Dhanya Narayanan

Sequentially releasing dual-drug-loaded PLGA-casein core/shell nanomedicine: Design, synthesis, biocompatibility and pharmacokinetics

The present study reports an engineered poly-l-lactide-co-glycolic acid (PLGA)-casein polymer-protein hybrid nanocarrier 190±12nm in size entrapping a combination of chemically distinct (hydrophobic/hydrophilic) model drugs. A simple emulsion-precipitation route was adopted to prepare nearly monodispersed nanoparticles with distinct core/shell morphology entrapping paclitaxel (Ptx) in the core and epigallocatechin gallate (EGCG) in the shell, with the intention of providing a sequential and sustained release of these drugs. The idea was that an early release of EGCG would substantially increase the sensitivity of Ptx to cancer, thereby providing improved therapeutics at lower concentrations, with less toxicity. The hemo- and immunocompatibility of the core/shell nanomedicine was established in this study. The core/shell nanoparticles injected via the tail vein in Sprague-Dawley rats did not reveal any organ toxicity as was evident from histopathological evaluations of the major organs. In vivo pharmacokinetic studies in rats by high-performance liquid chromatography confirmed a sustained and sequential release of both the drugs in plasma, indicating prolonged circulation of the nanomedicine and enhanced availability of the drugs when compared to the bare drugs. Overall, the polymer-protein multilayered nanoparticles proved to be a promising platform for nanopolypharmaceutics.

Poly-(ethylene glycol) modified gelatin nanoparticles for sustained delivery of the anti-inflammatory drug Ibuprofen-Sodium: An in vitro and in vivo analysis

UNLABELLED The limited bioavailability and rapid clearance of the anti-inflammatory drug Ibuprofen Sodium (IbS) necessitates repeated drug administration. To address this, injectable IbS loaded PEGylated gelatin nanoparticles (PIG NPs) of size ~200nm and entrapment efficiency ~70%, providing sustained release in vitro were prepared by a modified two-step desolvation process. The developed nanomedicine, containing a range of IbS concentrations up to 1mg/mL proved to be non-toxic, hemocompatible and non-immunogenic, when tested through various in vitro assays and was reaffirmed by in vivo cytokine analysis. HPLC analysis of intravenously administered PIG NPs showed a sustained release of IbS for ~4days with improved bioavailability and pharmacokinetics when compared to bare IbS and IbS-loaded non-PEGylated GNPs. Histological analysis of liver and kidney revealed tissue integrity as in the control, indicating biocompatibility of PIG NPs. The results demonstrate improved plasma half-life of IbS when encapsulated within nanogelatin, thereby aiding reduction in its frequency of administration. FROM THE CLINICAL EDITOR In this preclinical study, improved plasma half-life of ibuprofen sodium was demonstrated when encapsulated within PEGylated gelatin nanoparticles of ~200 nm size, expected to lead to reduced frequency of administration in future clinical applications.

A systematic evaluation of hydroxyethyl starch as a potential nanocarrier for parenteral drug delivery

Development of parenteral nanoformulations is highly challenging due to the stringent demands on stability, reproducibility and high drug loading with minimal excipients. This study focuses on the development of a pharmaceutically acceptable nanomatrix system for parenteral delivery based on Hydroxyethyl Starch (HES), a FDA approved polymer that is relatively unexplored in drug delivery research. HES nanoparticles were prepared through a simple, two-step crosslinking-precipitation route, yielding 160±5 nm, nearly monodispersed spherical particles with high colloidal stability. The utility of this nanocarrier for parenteral delivery was verified by a panel of hemo/cytocompatibility assays at high concentrations (0.05-1 mg/ml) in vitro and in vivo. HES nanomatrix was found effective in encapsulating two chemically distinct drugs having varying hydrophobicities, with the release behavior being influenced by their chemical nature and drug-matrix interactions. Better in vitro efficacy was measured for the nanoencapsulated drug than its bare form, establishing the potential of HES nanocarriers for controlled drug delivery.

Hematotoxicological analysis of surface-modified and -unmodified chitosan nanoparticles.

