Polymer-mediated delivery of vaccines to treat opioid use disorders and to reduce opioid-induced toxicity.

Vaccines offer a potential strategy to treat opioid use disorders (OUD) and to reduce the incidence of opioid-related overdoses. Vaccines induce opioid-specific polyclonal antibodies that selectively and effectively bind the target opioid and prevent its distribution across the blood-brain barrier. Because antibody-mediated reduction of drug distribution to the brain reduces drug-induced behavior and toxicity, vaccine efficacy depends on the quantity and quality of the antibody response. This study tested whether polymer-mediated delivery could improve vaccine efficacy against opioids as well as eliminate the need for booster injections normally required for a successful immunization. A series of novel biodegradable biocompatible thermogelling pentablock co-polymers were used to formulate a candidate vaccine against oxycodone in mice and rats. Polymer-based delivery of the anti-oxycodone vaccine was equally or more effective than administration in aluminum adjuvant in generating oxycodone-specific antibodies and in reducing oxycodone-induced effects and oxycodone distribution to the brain in mice and rats. The composition and release kinetics of the polymer formulations determined vaccine efficacy. Specifically, a formulation consisting of three simultaneous injections of the anti-oxycodone vaccine formulated in three different polymers with slow, intermediate, and fast release kinetics was more effective than an immunization regimen consisting of three sequential injections with the vaccine adsorbed on aluminum. The novel three-phased polymer vaccine formulation was effective in blocking oxycodone-induced antinociception, respiratory depression and bradycardia in rats.

Evaluation of Intracameral Pentablock Copolymer Thermosensitive Gel for Sustained Drug Delivery to the Anterior Chamber of the Eye.

PURPOSE: To investigate PTSgels (Pentablock copolymers) as an injectable formulation technology for sustained ocular drug delivery. Drug release profile, tolerability, and polymer degradation for one of the thermosensitive, biodegradable, and biocompatible compositions were investigated through intracameral (IC) injection in rabbits. METHODS: New Zealand White rabbit eyes were injected IC (50 µL) with 100 µg near-infrared-immunoglobulin G (NIR-IgG) in balanced salt solution (BSS) or 20% PTSgel; or with PTSgel or BSS alone. Ocular irritation scoring, intraocular pressure (IOP), and corneal thickness (CT) measurement, as well as color and infrared photography, were performed for up to 28 days postinjection. Upon euthanasia at 7, 14, or 28 days, eyes underwent ex vivo imaging (Xenogen IVIS) followed by tissue fixation and histopathology. RESULTS: IC injection of PTSgel (liquid at room temperature) was performed without difficulty using a 31G needle. The polymer quickly gelled in the IC space resulting in an inferior anterior chamber deposit. The tested PTSgel was well tolerated, with no significant changes in IOP or CT. Eyes injected with NIR-IgG in PTSgel had visible NIR-IgG through 9 days postinjection, and ex vivo imaging detected a strong NIR-IgG signal in the anterior chamber through day 28. The gel deposit steadily decreased in size over time and was nearly eliminated by 28 days. CONCLUSIONS: The PTSgel released IgG for 28 days and was well tolerated. The polymer degraded in parallel with drug release. These results demonstrate the potential of intracameral PTSgel formulations for sustained delivery of biologic therapies to the ocular anterior segment.

Sustained Release of Protein Therapeutics from Subcutaneous Thermosensitive Biocompatible and Biodegradable Pentablock Copolymers (PTSgels).

Objective. To evaluate thermosensitive, biodegradable pentablock copolymers (PTSgel) for sustained release and integrity of a therapeutic protein when injected subcutaneously. Materials and Methods. Five PTSgels with PEG-PCL-PLA-PCL-PEG block arrangements were synthesized. In vitro release of IgG from PTSgels and concentrations was evaluated at 37°C. Released IgG integrity was characterized by SDS-PAGE. In vitro disintegration for 10GH PTSgel in PBS was monitored at 37°C over 72 days using gravimetric loss and GPC analysis. Near-infrared IgG in PTSgel was injected subcutaneously and examined by in vivo imaging and histopathology for up to 42 days. Results. IgG release was modulated from approximately 7 days to more than 63 days in both in vitro and in vivo testing by varying polymer composition, concentration of PTSgel aqueous solution, and concentration of IgG. Released IgG in vitro maintained structural integrity by SDS-PAGE. Subcutaneous PTSgels were highly biocompatible and in vitro IgG release occurred in parallel with the disappearance of subcutaneous gel in vivo. Conclusions. Modulation of release of biologics to fit the therapeutic need can be achieved by varying the biocompatible and biodegradable PTSgel composition. Release of IgG parallels disappearance of the polymeric gel; hence, little or no PTSgel remains after drug release is complete.

