scholarly journals Reduction-Responsive Molecularly Imprinted Poly(2-isopropenyl-2-oxazoline) for Controlled Release of Anticancer Agents

Pharmaceutics ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 506 ◽  
Author(s):  
Michał Cegłowski ◽  
Valentin Victor Jerca ◽  
Florica Adriana Jerca ◽  
Richard Hoogenboom
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Anticancer Agents ◽  
Release Kinetics ◽  
Controlled Drug Release ◽  
Release Mechanism ◽  
Molecularly Imprinted ◽  
Responsive Materials ◽  
Future Work ◽  
Specific Trigger

Trigger-responsive materials are capable of controlled drug release in the presence of a specific trigger. Reduction induced drug release is especially interesting as the reductive stress is higher inside cells than in the bloodstream, providing a conceptual controlled release mechanism after cellular uptake. In this work, we report the synthesis of 5-fluorouracil (5-FU) molecularly imprinted polymers (MIPs) based on poly(2-isopropenyl-2-oxazoline) (PiPOx) using 3,3′-dithiodipropionic acid (DTDPA) as a reduction-responsive functional cross-linker. The disulfide bond of DTDPA can be cleaved by the addition of tris(2-carboxyethyl)phosphine (TCEP), leading to a reduction-induced 5-FU release. Adsorption isotherms and kinetics for 5-FU indicate that the adsorption kinetics process for imprinted and non-imprinted adsorbents follows two different kinetic models, thus suggesting that different mechanisms are responsible for adsorption. The release kinetics revealed that the addition of TCEP significantly influenced the release of 5-FU from PiPOx-MIP, whereas for non-imprinted PiPOx, no statistically relevant differences were observed. This work provides a conceptual basis for reduction-induced 5-FU release from molecularly imprinted PiPOx, which in future work may be further developed into MIP nanoparticles for the controlled release of therapeutic agents.

scholarly journals Optimizing the Role of Polymer Blend in the Preparation of Acyclovir Controlled-Release Tablets: An Approach for Better Patient Compliance

2018 ◽  
Author(s):  
Barkat Khan ◽  
Faheem Haider ◽  
Kifayat Shah ◽  
Bushra Uzair ◽  
Kaijian Hou ◽  
...  
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Release Kinetics ◽  
Immediate Release ◽  
Matrix Tablets ◽  
Release Mechanism ◽  
In Vitro Drug Release ◽  
Solubility Study ◽  
Release Data

This study was carried out to formulate and evaluate controlled release (CR) matrix tablets of Acyclovir using combination of hydrophilic and hydrophobic polymers. Acyclovir is a guanine derivative and is its half-life is short hence administered five times a day using immediate release tablets. Six formulations (F1-F6) were developed using Ethocel and Carbopol in equal combinations at drug-polymer (D:P) ratio of 10:5, 10:6, 10:7, 10:8, 10:9 and 10:10. Solubility study was performed using six different solvents. The compatibility studies were carried out using FTIR and DSC. According to USP, Quality Control and dimensional tests (hardness, friability, disintegration and thickness) were executed. In-vitro drug release studies of Acyclovir was carried out in dissolution apparatus using using 0.1 N HCl medium at constant temperature of 37 ± 0.5 ºC. In order to analyze the drug release kinetics, five different mathematical models were applied to the release data. The results showed that there was no incompatibility between drug and polymers. Physical QC tests were found within limits of USP. The release was retarded upto 24 hrs and non-fickian in-vitro drug release mechanism was found. A formulation developed using blend of polymers, showed excellent retention and desired release profiles thus providing absolute control for 24 hrs.

Optimization Study to Develop Once-a-day Controlled Release Formulation of Metoclopramide with Predictable Design Space

1970 ◽  
Vol 1 (1) ◽  
pp. 71-76
Author(s):  
Rajesh Dubey ◽  
Udaya K. Chowdary ◽  
Venkateswarlu V.
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Design Space ◽  
Release Kinetics ◽  
Release Profile ◽  
Release Formulation ◽  
Linear Effect ◽  
Controlled Release Formulation ◽  
The Difference ◽  
Face Centered

A controlled release formulation of metoclopramide was developed using a combination of hypromellose (HPMC) and hydrogenated castor oil (HCO). Developed formulations released the drug over 20 hr with release kinetics following Higuchi model. Compared to HCO, HPMC showed significantly higher influence in controlling the drug release at initial as well as later phase. The difference in the influence can be explained by the different swelling and erosion behaviour of the polymers. Effect of the polymers on release was optimized using a face-centered central composite design to generate a predictable design space. Statistical analysis of the drug release at various levels indicated a linear effect of the polymers’ levels on the drug release. The release profile of formulations containing the polymer levels at extremes of their ranges in design space was found to be similar to the predicted release profile

Design, Synthesis and Studies on Novel Polymeric Prodrugs of Erlotinib for Colon Drug Delivery

