Coated microneedles for transdermal delivery of a potent pharmaceutical peptide.

Minimally invasive delivery of peptide and protein molecules represents a significant opportunity for product differentiation and value creation versus standard injectable routes of administration. One such technology utilizes microneedle (MN) patches and it has made considerable clinical advances in systemic delivery of potent macromolecules and vaccines. A sub-class of this technology has focused on preparation of solid dense MN arrays followed by precision formulation coating on the tips of the MN. The objective of this study was to develop a drug product using the MN technology that has similar bioperformance when compared to subcutaneous route of delivery and can provide improved stability under storage. Therapeutic peptide (Peptide A, Merck & Co., Inc., Kenilworth, NJ, USA) is being developed as a subcutaneous injection for chronic dosing with a submilligram estimated therapeutic dose. Peptide A has chemical and physical stability challenges in solution and this led to exploration of a viable drug product which could provide therapeutic dosages while overcoming the stability issues seen with the compound. This work focused on developing a coated solid microstructure transdermal system (sMTS) for Peptide A followed by detailed in vitro and preclinical evaluation for two different coating formulations. Based on initial assessment, ~250 µg of Peptide A could be coated with precision on a 1.27cm2 patch which contained 316 MN's. The delivery from these systems was achieved with absolute bioavailability being similar to the subcutaneous delivery (88% and 74% for coated sMTS 1 & 2 and 75% for subcutaneous delivery). Stability of Peptide A was also found to be significantly improved when coated on the sMTS system with minimal degradation recorded at room temperature storage as compared to the subcutaneous liquid formulation. Additionally, skin irritation (on pig skin) was also measured in this study and it was found to be minimal and self-resolving. This evaluation provided a viable option for developing a drug product with improved stability and successful delivery of the investigated molecule. Graphical abstractSchematic showing uncoated sMTS, resulting product with coated peptide, successful skin penetration with high delivery efficiency and bioavailability.

An Extensive Study Regarding the Microscopic Anatomy of the Early Fetal Human Optic Nerve.

The development of the optic nerve and its surrounding tissues during the early fetal period is a convoluted period because it spans both the organogenesis period and the fetal period. This study details the microscopic anatomy and histoembryology of the optic nerve in embryos during the early fetal period, including the second half of the first trimester of pregnancy. Serial sections through the orbit of variously aged embryos allowed us to analyze the nerve in both longitudinal and transverse aspects. A histological assessment and description of the structures surrounding and inside the nerve were performed, highlighting the cellular subtypes involved. By employing immunohistochemical techniques, we could characterize the presence and distribution of astrocytes within the optic nerve. Our findings suggest that by the 8th gestational week (WG) the structures are homologs to all the adult ones but with an early appearance so that maturation processes take place afterward. By this age, the axons forming the nerve are definitive adult axons. The glial cells do not yet exhibit adult phenotype, but their aspect becomes adult toward the 13th week. During its development the optic nerve increases in size then, at 14 weeks, it shrinks considerably, possibly through its neural maturation process. The morphological primordium of the blood-nerve barrier can be first noted at 10 WG and at 13 WG the morphological blood-nerve barrier is definitive. The meningeal primordium can be first noted as a layer of agglomerated fibroblasts, later toward 13 WG splitting in pachymeninx and leptomeninges and leaving space for intrinsic blood vessels.

A Systematic Approach of the Intrauterine Morphogenesis of the Human Palpebral Apparatus.

The human eyelid embodies a vast diversity of functions. Acting as a protective shield for the ocular apparatus and as a light regulator in the sight process, eyelids stand a fascinating - yet omitted - role in facial aesthetics, serving as a racial trait by which humankind succeeded to manifest heterogeneity as a species. These assumptions are precisely forecasted right from in-utero life through intricate processes of growth and cell differentiation. In the Department of Anatomy of "Carol Davila" University of Medicine and Pharmacy, we performed morphological assessments on 41 embryos and fetuses with gestational ages ranging from 6 to 29 weeks. This study aims to illustrate the morphogenesis of eyelids in human embryos and fetuses and highlight macroscopic features which could potentially have significant clinical implications in ophthalmic pathology.

Ultrasound Pitfalls in a Complex Fetal Cardiac Malformation-Case Report of a New Arteriovenous Central Communication.

Cardiac and cardiovascular malformations are of real interest in terms of definition, epidemiology, and means of early diagnosis by imaging. Although ultrasound examination reaches exceptional performance nowadays, unusual pathologies are still exposed to the risk of either incorrect acquired image or misinterpretation by the specialist in a routine scan. Herein, we present a case of a 20-week-old fetus (from an apparently low-risk pregnancy) with complex cardiac and vascular abnormalities, including an arteriovenous malformation along with ventricular septal defect, ductal coarctation of the aorta, aneurysm of a brachiocephalic vein, and dilation of the entire neck and upper mediastinum venous system, and the limitations that were encountered in the process of diagnosis and management of the case.

A Comprehensive Study Regarding the Intrauterine Development of Nails.

The nail apparatus serves as a protective layer over the dorsal aspect of each distal phalanx of both hands and feet. Besides protection, other functions include serving as part of defense or attack mechanisms, scratching, and dexterity. Nail development has been a subject of interest since the 19th century, from both the phylogenetic and ontogenetic points of view. Despite the early spark of interest, nail embryology has yet been analyzed by a relatively small number of scientists. In the Department of Anatomy of "Carol Davila" University of Medicine and Pharmacy, we performed a morphological analysis on 41 embryos and fetuses with gestational ages that varied between 6 and 29 weeks.

