A Comparative Preclinical Evaluation of a Novel Difluprednate 0.04% BID Ophthalmic Solution and Marketed 0.05% QID Ophthalmic Emulsion.

Purpose: The purpose of this study was to compare the efficacy, and ocular pharmacokinetics of a new 0.04% w/v bis in die means twice a day (BID) ophthalmic solution and marketed 0.05% w/v quater in die means four times a day (QID) ophthalmic emulsion of difluprednate in New Zealand white (NZW) rabbits. Methods: The preclinical proof of concept was established in paracentesis-induced acute inflammation, endotoxin-induced acute uveitis, and bovine serum albumin-induced chronic uveitis in NZW rabbit animal models. A comparison of clinical score, total cell count, and total protein was performed to determine efficacy. An ocular pharmacokinetic study was conducted to study the influence of the vehicle on the ocular absorption of the drug. Results: In both uveitis models, the new solution formulation and marketed emulsion formulation inhibited total clinical score, total cell count, PGE2, and total protein significantly more than the placebo and lipopolysaccharide (disease control) groups and were comparable. In an ocular pharmacokinetic study, the Cmax and AUC0-t of difluoroprednisolone 17-butyrate in humor were ∼2-fold higher after 14 days' instillation of new solution formulation (0.04% w/v, BID) compared with 14 days' instillation of marketed emulsion (0.05% w/v, QID). Conclusions: The study demonstrated that the efficacy of the solution formulation at a lower dose and reduced dosing regimen were comparable to that of the emulsion formulation. The reduction in strength and regimen may result in improved patient adherence and outcomes.

Preclinical Evaluation of a Novel Once-a-Day Brimonidine Ophthalmic Nanosuspension.

Purpose: This article aims to describe a preclinical proof of concept for a novel once-a-day (OD) brimonidine ophthalmic nanosuspension. Methods: The preclinical proof of concept was established using New Zealand white rabbits as animal models. Dose-finding, multiple-dose efficacy, ocular pharmacokinetic, and hemodynamic studies were performed in normotensive rabbits. Steroid-induced ocular hypertension model in rabbits was used to study efficacy in glaucomatous pathophysiology. The test (0.35% OD suspension) and reference (0.15% three times a day [TID] solution) were compared. Results: The intraocular pressure (IOP) reduction was sustained for 0.35% and 0.5% strengths but not for other lower strengths tested or reference strengths. A 0.35% OD suspension reduced IOP >2 mmHg after 24 h of dosing, which was not seen with the reference. After multiple dosing, 0.35% OD suspension reduced IOP by 4-6 mmHg after 24 h, which was comparable to the 0.15% TID reference solution. An ocular pharmacokinetic study showed that the brimonidine was rapidly absorbed and distributed throughout the eye after topical administration. Concentration was higher in tissues with high α2 receptors, such as cornea-conjunctiva, iris/ciliary body, and choroid/retina. The steady-state concentrations in these organs were also significant after 24 h of the last dose. There was an indication of increased plasma levels, so a hemodynamic study was performed to assess any adverse effects. All hemodynamic parameters were normal and no new unusual safety findings were observed. Conclusions: The study demonstrated that the novel brimonidine 0.35% ophthalmic nanosuspension is both safe and effective when administered OD and is comparable to the marketed reference formulation administered TID.

Comparison of Physicochemical Properties of Generic Doxorubicin HCl Liposome Injection with the Reference Listed Drug.

BACKGROUND: Liposomal doxorubicin is widely used for treating ovarian cancer and Kaposi's sarcoma. Encapsulation of doxorubicin in highly complex polyethylene glycol-coated (stealth) liposomes prolongs residence time and avoids the systemic toxicity associated with administration of the free drug. Small variations in physicochemical properties introduced during manufacture of liposomes can influence the payload of encapsulated drug, stability of liposomes under physiological conditions, and release of drug at the target tissue. Accordingly, the US Food and Drug Administration and the European Medicines Agency have issued guidance for manufacturers of generic liposomal doxorubicin that is designed to ensure that more than 30 physicochemical parameters that influence its safety and efficacy should be similar in the generic and reference listed drugs. OBJECTIVE: This study aims to describe the physicochemical characterization procedures used to ensure consistency between batches of generic liposomal doxorubicin and with the reference listed drug. METHODS: A range of spectroscopic, chromatographic, and other physicochemical tests was used to compare relative concentrations of liposome components, liposome morphology, ratios of free/entrapped doxorubicin, stability, and in vitro doxorubicin release rates in physiologically and clinically relevant media. RESULTS: The tests established that generic and reference liposomes contained similar concentrations of drug, lipids, and excipients and that their physical forms were also similar. CONCLUSION: The results of the tests demonstrate the physicochemical equivalence of generic liposomal doxorubicin hydrochloride and the reference listed drug, Doxil®/Caelyx®. Biochemical and clinical equivalence must also be demonstrated to fully meet regulatory requirements for generic liposomal medicines, and these are the subjects of separate studies.