scholarly journals Encapsulation of Liposomes within pH Responsive Microspheres for Oral Colonic Drug Delivery

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
M. J. Barea ◽  
M. J. Jenkins ◽  
Y. S. Lee ◽  
P. Johnson ◽  
R. H. Bridson
Keyword(s):  
Drug Delivery ◽  
Small Intestine ◽  
Drug Release ◽  
Ph Responsive ◽  
Site Specific ◽  
Colonic Drug Delivery ◽  
Eudragit S100 ◽  
Release Studies ◽  
Model Drug

A novel liposome-in-microsphere (LIM) formulation has been created comprising drug-loaded liposomes within pH responsive Eudragit S100 microspheres. The liposomes contained the model drug 5-ASA and were coated with chitosan in order to protect them during encapsulation within the microspheres and to improve site-specific release characteristics.In vitrodrug release studies showed that LIMs prevented drug release within simulated stomach and small intestine conditions with subsequent drug release occurring in large intestine conditions. The formulation therefore has potential for oral colonic drug delivery.

scholarly journals Smart Microneedles with Porous Polymer Coatings for pH-Responsive Drug Delivery

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1834 ◽  
Author(s):  
Ullah ◽  
Khan ◽  
Choi ◽  
Kim
Keyword(s):  
Drug Delivery ◽  
Controlled Release ◽  
Drug Release ◽  
Sodium Bicarbonate ◽  
Porous Polymer ◽  
Polymer Layer ◽  
Ph Responsive ◽  
Acidic Microenvironment ◽  
Model Drug

: This work demonstrates a simple approach for coating a porous polymer layer on stainless-steel (SS) microneedles characterized by a pH-responsive formulation for self-regulated drug delivery. For many drug-delivery applications, the release of therapeutic agents in an acidic microenvironment is desirable. Acid-sensitive polymers and hydrogels were extensively explored, but easily prepared polymeric microcarriers that combine acid sensitivity and biodegradability are rare. Here, we describe a simple and robust method of coating a porous polymer layer on SS microneedles (MNs) that release a model drug (lidocaine) in a pH-responsive fashion. It was constructed by packing the model drug and a pH-sensitive component (sodium bicarbonate) into the pores of the polymer layer. When this acid-sensitive formulation was exposed to the acidic microenvironment, the consequent reaction of protons (H+) with sodium bicarbonate (NaHCO3) yielded CO2. This effect generated pressure inside the pores of the coating and ruptured the thin polymer membrane, thereby releasing the encapsulated drug. Scanning electron micrographs showed that the pH-sensitive porous polymer-coated MNs exposed to phosphate-buffered saline (PBS) at pH 7.4 were characterized by closed pores. However, MNs exposed to PBS at pH 5.5 consisted of open pores and the thin membrane burst. The in vitro studies demonstrated the pH sensitivity of the drug release from porous polymer-coated MNs. Negligible release was observed for MNs in receiving media at pH 7.4. In contrast, significant release occurred when the MNs were exposed to acidic conditions (pH 5.5). Additionally, comparable results were obtained for drug release in vitro in porcine skin and in PBS. This revealed that our developed pH-responsive porous polymer-coated MNs could potentially be used for the controlled release of drug formulations in an acidic environment. Moreover, the stimuli-responsive drug carriers will enable on-demand controlled release profiles that may enhance therapeutic effectiveness and reduce systemic toxicity.

Synthesis of Chitosan-Polyvinyl Alcohol Copolymers for Smart Drug Delivery Application

2017 ◽  
Vol 25 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Neha Mulchandani ◽  
Nimish Shah ◽  
Tejal Mehta
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Polyvinyl Alcohol ◽  
Morphological Changes ◽  
Crosslinking Agent ◽  
Ph Responsive ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Model Drug

Chitosan is a natural polymer obtained from exoskeletons of crustaceans and polyvinyl alcohol (PVA) is a synthetic polymer which has excellent film forming ability along with non-toxic nature. The current work focuses on synthesizing a smart polymer by copolymerization of natural and synthetic polymers and exploring its applications in drug delivery. The copolymers were blended in different ratios and were synthesized using ammonium ceric nitrate as initiator and glutaraldehyde as a crosslinking agent which were converted to films by casting method. Amoxicillin, as a model drug was incorporated to the copolymerized films to study the in-vitro drug release. The films obtained were evaluated by varying the pH to study the pH responsive nature of films. Drug release studies were performed to obtain the release profile of drug; water uptake capacity of the copolymerized film were measured to determine the swelling behaviour of the films. The films were further characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Differential Scanning Calorimetry (DSC) to identify the structural and morphological changes along with thermal transitions. The results indicate that the synthesized copolymers are pH responsive in nature having great potential for application in controlled and targeted drug delivery.

