sodium-dodecyl-sulfate and dorzolamide

Topical medications that inhibit the enzyme carbonic anhydrase (CAI) are widely used to lower intraocular pressure in glaucoma; however, their clinical efficacy is limited by the requirement for multiple-daily dosing, as well as side effects such as blurred vision and discomfort on drop instillation. We developed a biodegradable polymer microparticle formulation of the CAI dorzolamide that produces sustained lowering of intraocular pressure after subconjunctival injection. Dorzolamide was ion paired with sodium dodecyl sulfate (SDS) and sodium oleate (SO) with 0.8% and 1.5% drug loading in poly(lactic-co-glycolic acid) (PLGA), respectively. Encapsulating dorzolamide into poly(ethylene glycol)-co-poly(sebacic acid) (PEG3-PSA) microparticles in the presence of triethylamine (TEA) resulted in 14.9% drug loading and drug release that occurred over 12 days in vitro. Subconjunctival injection of dorzolamide-PEG3-PSA microparticles (DPP) in Dutch belted rabbits reduced IOP as much as 4.0 ± 1.5 mmHg compared to untreated fellow eyes for 35 days. IOP reduction after injection of DPP microparticles was significant when compared to baseline untreated IOPs (P < 0.001); however, injection of blank microparticles (PEG3-PSA) did not affect IOP (P = 0.9). Microparticle injection was associated with transient clinical vascularity and inflammatory cell infiltration in conjunctiva on histological examination. Fluorescently labeled PEG3-PSA microparticles were detected for at least 42 days after injection, indicating that in vivo particle degradation is several-fold longer than in vitro degradation. Subconjunctival DPP microparticle delivery is a promising new platform for sustained intraocular pressure lowering in glaucoma.

Topics: Animals; Antihypertensive Agents; Carbonic Anhydrase Inhibitors; Ethylamines; Female; Glaucoma; Intraocular Pressure; Lactic Acid; Male; Oleic Acid; Polyethylene Glycols; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Polymers; Rabbits; Sodium Dodecyl Sulfate; Sulfonamides; Thiophenes

Structural properties, and especially the differential stability, of complexes between carbonic anhydrase (CA) and three sulfonamide inhibitors, acetazolamide, dorzolamide and methazolamide, were investigated by spectroscopic and electrophoretic techniques. These included denaturant gradient gel electrophoresis either across a urea or a steady-state transverse sodium dodecyl sulfate (SDS) gradient. Acetazolamide, the smallest and most hydrophilic of the sulfonamides, forms the most stable complex in the presence of urea, whereas dorzolamide, with a bulky and hydrophobic structure, is most stable against the effects of SDS. At pH 7.4, complexes with dorzolamide show minimal changes in mobility across the SDS gradient, as if unaffected by the detergent, both in the presence and in the absence of excess ligand in the gel. When bound to both acetazolamide and methazolamide, on the other hand, CA displays an increase in mobility above 0.05% SDS, lower in the presence than in the absence of excess ligand. The finding of a distinct pattern for the unliganded enzyme, however, suggests the complexes can still retain the ligand, although binding of the surfactant changes their charge density. Under saturating conditions and in the presence of SDS, the surface charge of all complexes is much lower than for unliganded, denatured CA. Circular dichroism (CD) spectra clearly indicate that the increase in secondary structure and the decrease in tertiary structure brought about in CA by the presence of low concentrations of SDS are largely prevented by complexing with the inhibitors. These observations point out peculiar properties of each CA inhibitor, of potential value in the definition of their biological activities and also in the potential development of novel antagonist molecules.

Topics: Acetazolamide; Animals; Carbonic Anhydrase Inhibitors; Carbonic Anhydrases; Cattle; Circular Dichroism; Electrophoresis, Polyacrylamide Gel; Isoelectric Focusing; Methazolamide; Sodium Dodecyl Sulfate; Sulfonamides; Thiophenes; Titrimetry; Urea