Systemic bioavailability of ocularly applied 1% atropine eyedrops

A validated LC-MS/MS method for the determination of L-hyoscyamine in human plasma: Application in clinical study

Atropine is a racemic mixture of D- and L-hyoscyamine, while L-hyoscyamine is the only effective ingredient. In this study, a new sensitive, stable, and selective LC/MS assay was developed for determination of L-hyoscyamine and applied to the clinical study. The parent-product (m/z) transition pair of L-hyoscyamine was 290.1→124.1. Chromatographic separations were performed using a Chiral MZ column (250 mm×4.6 mm, 5.0 μm) by a stepwise gradient elution mode with n-hexane, isopropanol and diethylamine as mobile phases. L-hyoscyamine in human plasma were extracted using liquid-liquid extraction process. This assay displayed a good linearity over a concentration range of 20.0-400 pg/mL for L-hyoscyamine. The accuracy of the validation assay for L-hyoscyamine ranged from -2.7% to 4.5%, and the precision were within 6.3% coefficient of variation. L-hyoscyamine in human plasma were stable at different storage conditions. The method has been successfully applied to plasma samples obtained from a safety study in human.

The Role of Atropine in Preventing Myopia Progression: An Update

Several approaches have been investigated for preventing myopia progression in children and teenagers. Among them, topical atropine has shown promising results and it is being adopted in clinical practice more and more frequently. However, the optimal formulation and treatment algorithm are still to be determined. We discuss the pharmacokinetic, pharmacodynamic, clinical, and tolerability profile revealed first by the multicenter, randomized ATOM 1 and 2 trials and, more recently, by the LAMP Study. Results from these trials confirmed the efficacy of low-concentration atropine with a concentration-dependent response. Although atropine at 0.025% and 0.05% concentrations has shown the most encouraging results in large-scale studies, these formulations are not yet commonplace in worldwide clinical practice. Moreover, their rebound effect and the possibility of reaching a stabilization effect have not been fully investigated with real-life studies. Thus, further larger-scale studies should better characterize the clinical efficacy of atropine over longer follow-up periods, in order to define the optimal dosage and treatment regimen.

Prevention of Choroidal Thinning by 0.01% Atropine Administered 24 h Before Exposure to Hyperopic Blur in Young Myopes

Purpose: To evaluate the persistence of atropine's effect upon choroidal thickness and ocular biometrics and its interaction with hyperopic blur in a population of young adult myopes. Methods: Twenty young (aged 18-35 years) myopic participants with spherical equivalent refractive error of -0.75 to -6.00 D (mean ± SD -2.85 ± 1.64 D) had subfoveal choroidal thickness (SFCT) measurements derived from scans collected from the right eye only with a SD-OCT instrument (Copernicus SOCT-HR) before, as well as 60 min following the introduction of 3 testing conditions: (1) placebo/hyperopic (-3 D) blur, (2) placebo/hyperopic blur one day after administration of 0.01% atropine, and (3) placebo/no blur. Each combination of blur and pharmacological agent was tested on a separate day at approximately the same time of day between 9 am and 2 pm. Results: Repeated measures ANOVA revealed that hyperopic blur and placebo were associated with a decrease in choroidal thickness (mean change: -10.7 ± 2.7 μm, P < 0.001 after 60 min), whereas administration of 0.01% atropine one day before the introduction of hyperopic blur prevented the thinning of the choroid (mean change of +1.1 ± 3.7 μm after 60 min) compared to baseline (both, P > 0.05). There was also no significant difference between the baseline choroidal thickness measurements for any of the conditions tested. Conclusion: Low dose atropine can inhibit signals associated with hyperopic defocus that cause thinning of the choroid for at least 24 h after initial instillation.

Atropine in topical formulations for the management of anterior and posterior segment ocular diseases

INTRODUCTION

Atropine is an old-known drug which is gaining increasing attention due to the myriad of therapeutic effects it may trigger on eye structures. Nevertheless, novel applications may require more adequate topical formulations.

AREAS COVERED

This review aims to gather the existing knowledge about atropine and its clinical applications in the ophthalmological field when administered topically. Atropine ocular pharmacokinetics is paid a special attention, including recent evidences of the capability of the drug to access to the posterior segment. Ocular bioavailability and systemic bioavailability are counterbalanced. Finally, limitations of traditional dosage forms and potential advantages of under investigation delivery systems are analyzed.