The increasing interest in using chitosan nanoparticles for controlled drug delivery is hampered by its blood incompatibility, especially for intravenous applications. This study investigated the effects of processing solvents (acetic acid/lactic acid), dispersing media (acidic medium/saline), and surface modifiers (polyethylene glycol, polyvinyl alcohol, and ethylenediaminetetraacetatic acid) on the hemocompatibility of chitosan. Blood compatibility of chitosan nanoparticles prepared by ionotropic gelation with altered surface chemistry was evaluated by assessing their hemolytic activity, platelet aggregation, coagulation, and cytokine induction. It was observed that nanoparticles prepared in lactic acid and dispersed in saline did not show hemolysis, platelet aggregation, or coagulation, whereas nanoparticles prepared in acetic acid showed strong hemolysis. Surface modifiers were not observed to significantly affect blood compatibility, with the exception of EDTA, which delayed blood clotting times. Thus, chitosan nanoparticles prepared in lactic acid and dispersed in saline may be an ideal nanocarrier for parenteral applications.

Infantile Systemic Hyalinosis with Mutation in ANTXR2.

To the Editor: Infantile systemic hyalinosis (OMIM 236490) is a rare autosomal recessive disorder characterized by deposition of hyaline in skin, gingiva, adrenals, skeletal muscles and gastro intestinal tract [1, 2]. It presents in a new born or in early infancy with painful movements, joint contractures, gingival nodules, progressive skin thickening and hyperpigmented patches over bony prominances [3] and is caused by homozygous or compound heterozygous mutations in ANTXR2 on 4q21, which encodes capillary morphogenesis protein 2(CMG2) [4]. Mutation analysis is essential in confirming the diagnosis and offering prenatal diagnosis. We report a case of 2-mo-old boy with a homozygous mutation in ANTXR2. To our knowledge this is the first mutation proven case being reported from North India. A 2-mo-old boy who was the second child of third degree consanguineous parents had excessive cry during handling noticed since birth. Antenatal period of the mother was uneventful. He also had progressively increasing joint contractures of both elbows, ankles and knees with thick and shiny skin. He did not have chronic diarrhea and was gaining weight adequately. His elder sibling was a 3-y-old girl who was normal. On examination, he was very irritable and cried when touched. He had hyperpigmented macules over dorsum of hands over the knuckles, knees and on both malleoli. Skin was indurated and thickened (Fig. 1). He had contracture of bilateral elbows, knees and ankles. He did not have gingival nodules or perianal papules or tags. His weight was 4 kg, length 52 cm and head circumference 34 cm (Normal for age). He did not have hepatosplenomegaly. Routine hematology and serum chemistry were normal. Radiographs did not show osteopenia or lytic lesions. Mutation analysis of ANTXR2 was done by Sanger sequencing and a homozygous c.1073_1074insC in exon 13 was identified. This mutation is a previously described disease causing mutation. Infantile systemic hyalinosis was first described by Landing and Nadorra in 1986 [1]. Systemic infantile hyalinosis should be suspected in a newborn or infant presenting with excessive cry during handling, skin thickening, hyperpigmented skin over bony prominences and joint contractures [1, 2]. Other features include gingival thickening, pearly white skin papules, perianal fleshy lesions and failure to thrive. Thickened skin can be seen in other conditions like Winchester syndrome, congenital fascial dystrophy, infantile restrictive dermopathy, Farber disease, I cell disease and mucolipidosis III A. The presence of characteristic purplish patches over the malleoli, metacarpophalangeal joints, elbow and spine is a distinctive clinical clue that helps to establish the diagnosis. Till date 25 different mutations in ANTXR2 have been described [5]. Two cases were reported from India previously, but molecular diagnosis was not done. Since it is inherited in an autosomal recessive manner, there is 25 % chance of recurrence in subsequent pregnancies. Hence, clinical suspicion and molecular diagnosis is very essential to provide prenatal diagnosis in subsequent pregnancies. * Shubha R. Phadke shubharaophadke@gmail.com; shubha@sgpgi.ac.in

Proteins and Carbohydrates as Polymeric Nanodrug Delivery Systems: Formulation, Properties, and Toxicological Evaluation

