scholarly journals Fixed Bed Adsorption of Drugs on Silica Aerogel from Supercritical Carbon Dioxide Solutions

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Giuseppe Caputo
Keyword(s):  
Silica Aerogel ◽  
Release Kinetics ◽  
Drug Loading ◽  
Fixed Bed ◽  
Fluid Phase ◽  
Water Soluble ◽  
In Vitro Dissolution ◽  
Fixed Bed Adsorption ◽  
Supercritical Adsorption

Supercritical adsorption coupled with the high adsorption capacity of silica aerogel allows the preparation of a new kind of delivery systems of poor water soluble drugs. In order to overcome drawbacks of conventional techniques where the use of liquid solvents can cause the fracture of aerogel porous structure, in this work a new adsorption process of drugs from a supercritical mixture is proposed. Adsorption takes place from a fluid solution of the drug in supercritical CO2and ethanol as cosolvent. A fixed bed adsorption plant has been developed to allow fast mixing of fluid phase and effective contact in the adsorption column. The use of ethanol as cosolvent allows to overcome the limitation of supercritical adsorption due to low solubility of many drugs in supercritical CO2. Adsorption isotherms were measured for one-model substance, nimesulide, at 40°C, and breakthrough curve was experimentally obtained. The drug loading of the drug into silica aerogel was up to 9 wt%. The drug composite was characterized using scanning electron microscopy, and release kinetics of the adsorbed drug were also evaluated by in vitro dissolution tests. The dissolution of nimesulide from loaded aerogel is much faster than dissolution of crystalline nimesulide. Around 80% of nimesulide dissolves from the aerogel within 6 minutes, whereas dissolving 80% of the crystalline drug takes about 90 min.

DEVELOPMENT AND CHARACTERIZATION OF GASTRO RETENTIVE MUCOADHESIVE MICROBEADS CONTAINING SIMVASTATIN WITH DIFFERENT CROSS LINKING AGENTS

2020 ◽  
pp. 118-126
Author(s):  
VENKATA RAMANA REDDY K. ◽  
NAGABHUSHANAM M. V. ◽  
PAMULA REDDY B. ◽  
RAVINDAR NAIK E.
Keyword(s):  
Drug Release ◽  
Release Kinetics ◽  
Drug Loading ◽  
Aluminium Chloride ◽  
In Vitro Dissolution ◽  
Cross Linking ◽  
Stability Studies ◽  
Study Results ◽  
Curing Agents

Objective: The aim of the present work was to prepare and examine drug release of the oral controlled release microbeads using different curing agents by emulsification internal ionic gelation technique. Methods: Cross-linked alginate microbeads were prepared with different cross linking agents by using mucoadhesive properties. The formation and compatibility of microbeads were confirmed by compatibility studies. Prepared microbeads evaluated for encapsulated efficiency, micromeritic properties, drug loading, in vitro wash off studies, in vitro dissolution studies, drug release kinetics and stability studies Results: The in vitro drug release was influenced by both type of curing agents and type of polymers and no significant changes in characterization parameters was observed after 3 mo stability studies. The sustained release profile of optimized batch was found to be 99.66±0.18% in comparison to pure drug profile of 28.64±0.02% at 12 h release study. Results of both wash-off and in vitro studies suggests that batch (SF2) prepared with aluminium chloride has shown better mucoadhesive property. Drug release of optimized batch follows zero order with non fickian mechanism according to Korsmeyer-Peppas equation. Conclusion: The data suggest the use of simvastatin mucoadhesive cross linked microbeads to offer the potential for oral controlled drug delivery with improved gastric retention and capable to provide sustained drug release by using cross linking agents.

scholarly journals In vitro Release Kinetics of Progesterone from Biodegradable In situ Implant System

1970 ◽  
Vol 6 (2) ◽  
pp. 99-103 ◽  
Author(s):  
Irin Dewan ◽  
Md Elias-Al-Mamun ◽  
Reza-ul Jalil
Keyword(s):  
Release Kinetics ◽  
Drug Loading ◽  
Static Condition ◽  
Surrounding Tissue ◽  
In Vitro Dissolution ◽  
Release Mechanism ◽  
Water Mixture ◽  
Biodegradable Implant

