Safety and tolerability of tafluprost in treatment of elevated intraocular pressure in open-angle glaucoma and ocular hypertension

Palladium-catalyzed highly selective gem-difluoroallylation of propargyl sulfonates with gem-difluoroallylboron

A palladium-catalyzed gem-difluoroallylation of propargyl sulfonates with gem-difluoroallylboron has been developed. The reaction features synthetic simplicity and high functional group tolerance, affording 3,3-difluoro-skipped 1,5-enynes with high efficiency and regioselectivity. In particular, the resulting products can serve as versatile synthons for diversified transformations, having potential applications in medicinal chemistry.

Trends in development and quality assessment of pharmaceutical formulations - F2α analogues in the glaucoma treatment

The ocular delivery route presents a number of challenges in terms of drug administration and bioavailability. The low bioavailability following topical ophthalmic administration shows that there is a clear need for in-depth research aimed at finding both more efficacious molecules and formulations precisely targeted at the site of action. Continuous technological development will eventually result in improved bioavailability, lower dosages, reduced toxicity, fewer adverse effects, and thus better patient compliance and treatment efficacy. Technological development, as well as increasingly stringent quality requirements, help stimulate analytical progress. This is also clearly evident in the case of medicinal products used in the treatment of glaucoma, which are the subject of this review. Impurity profiling of PGF2α analogues, either in the pure substance or in the finished formulation, is a crucial step in assessing their quality. The development of specific, accurate and precise stability-indicating analytical methods for determining the content and related substances seems to be an important issue in relation to this tasks. A total of 27 official and in-house analytical methods are presented that are used for the analysis of latanoprost, travoprost and bimatoprost. The conditions for chromatographic separation with UV or MS/MS detection and the available results obtained during method validation are described. In addition, several aspects are discussed, with particular emphasis on the instability of the analogues in aqueous solution and the phenomenon of isomerism, which affects a potentially large number of degradation products.

Travoprost- and Tafluprost-induced Changes in Intraocular Pressure and Ocular Pulse Amplitude

Purpose: To compare the intraocular pressure reduction and changes in ocular pulse amplitude of travoprost 0.003% and tafluprost 0.0015%. Methods: We assessed patients who were diagnosed with open-angle glaucoma from January 2017 to July 2019 for the first time at our hospital. Forty-two eyes were assigned to the travoprost group (23 patients) and 26 eyes were assigned to the tafluprost group (14 patients). Changes in intraocular pressure were measured by Goldmann applanation tonometry (GAT), and corrected ocular pulse amplitude (cOPA) was measured using dynamic contour tonometry. Changes in these parameters were observed and compared for 1 year. Results: No significant differences were observed between the GAT measurements and the cOPA of patients treated with travoprost and tafluprost for 1 year (<i>p</i> = 0.512, <i>p</i> = 0.105). The change in initial intraocular pressure on GAT observed after 1 week was -5.32 ± 2.63 mmHg for travoprost and -3.79 ± 3.19 mmHg for tafluprost (<i>p</i> = 0.0457). The initial change in cOPA was +0.04 ± 0.9 mmHg in the travoprost group and -0.76 ± 0.97 mmHg in the tafluprost group (<i>p</i> = 0.0028). Conclusions: Travoprost and tafluprost reached the targeted intraocular pressure with no difference in the long-term effects of reduced intraocular pressure. However, travoprost was initially better at lowering intraocular pressure faster, and tafluprost had a greater effect on lowering OPA. Prostaglandin analogs can be selected individually by considering the aforementioned factors.

Ocular microemulsion of brinzolamide: Formulation, physicochemical characterization, and in vitro irritation studies based on EpiOcular™ eye irritation assay

In recent years, the hydrophobic active substances have led researchers to develop new formulations to enhance bioavailability and dissolution rate; brinzolamide, a lipophilic drug belongs to carbonic anhydrase inhibitors, which cause reduction of intraocular pressure in patients suffering from glaucoma. Currently, the marketed product of brinzolamide is in the form of ocular drops; nonetheless, the conventional drops provide decreased therapeutic efficacy owing to their low bioavailability and pulsed drug release. Thus, the development of novel ocular formulations such as topical microemulsions is of high importance. In this work, the preparation of new microemulsions containing brinzolamide (0.2, 0.5 and 1% w/w) and comprised from isopropyl myristate, tween 80 and span 20 and Cremophor EL was performed. The obtained microemulsions were further characterized for their physicochemical properties. In addition, Fourier Transformed-Infrared spectroscopy was used touate the compatibility of active ingredients and components. In vitro release studies along with kinetic modeling were performed using the dialysis membrane method in simulated tear fluid. Bioadhesion studies were performed using Texture analysis. Finally, in vitro ocular irritation based on EpiOcular™ Eye Irritation Test and cytocompatibility studies was performed to examine any possible harm on ocular cells and predict in vivo safety profile.

