scholarly journals Layered Silicate-Alginate Composite Particles for the pH-Mediated Release of Theophylline

2020 ◽  
Vol 13 (8) ◽  
pp. 182
Author(s):  
Uttom Nandi ◽  
Vivek Trivedi ◽  
Dennis Douroumis ◽  
Andrew P. Mendham ◽  
Nichola J. Coleman

Numerous natural and synthetic clay minerals have proven to be excellent drug carriers for high drug-loaded and sustained release formulations due to their considerable ion exchange, adsorption, and swelling capacities. Moreover, the synthetic smectite clays have added advantages in terms of compositional purity and controlled cation exchange capacity in comparison to natural clays. This study involves the intercalation of theophylline (TP) in a synthetic clay, Laponite® (LP), followed by the inclusion of the resulting intercalates into sodium alginate (SA) beads to achieve pH-controlled drug release. Maximum intercalated drug incorporation of 68 mg/g was obtained by ion exchange at pH 1.2 and confirmed by an increase in basal spacing of the clay from 12.9 to 15.5 Å. TP release from the binary LP-TP intercalates in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) was found to be 40% and 70%, respectively. LP-TP particles were also incorporated in an SA matrix via polymer crosslinking using CaCl2(aq) to improve the pH selective release. The ternary polymer-clay-drug composite particles effectively prevented the release of TP at low pH in SGF and resulted in sustained release in SIF, with 40% dissolution within 120 min.

Author(s):  
ALIYAH ALIYAH ◽  
EMILIA UTOMO ◽  
ANDI DIAN PERMANA ◽  
ERNAWATI

Objective: The aim of this study was to develop a liquisolid formulation of propranolol hydrochloride to obtain an improved sustained release profile by varying the ratio of liquid vehicles. Methods: In this study, propranolol hydrochloride (PPH) was dispersed in the combination of propylene glycol and polysorbate 80, as the liquid vehicles, with different ratios. Eudragit® RL and Aerosil® were used as carrier and coating materials, respectively, to produce a dry and free-flowing powder. In addition, HPMC was used to amplify the retardation effect. The prepared formulations were evaluated for its physicochemical properties, including loss on drying, flow rate, angle of repose calculation, drug content analysis, FT-IR spectroscopy, as well as dissolution studies. The obtained dissolution profiles were subsequently fitted to the mathematical model in order to determine the drug kinetics. Results: The results show that all formulations performed dry and free-flowing granules containing PPH in the range of 7-9%. Furthermore, all the prepared formulations were able to sustain the drug release for a total of 8 h in two different dissolution media, namely simulated gastric fluid and simulated intestinal fluid. F4 containing propylene glycol and polysorbate 80 (1:2) possessed the lowest drug release rate. It was also obtained that F1 and F3 followed first-order kinetics while F2, F4, and F5 complied with the Higuchi model. Conclusion: Overall, there was no difference in all the dissolution profiles based on the calculation of the difference and similarities factor.


2020 ◽  
Vol 20 (1) ◽  
pp. 76-87
Author(s):  
S.A. Chime ◽  
A.A. Attama ◽  
G.C. Onunkwo

Background: Stavudine is an antiretroviral therapy with so many side effects and has a short half-life of 1.5 h. It degrades to thymine under hydrolytic, oxidative and photolytic conditions hence has major formulation challenges. Objectives: To formulate sustained release lipid based stavudine and to study the properties of the formulations by in vitro and in vivo methods. Methods: Stavudine tablets were formulated by moulding using validated tablets moulds. The carrier used were solidified reverse micellar solution (SRMS) made up of varying ratios of hydrogenated palm oil and Phospholipid admixtures. Evaluation tests were carried out on the tablets using both Pharmacopoeial and non Pharmacopoeial test. Drug release was studied in both simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.2). In vivo release was studied using Wistar rats. Results: The results showed that stavudine tablets exhibited weight range of 372 ± 0.14 to 386 ± 0.52 mg, friability ranged from 0.00 to 0.13 % and hardness ranged from 4.27 ± 0.25 to 5.30 ± 0.21 Kgf. Tablets formulated with SRMS 1:2 had erosion time range of 60.80 ± 1.23 to 87.90 ± 2.33 min and was affected significantly by the presence of Poloxamer 188 (p < 0.05). The formulations exhibited T100 % at 10 to13 h in SIF. Stavudine tablets showed the area under the curve (AUC) of 854.0 μg/h/ml, significantly higher than the AUC of the reference (p < 0.05). Conclusion: Stavudine SRMS-based tablets had good stability and sustained release properties. Formulations containing 1 % Poloxamer 188 exhibited enhanced in vivo absorption and hence could be used once daily in order to enhance the bioavailability of this drug..


Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 723
Author(s):  
He Xia ◽  
Ang Li ◽  
Jia Man ◽  
Jianyong Li ◽  
Jianfeng Li

In this work, we used a co-flow microfluidic device with an injection and a collection tube to generate droplets with different layers due to phase separation. The phase separation system consisted of poly(ethylene glycol) diacrylate 700 (PEGDA 700), PEGDA 250, and sodium alginate aqueous solution. When the mixture droplets formed in the outer phase, PEGDA 700 in the droplets would transfer into the outer aqueous solution, while PEGDA 250 still stayed in the initial droplet, breaking the miscibility equilibrium of the mixture and triggering the phase separation. As the phase separation proceeded, new cores emerged in the droplets, gradually forming the second and third layers. Emulsion droplets with different layers were polymerized under ultraviolet (UV) irradiation at different stages of phase separation to obtain microspheres. Microspheres with different layers showed various release behaviors in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The release rate decreased with the increase in the number of layers, which showed a potential application in sustained drug release.


2012 ◽  
Vol 560-561 ◽  
pp. 434-437 ◽  
Author(s):  
Lan Wang ◽  
Wen Ji Guo ◽  
Yan Zhao Zhao

The objective of this paper was to prepare the composite of crefradine/montmorillionite in the method of solution intercalation. The drug load and intercalation rate varied with the drug concentration. X-ray diffraction (XRD), Fourier transformed infrared (FT-IR) Spectroscopy, and thermal analysis (TG-DSC) were applied to characterize composite mentioned above. Together with drug release tests, results indicate cefradine intercalated into montmorillionite.The release profiles of cefradine/MMT in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 7.4) at 37°Cduring 10h are shown in Fig. 4. The amount of cefradine in the beginning 2h came up to 35% and 50%, and in the following time, cefradine released slowly. The release behaviors met the requirements of sustained release.


Author(s):  
Putra Imwa ◽  
Kusumawati Igaw

Objective: As an antidiabetic drug, metformin hydrochloride (HCl) has been well known to possess low oral bioavailability and short half-life. In this study, we prepared the drug delivery system (DDS) of metformin HCl and clinoptilolite as its carrier. The in vitro drug release profile was further investigated.Methods: DDS was made by encapsulating metformin HCl on clinoptilolite using the wet impregnation method at various pH and initial concentration of metformin HCl. Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), and N2 Sorption Analyzer were used to characterize the as-synthesized DDS. Drug release study was conducted by stirring the DDS in simulated gastric fluid and simulated intestinal fluid over 12 h.Results: The encapsulation process was achieved optimally at pH 7.0 and initial concentration of metformin HCl of 300 mg/l (CLI2-300 denoted DDS). The results of FTIR and N2 sorption analyzer confirmed the existence of metformin HCl on clinoptilolites. Meanwhile, the XRD result showed that the crystallinity of clinoptilolites remained unchanged after the encapsulation process. The cumulative drug release in the simulated gastric fluid was found to be higher than that in the simulated intestinal fluid, which indicated the potent influence of pH on the release properties of the drugs. The drug release kinetics of metformin HCl from clinoptilolite was best fitted into the Korsmeyer-Peppas model with non-Fickian transport mechanism.Conclusion: We found that clinoptilolite was suitable for DDS application, particularly as a carrier of metformin HCl.


2017 ◽  
Vol 5 (2) ◽  
Author(s):  
Nur Syahirah Sallehudin ◽  
Khalilah Abdul Khalil ◽  
Maslinda Musa ◽  
Hifa Nazirah Mohd Yazid ◽  
Anida Yusof

Probiotic encapsulation approach has the potential to protect microorganisms and to deliver them into the gut. Because of the promising preclinical and clinical results, probiotics have been incorporated into a range of products. However, there are still many challenges to overcome with respect to the encapsulation process and the conditions prevailing in the gut. Thus in this study, the release activity of encapsulated L. plantarum NBRC 3070 and Aloe vera gel within alginate coated chitosan matrices during simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) exposure were investigated. There were four groups of beads prepared in this study: 1) Encapsulated probiotic and Aloe vera within alginate beads (chitosan coated), 2) Encapsulated probiotic within alginate beads (chitosan coated), 3) Encapsulated probiotic and Aloe vera within alginate beads (uncoated) and 4) Encapsulated probiotic alone within alginate beads (uncoated). Encapsulation process was carried out using extrusion method. The optimized composition of alginate matrix (1.34% w/v) and Aloe vera gel (1.99% w/v) were used.  In order to investigate their release activity, all beads were exposed in Simulated Gastric (SGF) at pH 2.5 and Simulated Intestinal Fluids (SIF) at pH 6.5 for 120 min and 270 min, respectively. Based on the findings, alginate-Aloe vera beads with chitosan coated was able to protect L. plantarum NBRC 3070 during SGF exposure with only 1 log10 cfu/mL reduction. The presence of Aloe vera gel in the beads improved the survivability of the cells. Encapsulated cells were observed successfully slow released of cells from the beads after exposure in SIF. Scan Electron Microscope (SEM) result had shown that cross link activity of the optimum alginate-Aloe vera with chitosan coating resulted in better survival of cells after simulated gastro and able to deliver sufficient probiotic dose to intestinal region. The combinations were able to improve encapsulated cells survivability during low acidic environment passage and release activity into the intestinal target region.   