In situ implants containing Progesterone (PRG) were prepared by using biodegradable Poly (DLlactide- co-glycolide) polymer. Dimethyl sulfoxide (DMSO) was used as an aprotic solvent in this implant formulation. This system was prepared by dissolving a water insoluble and biodegradable polymer (PLGA) in a biocompatible organic solvent (DMSO) and then the drug progesterone was added to the polymer solution to produce the drug solution. When the PLGA-PRG solution (0.5 ml) was injected subcutaneously into rat (weight 130g), the solvent dissipated into the surrounding tissue leading phase separation and subsequent coagulation of the polymer & drug to form an implant in situ. The implants were removed from the rat after one hour and stored in freezing condition. The digital photographs of the in-situ formed implants obtained after 1hour shows the evidence of the formation of the implants. Two formulations of implants were made. One contained 10% of progesterone and the other 20%. In vitro dissolution studies of progesterone was performed at static condition in ethanol-water mixture (30:70) at 37°C for 30 days. The implants of 20% progesterone loading showed about 65% release and the implants of 10% loading showed 56% release within 30 days. The release mechanism from these implants resembles closely to Higuchian pattern and first order. The release rate was found faster from the implants with higher drug loading of 20% progesterone, compared to implants of 10% drug loading. Key words: Biodegradable; Implant; Biocompatible; Sustained Release Dhaka Univ. J. Pharm. Sci. 6(2): 99-103, 2007 (December)

scholarly journals Porous Nanostructure, Lipid Composition, and Degree of Drug Supersaturation Modulate In Vitro Fenofibrate Solubilization in Silica-Lipid Hybrids

Pharmaceutics ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 687
Author(s):  
Ruba Almasri ◽  
Paul Joyce ◽  
Hayley B. Schultz ◽  
Nicky Thomas ◽  
Kristen E. Bremmell ◽  
...  
Keyword(s):  
Solid State ◽  
Oral Delivery ◽  
Drug Loading ◽  
Medium Chain Triglyceride ◽  
Water Soluble ◽  
In Vitro Dissolution ◽  
Valuable Insight ◽  
Drug Load ◽  
The Impact

The unique nanostructured matrix obtained by silica-lipid hybrids (SLHs) is well known to improve the dissolution, absorption, and bioavailability of poorly water-soluble drugs (PWSDs). The aim of this study was to investigate the impact of: (i) drug load: 3–22.7% w/w, (ii) lipid type: medium-chain triglyceride (Captex 300) and mono and diester of caprylic acid (Capmul PG8), and (iii) silica nanostructure: spray dried fumed silica (FS) and mesoporous silica (MPS), on the in vitro dissolution, solubilization, and solid-state stability of the model drug fenofibrate (FEN). Greater FEN crystallinity was detected at higher drug loads and within the MPS formulations. Furthermore, an increased rate and extent of dissolution was achieved by FS formulations when compared to crystalline FEN (5–10-fold), a commercial product; APO-fenofibrate (2.4–4-fold) and corresponding MPS formulations (2–4-fold). Precipitation of FEN during in vitro lipolysis restricted data interpretation, however a synergistic effect between MPS and Captex 300 in enhancing FEN aqueous solubilization was attained. It was concluded that a balance between in vitro performance and drug loading is key, and the optimum drug load was determined to be between 7–16% w/w, which corresponds to (200–400% equilibrium solubility in lipid Seq). This study provides valuable insight into the impact of key characteristics of SLHs, in constructing optimized solid-state lipid-based formulations for the oral delivery of PWSDs.

scholarly journals In vitro Release Kinetics Study of Diltiazem Hydrochloride from Pellets using an Ethylcellulose Pseudolatex Coating System

1970 ◽  
Vol 6 (2) ◽  
pp. 87-92
Author(s):  
Golam Kibria ◽  
Reza-ul Jalil
Keyword(s):  
Release Kinetics ◽  
Water Soluble ◽  
In Vitro Dissolution ◽  
Coating System ◽  
Matrix System ◽  
Diltiazem Hydrochloride ◽  
Barrier Coating ◽  
Zero Order Kinetics ◽  
The Matrix