LX211 (voclosporin) suppresses experimental uveitis and inhibits human T cells.

PURPOSE: To test the therapeutic effectiveness of voclosporin against experimental autoimmune uveoretinitis (EAU) in rats and to evaluate its effect on human T cells. METHODS: EAU was induced by immunization with a uveitogenic protein. Voclosporin administration, by subcutaneous injection, began on day (d) 0 or d7 after immunization. Treatment effectiveness was evaluated in vivo using clinical EAU scoring (d7-d13) and histopathologic evaluation of enucleated eyes after experimental termination. Rodent lymphocytes were harvested from lymph nodes on d14 for antigen-specific proliferation assays. The effect of voclosporin on human T-cell proliferation and cytokine secretion was examined in vitro. RESULTS: Voclosporin prevented EAU development in rats receiving medium and high preventive doses, whereas high-dose voclosporin administration effectively treated EAU. Lymphocytes from animals treated with voclosporin had decreased antigen-specific proliferation in vitro compared with lymphocytes from untreated animals. No evidence of abnormal ocular histopathology was found in the eyes from animals that received high doses of therapeutic voclosporin. Using human T cells, voclosporin inhibited human T-cell proliferation up to 100-fold. Furthermore, voclosporin treatment of human T cells significantly reduced pan T-cell effector responses. CONCLUSIONS: Voclosporin effectively suppressed uveoretinitis in an animal model that imitates the human inflammatory ocular disease by inhibiting lymphocyte proliferation. In addition, voclosporin effectively inhibited human T-cell proliferation and function in vitro. The authors report the first evidence supporting the application of voclosporin to treat intraocular inflammation.

A sensitive LC-MS/MS assay for the determination of dextromethorphan and metabolites in human urine--application for drug interaction studies assessing potential CYP3A and CYP2D6 inhibition.

The commonly used antitussive dextromethorphan can be used to simultaneously assess potential cytochrome P450 3A (CYP3A) and CYP2D6 inhibition during drug development. The metabolism of dextromethorphan to dextrorphan and subsequently to 3-hydroxymorphinan are via the 2D6 pathway, while the metabolism of dextromethorphan to 3-methoxymorphinan is via the 3A pathway. A sensitive and specific LC-MS/MS assay has been developed to determine the human urine concentrations of dextromethorphan and three metabolites (dextrorphan, 3-methoxymorphinan and 3-hydroxymorphinan) in support of drug interaction studies. Urine samples (0.5 ml), after enzymatic hydrolysis of the conjugates and containing 3-ethylmorphine as an internal standard, were extracted with chloroform under basic conditions. Following concentration and reconstitution, the samples were analyzed by LC-MS/MS. The assay was linear over the range of 5.00-500 ng/ml for dextromethorphan and 3-methoxymorphinan; and 200-3000 ng/ml for dextrorphan and 3-hydroxymorphinan using a Perkin-Elmer Sciex triple quadrupole mass spectrometer (API 300). The intra- and inter-day relative standard deviation (RSD) across three validation runs over the entire concentration range for all analytes was less than 15%. Accuracy determined at three or four concentrations (9.00, 200, and 400 ng/ml for dextromethorphan and 3-methoxymorphinan; 250, 400, 1300 and 2500 ng/ml for dextrorphan and 3-hydroxymorphinan) ranged between 96.3 and 113.8%. The stability of analytes in urine was demonstrated for 9 months at -20 degrees C, 24 h under ambient conditions and for up to three freeze/thaw cycles. The method described herein is suitable for the rapid and efficient measurement of dextromethorphan and different metabolites to estimate potential CYP3A inhibition by drug candidates and for screening of extensive and poor metabolizers of CYP2D6 in the heterogeneous population. The method has subsequently been validated on a Sciex API 3000 with lower limit of quantitation; 1.00 ng/ml for dextromethorphan and 3-methoxymorphinan; 60.0 ng/ml for dextrorphan and 100 ng/ml for 3-hydroxymorphinan.