Author(s):  
Truong Duc Thang ◽  
Le Thi Hanh Quyen ◽  
Hoang Thi Thuy Hang ◽  
Nguyen Thien Luan ◽  
Dang Thi KimThuy ◽  
...  

Bread is a popular food in the world because of its variety and convenience. Currently, studies on the adding probiotics to bread are limited due to the adverse effects of processing, such as baking temperature, aerobic environment to the probiotic bacteria. The objective of this study was to produce probiotic cream bread, in which Lactobacillus acidophilus was microencapsulated with Alginate 2% (A); Alginate 2% + maltodextrin 1% (AM); Alginate 2% + xanthan gum 0.1% (AX); and Alginate 2% + maltodextrin 1% + xanthan gum 0.1% (AMX). Microcapsules were added to the kernel, conducting encapsulation yield investigations, survival in baking, preservation of bread, and in simulated gastric fluid and simulated intestinal fluid conditions after 8 days of storage. The results showed that the addition of xanthan gum enhanced the encapsulation yield, it reached 92.9% and 92.37% in AMX and AX samples, respectively. The viability of L. acidophilus during baking was decreased by 3.64 and 3.75 Log (CFU/bread) in AMX and AM samples, compared to A and AX which were decreased by 4.75 and 4.44 Log (CFU/ bread). In SGF (Simulated Gastric Fluid) and SIF (Simulated Intestinal Fluid) conditions, the AMX microcapsules provide the best probiotic protection among the four tested carriers. The combination of xanthan gum and maltodextrin in alginate matrix, eventually leading to having dual efficiency: First, xanthan gum would act as buffers that reduce acid activity; Second, maltodextrin acting as a protective agent of L. acidophilus against high temperature as well as potential prebiotic that improve the viability of probiotic.


2017 ◽  
Vol 9 (4) ◽  
pp. 54 ◽  
Author(s):  
Jose Raul Medina ◽  
Jonathan Hernandez ◽  
Marcela Hurtado

Objective: To characterize the in vitro release of carbamazepine tablets and benzoyl metronidazole suspensions using the flow-through cell apparatus and simulated gastrointestinal fluids.Methods: Tegretol® tablets, Flagyl® suspension, and generic formulations of each were tested. Release studies were performed using an automated flow-through cell apparatus. Simulated gastric fluid (with and without pepsin) and simulated intestinal fluid (without pancreatin) at 16 ml/min and fasted state simulated intestinal fluid at 8 ml/min, all at 37.0±0.5 °C, were used as dissolution media. The quantity of dissolved carbamazepine and benzoyl metronidazole was determined at 5-min intervals until 60 min at 285 and 278 nm, respectively. Percentage dissolved at 60 min, mean dissolution time, dissolution efficiency values, and t10%, t25%, t50% and t63.2% were calculated. Mean values for all parameters were compared between the reference and generic formulations using Studentʼs t-test. Dissolution data were fitted to different kinetic models.Results: Simulated gastric fluid without pepsin showed no discriminative capability for carbamazepine tablets. Significant differences were observed between the reference and generic formulations for almost all parameters (*P<0.05). In some cases, the logistic model best described the in vitro release of both drugs.Conclusion: Using an apparatus and media that best simulates the gastrointestinal environment, we identified differences in the rate and extent of dissolution of both drugs that could help to optimise the design of interchangeable formulations. Based on the physicochemical characteristics of carbamazepine and benzoyl metronidazole and the conditions in which the formulations were tested, these differences could be of clinical relevance. 


Author(s):  
Juliati Br Tarigan ◽  
Djendakita Purba ◽  
Cut Fatimah Zuhra

 Objective: This study demonstrated the incorporation of Vitamin E from palm fatty acid distillate onto crosslinked galactomannan phosphate (CGP) matrix.Methods: CGP was obtained from the crosslinking reaction of galactomannan from Arenga pinnata (GAP) with tri-sodium metaphosphate (TMF) ranging from 1:1 to 4:3 while incorporation of Vitamin E was conducted in two steps to form films. The reliability study of Vitamin E in CGPVE was conducted using a solution of pepsin and sodium chloride and also in solution of pancreatin and buffer phosphate.Results: The Fourier-transform infrared spectrum indicated the presence of phosphate in CGP while the scanning electron microscope images depicted the changes of surface morphology from smooth (GAP) to rough and hollow (CGP) which confirmed that crosslink had occurred. The swelling study of CGP showed that the swelling indexes were similar and decreased with the increase of TMF. The efficiency of CGP to absorb Vitamin E ranged from 89.66% to 91.09%. The in vitro releasing study of Vitamin E in simulated gastric fluid and simulated intestinal fluid showed that only a small amount of Vitamin E was released.Conclusions: This study demonstrated that CGP can be prepared and is potentially useful for drug delivery to the colon.


Sign in / Sign up

Export Citation Format

Share Document