Co(iii)-Catalyzed stereospecific synthesis of (E)-homoallylic alcohols with 4-vinyl-1,3-dioxan-2-ones: late-stage C–H homoallylation of indole derivatives

An Co(iii)-catalyzed stereoselective C–H homoallylation reaction to access (E)-homoallylic alcohols was developed. This protocol provides a powerful approach for the late-stage C–H homoallylation of indole-based molecules.

Aluminum-catalyzed tunable halodefluorination of trifluoromethyl- and difluoroalkyl-substituted olefins

Herein, we report unprecedented aluminum-catalyzed halodefluorination reactions of trifluoromethyl- and difluoroalkyl-substituted olefins with bromo- or chlorotrimethylsilane. The interesting feature of these reactions is that one, two, or three fluorine atoms can be selectively replaced with bromine or chlorine atoms by modification of the reaction conditions. The generated products can undergo a variety of subsequent transformations, thus constituting a valuable stock of building blocks for installing fluorine-containing olefin motifs in other molecules.

Aluminum-catalyzed halodefluorination reactions of fluoroalkyl-substituted olefins are developed. The reactions can selectively deliver mono-, di-, or trisubstituted products.

An Asymmetric Suzuki-Miyaura Approach to Prostaglandins: Synthesis of Tafluprost

We report the catalytic asymmetric synthesis of Tafluprost (1), a prostaglandin analogue. This synthesis demonstrates a new approach to prostaglandins involving symmetrization and desymmetrization of a racemic precursor to control the absolute and relative stereochemistry of the cyclopentyl core. Key steps include a diastereo- and enantioselective Rh-catalyzed Suzuki-Miyaura reaction of a racemic bicyclic allyl chloride and an alkenyl boronic acid and a regio- and diastereoselective Pd-catalyzed Tsuji-Trost reaction with an enolate surrogate.

Nanofluidic microsystem for sustained intraocular delivery of therapeutics

Globally, 145.2 million people suffer from moderate to severe vision impairment or blindness due to preventable or treatable causes. However, patient adherence to topical or intravitreal treatment is a leading cause of poor outcomes. To address this issue, we designed an intraocularly implantable device called the nanofluidic Vitreal System for Therapeutic Administration (nViSTA) for continuous and controlled drug release based on a nanochannel membrane that obviates the need for pumps or actuation. In vitro release analysis demonstrated that our device achieves sustained release of bimatoprost (BIM) and dexamethasone (DEX) at concentrations within clinically relevant therapeutic window. In this proof of concept study, we constructed an anatomically similar in silico human eye model to simulate DEX release from our implant and gain insight into intraocular pharmacokinetics profile. Overall, our drug-agnostic intraocular implant represents a potentially viable platform for long-term treatment of various chronic ophthalmologic diseases, including diabetic macular edema and uveitis.

A Novel Convergent Synthesis of the Potent Antiglaucoma Agent Tafluprost

Tafluprost (AFP-168, 5) is a unique 15-deoxy-15,15-difluoro-16-phenoxy prostaglandin F₂α (PGF_2α) analog used as an efficacious ocular hypotensive agent in the treatment of glaucoma and ocular hypertension, as monotherapy, or as adjunctive therapy to β-blockers. A novel convergent synthesis of 5 was developed employing Julia–Lythgoe olefination of the structurally advanced prostaglandin phenylsulfone 16, also successfully applied for manufacturing of pharmaceutical grade latanoprost (2), travoprost (3) and bimatoprost (4), with an aldehyde ω-chain synthon 17. The use of the same prostaglandin phenylsulfone 16, as a starting material in parallel syntheses of all commercially available antiglaucoma PGF_2α analogs 2–5, significantly reduces manufacturing costs resulting from its synthesis on an industrial scale and development of technological documentation. Another key aspect of the route developed is deoxydifluorination of a trans-13,14-en-15-one 30 with Deoxo-Fluor. Subsequent hydrolysis of protecting groups and final esterification of acid 6 yielded tafluprost (5). The main advantages are the preparation of high purity tafluprost (5) and the application of comparatively cheap reagents. The preparation and identification of two other tafluprost acid derivatives, tafluprost methyl ester (32) and tafluprost ethyl amide (33), are also described.

