, embedded in Epon, sectioned (60 nm), and examined with an electron microscope at 60 kV. Proteoglycan-Cuprolinic Blue complexes mainly appeared as networks of small electron-dense filaments throughout the posterior and anterior capsules. The posterior capsule was a single layer with a network of small proteoglycan filaments gradually decreasing in size from the humoral side (90 x 10 nm) to the lenticular side (30 x 8 nm). The humoral side of the anterior capsule had a thin lamina (400 nm) containing large (180 x 40 nm), very electron-dense proteoglycan-Cuprolinic Blue complexes plus small proteoglycans. Below this lamina, the complexes were only seen as filaments slightly smaller than those in the corresponding area of the posterior capsule. Cuprolinic Blue binding of the anterior and posterior lens capsules revealed differences in the size and distribution of their sulphated proteoglycans which do not correspond to the patterns of their immunoreactivity with anti-heparan sulphate proteoglycan. The humoral lamina in the anterior capsules, with large proteoglycan structures, might be a distinct structural and functional compartment.

Animals↗

PubMed1991

Effect of food on the bioavailability of cyclandelate from commercial capsules.

The bioavailability of five capsules of cyclandelate that are commercially available in Japan was determined in ten healthy volunteers by measuring mandelic acid (a main metabolite of cyclandelate) excreted in the urine. Bioinequivalence among the five capsules was demonstrated. The relative cumulative excretion of mandelic acid of the most poorly bioavailable capsule was 38% of the most highly bioavailable capsule. The effect of food on the bioavailability of these two capsules was investigated by use of two different kinds of food, one containing fat and one containing high carbohydrates but very low fat. The bioavailability of the two capsules was increased when subjects consumed both types of food before drug administration, although there was a greater effect on bioavailability with food containing fat. This suggests that the absorption of cyclandelate was incomplete in fasting subjects, even from the capsule with the highest bioavailability. Bioinequivalence between the two capsules remained after postprandial drug administration.

Administration, Oral↗

PubMed2003

Expression of CD18, CD49b, CD49c and CD49e on lens anterior capsules in human cataracts.

PURPOSE: To examine the lens epithelial cells obtained from the anterior lens capsules removed during cataract surgery and detect various subclasses of the cell surface adhesion molecules known as integrins. METHODS: The circular sections of anterior capsules with attached lens epithelial cells (LECs) were obtained during cataract surgery from 28 patients. The lens capsules were immunohistochemically stained. RESULTS: CD49b CD49c, CD49e, and CD18 were detected in varying degrees in specimens obtained from human cataractous lenses. The positive percentages were 33, 75, 33, and 20%, respectively. The most striking feature was the increasing staining profiles towards the edges of the capsules (away from the central part of the lens capsules) for CD49c, suggesting that the LECs showed higher immunoreactivity for this antibody. The immunoreactivity for CD49b and CD49e was weaker. This was absent for CD18 in the central part of the lens capsules. CONCLUSION: The positive expression of antibodies suggests that specific integrin subunits were expressed in LECs of human cataracts. These results suggest that lens epithelial cells expressing CD49b, CD49c, CD49e, and CD18 might be precursors in the process of anterior lens epithelial cell (A cell) adhesion, and hence play a role in anterior capsule opacification or in subsequent migration and a possible role in posterior capsule opacification.

Aged↗

PubMed2002

Colonic delivery of 4-aminosalicylic acid using amylose-ethylcellulose-coated hydroxypropylmethylcellulose capsules.

BACKGROUND: 4-Aminosalicylic acid has the potential for use in the treatment of diseases of the colon. AIM: To assess the feasibility of delivering 4-aminosalicylic acid directly to the colon using a hydroxypropylmethylcellulose capsule coated with a mixture of amylose, a polysaccharide metabolized by bacterial enzymes in the colon, and ethylcellulose. METHODS: Seven healthy male volunteers received, on three separate occasions, an uncoated or amylose-ethylcellulose-coated hydroxypropylmethylcellulose capsule containing 4-aminosalicylic acid Na (550 mg), or an intravenous injection of 4-aminosalicylic acid Na (135 mg). The capsules were radiolabelled with 99mTc to allow their positions in the gastrointestinal tract to be followed using a gamma camera. Plasma and urine samples were collected and assayed for 4-aminosalicylic acid and metabolite concentrations. RESULTS: The uncoated capsules broke down within 10 min in the stomach, allowing rapid and complete absorption of the drug. The coated capsules remained intact in the upper gastrointestinal tract, and had a median gastric emptying time of 61 min (interquartile range, 77 min) and a median colon arrival time of 363 min (interquartile range, 185 min). For the coated capsules, only the metabolite was detected in the plasma and/or urine after the capsules had reached the colon. CONCLUSIONS: The specific coating protected the drug until the capsule reached the colon, where 4-aminosalicylic acid was slowly released and absorbed. Thus, such a formulation has the potential for use in the treatment of inflammatory bowel disease.