EXPERT OPINION

Mydriasis and cyclopegia have been widely exploited for eye examination, management of anterior segment diseases, and more recently as antidotes of chemical weapons. Improved knowledge on drug receptors and related pathways explains atropine repositioning as an outstanding tool to prevent myopia. The ease with which atropine penetrates ocular tissues is a double edged sword, that is, while it ensures therapeutic levels in the posterior segment, the unspecific distribution causes a wide variety of untoward effects. The design of formulations that can selectively deliver atropine to the target tissue for each specific application is an urgent unmet need.

Systemic detectability of dexamethasone and prednisolone after eye drop application in horses

BACKGROUND

Equine sport agencies list steroids as prohibited substances for competing horses.

OBJECTIVES

The objective of this study was to investigate if the controlled substances dexamethasone and prednisolone are detectable in equine serum and urine samples during and after treatment with eye drops and if this can generate a positive doping test.

STUDY DESIGN

Prospective cohort study.

METHODS

The study cohort included 11 horses. One eye of the horses was treated with either dexamethasone (Maxitrol^® 0.1%, n = 5 eyes) or prednisolone (Pred forte^® 1%, n = 6 eyes) eye drops 3 times daily for 14 days. Dexamethasone and prednisolone concentrations were determined in serum and urine at day 0 (negative control), 1, 7, 14, 15, 17 and 21 using liquid chromatography-tandem mass spectrometry. Blood samples were collected within 2 hours post application. Urine samples were collected during spontaneous urination.

RESULTS

All serum samples (range: 0.7-43 ng/mL, mean 2.1 ng/mL) and urine samples (range 1.2-5 ng/mL, mean 0.8 ng/mL) showed measurable amounts of dexamethasone during the course of treatment. Concentrations in both serum and urine samples were below limit of detection (LOD) 24 hours after the last dexamethasone treatment (day 15). All serum samples (range 1.1-32.5 ng/mL, mean 6.4 ng/mL) and urine samples (range 3.7-19 ng/mL, mean 4.6 ng/mL) were positive for prednisolone during treatment. Urine samples were below LOD on day 15; serum samples on day 21.

CONCLUSIONS

Dexamethasone and prednisolone eye drops can induce detectable drug levels in serum and urine samples of horses after a 14-day treatment plan. This can lead to a positive doping result. All samples tested negative (below LOD of the analytical method) for dexamethasone one day and for prednisolone one week after treatment cessation.

Short-Term Effect of Low-Dose Atropine and Hyperopic Defocus on Choroidal Thickness and Axial Length in Young Myopic Adults

Purpose

To examine the interaction between a short period of hyperopic defocus and low-dose atropine upon the choroidal thickness and ocular biometrics of healthy myopic subjects.

Methods

Twenty young adult myopic subjects had subfoveal choroidal thickness (ChT) and ocular biometry measurements taken before and 30 and 60 min following the introduction of optical blur (0.00 D and −3.00 D) combined with administration of 0.01% atropine or placebo. Each combination of optical blur and drug was tested on different days in a fixed order.

Results

The choroid exhibited significant thinning after imposing hyperopic defocus combined with placebo (mean change of −11 ± 2 μm, p < 0.001). The combination of hyperopic blur and 0.01% atropine led to a significantly smaller magnitude of subfoveal choroidal thinning (−4 ± 8 μm), compared to placebo and hyperopic defocus (p < 0.01). Eyes treated with 0.01% atropine with no defocus exhibited a significant increase in ChT (+6 ± 2 μm, p < 0.01). Axial length also underwent small but significant changes after treatment with hyperopic blur and placebo and 0.01% atropine alone (both p < 0.01), but of opposite direction to the changes in choroidal thickness. However, the 0.01% atropine/hyperopic blur condition did not lead to a significant change in axial length compared to baseline (p > 0.05).

Conclusion

Low-dose atropine does inhibit the short-term effect of hyperopic blur on choroidal thickness and, when used alone, does cause a slight thickening of the choroid in young healthy myopic adults.

