methylcellulose and Glaucoma

Nine symmetrical ocular hypertensives used Adsorbocarpine in one eye and Isoptocarpine in the other. Each medication was given twice daily for one week, then Isoptocarpine was used 4 time daily. The 2 drugs were equally effective as twice daily medications while Isoptocarpine 4 times daily was significantly more effective than either given twice daily. The pH of the Adsorbocarpine may not have been optimal although commercially available solutions were used. The results indicated that pilocarpine in either vehicle can lower intraocular pressure when given less than 4 times daily; however, conclusive studies are needed before this can be recommended as a widespread clinical practice.

Topics: Clinical Trials as Topic; Delayed-Action Preparations; Drug Administration Schedule; Female; Glaucoma; Humans; Male; Methylcellulose; Ophthalmic Solutions; Pharmaceutical Vehicles; Pilocarpine; Povidone

In a double-blind study no significant difference was found in intraocular pressure control, mean pressure or comparative binocular intraocular pressure difference between pilocarpine in Adsorbobase compared to pilocarpine in 0.5% hydroxypropl-methylcellulose solution. Intraocular pressure control was achieved on fewer than 60% of visits using pilocarpine twice daily in either of the 2 vehicles. While pilocarpine retained some residual hypotensive effect 12 hours after application, twice-daily dosage with the solutions tested gave inadequate control for clinical usefulness.

Topics: Adult; Aged; Benzalkonium Compounds; Clinical Trials as Topic; Delayed-Action Preparations; Drug Administration Schedule; Edetic Acid; Evaluation Studies as Topic; Female; Glaucoma; Humans; Intraocular Pressure; Male; Methylcellulose; Middle Aged; Ophthalmic Solutions; Pharmaceutical Vehicles; Pilocarpine; Povidone

Topics: Chronic Disease; Clinical Trials as Topic; Drug Synergism; Drug Therapy, Combination; Glaucoma; Guanethidine; Humans; Intraocular Pressure; Methylcellulose; Ophthalmic Solutions; Pilocarpine

The bioavailability of therapeutic agents from eye drops is usually limited due to corneal barrier functions and effective eye protective mechanisms. Therefore, the current study aims to enhance ocular bioavailability of brimonidine, a potent antiglaucoma drug, through the preparation of ocular inserts. Solvent casting technique was employed to prepare the inserts using polyvinylpyrrolidone K-90 (PVP K-90) as film-forming polymer blended with different viscosity grades of bioadhesive polymers namely hydroxypropyl methycellulose, carbopol, sodium alginate, and chitosan. The prepared ocular inserts were evaluated for various physicochemical parameters, swelling behavior, and in vitro release patterns. Sodium alginate-based ocular inserts revealed the most sustainment in drug release (99% at 6 h), so it was selected for further modifications via coating it, on one side or dual sides, using hydrophobic film composed of either ethylcellulose or Eudragit RSPO. The obtained in vitro release results for the modified ocular inserts revealed that ethylcellulose is superior to Eudragit RSPO in terms of brimonidine release sustainment effect. Ocular inserts composed of 7% PVP K-90, 1.5% low molecular weight sodium alginate with or without ethylcellulose coat were able to sustain the in vitro release of brimonidine. Their therapeutic efficacy regarding intraocular pressure (IOP) lowering effect when inserted in albino rabbits eyes showed superior sustainment effect compared with that of brimonidine solution. Furthermore, due to both the mucoadhesive property and the drug sustainment effect, the one-side-coated ocular insert showed more IOP lowering effect compared with that of its non-coated or dual-side-coated counterpart.

Topics: Absorbable Implants; Acrylic Resins; Administration, Ophthalmic; Adrenergic alpha-2 Receptor Agonists; Alginates; Animals; Brimonidine Tartrate; Calorimetry, Differential Scanning; Cellulose; Chemistry, Pharmaceutical; Chitosan; Delayed-Action Preparations; Disease Models, Animal; Drug Carriers; Drug Compounding; Glaucoma; Glucuronic Acid; Hexuronic Acids; Hydrophobic and Hydrophilic Interactions; Hypromellose Derivatives; Intraocular Pressure; Kinetics; Methylcellulose; Ophthalmic Solutions; Polymers; Polymethacrylic Acids; Polyvinyls; Povidone; Quinoxalines; Rabbits; Solubility; Spectroscopy, Fourier Transform Infrared; Technology, Pharmaceutical; X-Ray Diffraction