Adult↗

PubMed1995

[Silicone one piece intraocular implant and anterior capsule fibrosis].

BACKGROUND: Foldable plate haptic silicone intraocular lenses (IOLs) were surmised to produce greater anterior capsule fibrosis than poly(methyl metacrylate) (PMMA) intraocular lenses. MATERIAL AND METHODS: A retrospective study of 34 eyes was carried out 12 to 15 months after phacoemulsification. All surgical procedures were performed by the same surgeon (M.G.) using two different techniques: 17 eyes were operated on through a temporal clear-cornea incison and implanted with a foldable plate haptic silicone IOL (STAAR AA4203); 17 eyes were operated on through a superior sclerocorneal incision and received a PMMA IOL (Kabi Pharmacia 809P). Secondary opacification of the anterior capsule was compared between the two groups. RESULTS: Seventy percent of eyes (12/17) with plate haptic silicone IOL had moderate or important anterior capsule fibrosis or shrinkage. Only 18% of eyes (3/17) with PMMA IOL presented with this complication. However, posterior capsule opacification was almost similar in both groups. CONCLUSION: Foldable plate haptic silicone IOLs seem to produce a more important anterior capsule fibrosis or shrinkage than PMMA IOL one year after phacoemulsification and saccular implantation. Although etiology is unknown, either huge contact between IOL and anterior capsule, or lack of contact between anterior and posterior capsules are hypotheses advanced. Posterior capsule opacification is similar in the two groups.

Fibrosis↗

PubMed2000

Matrix metalloproteinases and tissue inhibitors of metalloproteinases of fibrous humans lens capsules with intraocular lenses.

PURPOSE: We located immunohistochemically the matrix metalloproteinases (MMP) -1, -2, -3 and -9 and the tissue inhibitors of matrix metalloproteinases (TIMP) -1 and -2 in the fibrous capsule of patients with intraocular lenses (IOLs). METHODS: During vitreoretinal surgery in 10 patients we obtained post-cataract surgery lens capsules with or without an IOL. The mean interval between the previous cataract operation and the extraction of the specimens was 35.2 months (range: 2-120 months). Circular sections of the anterior capsule with lens epithelial cells (LECs) were also obtained during cataract surgery. Specimens were processed for immunohistochemical identification of MMPs and TIMPs by light microscopy. RESULTS: While all the members of MMPs and TIMPs were not detected in the normal anterior capsules, they were detected in the ECM and/or LECs on the lens capsules extracted within 18 months after IOL implantations in all of the 4 patients, but were not observed in specimens obtained 18 months or longer postoperatively. In LECs of 1 capsule specimen 10 years postoperatively, MMP-1, but not other MMPs and TIMPs, was detected. CONCLUSIONS: MMPs and TIMPs were detected in the ECM and/or LECs on post-cataract surgery capsules. These proteins may be remodeling the newly deposited ECM and regulating LEC behavior on residual lens capsules in the early phase of healing after cataract surgery.

Adult↗

PubMed2002

The in vitro dissolution of theophylline from different types of hard shell capsules.

The in vitro dissolution of theophylline from two-piece hard shell capsules has been investigated using different types of capsule shells (gelatin, gelatin/polyethylene glycol, hydroxypropyl methylcellulose), different formulations, different capsule fill weights, and different tamping forces. Analysis of variance confirmed that the formulation and the capsule shell materials were the most important factors influencing drug dissolution. The maximum extent of drug dissolution was significantly increased when hydroxypropyl methylcellulose (HPMC) capsules were used. The mean dissolution time (MDT) was significantly reduced, indicating a faster dissolution rate of the drug from HPMC capsules. The addition of microfine cellulose to the formulations as filler reduced the MDT in all cases, whereas the addition of lactose monohydrate did not enhance drug dissolution. The study confirmed that a change from gelatin hard shell capsules to gelatin/PEG or HPMC hard shell capsules should not pose problems with respect to drug absorption or bioavailability.