Comparison of Ocular Pulse Amplitude Lowering Effects of Preservative-Free Tafluprost and Preservative-Free Dorzolamide-Timolol Fixed Combination Eyedrops

Purpose. To compare the ocular pulse amplitude (OPA) lowering effects of preservative-free tafluprost and dorzolamide-timolol fixed combination (DTFC) using dynamic contour tonometry. Methods. In total, 66 eyes of 66 patients with normal tension glaucoma (NTG) (n = 34) or primary open angle glaucoma (POAG) (n = 32) were included. Patients were divided into two groups: the preservative-free tafluprost-treated group (n = 33) and the preservative-free DTFC-treated group (n = 33). Intraocular pressure (IOP) was measured using Goldmann applanation tonometry (GAT). OPA was measured using dynamic contour tonometry; corrected OPA (cOPA) was calculated at baseline and at 1 week and 1, 3, and 6 months after treatment. Results. After 6 months of treatment, tafluprost significantly reduced IOP (P < 0.001). The OPA lowering effects differed significantly between the two treatment groups (P = 0.003). The cOPA-lowering effect of tafluprost (1.09 mmHg) was significantly greater than that of DTFC (0.36 mmHg) after 6 months of treatment (P = 0.01). Conclusions. Tafluprost and DTFC glaucoma treatments provided marked OPA and IOP lowering effects. Tafluprost had a greater effect than DTFC; thus, this drug is recommended for patients at risk of glaucoma progression, due to the high OPA caused by large fluctuations in IOP.

Randomized clinical trial of the efficacy and safety of preservative-free tafluprost and timolol in patients with open-angle glaucoma or ocular hypertension

PURPOSE

To compare the efficacy and safety of tafluprost, a preservative-free (PF) prostaglandin analogue, with PF timolol in patients with open-angle glaucoma or ocular hypertension.

DESIGN

Randomized, double-masked, multicenter clinical trial.

METHODS

After discontinuation and washout of existing ocular hypotensive treatment, patients who had intraocular pressure (IOP) ≥23 and ≤36 mm Hg in at least 1 eye at the 08:00 hour time point were randomized 1:1 to 12 weeks of treatment with either PF tafluprost 0.0015% or PF timolol 0.5%. IOP was measured 3 times during the day (08:00, 10:00, 16:00 hours) at baseline and at weeks 2, 6, and 12. It was hypothesized that PF tafluprost would be noninferior to PF timolol over 12 weeks with regard to change from baseline IOP. The trial was powered for a noninferiority margin of 1.5 mm Hg at each of the 9 time points assessed.

RESULTS

A total of 643 patients were randomized and 618 completed (PF tafluprost = 306, PF timolol = 312). IOPs at the 3 time points assessed during the baseline visit ranged from 23.8 to 26.1 mm Hg in the PF tafluprost group and 23.5 to 26.0 mm Hg in the PF timolol group. IOPs at the 3 time points assessed during the 12-week visit ranged from 17.4 to 18.6 mm Hg for PF tafluprost and 17.9 to 18.5 mm Hg for PF timolol. At all 9 time points, the upper limits of the 2-sided 95% confidence intervals for the difference between treatments in IOP lowering were less than the prespecified noninferiority margin. Similar percentages of PF tafluprost and PF timolol patients reported ocular pain/stinging/irritation (4.4% vs 4.6%) and pruritus (2.5% vs 1.5%). The percentages of PF tafluprost and PF timolol patients reporting conjunctival hyperemia were 4.4% vs 1.2% (nominal P = .016).

CONCLUSIONS

The IOP-lowering effect of PF tafluprost was noninferior to that of PF timolol. PF tafluprost is an efficacious and generally well-tolerated ocular hypotensive agent.