Monographs of Topical Drugs that Have Caused Contact Allergy/Allergic Contact Dermatitis
Anton C. de Groot in Monographs in Contact Allergy, 2021
Echothiophate is a potent, long-acting cholinesterase inhibitor with parasympathomimetic activity. Its iodide salt echothiophate iodide (CAS number 513-10-0, EC number 208-152-1, molecular formula C9H23INO3PS) potentiates the action of endogenous acetylcholine by inhibiting acetylcholinesterase that hydrolyzes acetylcholine. When applied topically to the eye, this agent prolongs stimulation of the parasympathetic receptors at the neuromuscular junctions of the longitudinal muscle of the ciliary body. Contraction of longitudinal muscle pulls on the scleral spur, and opens the trabecular meshwork, thereby increasing aqueous humor outflow from the eye and reducing intraocular pressure. Echothiopate iodide is indicated for use in the treatment of subacute or chronic angle-closure glaucoma after iridectomy or where surgery is refused or contraindicated (1).
Corneal epithelium and limbal region alterations due to glaucoma medications evaluated by anterior segment optic coherence tomography: a case-control study
Published in Cutaneous and Ocular Toxicology, 2021
Hande Güçlü, Ayça Küpeli Çınar, Abdülkadir Can Çınar, İrfan Akaray, Merve Şambel Aykutlu, Ahmet Kürşad Sakallıoğlu, Vuslat Gürlü
Central corneal epithelial thickness (CCET) was identified as the distance between the tear film (red hyperreflective layer) and the Bowman’s membrane (first green hyperreflective layer) (Figure 2)8. CCET was measured manually at the region that fits the corneal apex. Limbal epithelium thickness (LET, Nasal quadrant) was identified as the zone between two manually created lines. Anatomically, the point where the scleral spur initiated was defined as point A. A vertical line was drawn from point A to the cornea epithelium. And this line was identified as Line A. The point where it reached the cornea epithelium was defined as point B. The point 1000 microns horizontally far from point B was defined as point C. The vertical line was drawn from point C to the Descemet’s membrane (DM) (second green hyperreflective layer) and this line defined as Line B. Limbal stem cells resided between point B and point C. The thickest part beginning from corneal epithelium to the Bowman’s membrane (BM) between the B and the C points was measured and defined as LET (Figure 1, Image C)10,11.
Formulation and investigation of pilocarpine hydrochloride niosomal gels for the treatment of glaucoma: intraocular pressure measurement in white albino rabbits
Published in Drug Delivery, 2020
Neelam Jain, Anurag Verma, Neeraj Jain
Pilocarpine hydrochloride is a drug used in the treatment of chronic open-angle glaucoma for over 100 years (Rosin, 1991). It is a parasympathomimetic alkaloid obtained from the leaves of tropical South American shrubs from the genus Pilocarpus. It is a nonselective muscarinic receptor agonist which acts therapeutically at the muscarinic acetylcholine receptor M3, found on the iris sphincter muscle, causing the muscle to contract resulting in pupil constriction (miosis). Pilocarpine hydrochloride also acts on the ciliary muscle and causes it to contract. When the ciliary muscle contracts, it opens the trabecular meshwork through increased tension on the scleral spur. This action facilitates the rate that aqueous humor leaves the eye to decrease in IOP (Khaw et al., 2004). The major drawbacks associated with pilocarpine HCl, administered as an eye drop, was its low ocular bioavailability (1–3%) and short precorneal residence time. These problems can be minimized by the use of niosomal vesicular system.
Biomechanics of suprachoroidal drug delivery: From benchtop to clinical investigation in ocular therapies
Published in Expert Opinion on Drug Delivery, 2021
Shelley E. Hancock, Chen-Rei Wan, Nathan E. Fisher, Rafael V. Andino, Thomas A. Ciulla
In addition to scleral thickness, the extracellular matrix connections between the sclera and the choroid/ciliary body should be considered in order to understand the boundaries of fluid flow within the SCS. At the scleral spur, the sclera adheres tightly to the ciliary body and thus the suprachoroidal and supraciliary spaces are occluded anteriorly, as seen in Figure 1. Consequently, fluid introduced into the pars plana region will expand the SCS and flow posteriorly, thereby minimizing anterior chamber exposure [23], as seen in Figure 2. The flow of fluid in the SCS is further enhance by the natural pressure differential in the eye which decreases posteriorly. Emi et al. measured the hydrostatic pressures in the SCS through direct cannulation, observing pressures 0.8 ± 0.2 mm Hg below the IOP anteriorly and 3.7 ± 0.4 mm Hg below the IOP posteriorly [24]. This pressure differential, the driving force for uveoscleral outflow, may enhance the posterior spread of drugs injected into the SCS, and thereby facilitate the treatment of macular disorders in addition to peripheral chorioretinal disorders.
Related Knowledge Centers
- Ciliary Muscle
- Eye
- Glaucoma
- Pilocarpine
- Trabecular Meshwork
- Visual System
- Sclera
- Anterior Chamber of Eyeball
- Lens
- Agonist