Administration, Oral↗

PubMed2001

Pharmacokinetic comparison of omeprazole capsules and a simplified omeprazole suspension.

The pharmacokinetics of omeprazole delayed-release capsules and a simplified omeprazole suspension (SOS) were studied. Seven healthy volunteers randomly received either one 20-mg omeprazole delayed-release capsule or SOS (omeprazole 20 mg in 10 mL) for seven days before being crossed over to the opposite treatment for seven more days after a two-week washout period. On days 1 and 7, blood samples were drawn at intervals up to 360 minutes after drug administration. Plasma omeprazole concentrations were determined by a validated high-performance liquid chromatographic method, and pharmacokinetic values were determined. Area under the concentration-versus-time curve (AUC) from zero to six hours, AUC from time zero to infinity (AUC0-infinity), and maximum plasma concentration (Cmax) increased by 102%, 113%, and 85%, respectively, after seven days of treatment with the capsule. AUC0-infinity for SOS on day 1 was 58% of that for the capsule (p = 0.0141), and on day 7 it was 49% of that for the capsule (p = 0.0044). AUC0-infinity for SOS increased by 85% from day 1 to 7, but the difference was not significant. Cmax for SOS on day 1 was twice that for the capsule (p = 0.0014), but by day 7 the difference between the two formulations was negligible. Time to Cmax (tmax) for SOS on days 1 and 7 was shorter than for the capsule by 82% (p < 0.0001) and 70% (p < 0.0006), respectively. After one week of therapy, omeprazole absorption was faster and tmax was 70% shorter for SOS than for the capsule formulation, but AUC0-infinity was 49% lower for SOS.

Adult↗

PubMed1996

A morphological study of the fibrous capsule of the human lumbar facet joint.

STUDY DESIGN: Macroscopic and microscopic investigations of the human lumbar facet joint capsule were undertaken. OBJECTIVE: To describe the morphologic characteristics of the fibrous capsule of the lumbar facet joints. SUMMARY OF BACKGROUND DATA: Previous biomechanical and neurophysiologic studies by the authors have shown that the lumbar facet joint capsule may be a source of low back pain. METHODS: Macroscopic investigation was performed on the facet joint capsules dissected from five fresh adult cadavers. For microscopic studies, facet joint capsules obtained from cadaver dissection and spinal surgeries were stained by the hematoxylin and eosin method and the Elastica-Van Gieson method. RESULTS: The outer layer of the fibrous capsule is a dense regular connective tissue that is composed of parallel bundles of collagenous fibers. The inner layer of the fibrous capsule consists of bundles of elastic fibers, similar to the ligamentum flavum. In the superior and middle part of the joint, the fibers run in the medial to lateral direction, crossing over the joint gap. In the inferior part of the joint, the fibers are relatively long and run in a superior-medial to inferior-lateral direction, covering the inferior articular recess. They are thicker than the layer in the superior and middle parts of the joint. CONCLUSIONS: Anatomical and histologic features of the lumbar facet joint capsule are different between its outer layer and inner layer. This complex of morphologic factors can affect the biomechanics and neurophysiology of the lumbar facet joint.

Adult↗

PubMed1992

Effect of capsulation on the resistance of Staphylococcus aureus to the bactericidal lipids produced in abscesses.

Staphylococcus aureus strains differ in their sensitivity to some of the bactericidal lipids produced by the host in staphylococcal abscesses. To evaluate whether the presence of a capsule might account for these differences, capsulate and non-capsulate S. aureus strains were compared for their sensitivity to staphylococcal abscess homogenates and the neutral lipid fraction derived from such material. Although the presence of a capsule appeared to reduce sensitivity, two non-capsulate mutants were only about three-to-four times more sensitive than their capsulate parent strains. Another strain, known for its resistance to these bactericidal lipids, was not capsulate. This suggests that mechanisms other than capsule formation must also determine sensitivity to the lipids.

Abscess↗