Glaucoma is a chronic and progressive optic nerve neuropathy involving the death of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is considered to be the major risk factor associated with the development of this neuropathy. The objective of the present study was to compare the effects on RGC survival of three different experimental methods to induce chronic elevation of IOP in rats. These methods were: (i) injections of latex microspheres into the eye anterior chamber; (ii) injections into the anterior chamber of a mixture of microspheres plus hydroxypropylmethylcellulose (HPM) and (iii) cauterization of three episcleral veins. The IOP of right (control) and left (glaucomatous) eyes was measured with an applanation tonometer in awake animals. Thirteen to 30 weeks later, RGCs were retrogradely labeled with 3% fluorogold. Subsequently, we analyzed the density of RGCs, as well as the major axis length and area of RGC soma resulting from the application of each method. A significant increase in IOP was found following application of each of the three methods. Cell death was evident in the glaucomatous eyes as compared to controls. However, no statistical differences were found between the extent of cell death associated with each of the three methods. IOP increase also induced a significant increase in the size of the soma of the remaining RGCs. In conclusion, the three methods used to increase IOP induce a similar degree of RGC death. Moreover, the extent of cell death was similar when the retinas were maintained under conditions of elevated IOP for 24 weeks in comparison to 13 weeks.

Topics: Animals; Anterior Chamber; Cautery; Cell Count; Cell Death; Cell Size; Cell Survival; Disease Models, Animal; Female; Glaucoma; Hypromellose Derivatives; Injections; Intraocular Pressure; Latex; Methylcellulose; Microspheres; Ophthalmic Solutions; Rats; Rats, Sprague-Dawley; Retinal Ganglion Cells; Sclera; Veins

The changes in intraocular pressure and pupil size in glaucomatous dogs were evaluated after instillations of 0.03% bimatoprost (Lumigan, Allergan, Irvine, CA USA) once in the morning, or once in the evening, or twice daily in five day multiple dose studies. Applanation tonometry (IOP) and pupil size (PS) measurements were obtained at 8 am, 10 am, 12 noon, 2 pm, and 4 pm in 8 glaucoma dogs. Methylcellulose (0.5% as placebo) was instilled in the control eye, and 0.03% bimatoprost was instilled in the opposite drug eye. Methylcellulose (0.5%) and 0.03% bimatoprost were instilled the second through the fifth days with instillations in the morning (8:30 am), or evening (8 pm), or twice daily (8:30 am and 8 pm). The mean +/- SEM diurnal changes in IOP from baseline values after 0.03% bimatoprost at 8 am once daily for the next four days were 25.0 +/- 3.2 mm Hg, 25.6 +/- 2.9 mm Hg, 25.5 +/- 3.0 mm Hg, and 26.0 +/- 3.2 mm Hg respectively, and were significantly different from the control eye. After bimatoprost was instilled at 8 pm, the mean +/- SEM changes in IOP from baseline values in the drug eyes were 27.3 +/- 2.4 mm Hg, 26.6 +/- 2.2 mm Hg, 27.2 +/- 2.5 mm Hg, and 27.3 +/- 2.6 mm Hg respectively. When 0.03% bimatoprost was instilled twice daily, the mean +/- SEM changes in IOP from baseline values were 39.1 +/- 2.3 mm Hg, 39.9 +/- 2.2 mm Hg, 39.9 +/- 2.3 mm Hg, and 39.6 +/- 2.1 mm Hg respectively, and were significantly different from the control eyes. Miosis of varying duration was frequent during the three studies. Bimatoprost instilled once daily (am or pm) as well as twice daily produces significant decreases in IOP and PS in the glaucomatous Beagle.

Topics: Amides; Animals; Bimatoprost; Cloprostenol; Dogs; Drug Administration Schedule; Female; Glaucoma; Intraocular Pressure; Lipids; Male; Methylcellulose; Ophthalmic Solutions; Placebos; Pupil

To establish models of experimental glaucoma in rabbits to investigate the treatment of glaucoma.. Twenty-one normal albino rabbits weighing 2.5 - 3.0 kg were studied. The rabbits were divided randomly into 4 groups: I, II, III and IV. Anterior chamber injection of 0.1 ml of 0.3% carbomer (I), 0.2 ml of methylcellulose (II), 0.2 ml of compound methylcellulose (III) and subconjunctival injection of 5 mg of dexamethasone (IV) were performed respectively on them to induce glaucoma. The intraocular pressure (IOP) was monitored with a Tono-pen XL tonometer several times prior to injection and 2 times per week after injection. The basic IOP in every group served as control.. Experimental glaucoma occurred in eleven of twelve eyes in group I and IOP lasted from 20 to 50 days. The mean IOP levels were 29 - 35 mmHg (1 mm Hg = 0.133 kPa) and the peak IOP levels were 37 - 45 mm Hg. The IOP in 2 out of 10 eyes in group II increased to 22 - 50 mm Hg and lasted for 3 days. The IOP of 1 out of 10 eyes in group III increased to 25 - 40 mm Hg and lasted for 4 days. The IOP in eyes of group IV increased only 3 mmHg in the mean and lasted for one week. According to the standard, IOP above 22 mmHg for one week as the successful experimental glaucoma, group II and III were not the ideal ones and group IV was a failure.. Experimental glaucoma model induced by carbomer has the advantages of producing moderate and sustained IOP elevation. The model is easy to be carried out. It is simple, reliable, and useful for investigating optic nerve and retinal damage in glaucoma and testing the toxicity and efficacy of various therapies.

