Borate aided Schiff's base formation yields in situ gelling hydrogels for cartilage regeneration

Collagen (Col)-based injectable hydrogels are desirable scaffolds for cartilage tissue engineering. However, fabrication of Col-based injectable hydrogels with short gelation times, good biocompatibility and high mechanical properties still faces great...

Download Full-text

Novel Formulation Development and Evaluation of Nanoparticles Based in Situ Gelling System for The Ophthalmic Delivery of Ciprofloxacin Hydrochloride

International Journal of Drug Delivery Technology ◽

10.25258/ijddt.v5i4.8880 ◽

2015 ◽

Vol 5 (4) ◽

Author(s):

Kranti Singh ◽

Surajpal Verma ◽

Shyam Prasad ◽

Indu Bala

Keyword(s):

Particle Size ◽

Zeta Potential ◽

Drug Loading ◽

In Vitro Release ◽

Formulation Development ◽

Ciprofloxacin Hydrochloride ◽

Potential Value ◽

The Mean ◽

In Situ Gelling

Ciprofloxacin hydrochloride loaded Eudragit RS100 nanoparticles were prepared by using w/o/w emulsification (multiple emulsification) solvent evaporation followed by drying of nanoparticles at 50°C. The nanoparticles were further incorporated into the pH-triggered in situ gel forming system which was prepared using Carbopol 940 in combination with HPMC as viscosifying agent. The developed nanoparticles was evaluated for particle size, zeta potential value and loading efficiency; nanoparticle incorporated in situ gelling system was evaluated for pH, clarity, gelling strength, rheological studies, in-vitro release studies and ex-vivo precorneal permeation studies. The nanopaticle showed the mean particle size varying between 263.5nm - 325.9 nm with the mean zeta potential value of -5.91 mV to -8.13 mV and drug loading capacity varied individually between 72.50% to 98.70% w/w. The formulation was clear with no suspended particles, showed good gelling properties. The gelling was quick and remained for longer time period. The developed formulation was therapeutically efficacious, stable and non-irritant. It provided the sustained release of drug over a period of 8-10 hours.

Download Full-text

Scaffolds for Drug Delivery in Tissue Engineering

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2008.1.2.1 ◽

2008 ◽

Vol 1 (2) ◽

pp. 113-123 ◽

Cited By ~ 2

Author(s):

Vikas V. Gaikwad ◽

Abasaheb B. Patil ◽

Madhuri V. Gaikwad

Keyword(s):

Drug Delivery ◽

Tissue Engineering ◽

Heart Diseases ◽

Cartilage Regeneration ◽

Tissue Growth ◽

The Body ◽

Patient Specific ◽

In Situ Gel ◽

Heart Muscle Cells

Scaffolds are used for drug delivery in tissue engineering as this system is a highly porous structure to allow tissue growth. Although several tissues in the body can regenerate, other tissue such as heart muscles and nerves lack regeneration in adults. However, these can be regenerated by supplying the cells generated using tissue engineering from outside. For instance, in many heart diseases, there is need for heart valve transplantation and unfortunately, within 10 years of initial valve replacement, 50–60% of patients will experience prosthesis associated problems requiring reoperation. This could be avoided by transplantation of heart muscle cells that can regenerate. Delivery of these cells to the respective tissues is not an easy task and this could be done with the help of scaffolds. In situ gel forming scaffolds can also be used for the bone and cartilage regeneration. They can be injected anywhere and can take the shape of a tissue defect, avoiding the need for patient specific scaffold prefabrication and they also have other advantages. Scaffolds are prepared by biodegradable material that result in minimal immune and inflammatory response. Some of the very important issues regarding scaffolds as drug delivery systems is reviewed in this article.

Download Full-text

Lipid Metabolic Events Underlying the Formation of the Corneocyte Lipid Envelope

Skin Pharmacology and Physiology ◽

10.1159/000513261 ◽

2021 ◽

pp. 1-13

Author(s):

Philip W. Wertz

Keyword(s):

Stratum Corneum ◽

Outer Surface ◽

Barrier Function ◽

Skin Surface ◽

Schiff’S Base ◽

Cornified Envelope ◽

Epoxy Alcohol ◽

Viable Epidermis ◽

Transglutaminase 1 ◽

Base Formation

Cornified cells of the stratum corneum have a monolayer of an unusual lipid covalently attached to the outer surface. This is referred to as the corneocyte lipid envelope (CLE). It consists of a monolayer of ω-hydroxyceramides covalently attached to the outer surface of the cornified envelope. The CLE is essential for proper barrier function of the skin and is derived from linoleate-rich acylglucosylceramides synthesized in the viable epidermis. Biosynthesis of acylglucosylceramide and its conversion to the cornified envelope is complex. Acylglucosylceramide in the bounding membrane of the lamellar granule is the precursor of the CLE. The acylglucosylceramide in the limiting membrane of the lamellar granule may be oriented with the glucosyl moiety on the inside. Conversion of the acylglucosylceramide to the CLE requires removal of the glucose by action of a glucocerebrosidase. The ester-linked fatty acid may be removed by an as yet unidentified esterase, and the resulting ω-hydroxyceramide may become ester linked to the outer surface of the cornified envelope through action of transglutaminase 1. Prior to removal of ester-linked fatty acids, linoleate is oxidized to an epoxy alcohol through action of 2 lipoxygenases. This can be further oxidized to an epoxy-enone, which can spontaneously attach to the cornified envelope through Schiff’s base formation. Mutations of genes coding for enzymes involved in biosynthesis of the CLE result in ichthyosis, often accompanied by neurologic dysfunction. The CLE is recognized as essential for barrier function of skin, but many questions about details of this essentiality remain. What are the relative roles of the 2 mechanisms of lipid attachment? What is the orientation of acylglucosylceramide in the bounding membrane of lamellar granules? Some evidence supports a role for CLE as a scaffold upon which intercellular lamellae unfold, but other evidence does not support this role. There is also controversial evidence for a role in stratum corneum cohesion. Evidence is presented to suggest that covalently bound ω-hydroxyceramides serve as a reservoir for free sphingosine that can serve in communicating with the viable epidermis and act as a potent broad-acting antimicrobial at the skin surface. Many questions remain.

Download Full-text