Association of Drug Burden Index with grip strength, timed up and go and Barthel index activities of daily living in older adults with intellectual disabilities: an observational cross-sectional study

BACKGROUND

Drug Burden Index (DBI), a measure of exposure to medications with anticholinergic and sedative activity, has been associated with poorer physical function in older adults in the general population. While extensive study has been conducted on associations between DBI and physical function in older adults in the general population, little is known about associations in older adults with intellectual disabilities (ID). This is the first study which aims to examine the association between DBI score and its two sub-scores, anticholinergic and sedative burden, with two objective measures of physical performance, grip strength and timed up and go, and a measure of dependency, Barthel Index activities of daily living, in older adults with ID.

METHODS

Data from Wave 2 (2013/2014) of the Intellectual Disability Supplement to the Irish Longitudinal Study on Ageing (IDS-TILDA) was analysed. Analysis of Covariance (ANCOVA) was used to detect associations and produce adjusted means for the physical function and dependency measures with respect to categorical DBI scores and the anticholinergic and sedative sub-scores (DBA and DBS).

RESULTS

After adjusting for confounders (age, level of ID, history of falls, comorbidities and number of non-DBI medications, Down syndrome (grip strength only) and gender (timed up and go and Barthel Index)), neither grip strength nor timed up and go were significantly associated with DBI, DBA or DBS score > 0 (p > 0.05). Higher dependency in Barthel Index was associated with DBS exposure (p < 0.001).

CONCLUSIONS

DBI, DBA or DBS scores were not significantly associated with grip strength or timed up and go. This could be as a result of established limitations in physical function in this cohort, long-term exposure to these types of medications or lifelong sedentary lifestyles. Higher dependency in Barthel Index activities of daily living was associated with sedative drug burden, which is an area which can be examined further for review.

The penetration and distribution of topical atropine in animal ocular tissues

PURPOSE

To conduct a multi-tissue investigation on the penetration and distribution of topical atropine in myopia treatment, and determine if atropine is detectable in the untreated contralateral eye after uniocular instillation.

METHODS

Nine mature New Zealand white rabbits were evenly divided into three groups. Each group was killed at 5, 24 and 72 hr, respectively, following uniocular instillation of 0.05 ml of 1% atropine. Tissues were sampled after enucleation: conjunctiva, sclera, cornea, iris, ciliary body, lens, retina, aqueous, and vitreous humors. The assay for atropine was performed using liquid chromatography-mass spectrometry (LC-MS), and molecular tissue distribution was illustrated using matrix-assisted laser desorption ionization-imaging mass spectrometry (MALDI-IMS) via an independent experiment on murine eyes.

RESULTS

At 5 hr, the highest (mean ± SEM) concentration of atropine was detected in the conjunctiva (19.05 ± 5.57 ng/mg, p < 0.05) with a concentration gradient established anteriorly to posteriorly, as supported by MALDI-IMS. At 24 hr, preferential binding of atropine to posterior ocular tissues occurred, demonstrating a reversal of the initial concentration gradient. Atropine has good ocular bioavailability with concentrations of two magnitudes higher than its binding affinity in most tissues at 3 days. Crossing-over of atropine to the untreated eye occurred within 5 hr post-administration.

CONCLUSION

Both transcorneal and transconjunctival-scleral routes are key in atropine absorption. Posterior ocular tissues could be important sites of action by atropine in myopic reduction. In uniocular atropine trials, cross-over effects on the placebo eye should be adjusted to enhance results reliability. Combining the use of LC-MS and MALDI-IMS can be a viable approach in the study of the ocular pharmacokinetics of atropine.

Inhibition of platelet function after ocular administration of non-steroidal anti-inflammatory drugs

INTRODUCTION

The use of topical NSAIDs is frequent in ophthalmology to reduce the local inflammatory reaction resulting from surgical procedures. Ocular use of some drugs was previously found to lead to significant systemic absorption with possible systemic effects. NSAIDs may enhance the hemorrhagic risk of anticoagulant and antiplatelet drugs. Aim of our study was to evaluate the systemic effects of two NSAIDs given by eyedrops on platelet COX-1 and on ex vivo and in vivo platelet activation.

