methylcellulose and Keratoconjunctivitis-Sicca

For patients with conditions requiring chronic rather than acute therapy, the advantages of collagen shields in providing high and sustained levels of drugs and/or lubricants to the cornea are outweighed by the difficulty of insertion of the shield and the problem of blurred vision. We have developed a delivery system in which collagen pieces suspended in a viscous vehicle can be instilled into the lower forniceal space, thereby simplifying application and reducing blurring of vision. The collagen pieces (Collasomes) can be formulated with various constituents such as antibiotics or cyclosporine, or with chemical alterations such as the inclusion of a lipid (Lacrisomes) for the treatment of dry eyes. In the normal eyes of volunteers, Collasomes hydrated in a solution of sodium fluorescein and suspended in a methylcellulose vehicle as a model for delivery of water-soluble drugs produced fluorescein concentrations 17 to 42 times higher in the cornea and 6 to 8 times higher in the aqueous humor, compared with fluorescein-containing vehicle alone. In a preliminary controlled study, 76% of patients with moderately severe keratoconjunctivitis sicca (KCS) preferred Lacrisomes to the vehicle control because of a more soothing effect and longer duration of comfort. All preparations were well tolerated by all study subjects. Current studies involve improving drug delivery by chemically modifying the collagen molecule to slow diffusion of the drug from the Collasome matrix, as well as varying the amount of cetyl alcohol and combining it with modified collagen in Lacrisomes to maximize comfort in patients with dry eyes.

Topics: Adult; Aged; Aged, 80 and over; Collagen; Double-Blind Method; Drug Delivery Systems; Fatty Alcohols; Female; Humans; Keratoconjunctivitis Sicca; Male; Methylcellulose; Middle Aged; Ophthalmic Solutions

In order to evaluate the therapeutic value of an unpreserved carboxymethylcellulose-based artificial tear in treatment of keratoconjunctivitis sicca (KCS), 56 patients with severe keratoconjunctivitis sicca were enrolled, at a single study center, in a randomized, double-masked, 8-week comparison with a preserved hydroxypropylmethylcellulose (HMC)-based artificial tear. Patients treated with the carboxymethylcellulose (CMC)-based tear showed significant improvement in fluorescein staining, symptoms, and impression cytology grades. Patients treated with HMC-based tears showed minimal improvement in a few variables. Impression cytology specimens were analyzed by a modified technique that maps the distribution of the various grades present on the specimen. With this technique, improvement in the cytology grades was noted in the group of patients using CMC-based tears. The improvement correlated with observed decreases in symptoms of discomfort and with scores for superficial punctate staining. This study supports the observed therapeutic value of unpreserved CMC-based artificial tears and suggests the possible reversal of squamous metaplasia in patients with KCS. Further studies are required to separate the benefit of the CMC formulation from the benefits of preservative elimination.

Topics: Carboxymethylcellulose Sodium; Cornea; Double-Blind Method; Drug Administration Schedule; Drug Tolerance; Epithelium; Humans; Hypromellose Derivatives; Keratoconjunctivitis Sicca; Methylcellulose; Ophthalmic Solutions; Ophthalmoscopy; Preservatives, Pharmaceutical; Visual Acuity

Patients with clinically well defined keratoconjunctivitis sicca (KCS) participated in two trials of hypo-osmolar tear substitutes. The trials were double masked, single crossover studies with computer generated random order allocation and were conducted by postal questionnaire. In the first trial a hypo-osmolar formulation using polyvinylpyrrolidone and hydroxyethyl cellulose was compared with the patients' usual treatment (BJ6 or hypromellose) and found to be inferior, especially in respect of blurring and stickiness caused by higher viscosity. In the second trial hypo-osmolar preparations of BJ6 and hypromellose were compared with their iso-osmolar equivalents and found not to be significantly different in their effects. Hypo-osmolarity alone does not seem to guarantee relief of symptoms in KCS. Other factors including viscosity and colloid osmotic pressure may be more significant.

Topics: Cellulose; Clinical Trials as Topic; Drug Combinations; Female; Humans; Hypotonic Solutions; Hypromellose Derivatives; Keratoconjunctivitis; Keratoconjunctivitis Sicca; Male; Methylcellulose; Middle Aged; Ophthalmic Solutions; Osmolar Concentration; Povidone; Xerophthalmia

Topics: Adult; Aged; Conjunctiva; Cornea; Drug Administration Schedule; Female; Humans; Keratoconjunctivitis Sicca; Lactose; Methylcellulose; Middle Aged; Ophthalmic Solutions; Oxazines; Rose Bengal; Tears

Solutions of hydroxypropylmethylcellulose (HPMC) and polyvinyl alcohol (PVA) are widely used as artificial tears. However, their usefulness is limited by the short duration of their effect. Dilute sodium hyaluronate (SH) solutions exhibit non-Newtonian rheology with high viscosities at low shear rates, which would be expected to enhance their ocular surface residence time. Using quantitative gamma scintigraphy, estimates of the ocular surface residence times of 0.3% HPMC, 1.4% PVA, and 0.2% SH were made in six patients with keratoconjunctivitis sicca. The sodium hyaluronate solution had a mean half-life on the ocular surface of 321 s, significantly longer than hydroxypropylmethylcellulose (44 s; p = 0.012) and polyvinyl alcohol (39 s; p = 0.013).

Topics: Biological Availability; Cornea; Half-Life; Humans; Hyaluronic Acid; Hypromellose Derivatives; Keratoconjunctivitis Sicca; Methylcellulose; Ophthalmic Solutions; Polyvinyl Alcohol; Radionuclide Imaging; Technetium Tc 99m Pentetate; Viscosity

The author reports on 16 patients (9 with keratoconjunctivitis sicca, 7 with Sjögren's syndrome) treated with Isopto-Naturale eye drops for 10 months. Reduction of photophobia, burning, dryness and foreign-body sensation were achieved by local administration of the drug 2 to 5 times a day. The lesions in the corneal epithelium also improved significantly during the treatment period. Thus, Isopto-Naturale eye drops have proved to be more effective than 1% methylcellulose or 1.4% PVA artificial tear eye drops in the treatment of dry-eye syndrome.

Topics: Humans; Hypromellose Derivatives; Keratoconjunctivitis; Keratoconjunctivitis Sicca; Methylcellulose; Ophthalmic Solutions; Sjogren's Syndrome

Topics: Humans; Iodine; Keratitis; Keratoconjunctivitis Sicca; Methylcellulose