The safety and efficacy of timolol 0.5% in xanthan gum versus timolol gel forming solution 0.5%.
OBJECTIVE
To evaluate the efficacy and safety of timolol maleate 0.5% gel forming solution (TXE, Merck) versus timolol maleate 0.5% gel forming solution (TXG, Falcon) in primary open-angle glaucoma and ocular hypertension patients.


METHODS
Following a washout period patients were randomly begun on either TXE or TXG each given once each morning for six weeks (Period 1). Patients then were crossed over to the opposite medicine for Period 2. Following each 6-week treatment period the intraocular pressure was obtained at 08:00 trough and +2 and +8 hours post-dosing. Anterior segment staining and photography were performed to assess surface irritation.


RESULTS
Thirty-two patients were enrolled in this study; 28 completed. The diurnal intraocular pressure as well as the 08:00 trough and +2 hour post dosing pressures were statistically equal between groups, although a trend to a lower mean pressure was observed in the TXE (17.9 +/- 3.2 mm Hg) compared to the TXG (18.6 +/- 3.4 mm Hg) group. However, eight hours after dosing the pressure was 17.5 +/- 3.2 mm Hg in the TXE group and 18.9 +/- 3.3 mm Hg in the TXG group (P = 0.0019). Safety was similar between groups, including corneal and conjunctival staining, conjunctival hyperemia graded by anterior segment photography and at the slit lamp, and unsolicited and solicited side effects. Vision recovery after instillation was similar between groups.


CONCLUSIONS
TXE demonstrates a lower intraocular pressure eight hours after dosing than does TXG, but safety appears similar between products.
Stewart
William C
WC
Pharmaceutical Research Corporation, Charleston, SC 29412, USA. pr_admn@bellsouth.net
Sharpe
Elizabeth D
ED
Stewart
Jeanette A
JA
Hott
Chaney E
CE
D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D000328:Adult; D000869:Anterior Eye Segment / Q000378:metabolism; D003228:Conjunctiva / Q000098:blood supply; D005782:Gels; D005902:Glaucoma, Open-Angle / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D006940:Hyperemia / Q000188:drug therapy; D007429:Intraocular Pressure / Q000187:drug effects; D009798:Ocular Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D011135:Polysaccharides, Bacterial / Q000009:adverse effects; D011446:Prospective Studies; D012449:Safety; D016037:Single-Blind Method; D012996:Solutions; D013194:Staining and Labeling; D013999:Timolol / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D014792:Visual Acuity / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D005782:Gels; D011135:Polysaccharides, Bacterial; D012996:Solutions; C048288:gellan gum; D013999:Timolol; C002563:xanthan gum