In the present study an attempt has been made to investigate the effect of ethylcellulose as a rate retarding material to sustain the release of diltiazem hydrochloride from pellets prepared by air suspension technique. Aqueous ethylcellulose dispersion (Surelease) with different weight ratios was chosen to sustain the release of the drug. Drug was loaded on dummy seeds by following matrix system as well as barrier coating system. The comparative study of this two manufacturing processes was also the goal of this study. In vitro dissolution studies were carried out using USP dissolution apparatus Type-2. The release of drug was faster from matrix system than that of barrier coating system. About 100% drug was released within 3 hours with 5% polymer load from both systems. While the polymer content was 10%, about 4h & 7h required for 50% & 80% drug release respectively from barrier coating system. The effect of ethylcellulose on the release of diltiazem hydrochloride was found to be predominant in barrier coating system than that of the matrix system. In the matrix system the drug comes to dissolution media easily and water soluble additives form channel very fast. The kinetic study of the drug was performed and it was revealed that the release of drug from pellets appeared to follow zero order kinetics. Key words: Diltiazem; Pellets; Pseudolatex; Aqueous coating; Manufacturing process; Release kinetics. Dhaka Univ. J. Pharm. Sci. 6(2): 87-92, 2007 (December)

scholarly journals Enhancement of the dissolution profile of the diuretic hydrochlorothiazide by elaboration of microspheres

2018 ◽  
Vol 83 (11) ◽  
pp. 1243-1259
Author(s):  
Oum Larbi ◽  
Haouaria Merine ◽  
Youssef Ramli ◽  
Fawzia Toumi ◽  
Kaddour Guemra ◽  
...  
Keyword(s):  
Ftir Spectroscopy ◽  
Release Kinetics ◽  
Drug Loading ◽  
In Vitro Release ◽  
Aqueous Solubility ◽  
Xrd Analysis ◽  
In Vitro Dissolution ◽  
Dissolution Profile ◽  
Scanning Calorimetry

Hydrochlorothiazide (HCTZ), which was developed and introduced in the late 1950s, is still one of the most frequently employed drugs in antihypertensive treatments. Its poor aqueous solubility is one of the reasons for its limited bioavailability after oral administration. The present paper provides details of the preparation of HCTZ-loaded microspheres by the solvent evaporation technique. A total of seven formulations were prepared using ethyl cellulose, poly(?-caprolactone) (PCL), ?-cyclodextrin (?-CD) and synthesized poly-(methyl methacrylate) (PMMA) of different molecular weights in different drug-to-carrier ratios in order to investigate their effect on the encapsulation efficiency and drug release kinetics. The prepared formulations were characterized by Fourier transform-infrared (FTIR) spectroscopy, powder X-ray diffractometry, differential scanning calorimetry, yield, drug loading, optical microscopy, surface morphology by scanning electron microscopy (SEM), and in vitro release studies in simulated gastrointestinal tract fluid. The loading efficiency was found in the range from 18?0.34 to 39?0.95 %. The microspheres were spherical, and the mean Sauter diameter (d32) of the obtained microparticles ranged from 26?0.16 to 107?0.58 ?m. The presence of the drug and polymer carriers in the microparticles was confirmed by FTIR spectroscopy and XRD analysis. In vitro dissolution studies showed that the release rate was largely affected by the characteristics of the microparticles, namely the particle size and the nature of the matrix. The release data are best fitted to the Higuchi model with high correlation coefficients (r?).

scholarly journals Comparative Evaluation of Bromhexine HCl Mucoadhesive Microspheres Prepared by Anionic, Cationic and Nonionic Polymers

2020 ◽  
Vol 23 (2) ◽  
pp. 117-124
Author(s):  
Sabirah Ishaque Limpa ◽  
Zahirul Islam ◽  
Md Selim Reza
Keyword(s):  
Surface Morphology ◽  
Release Kinetics ◽  
Drug Loading ◽  
Entrapment Efficiency ◽  
Pharmaceutical Journal ◽  
In Vitro Dissolution ◽  
Release Mechanism ◽  
Drug Entrapment Efficiency ◽  
Ph Range