2020 ◽  
Vol 20 ◽  
Author(s):  
Sahil Kumar ◽  
Bandna Sharma ◽  
Tilak R. Bhardwaj ◽  
Rajesh K. Singh
Keyword(s):  
Drug Delivery ◽  
Colon Cancer ◽  
Drug Release ◽  
Anticancer Agents ◽  
Release Kinetics ◽  
In Vitro Release ◽  
Specific Treatment ◽  
Drug Conjugates ◽  
Polymer Drug Conjugates

Aims: In the present study, polymer-drug conjugates were synthesized based on azo-bond cleavage drug delivery approach for targeting erlotinib as anticancer drug specifically to the colon for the proficient treatment of colon cancer. Background: Colon cancer (CC) is the third commonly detected tumor worldwide and it make up about 10 % of all cases of cancers. Most of the chemotherapeutic drugs available for treating colon cancer are not only toxic to cancerous cells but also to the normal healthy cells. Among the various approaches to get rid of the adverse effects of anticancer agents, prodrugs are one of the most imperative approaches. Objective: The objective of the study is to chemically modify the erlotinib drug through azo-bond linkage and suitable spacer which will be finally linked to polymeric backbone to give desired polymer linked prodrug. The azo reductase enzyme present in colon is supposed to cleave the azo-bond specifically and augment the drug release at the colon. Methods: The synthesized conjugates were characterized by IR and 1H-NMR spectroscopy. The cleavage of aromatic azobond resulted in a potential colon-specific liberation of drug from conjugate studied in rat fecal contents. In vitro release profiles of polyphosphazene-linked conjugates of erlotinib have been studied at pH 1.2, pH 6.8 and pH 7.4. The stability study was designed to exhibit that free drug was released proficiently and unmodified from polyphosphazene-erlotinib conjugates having aromatic azo-bond in artificial colon conditions. Results: The synthesized conjugates were demonstrated to be stable in simulated upper gastro-intestinal tract conditions. The drug release kinetics shows that all the polymer-drug conjugates of erlotinib follow zero-order release kinetics which indicates that the drug release from the polymeric backbone is independent of its concentration. Kinetic study of conjugates with slope (n) shows the anomalous type of release with an exponent (n) > 0.89 indicating a super case II type of release. Conclusion: These studies indicate that polyphosphazene linked drug conjugates of erlotinib could be the promising candidates for the site-specific treatment of colon cancer with least detrimental side-effects.

Photonic Crystal-Embedded Molecularly Imprinted Contact Lenses for Controlled Drug Release

2021 ◽  
Author(s):  
Zhaoran Chu ◽  
Chao Xue ◽  
Kan Shao ◽  
Lanlan Xiang ◽  
Xueling Zhao ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Drug Release ◽  
Contact Lenses ◽  
Controlled Drug Release ◽  
Molecularly Imprinted

scholarly journals DESIGN AND EVALUATION OF CONTROLLED-RELEASE OCULAR INSERTS OF BRIMONIDINE-TARTRATE AND TIMOLOL MALEATE

2016 ◽  
Vol 9 (1) ◽  
pp. 79 ◽  
Author(s):  
Preethi G. B. ◽  
Prashanth Kunal
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Sodium Alginate ◽  
Calcium Chloride ◽  
Release Kinetics ◽  
Water Soluble ◽  
Moisture Loss ◽  
Timolol Maleate ◽  
Brimonidine Tartrate

<p><strong>Objective: </strong>The current work was attempted to formulate and evaluate a controlled-release matrix-type ocular inserts containing a combination of brimonidine tartrate and timolol maleate, with a view to sustain the drug release in the cul-de-sac of the eye.<strong></strong></p><p><strong>Methods: </strong>Initially, the infrared studies were done to determine the drug–polymer interactions. Sodium alginate-loaded ocuserts were prepared by solvent casting technique. Varying the concentrations of polymer—sodium alginate, plasticizer—glycerine, and cross-linking agent—calcium chloride by keeping the drug concentration constant, made a total of nine formulations. These formulations were evaluated for its appearance, drug content, weight uniformity, thickness uniformity, percentage moisture loss, percentage moisture absorption, and <em>in vitro </em>release profile of the ocuserts. Finally, accelerated stability studies and the release kinetics were performed on the optimised formulation.<strong></strong></p><p><strong>Results: </strong>It was perceived that polymer, plasticizer, and calcium chloride had a significant influence on the drug release. The data obtained from the formulations showed that formulation—F9 was the optimised formulation, which exhibited better drug release. The release data of the optimised formulation tested on the kinetic models revealed that it exhibited first-order release kinetics. <strong></strong></p><p><strong>Conclusion: </strong>It can be concluded that a natural bioadhesive hydrophilic polymer such as sodium alginate can be used as a film former to load water soluble and hydrophilic drugs like brimonidine tartrate and timolol maleate. Among all formulations, F9 with 400 mg sodium alginate, 2% calcium chloride and 60 mg glycerin were found to be the most suitable insert in terms of appearance, ease of handling, thickness, <em>in vitro</em> drug release and stability.</p>

Preparation and Characterization of Mucoadhesive Microcapsules of Gliclazide with Natural Gums