MATERIALS AND METHODS

20 patients planned to undergo cataract surgery were randomized to the use of an ophthalmic solution containing Diclofenac or Indomethacin. Blood was taken at enrollment (baseline) and after 3 days of therapy (1 drop, 4 times a day). Arachidonic Acid (AA)-induced light transmission aggregometry (LTA), PFA-100® C-EPI, circulating platelet P-Selectin expression by flow cytometry and serum and AA-induced TxB₂ production were evaluated before and after eyedrop therapy.

RESULTS

AA (0.1-0.2 mM)-induced LTA was significantly reduced after ocular indomethacin but not after diclofenac. PFA-100® C-EPI closure time was also significantly prolonged in the indomethacin group but not in the diclofenac group. Circulating platelet P-selectin expression was significantly reduced after treatment with indomethacin compared with diclofenac. Finally, treatment with eyedrop indomethacin, but not with diclofenac, strikingly suppressed AA-induced TxB₂ generation, while treatment with diclofenac did not modify it.

CONCLUSIONS

Our data show that indomethacin administered by ophthalmic eye drops has a relevant systemic antiplatelet effect. This should be taken into account in patients under concurrent therapy with antiplatelet or anticoagulant agents.

Contingency Medical Countermeasures for Mass Nerve-Agent Exposure: Use of Pharmaceutical Alternatives to Community Stockpiled Antidotes

Having sufficient medical countermeasures (MCMs) available for the treatment of acetylcholinesterase-inhibiting nerve agent poisoned patients following a mass chemical exposure is a challenge for communities. After stockpiles containing auto-injectors are exhausted, communities need to be aware of alternative pharmaceutical options. The Department of Homeland Security Chemical Defense Program convened a federal interagency working group consisting of first responders, clinicians, and experts from the fields of medical toxicology, pharmacology, and emergency management. A literature review of pharmaceutical alternatives for treating nerve agent toxicity was performed. Pharmaceuticals that met the federal Public Health Emergency Medical Countermeasures Enterprise Product Specific Requirements were prioritized. Food and Drug Administration approval for one indication, market availability, and alignment to government procurement strategy were considered. This article summarizes the literature on comparative pharmacokinetics and efficacy against nerve agents (where available) of Food and Drug Administration approved drugs with muscarinic acetylcholine receptor antagonist and gamma-aminobutyric acid receptor agonist effects. This work is intended to serve as a resource of pharmaceutical options that may be available to communities (ie, emergency managers, planners, clinicians, and poison centers) when faced with a mass human exposure to a nerve agent and inadequate supplies of MCMs. (Disaster Med Public Health Preparedness. 2019;13:605-612).

Drug burden index to define the burden of medicines in older adults with intellectual disabilities: An observational cross-sectional study

AIMS

The drug burden index (DBI) is a dose-related measure of anticholinergic and sedative drug exposure. This cross-sectional study described DBI in older adults with intellectual disabilities (ID) and the most frequently reported therapeutic classes contributing to DBI and examined associations between higher DBI scores and potential adverse effects as well as physical function.

METHODS

This study analysed data from Wave 2 (2013/2014) of the Intellectual Disability Supplement to the Irish Longitudinal Study on Ageing (IDS-TILDA), a representative study on the ageing of people with ID in Ireland. Self- and objectively-reported data were collected on medication use and physical health, including health conditions. The Barthel index was the physical function measure.

RESULTS

The study examined 677 individuals with ID, of whom 644 (95.1%) reported taking medication and 78.6% (n = 532) were exposed to medication with anticholinergic and/or sedative activity. 54.2% (n = 367) were exposed to high DBI score (≥1). Adjusted multivariate regression analysis revealed no significant association between DBI score and daytime dozing, constipation or falls. After adjusting for confounders (sex, age, level of ID, comorbidities, behaviours that challenge, history of falls), DBI was associated with significantly higher dependence in the Barthel index (P = 0.002).

CONCLUSIONS

This is the first time DBI has been described in older adults with ID. Scores were much higher than those observed in the general population and higher scores were associated with higher dependence in Barthel index activities of daily living.