Stabilization and Transdermal Delivery of an Investigational Peptide Using MicroCor® Solid-State Dissolving Microstructure Arrays.

The formulation of biotherapeutics presents unique challenges especially with regard to physical and chemical stability and often requires refrigerated storage conditions of final drug products. Peptide A is an example of a developmental compound which showed significant stability challenges when prepared as a liquid formulation for a subcutaneous injection. The aim of the present study was to evaluate whether Peptide A can be successfully formulated in MicroCor® microstructure arrays (MSAs) as an alternative delivery option. MSAs contain a high density of dissolving microstructures allowing for transdermal delivery. In the present work, a 5600-needle MSA (~200 µm long microstructures, 2 cm2 array) was prepared with a therapeutically-relevant dose of Peptide A. The array was shown to be stable under room-temperature storage conditions for 3 months. On in vivo application to Yucatan minipigs, Peptide-A-loaded MSAs demonstrated only mild and transient skin irritation and a very high efficiency of peptide transfer from dissolving microstructures into the skin resulting in absolute bioavailability of 74%. This transdermal bioavailability was very similar to the 73% bioavailability obtained from a subcutaneous injection. This technical feasibility study demonstrated that MicroCor® technology represents a viable option for delivery of Peptide A with significant improvements in peptide stability.

A novel method for strict intranasal delivery of non-replicating RSV vaccines in cotton rats and non-human primates.

Respiratory syncytial virus (RSV) is the most common viral cause of bronchiolitis and pneumonia in children twelve months of age or younger and a significant cause of lower respiratory disease in older adults. As various clinical and preclinical candidates advance, cotton rats (Sigmodon hispidus) and non-human primates (NHP) continue to play a valuable role in RSV vaccine development, since both animals are semi-permissive to human RSV (HRSV). However, appropriate utilization of the models is critical to avoid mis-interpretation of the preclinical findings. Using a multimodality imaging approach; a fluorescence based optical imaging technique for the cotton rat and a nuclear medicine based positron emission tomography (PET) imaging technique for monkeys, we demonstrate that many common practices for intranasal immunization in both species result in inoculum delivery to the lower respiratory tract, which can result in poor translation of outcomes from the preclinical to the clinical setting. Using these technologies we define a method to limit the distribution of intranasally administered vaccines solely to the upper airway of each species, which includes volume restrictions in combination with injectable anesthesia. We show using our newly defined methods for strict intranasal immunization that these methods impact the immune responses and efficacy observed when compared to vaccination methods resulting in distribution to both the upper and lower respiratory tracts. These data emphasize the importance of well-characterized immunization methods in the preclinical assessment of intranasally delivered vaccine candidates.

Development of a recombinant toxin fragment vaccine for Clostridium difficile infection.

Clostridium difficile infection (CDI) is the major cause of antibiotic-associated diarrhea and pseudomembranous colitis, a disease associated with significant morbidity and mortality. The disease is mostly of nosocomial origin, with elderly patients undergoing anti-microbial therapy being particularly at risk. C. difficile produces two large toxins: Toxin A (TcdA) and Toxin B (TcdB). The two toxins act synergistically to damage and impair the colonic epithelium, and are primarily responsible for the pathogenesis associated with CDI. The feasibility of toxin-based vaccination against C. difficile is being vigorously investigated. A vaccine based on formaldehyde-inactivated Toxin A and Toxin B (toxoids) was reported to be safe and immunogenic in healthy volunteers and is now undergoing evaluation in clinical efficacy trials. In order to eliminate cytotoxic effects, a chemical inactivation step must be included in the manufacturing process of this toxin-based vaccine. In addition, the large-scale production of highly toxic antigens could be a challenging and costly process. Vaccines based on non-toxic fragments of genetically engineered versions of the toxins alleviate most of these limitations. We have evaluated a vaccine assembled from two recombinant fragments of TcdB and explored their potential as components of a novel experimental vaccine against CDI. Golden Syrian hamsters vaccinated with recombinant fragments of TcdB combined with full length TcdA (Toxoid A) developed high titer IgG responses and potent neutralizing antibody titers. We also show here that the recombinant vaccine protected animals against lethal challenge with C. difficile spores, with efficacy equivalent to the toxoid vaccine. The development of a two-segment recombinant vaccine could provide several advantages over toxoid TcdA/TcdB such as improvements in manufacturability.

Generation and characterization of monoclonal antibodies against the intracellular domain of hemidesmosomal type XVII collagen.

Type XVII collagen, also referred to as bullous pemphigoid antigen 2 (BPAG2) or bullous pemphigoid antigen 180 (BP180), is a transmembrane protein of the hemidesmosomal complexes of keratinocytes. Type XVII collagen has an unusual type II orientation with its N-terminus intracellularly located and with a large extracellular domain that spans lamina lucida of the dermal-epidermal junction. Type XVII collagen is an autoantigen in patients with pemphigoid diseases and its gene is mutated in patients with junctional epidermolysis bullosa. In the present work, we generated new monoclonal antibodies (MAbs) against the intracellular domain of type XVII collagen. We further characterized reactivity and fine specificity of an MAb (clone V58) from this panel of antibodies. The epitope recognized by the mAb V58 was mapped to a stretch of type XVII collagen corresponding to residues 234-398 of its sequence. Possible applications of this new MAb include antigen mapping in patients with hereditary epidermolysis bullosa and immunoaffinity purification of cell-derived type XVII collagen.