scholarly journals Formulation and characterization of flurbiprofen loaded microsponge based gel for sustained drug delivery

2019 ◽  
Vol 10 (4) ◽  
pp. 2765-2776
Author(s):  
Naresh Kshirasagar ◽  
Goverdhan Puchchakayala ◽  
Balamurgan K
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Drug Release ◽  
Diffusion Method ◽  
Skin Delivery ◽  
Sustained Action ◽  
Release Studies ◽  
Ft Ir ◽  
Polymer Ratio

The new investigation in this present work is to develop microsponges constructed novel drug delivery system for sustained action of Flurbiprofen. Quai-emulsion solvent diffusion method was engaged using Ethyl cellulose and Eudragit RS100 with drug: polymer ratio for development of microsponges. For optimization purposes, several factors are considered in the investigation. Several evaluation studies for the formed microsponges were carried out FT-IR, SEM, DSC, X-RD, particle size analysis, morphology, drug loading and In vitro drug release studies were carried out. Finally, it was concluded that there is no drug-polymer interaction as per DSC & FT-IR. Encapsulation efficiency, particle size and drug content showed a higher impact on alteration of drug-polymer ratio. SEM studies showed that morphological microsponges are spherical and porous in nature and with the mean particle size of 38.86 μm. The gel loaded with microsponges, were followed by In vitro and Ex vivo drug release studies by modified Franz diffusion cell. Skin delivery of optimized formulation enhanced the drug residence time and maintained therapeutic concentration for an extended period of time, which is possible to show sustained action of the drug.

Preparation and Characterization of Biopolymeric Nanoparticles as Drug Delivery Vehicles

2017 ◽  
pp. 225-246
Author(s):  
Sai S. Sagiri ◽  
Suraj K. Nayak ◽  
S. Lakshmi ◽  
Kunal Pal
Keyword(s):  
Drug Delivery ◽  
Salicylic Acid ◽  
Drug Release ◽  
Chitosan Nanoparticles ◽  
Xrd Analysis ◽  
Gelatin Nanoparticles ◽  
Drug Delivery Vehicles ◽  
Model Drug ◽  
Bioactive Agents

In recent years, the use of biopolymeric nanoparticles as vehicles for drug delivery has increased exponentially. In the present study, chitosan and gelatin nanoparticles were prepared by ionic gelation and desolvation methods, respectively. Salicylic acid was used as the model drug. The nanoparticles were characterized using SEM, XRD analysis and FTIR spectrophotometric studies. In vitro drug release experiments were carried out to understand the mechanism of drug release. SEM micrographs showed the formation of spherical nanoparticles. XRD studies indicated a higher crystalline nature of the chitosan nanoparticles as compared to the gelatin nanoparticles. FTIR studies indicated the presence of salicylic acid within the drug- loaded nanoparticles. Drug release studies indicated that the developed nanoparticles may be used as carriers for various bioactive agents.

Fabrication of Vesicular Drug Delivery of Niosomal Topical Formulation for the Effective Treatment of Osteoarthritis

2016 ◽  
Vol 12 ◽  
pp. 1-8
Author(s):  
S. Nagalakshmi ◽  
T. Sandeep ◽  
S. Shanmuganathan
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Methyl Cellulose ◽  
Entrapment Efficiency ◽  
Lipid Vesicles ◽  
Tween 20 ◽  
Injection Method ◽  
Topical Gel ◽  
Release Studies

Delivery of drug through topical route, delivers most convenient and novel approach. The Skin can offer several advantages as a route of drug administration although its barrier nature makes it difficult for most drugs to penetrate in to and permeate through it. During the past decades there has been a lot of interest in lipid vesicles as a tool to improve topical drug delivery. Vesicular system such as liposomes, niosomes, ethosomes and elastic deformable vesicles provide an alternative for improved skin drug delivery. In fact vesicles can act as drug carriers controlling drug release. The Research findings were intended to develop sustained release of aceclofenac niosomes formulations in order to reduce gastrointestinal disturbances and to provide better effect when applied topically. Niosomes of aceclofenac was prepared by modified ether injection method using different ratio of surfactants (Tween 20, 40, 60 & 80) with cholesterol and drug. The developed formulations were optimized based on the high entrapment efficiency and in-vitro release studies. Optimized batch was selected and made in to topical niosomal gel using gelling agents like carbopol and sodium carboxy methyl cellulose. Formulation were evaluated for various parameters like vesicle shape, vesicle size, entrapment efficiency, drug content, compatibility studies, in-vitro release studies and stability studies. Ether injection method was found to be most satisfactory in terms of niosome particle size, drug entrapment efficiency was found to be 88.68 ±0.64 % and in-vitro release studies showed 40% of sustain drug release at the end of 8 hrs of study when compared with marketed formulation. Hence, the formulated niosomal topical gel was found to be a better alternative when compared to the marketed formulation in terms of better efficacy, bioavailability and permeation.