1970 ◽  
Vol 4 (1) ◽  
pp. 38-48 ◽  
Author(s):  
Santhosh Kumar Mankala ◽  
Nishanth Kumar Nagamalli ◽  
Ramakrishna Raprla ◽  
Rajyalaxmi Kommula
Keyword(s):  
Drug Release ◽  
Dosage Form ◽  
Guar Gum ◽  
Release Kinetics ◽  
Insulin Dependent Diabetes Mellitus ◽  
Dependent Diabetes Mellitus ◽  
Release Mechanism ◽  
Ionic Gelation ◽  
Release Formulation

Gliclazide is an oral hypoglycemic agent used in management of non-insulin dependent diabetes mellitus. Among people who are suffering from long term disorders, the major were categorized under diabetes so, a dosage form is needed to provide continuous therapy with high margin of safety & such dosage form can be achieved by microencapsulation. Gliclazide microspheres with sodium alginate (coat material, gum kondagogu, gum guar and xanthan gum (mucoadhesive agents) were prepared by orifice-ionic gelation and emulsification ionic gelation techniques varying concentrations (1:0.25, 1:0.5, 1:0.75 and 1:1). Formulations were then evaluated for surface morphology, particle shape, Carr’s index, microencapsulation efficiency, drug release, mucoadhesion studies. Compatibility studies were performed by FTIR, DSC, and XRD techniques and no interactions were found between drug and excepients used. The microspheres were found spherical and free flowing with emulsion ionic gelation technique with a size range 400-600μm. % drug content and encapsulation efficiency found in the range of 55%-68% and, 86.23%-94.46% respectively. All microspheres showed good mucoadhesive property in in-vitro wash of test. In vitro drug release studies showed that the guar gum has more potentiality to retard the drug release compared to other gums and concentrations. Drug release from the microspheres was found slow following zero order release kinetics with non-fickian release mechanism stating release depended on the coat: core ratio and the method employed. The concentration of 1:1 of SA: GG (EMG 4) found suitable for preparing the controlled release formulation of gliclazide stating emulsification gelation technique is the best among followed.   Key words: Gliclazide; Natural gums; orifice ionic gelation technique; emulsification ionic gelation technique DOI: http://dx.doi.org/10.3329/sjps.v4i1.8865 SJPS 2011; 4(1): 38-48

scholarly journals ATRP-based synthesis of a pH-sensitive amphiphilic block polymer and its self-assembled micelles with hollow mesoporous silica as DOX carriers for controlled drug release

RSC Advances ◽  
2021 ◽  
Vol 11 (48) ◽  
pp. 29986-29996
Author(s):  
Xiuxiu Qi ◽  
Hongmei Yan ◽  
Yingxue Li
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Self Assembly ◽  
Drug Loading ◽  
Controlled Drug Release ◽  
Ph Sensitive ◽  
Core Shell ◽  
Assembly Process ◽  
Block Polymer ◽  
Hollow Mesoporous Silica

A pH-sensitive core–shell nanoparticle (HMS@C18@PSDMA-b-POEGMA) was developed via a self-assembly process as the carrier of anticancer drug doxorubicin (DOX) for drug loading and controlled release.

scholarly journals DESIGN AND IN VITRO/IN VIVO EVALUATION OF EXTENDED RELEASE MATRIX TABLETS OF NATEGLINIDE

2018 ◽  
Vol 7 (6) ◽  
Author(s):  
Mohini Sihare ◽  
Rajendra Chouksey
Keyword(s):  
Drug Release ◽  
Release Kinetics ◽  
In Vitro Release ◽  
Release Profile ◽  
Matrix Tablets ◽  
In Vivo Studies ◽  
Release Mechanism ◽  
In Vivo Evaluation

Aim: Nateglinide is a quick acting anti-diabetic medication whose potent activity lasts for a short duration. One of the dangerous side effects of nateglinide administration is rapid hypoglycemia, a condition that needs to be monitored carefully to prevent unnecessary fatalities. The aim of the study was to develop a longer lasting and slower releasing formulation of nateglinide that could be administered just once daily. Methods: Matrix tablets of nateglinide were prepared in combination with the polymers hydroxypropylmethylcellulose (HPMC), eudragits, ethyl cellulose and polyethylene oxide and the formulated drug release patterns were evaluated using in vitro and in vivo studies. Conclusion: Of the seventeen formulated matrix tablets tested, only one formulation labelled HA-2 that contained 15% HPMC K4M demonstrated release profile we had aimed for. Further, swelling studies and scanning electron microscopic analysis confirmed the drug release mechanism of HA-2. The optimized formulation HA-2 was found to be stable at accelerated storage conditions for 3 months with respect to drug content and physical appearance. Mathematical analysis of the release kinetics of HA-2 indicated a coupling of diffusion and erosion mechanisms. In-vitro release studies and pharmacokinetic in vivo studies of HA-2 in rabbits confirmed the sustained drug release profile we had aimed for. Keywords: Hydroxypropylmethylcellulose, Matrix tablets, Nateglinide, Sustained release

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