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Roy Chowdhury U, Kudgus RA, Holman BH, Rinkoski TA, Hann CR, Bahler CK, McCloud E, Appt SE, Reid JM, Dosa PI, Fautsch MP. Pharmacological Profile and Ocular Hypotensive Effects of Cromakalim Prodrug 1, a Novel ATP-Sensitive Potassium Channel Opener, in Normotensive Dogs and Nonhuman Primates. J Ocul Pharmacol Ther 2021; 37:251-260. [PMID: 33784195 PMCID: PMC8215408 DOI: 10.1089/jop.2020.0137] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/27/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: To evaluate pharmacokinetic parameters and ocular hypotensive effects of cromakalim prodrug 1 (CKLP1) in normotensive large animal models. Methods: Optimal CKLP1 concentration was determined by dose response and utilized in short- (5-8 days) and long-term (60 days) evaluation in hound dogs (n = 5) and African Green Monkeys (n = 5). Blood pressure was recorded 3-5 times per week with a tail cuff. Concentrations of CKLP1 and the parent compound levcromakalim were assessed in hound dog plasma and select tissues by LC-MS/MS after bilateral ocular treatment with CKLP1 for 8 days. Pharmacokinetic parameters were calculated from days 1, 4, and 8 data. After necropsy, histology was assessed in 43 tissue samples from each animal. Results: In hound dogs and African Green monkeys, 10 mM CKLP1 (optimal concentration) significantly lowered intraocular pressure (IOP) by 18.9% ± 1.1% and 16.7% ± 6.7%, respectively, compared with control eyes (P < 0.05). During treatment, no significant change in systolic or diastolic blood pressure was observed in either species (P > 0.1). Average values for half-life of CKLP1 was 295.3 ± 140.4 min, Cmax, 10.5 ± 1.6 ng/mL, and area under the concentration vs. time curve (AUClast) 5261.4 ± 918.9 ng·min/mL. For levcromakalim, average values of half-life were 96.2 ± 27 min, Cmax 1.2 ± 0.2 ng/mL, and AUClast 281.2 ± 110.8 ng·min/mL. No significant pathology was identified. Conclusions: CKLP1 lowered IOP in hound dogs and African green monkeys with no effect on systemic blood pressure. Ocular topical treatment of CKLP1 showed excellent tolerability even after extended treatment periods.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Rachel A. Kudgus
- Department of Oncology Research, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Bradley H. Holman
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Tommy A. Rinkoski
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Cheryl R. Hann
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Cindy K. Bahler
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Eric McCloud
- Department of Pathology, Section of Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Susan E. Appt
- Department of Pathology, Section of Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Joel M. Reid
- Department of Oncology Research, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Peter I. Dosa
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Michael P. Fautsch
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
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Ashrafpour M, Babaei JF, Saghiri R, Sepehri H, Sharifi H. Modulation of the hepatocyte rough endoplasmic reticulum single chloride channel by nucleotide-Mg2+ interaction. Pflugers Arch 2012; 464:175-82. [PMID: 22684478 DOI: 10.1007/s00424-012-1121-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 05/27/2012] [Accepted: 05/30/2012] [Indexed: 01/07/2023]
Abstract
The effect of nucleotides on single chloride channels derived from rat hepatocyte rough endoplasmic reticulum vesicles incorporated into bilayer lipid membrane was investigated. The single chloride channel currents were measured in 200/50 mmol/l KCl cis/trans solutions. Adding 2.5 mM adenosine triphosphate (ATP) and adenosine diphosphate (ADP) did not influence channel activity. However, MgATP addition inhibited the chloride channels by decreasing the channel open probability (Po) and current amplitude, whereas mixture of Mg(2+) and ADP activated the chloride channel by increasing the Po and unitary current amplitude. According to the results, there is a novel regulation mechanism for rough endoplasmic reticulum (RER) Cl(-) channel activity by intracellular MgATP and mixture of Mg(2+) and ADP that would result in significant inhibition by MgATP and activation by mixture of Mg(2+) and ADP. These modulatory effects of nucleotide-Mg(2+) complexes on chloride channels may be dependent on their chemical structure configuration. It seems that Mg-nucleotide-ion channel interactions are involved to produce a regulatory response for RER chloride channels.
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Affiliation(s)
- M Ashrafpour
- Cellular and Molecular Research Center, Department of Physiology and Pharmacology, Babol University of Medical Sciences, Babol, Iran.
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