scholarly journals Influence of sterilization on the drug release behaviour of drug coated silicone

2021 ◽  
Vol 7 (2) ◽  
pp. 672-675
Author(s):  
Katharina Wulf ◽  
Stefan Raggl ◽  
Thomas Eickner ◽  
Gerrit Paasche ◽  
Niels Grabow
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Polymer Coating ◽  
Drug Loading ◽  
In Vitro Release ◽  
Physical Chemical ◽  
Release Studies ◽  
Vitro Release ◽  
Dual Drug

Abstract Sterilization processes ensure sterility of drug delivery systems, but may negatively affect the properties of biomaterials and incorporated drugs by changing their physical, chemical, mechanical properties and drug release behaviour. Therefore, it is important to investigate their influence. In this study, the influence of ethylene oxide (EtO) sterilization on the drug loading and release behaviour of incorporated Diclofenac (DCF) in a Poly-L-lactide (PLLA) coating and Dexamethasone (DMS) in the silicone carrier is presented. Silicone samples containing DMS were coated with PLLA containing DCF varying in layer thickness (5, 10, and 20 μm). Half of the samples underwent EtO sterilization, the other half was not sterilized. All un-/sterilized sample surfaces were in view of the morphology and hydrophilicity examined. Furthermore, in vitro release studies of DMS and DCF were conducted. The sterilized sample surfaces showed no morphological and hydrophilicity changes. The DCF and DMS loadings were similar for the sterile and untreated samples. This also applied to the in vitro DMS release profiles apart from the end of the studies where slight differences were evident. The results indicate that both drugs loaded in the polymer coating and the silicone were not impaired by the sterilization process. Thus, EtO sterilization appears suitable for DMS containing silicone and DCF incorporated PLLA coatings as a dual drug delivery system.

scholarly journals Steroid Eluting Esophageal-Targeted Drug Delivery Devices for Treatment of Eosinophilic Esophagitis

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 557
Author(s):  
Alka Prasher ◽  
Roopali Shrivastava ◽  
Denali Dahl ◽  
Preetika Sharma-Huynh ◽  
Panita Maturavongsadit ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Porcine Model ◽  
Pharmacokinetic Studies ◽  
Specific Drug ◽  
In Vitro Drug Release ◽  
Release Studies ◽  
3D Printed

Eosinophilic esophagitis (EoE) is a chronic atopic disease that has become increasingly prevalent over the past 20 years. A first-line pharmacologic option is topical/swallowed corticosteroids, but these are adapted from asthma preparations such as fluticasone from an inhaler and yield suboptimal response rates. There are no FDA-approved medications for the treatment of EoE, and esophageal-specific drug formulations are lacking. We report the development of two novel esophageal-specific drug delivery platforms. The first is a fluticasone-eluting string that could be swallowed similar to the string test “entero-test” and used for overnight treatment, allowing for a rapid release along the entire length of esophagus. In vitro drug release studies showed a target release of 1 mg/day of fluticasone. In vivo pharmacokinetic studies were carried out after deploying the string in a porcine model, and our results showed a high local level of fluticasone in esophageal tissue persisting over 1 and 3 days, and a minimal systemic absorption in plasma. The second device is a fluticasone-eluting 3D printed ring for local and sustained release of fluticasone in the esophagus. We designed and fabricated biocompatible fluticasone-loaded rings using a top-down, Digital Light Processing (DLP) Gizmo 3D printer. We explored various strategies of drug loading into 3D printed rings, involving incorporation of drug during the print process (pre-loading) or after printing (post-loading). In vitro drug release studies of fluticasone-loaded rings (pre and post-loaded) showed that fluticasone elutes at a constant rate over a period of one month. Ex vivo pharmacokinetic studies in the porcine model also showed high tissue levels of fluticasone and both rings and strings were successfully deployed into the porcine esophagus in vivo. Given these preliminary proof-of-concept data, these devices now merit study in animal models of disease and ultimately subsequent translation to testing in humans.

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