Enhancing the clinical benefits of pharmaceuticals at reduced doses with negligible side effects has been an ever-challenging goal in drug delivery. This pursuit towards an optimal formulation is hugely supported through the development of nanoparticulate delivery systems, which encapsulate the drug in its active form. Nanocarriers have emerged as successful candidates in pharmaceutics owing to their multifaceted characteristics such as the capability to entrap pharmaceutical ingredients at therapeutic dose, better biodistribution, size-dependent clearance, targetability, and controlled/sustained release of single or multiple payloads at the site of interest. Additionally, the requirement that the chosen carrier be biocompatible and biodegradable necessitates the use of biopolymers in entrapping payloads. Among the biopolymers, a wide variety of natural and synthetic carbohydrates and proteins (including starch, chitosan, chitin, dextran, alginate, albumin, casein, fibrin/fibrinogen, gelatin, collagen, whey protein, etc.) have evolved as useful materials for delivering hydrophobic or hydrophilic drugs through oral, intravenous, mucosal, ocular, or nasal routes. Targeted-controlled release of pharmaceuticals to diseased sites, environmentally stimulated drug release at desired locations, and many more drug release strategies have been made available by efficient engineering and nanoformulation of carbohydrate and protein biopolymers. This chapter embodies an in-depth discussion of various carbohydrate- and protein-based nanomedicines with respect to the formulation and properties of the nanoconstructs. The manipulation and utilization of these properties for development of better drug delivery devices is described and the toxicological interactions of these nanocarriers with host physiological systems discussed.

Sirenomelia: Case Reports and Current Concepts of Pathogenesis

We present 2 cases of sirenomelia and highlight the recent theories about its pathogenesis. Both cases had a large aberrant abdominal umbilical artery (AAUA) arising from the aorta, suggesting vascular steal as the pathophysiology. However, the bilateral upper limb defects noted in 1 case, the reported 10% association of holoprosencephaly and anencephaly, and the reports of sirenomelia with normal umbilical arteries point to the alternative caudal dysgenesis (CD) theory. This proposes that an insult at the early blastogenic stage interferes with the formation of the notochord, resulting in abnormal development of caudal structures, an AAUA, and occasional neural tube defects. We have also analyzed the implications of the similarities between sirenomelia/CD and the VATER association; the increased risk of CD but not sirenomelia in infants of diabetic mothers; the fact that sirenomelia, holoprosencephaly, and the VATER association are all more common in monozygotic twins; the experimental production of sirenomelia in mice; and the possible genetic implications of the co-occurrence of sirenomelia and CD.

Hotspots in PTPN11 gene among Indian children with Noonan syndrome

ObjectivesTo test for PTPN11 mutations in clinically diagnosed cases of Noonan syndrome.Methods17 individuals with clinical diagnosis of Noonan syndrome were included in the study. Sanger sequencing of all the 15 exons of PTPN11 was done. A genotype-phenotype correlation was attempted.ResultsMutation in PTPN11 was detected in 11 out of 17 (64.7 %) patients with Noonan syndrome; 72% had mutation in exon 3 and 27 % had mutation in exon 13.ConclusionPTPN11 mutation accounts for 64.7% of cases with clinical features of Noonan syndrome in India. Majority of the mutations are in exon 3 and exon 13 of PTPN11, making them the hotspots in Indian population.

A novel variant in MED12 gene: Further delineation of phenotype

MED12 is a multiprotein mediator complex, which has a role in cell growth and differentiation and has been implicated in three distinct X‐linked intellectual disability syndromes with distinctive clinical features. These include Opitz–Kaveggia syndrome (FG syndrome), Lujan syndrome, and X‐linked Ohdo syndrome. Recently MED12 variants have been implicated in isolated X‐linked intellectual disability. We describe a 5‐year‐old male patient with intellectual disability and facial dysmorphism and a novel variant in MED12 gene identified by Whole Exome Sequencing. His dysmorphic facial features are distinct from the previously described phenotypes. With a strong genotype–phenotype correlation that is already known for MED12, this could be a new phenotype linked to MED12, thus expanding the phenotypic spectrum of MED12‐related disorders.

Metatropic Dysplasia with a Novel Mutation in TRPV4.

Back groundMetatropic dysplasia is a skeletal dysplasia characterized by rhizomelia, severe kyphoscoliosis and a coccygeal tail.Case characteristicsA 12 day-old male neonate had facial dysmorphism, short limbs and coccygeal tail and showed radiological features of metatropic dysplasia.ObservationA novel heterozygous variant was observed in TRPV4 gene.MessageWe report a novel mutation in an Indian neonate with metatropic dysplasia.