The purpose of this study was to formulate and assess the mucoadhesive microspheres of bromhexine hydrochloride, a mucolytic agent, using three different types of polymers to achieve gastric retention for improved solubility and bioavailability of the drug. The mucoadhesive formulation was prepared because it dissolved in the pH range of 1 to 4. The characteristics of the prepared microspheres were evaluated by determining the particle size, percent drug loading, surface morphology, swelling behavior, mucoadhesive bond strength and drug entrapment efficiency. The in vitro dissolution was studied using the USP dissolution apparatus I in 0.1N HCl (pH 1.2) media for 8 hours. The release kinetics were analyzed by using zero order, first order, Higuchi, Korsmeyer-Peppas and Hixon-crowell equations to explain the release mechanism from the microspheres. The microspheres exhibited good swelling index and the drug entrapment efficiency was above 79 % for all the formulations. All the formulations showed drug release above 25%, 35%, 50% and 75% after 2 hrs, 4 hrs, 6 hrs and 8 hrs of dissolution respectively. The mucoadhesive bond was observed up to 8 hrs in acidic media. The surface morphology of the prepared microspheres was studied by Scanning Electron Microscope (SEM) and no interaction was found between drug and polymer from the FTIR study. Bangladesh Pharmaceutical Journal 23(2): 117-124, 2020

Gastroretentive System of Fluvastatin Sodium by Using Natural Mucilage and Synthetic Polymer

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Umamaheswara G. ◽  
Anudeep D.
Keyword(s):  
Half Life ◽  
Release Kinetics ◽  
Kinetic Studies ◽  
Diffusion Path ◽  
Synthetic Polymer ◽  
In Vitro Dissolution ◽  
Direct Compression ◽  
Drug Content ◽  
Biological Half Life

Fluvastatin sodium is a novel compound used as cholesterol lowering agent which acts through the inhibition of 3- hydroxyl-3- methyl glutaryl- coenzyme A (HMG-Co A) reductase. It has short biological half life (1-3h) in humans required a dosing frequency of 20 to 40mg twice a day. Due to its short variable biological half life it has been developed to a sustained gastroretentive system with a natural and synthetic polymer and to study how far the natural mucilage improves the sustained activity. Floating tablets were prepared by direct compression method using in combination of natural mucilage and synthetic polymer. Prior to the preparation of tablets the physical mixtures were subjected to FT IR studies and pre compression parameters. After preparation of tablets they were subjected to various tests like swollen index, drug content, In vitro dissolution and release kinetics with pcp disso software etc. The tablets prepared by direct compression shown good in thickness, hardness and uniformity in drug content, the prepared tablets floated more than 12h except FS1 and FS2 shows 9 and 11h. Swollen index studies shows with increase in concentration of polymer the swelling increases the diffusion path length by which the drug molecule may have to travel and cause lag time. In vitro results shows that on increasing the amount of hibiscus polymer the sustain activity is increased because of its integrity and forms a thick swollen mass and reduces the erosion property of the HypromelloseK100M, kinetic studies shows that FS 1, FS2, FS3 followed the Korsmeyer peppas model and the rest FS 4, FS 5, FS6 follows the zero order respectively. Based on n value indicating that the drug release followed super case II transport mechanism due to the erosion of the polymer.

Formulation and Evaluation of Orally Disintegrating Tablets of Lamotrigine

2015 ◽  
Vol 8 (2) ◽  
pp. 2881-2888
Author(s):  
Sudarshan Singh ◽  
S S Shyale ◽  
P Karade
Keyword(s):  
Drug Release ◽  
Water Soluble ◽  
In Vitro Dissolution ◽  
Disintegration Time ◽  
Orally Disintegrating Tablet ◽  
Drug Content ◽  
Weight Variation ◽  
Wetting Time ◽  
Croscarmellose Sodium