Evaluation of the mydriatic effect of intracameral lidocaine hydrochloride injection in eyes of clinically normal dogs

OBJECTIVE-To evaluate the mydriatic effect of intracameral injection of preservative-free 1% and 2% lidocaine hydrochloride solutions and determine the onset and duration of mydriasis according to the concentration and volume of lidocaine administered in healthy dogs. ANIMALS-5 healthy adult Beagles weighing 7 to 10 kg, with no apparent ocular disease. PROCEDURES-A double-blind randomized 9-session crossover trial was designed. Both eyes were assigned to 9 treatments with a minimum 7-day washout period between treatments: 0.1, 0.2, and 0.3 mL of 2% lidocaine solution; 0.1, 0.2, and 0.3 mL of 1% lidocaine solution; and 0.1, 0.2, and 0.3 mL of balanced salt solution. Dogs were anesthetized, and the allocated treatment was injected intracamerally after aspiration of the same volume of aqueous humor from the anterior chamber of each eye. Two perpendicular pupil diameters were measured. Intraocular pressure, heart rate, respiratory rate, ECG readings, and end-tidal partial pressure of CO(2) were monitored. RESULTS-Intracameral injection of 1% or 2% lidocaine solutions in volumes of 0.1 to 0.3 mL induced a significant degree of mydriasis, and the effect was maintained for 74 to 142 minutes. Lidocaine injection had no significant effect on intraocular pressure, heart rate, respiratory rate, ECG readings, or end-tidal partial pressure of CO(2). CONCLUSIONS AND CLINICAL RELEVANCE-Intracameral lidocaine injection in healthy dogs induced mydriasis, the timing of which was affected by concentration and volume of lidocaine. This technique could serve as an alternative to topically administered mydriatics for intraocular surgery in dogs.

Chirality in ocular agents

PURPOSE OF REVIEW

To review the role of chirality in current ocular pharmacology. The importance of stereo-isomeric purity has frequently been emphasized in recent years. Development of chirally pure medications can lead to improved efficacy and side-effect profiles. Practitioners prescribing ocular agents may benefit from understanding the effects of chirality in their evaluation of old and new medications.

RECENT FINDINGS

Chirality can affect multiple classes of ocular agents. Although the ways in which stereo-isomers influence the properties of a drug differ, this review illustrates the benefit of knowledge of individual isomers' effects in clinical decision making. The variety of possible effects stereo-isomers produce further underlines the importance of purification and in-depth analysis of chiral compounds.

SUMMARY

Many important agents exist as a mixture of two different stereoisomers. Both isomers may produce a pharmacological effect; however, these effects may be different from one another and one isomer may even give a result opposite from the desired pharmacological effect. Here we examine published findings on ocular medications relating to their chiral nature and summarize the possible ways chirality affects the activity of a few ocular agents. Many more ocular medications have not been investigated to ascertain their chiral properties. This review adds to the recent emphasis on investigating stereo-isomers for individual selectivity of beneficial and adverse profiles.

Evaluation of surgical performance with intracameral mydriatics in phacoemulsification surgery

PURPOSE

To evaluate surgical performance using intracameral mydriatics (ICM) in phacoemulsification surgery in a series of consecutive cases.

METHODS

In a series of 198 consecutive procedures 50-200 microl of cyclopentolate 0.1%, phenylephrine 1.5% and lidocaine 1% was given intracamerally for mydriasis and anaesthesia. The previous 198 cases, dilated with topical mydriatics, were studied for comparison. Several pre- intra- and postoperative parameters were registered, and the subjective surgical performance was graded after each procedure. In 41 consecutive cases, the change in pulse and oxygen saturation induced by the ICM injection was registered.

RESULTS

No increase in operation time or complication rates was seen with ICM, compared to when standard topical mydriatics were used. The subjective surgical performance was ranked as equally good for both groups.

CONCLUSION

From this clinical evaluation, our impression is that ICM performs well in routine phacoemulsification surgery.

Analysis of tropane and related alkaloids

The current methods for tropane alkaloid chromatographic separation and determination are summarised. The alkaloids included are: the medicinally applied tropic acid esters hyoscyamine and scopolamine and their derivatives, cocaine and derivatives, the metabolites and degradation products of these compounds occurring in plant material, calystegines as nortropane alkaloids, anatoxins as homonortropane alkaloids, pelletierines and pseudopelletierines as alkaloids with isomeric structures. Developments in GC, HPLC, CE and TLC are presented and the advantages of each method for plant analysis are discussed. A summary for each chromatographic method lists the instrumentation and parameters applied for tropane alkaloids.