Topics: Acrylic Resins; Animals; Dexamethasone; Disease Models, Animal; Female; Glaucoma; Intraocular Pressure; Male; Methylcellulose; Rabbits

The anterior chamber tamponade with Healon and 2.5% solution of hydroxymethyl-cellulose has been applied in 10 patients, aged 9-65 years, during antiglaucomatous surgery connected with interscleral dislocation of iris. The tamponade prevented the rupture of blood vessels of iris. Bleeding connected with the cutting of blood vessels was stopped by filling the anterior chamber with viscoelastic substance under increased pressure. It was possible to preserve the anterior chamber during surgery. The properties of Healon and 2.5% solution of hydroxymethyl-cellulose were similar.

Topics: Adolescent; Adult; Aged; Child; Glaucoma; Humans; Hyaluronic Acid; Hyphema; Intraoperative Complications; Methylcellulose; Middle Aged

Heavily pigmented eyes have been shown to be relatively resistant to pilocarpine, and present special problems in management of open-angle glaucoma. Studies have suggested that the hypotensive effect of pilocarpine may be influenced by the vehicle; therefore, 13 relatively resistant black patients (26 eyes) were selected for a clinical comparison of pilocarpine as delivered in two different polymer vehicles. One vehicle was composed of 1.67% polyvinylpyrrolidone and BP water-soluble polymers (Adsorbobase); the other of hydroxypropyl methylcellulose 0.5%. All patients had been under treatment with the pilocarpine/methylcellulose preparation; 20 of the 26 eyes were judged to be uncontrolled (IOP above 21 mm Hg). Control of intraocular pressure was promptly obtained with the pilocarpine/Adsorbobase solution, and maintained at lower pilocarpine concentrations than with the previous therapy. Often, frequency of instillation could be decreased. This clinical comparison suggests that the Adsorbobase vehicle appreciably enhances corneal penetration and availability of pilocarpine. Three cases are discussed demonstrating the need for titration when instituting a new therapy with as little as one fourth the concentration of the previous pilocarpine therapy.

Topics: Aged; Black People; Eye Color; Female; Glaucoma; Humans; Intraocular Pressure; Male; Methylcellulose; Middle Aged; Pharmaceutical Vehicles; Pilocarpine; Polymers; Povidone

Topics: Administration, Topical; Echothiophate Iodide; Female; Glaucoma; Humans; Intraocular Pressure; Male; Methods; Methylcellulose; Miotics; Pharmaceutical Vehicles; Pilocarpine; Time Factors; Tonometry, Ocular

Topics: Animals; Choroid; Disease Models, Animal; Eye; Glaucoma; Inbreeding; Intraocular Pressure; Methylcellulose; Optic Nerve; Rabbits; Retinal Vessels

Topics: Animals; Ciliary Body; Eye Injuries; Glaucoma; Hemorrhage; Intraocular Pressure; Methylcellulose; Rabbits; Rupture

Topics: Acrylic Resins; Adolescent; Adult; Aged; Child; Child, Preschool; Eye Diseases; Eye Injuries; Eye Neoplasms; Eye, Artificial; Female; Follow-Up Studies; Glaucoma; Humans; Male; Melanoma; Methods; Methylcellulose; Middle Aged; Nystagmus, Pathologic; Ophthalmic Solutions; Ophthalmologic Surgical Procedures; Pemphigus; Postoperative Complications; Silicones; Suture Techniques; Trachoma

Topics: Adult; Aged; Cornea; Glaucoma; Gonioscopy; Humans; Methods; Methylcellulose; Middle Aged; Ointments; Rose Bengal

Topics: Animals; Anterior Chamber; Cranial Nerve Injuries; Dogs; Epinephrine; Eye; Eye Injuries; Glaucoma; Injections; Intraocular Pressure; Iris; Isoflurophate; Methylcellulose; Nitrogen Mustard Compounds; Rabbits; Sympathomimetics; Synaptic Transmission

Topics: Animals; Glaucoma; Intraocular Pressure; Methylcellulose; Optic Nerve; Rabbits; Retina; Thiamine

Topics: Animals; Antihypertensive Agents; Glaucoma; Intraocular Pressure; Mannitol; Methylcellulose; Ocular Hypertension; Pharmacology; Rabbits; Research; Tonometry, Ocular

Topics: Glaucoma; Methylcellulose; Pilocarpine