The aim of this study was to design orally disintegrating tablet (ODT) of Lamotrigine. It is an Antiepileptic drug which is widely used in epilepsy. It is also used in simple and complex partial seizures and secondary generalized tonic-clonic seizures. It is poorly water soluble drug (0.46 mg/ml). Thus, an attempt was made to enhance the water solubility by complexation with β-cyclodextrin (1:1 molar ratios). The orally disintegrating tablet of lamotrigine was prepared by direct compression method using different concentration of superdisintegrants such as Sodium starch glycollate, croscarmellose sodium by sublimating agent such as camphor. The formulations were evaluated for weight variation, hardness, friability, drug content, wetting time, in vitro disintegration time and in vitro dissolution studies. The prepared tablets were characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. The disintegration time for the complexed tablets prepared by different concentration of superdisintegrants was found to be in range of 32.54 ± 0.50 to 55.12 ± 0.57 sec and wetting time of the formulations was found to be in range of 28.47 ± 0.67 to 52.19 ± 0.72 sec. All the formulation showed almost 100 percent of drug release within 15 min. Among all the formulation F6 and F7 prepared with 18% croscarmellose sodium and camphor shows faster drug release, respectively 10 min, F6 gives good result for disintegration time, drug release, wetting time and friability. Further formulations were subjected to stability testing for 30 days at temperature of 40 ± 5 ºC/75 ± 5 %RH. Tablets showed no appreciable changes with respect to physical appearance, drug content, disintegration time and dissolution profiles. Results were statistically analyzed by one-way ANOVA at a p < 0.05. It was found that, the data at any point of time are significant at p < 0.05.

Mesoporous Silica Molecular Sieve based Nanocarriers: Transpiring Drug Dissolution Research

2017 ◽  
Vol 23 (3) ◽  
pp. 467-480 ◽  
Author(s):  
Satyanarayan Pattnaik ◽  
Kamla Pathak
Keyword(s):  
Drug Release ◽  
Mesoporous Silica ◽  
Molecular Sieves ◽  
Release Kinetics ◽  
Drug Loading ◽  
Scale Up ◽  
Water Soluble ◽  
Drug Dissolution ◽  
Water Soluble Drugs ◽  
Loading Methods

Background: Improvement of oral bioavailability through enhancement of dissolution for poorly soluble drugs has been a very promising approach. Recently, mesoporous silica based molecular sieves have demonstrated excellent properties to enhance the dissolution velocity of poorly water-soluble drugs. Description: Current research in this area is focused on investigating the factors influencing the drug release from these carriers, the kinetics of drug release and manufacturing approaches to scale-up production for commercial manufacture. Conclusion: This comprehensive review provides an overview of different methods adopted for synthesis of mesoporous materials, influence of processing factors on properties of these materials and drug loading methods. The drug release kinetics from mesoporous silica systems, the manufacturability and stability of these formulations are reviewed. Finally, the safety and biocompatibility issues related to these silica based materials are discussed.

The Potential Migrated Mechanism of Water-Soluble Components in Pellets Prepared by Wet Extrusion/Spheronization: Effect of Drying Rate

2020 ◽  
Vol 17 ◽  
Author(s):  
Bingwei Wang ◽  
Jianping Liu ◽  
Zhenghua Li ◽  
Yulong Xia ◽  
Shuangshuang Zhang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Soluble ◽  
In Vitro Dissolution ◽  
Drying Rate ◽  
Scanning Calorimetry ◽  
Drying Temperature ◽  
Wet Extrusion ◽  
Extrusion Spheronization ◽  
Soluble Components

Background: At present, there were numerous researches on the migration of components in tablets and granules, the investigation in the pharmaceutical literatrue concerning the effect of drying rate on the migration of water-soluble components of pellets was limited. Temperature and relative humidity (RH) were crucial parameters during the drying process which was an essential step in the preparation of pellets via wet extrusion/spheronization. To quantify these variables, the water loss percentage of pellets per minute was defined as drying rate. Objective: The study aimed to investigate the influence of drying rate on the migration of water-soluble components in wet pellets and the potential migrated mechanism. Methods: The pellets containing tartrazine as a water-soluble model drug and microcrystalline cellulose as a matrix former were prepared by extrusion/spheronization and dried at four different drying temperature and relative humidity. Afterward, the extent of migrated tartrazine was assessed regarding appearance, in-vitro dissolution test, Differential Scanning Calorimetry, X-Ray Powder Diffraction, Attenuated total reflectance Fourier transform infrared spectroscopy and Confocal Raman Mapping. Results: Results demonstrated that red spots of tartrazine appeared on the surface of pellets and more than 40% tartrazine were burst released within 5 minutes when pellets dried at 60℃/RH 10%. While pellets dried at 40℃/RH 80%, none of these aforementioned phenomena was observed. Conclusion: In conclusion, the faster drying rate was, the more tartrazine migrated to the exterior of pellets. Adjusting drying temperature and relative humidity appropriately could inhibit the migration of water-soluble components within wet extrusion/spheronization pellets.

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