Scintigraphic assessment of an ophthalmic gelling vehicle in man and rabbit

Greaves, Jane; Wilson, Clive G.; Rozier, Annouk; Grove, Jeffrey; Plazonnet, Bernard

doi:10.3109/02713689008999606

Cited by 64 publications

(19 citation statements)

References 8 publications

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“…However, in another study, we examined contrast sensitivity function after instillation of timolol gel-forming solution, which is the same drug used in this study, and found that the gel-forming solution significantly decreased contrast sensitivity for at least 5 min following instillation, whereas standard timolol solution (without gels) did not reduce contrast sensitivity. 34 On the basis of this finding, it seems quite probable that eye ointment decreases contrast sensitivity during 6 h after application because HOAs and FI at 6 h after administration of eye ointment were still higher than those at 5 min after the gel-forming solution in the present study. The verification of such a long visual deterioration requires further studies.…”

Section: Discussionsupporting

confidence: 46%

“…33 It is considered that such dynamics of gels on ocular surface induces transient changes in ocular HOAs. 24,34 On the other hand, as eye ointment is not fragmented by blinks as gels, it is slowly cleared from the interpalpebral space through the lacrimal drainage system or by moving onto the lid skin. 1 Furthermore, its high viscosity retards these clearances.…”

Section: Discussionmentioning

confidence: 99%

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Time course of changes in ocular wavefront aberration after administration of eye ointment

Hiraoka

Yamamoto²,

Okamoto

et al. 2012

Eye

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Purpose To investigate the influence of an eye ointment on ocular aberration. Design Prospective, comparative study. Methods In 10 normal volunteers, ocular aberration was assessed before and 5, 30 min, 1, 2, 3, 6, and 12 h after administration of ofloxacin eye ointment. Ocular aberration was sequentially measured over a period of 10 s, and the root mean square (RMS) of the second-, third-, fourth-, and total higher-order aberrations (HOAs) were determined. From the sequential changes in total HOAs during 10 s, the fluctuation index (FI) and stability index (SI) were calculated. The obtained data were compared with those of another 17 normal volunteers who received timolol maleate gel-forming ophthalmic solution.Results No significant changes in secondorder RMS were observed after administration of the ointment. HOAs such as third-, fourth-, and total higher-order RMS significantly changed during the study period (Po0.05, repeated-measures analysis of variance). The RMS of each HOA component significantly increased 5 min after administration compared with the baseline values (Po0.05, Dunnett test). FI also increased significantly 5 min after administration (Po0.05), but SI did not change significantly. When compared with the results of the gel-forming solution group, HOAs and FI showed significantly higher values at several time points during 6 h after application (Po0.05, Mann-Whitney U-test). Conclusions Administration of eye ointment significantly degrades optical quality of the eye by increasing and oscillating HOAs. These changes were more pronounced than those after instillation of gel-forming ophthalmic solution for at least several hours.

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Section: Discussionsupporting

confidence: 46%

Section: Discussionmentioning

confidence: 99%

Time course of changes in ocular wavefront aberration after administration of eye ointment

Hiraoka

Yamamoto²,

Okamoto

et al. 2012

Eye

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“…Gellan gum is an anionic heteropolysaccharide that gives a colorless and transparent solution and forms a gel when it comes in contact with monovalent and divalent cations present in tears [5,13]. In this study, TMGS showed significant changes at 24 hr after the first instillation.…”

mentioning

confidence: 55%

The Effects of a Timolol Maleate Gel-Forming Solution on Normotensive Beagle Dogs

Takiyama

Shoji²,

Habata

et al. 2006

The Journal of Veterinary Medical Science

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ABSTRACT. The effects of a timolol maleate gel-forming solution (TMGS) on intraocular pressure (IOP), blood pressure (BP), and pupil size (PS) were evaluated in normotensive dogs. TMGS was administered once daily to six normotensive beagle dogs. TMGS administration reduced IOP and PS. The hypotensive effect persisted for 24 hr after the administration. The mean reduction in IOP was 5.3 mm Hg (P<0.01). The changes in BP and PS were not significant. These results suggest that TMGS can potentially be used in the treatments of glaucoma and ocular hypertension in dogs. KEY WORDS: canine, gellan gum, timolol.J. Vet. Med. Sci. 68(6): 631-633, 2006 Glaucoma is a painful disease and is characterized by retinal ganglion cell death, optic nerve damage that is usually associated with elevated intraocular pressure (IOP), and progressive loss of vision that could result in blindness. Glaucoma therapy aims to lower IOP in order to preserve ocular function and reduce pain [1].Timolol maleate (TM) is a nonselective beta-adrenergic that substantially reduces the volume of aqueous humor and thereby reduces IOP [1,3,20]. TM ophthalmic solution is widely used to treat glaucoma in humans and dogs. However, TM has the potential to cause systemic side effects [4, 6, 8-10, 15-17, 19, 20]. The TM gel-forming solution (TMGS) is delivered in a gellan gum solution and can be administered to the eye as a drop; this drop forms a viscous solution on contact with the ocular surface. TMGS holds TM for a longer period of time than the TM aqueous solution; consequently, TMGS is administered once daily [2,10,[12][13][14]. In this study, we evaluated the effects of TMGS on IOP, systolic and diastolic blood pressure (BP), and pupil size (PS) in normotensive beagle dogs.All animals were treated in accordance with the Association for Research in Vision and Ophthalmology Statement for the Use of Animals in Ophthalmic and Vision Research. Six clinically normal beagle dogs (two males and four females) were used in this study. Their body weights ranged from 9.7 to 13.0 kg (median weight: 12.2 kg), and their ages ranged from 4 to 11 years (median age: 8.0 years). Dogs were defined as normotensive after a complete physical and ophthalmic examination, including tonometry, slit-lamp biomicroscopy, and ophthalmoscopy; these examinations did not reveal any abnormalities. A 0.5% TMGS (Timoptol XE 0.5%, Banyu Pharmaceutical Co., Ltd., Tokyo) was used in this study. TMGS was administered in one eye (treated eye) of each dog. Once-a-day administration (9:00 AM) was continued for 7 days. The contralateral eyes (nontreated eyes) were not treated. IOP was measured using an applanation tonometer (Tono-Pen XL, Medtronic, FL, U.S.A.); BP, an oscillometric hematomanometer (BP100D, Fukuda M-E Kogyo Co., Ltd., Tokyo, Japan); and PS, a pupillometer (Mita's pupillometer, Inami, Tokyo, Japan). IOP, BP, and PS were measured before administration of TMGS; 1, 2, 4, 6, 10, and 24 hr after administration on the first day; and at 7:00 PM everyday from the second day until the en...

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“…Studies on the medical and pharmaceutical applications of gellan gum have also been reported. For example, it has been used as a scaffold material for the application of tissue engineering 232,233 , as a vehicle for ophthalmic drugs 234,235 , and in eye drops 236 .…”

Section: Gellan Gummentioning

confidence: 99%