scholarly journals Investigation of Drug Release From Biodegradable PLG Microspheres: Experiment and Theory

Author(s):  
Nader S. Berchane ◽  
Kenneth H. Carson ◽  
Allison C. Rice-Ficht ◽  
Malcolm J. Andrews

Piroxicam containing PLG microspheres having different size distributions were fabricated, and in vitro release kinetics were determined for each preparation. Based on the experimental results, a suitable mathematical theory has been developed that incorporates the effect of microsphere size distribution and polymer degradation on drug release. We show from in vitro release experiments that microsphere size has a significant effect on drug release rate. The initial release rate decreased with an increase in microsphere size. In addition, the release profile changed from first order to concave-upward (sigmoidal) as the system size was increased. The mathematical model gave a good fit to the experimental release data.

2020 ◽  
pp. 1-9
Author(s):  
Yunhong Wang ◽  
Rong Hu ◽  
Yanlei Guo ◽  
Weihan Qin ◽  
Xiaomei Zhang ◽  
...  

OBJECTIVE: In this study we explore the method to prepare tanshinone self-microemulsifying sustained-release microcapsules using tanshinone self-microemulsion as the core material, and chitosan and alginate as capsule materials. METHODS: The optimal preparation technology of chitosan-alginate tanshinone self-microemulsifying sustained-release microcapsules was determined by using the orthogonal design experiment and single-factor analysis. The drug loading and entrapment rate were used as evaluation indexes to assess the quality of the drug, and the in vitro release rate was used to evaluate the drug release performance. RESULTS: The best technology of chitosan-alginate tanshinone self-microemulsifying sustained-release microcapsules is as follows: the concentration of alginate is 1.5%, the ratio of tanshinone self-microemulsion volume to alginate volume to chitosan mass is 1:1:0.5 (ml: ml: g), and the best concentration of calcium chloride is 2.0%. To prepare the microcapsules using this technology, the drug loading will be 0.046%, the entrapment rate will be 80.23%, and the 24-hour in vitro cumulative release rate will be 97.4%. CONCLUSION: The release of the microcapsules conforms to the Higuchi equation and the first-order drug release model and has a good sustained-release performance.


1970 ◽  
Vol 8 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Mohammad Nezab Uddin ◽  
Ishtiaq Ahmed ◽  
Monzurul Amin Roni ◽  
Muhammad Rashedul Islam ◽  
Mohammad Habibur Rahman ◽  
...  

The objective of this study was to design oral sustained release matrix tablets of Ranolazine usinghydroxypropyl methylcellulose (HPMC) as the retardant polymer and to study the effect of formulation factors suchas polymer proportion and polymer viscosity on the release of drug. In vitro release studies were performed usingUSP type II apparatus (paddle method) in 900 mL of 0.1N HCl at 100 rpm for 12 hours. The release kinetics wasanalyzed using the zero-order, first order, Higuchi and Korsmeyer-Peppas equations to explore and explain themechanism of drug release from the matrix tablets. In vitro release studies revealed that the release rate decreasedwith increase in polymer proportion and viscosity grade. Mathematical analysis of the release kinetics indicated thatthe nature of drug release from the matrix tablets was dependent on drug diffusion and polymer relaxation andtherefore followed non-Fickian or anomalous release. The developed controlled release matrix tablets of Ranolazineprepared with high viscosity HPMC extended release up to 12 hours.Key words: Ranolazine; Sustained release; Methocel E50 Premium LV; Methocel K100LV CR; Methocel K4M CR;Methocel K15M CR.DOI: 10.3329/dujps.v8i1.5333Dhaka Univ. J. Pharm. Sci. 8(1): 31-38, 2009 (June)


Author(s):  
O. SREEKANTH REDDY ◽  
M. C. S. SUBHA ◽  
T. JITHENDRA ◽  
C. MADHAVI ◽  
K. CHOWDOJI RAO ◽  
...  

Objective: The aim of the present study was to fabricate and evaluate the drug release studies using Sodium Alginate (SA) and Gelatin (GE) microbeads intercalated with Kaolin (KA) nanoclay for sustained release of D-Penicillamine (D-PA). Methods: Sodium alginate/gelatin/Kaolin blend microbeads were prepared by an extrusion method by using glutaraldehyde (GA) as a crosslinker. The obtained microbeads were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X–ray diffraction (XRD). Drug release kinetics of the microbeads was investigated in simulated intestinal fluid (pH 7.4) at 37 °C. Results: Microbeads formation was confirmed by FTIR spectroscopy. X-RD reveals that the KA should be intercalated with the drug and also it confirms the molecular level dispersion of D-Penicillamine into microbeads. Scanning Electron Microscopy (SEM) studies reveal that the beads were in spherical shape with some wrinkled depressions on the surface. The in vitro release study indicates the D-Penicillamine released in a controlled manner. The in vitro release kinetics was assessed by Korsmeyer-Peppas equation and the ‘n’ value lies in between 0.557-0.693 indicates Non-Fickian diffusion process. Conclusion: The results suggest that the developed KA intercalated microbeads are good potential drug carrier for the controlled release of D-PA.


2019 ◽  
Vol 179 ◽  
pp. 445-452 ◽  
Author(s):  
Akhtar Jahan Siddiqa ◽  
Nilesh Kumar Shrivastava ◽  
M.E. Ali Mohsin ◽  
Mustufa Haider Abidi ◽  
Tauqeer Ahmed Shaikh ◽  
...  

Author(s):  
Chandra Sekhar Kolli ◽  
Ramesh Gannu ◽  
Vamshi Vishnu Yamsani ◽  
Kishan V ◽  
Madhsudan Rao Yamsani

The aim of this investigation was to develop and evaluate mucoadhesive buccal patches of prochlorperazine (PCPZ). Permeation of PCPZ was calculated in vitro using porcine buccal membrane. Buccal formulations were developed by solvent-casting technique using hydroxy propylmethyl cellulose (HPMC) as mucoadhesive polymer. The patches were evaluated for in vitro release, moisture absorption and mechanical properties. The optimized formulation, based on in vitro release and moisture absorption studies, was subjected for bioadhesion studies using porcine buccal membrane. In vitro flux of PCPZ was calculated to be 2.14 ± 0.01 µg. h–1.cm–2 and buccal absorption was also demonstrated in vivo in human volunteers.             In vitro drug release and moisture absorbed was governed by HPMC content. Increasing concentration of HPMC delayed the drug release. All formulations followed Zero order release kinetics whereas the release pattern was non-Fickian. The mechanical properties, tensile strength (10.28 ± 2.27 kg mm–2 for formulation P3) and elongation at break reveal that the formulations were found to be strong but not brittle. The peak detachment force and work of adhesion for formulation P3 were 0.68 ± 0.15 N and 0.14 ± 0.08 mJ, respectively. The results indicate that suitable bioadhesive buccal patches of PCPZ with desired permeability and suitable mechanical properties could be prepared


Fig. 12 Scanning electron micrograph of D.L-PLA nanoparticles loaded with CGP 57813. (Ref. 51.) scanning force microscopy (also called atomic force microscopy), enable the visualiza-tion of nanoparticles at atmospheric pressure without gold coating [12,64]. Neverthe-less, the resolution obtained with these new tools is still lower than that with SEM. For size determination, transmission electron microscopy is not as widely used as PCS and SEM, but it is still a powerful method for determining the morphology of particles. With this technique, Fessi et al. [42] estimated the wall thickness of PLA nanocapsules. Krause et al. [18] described the highly porous structure of PLA nano-spheres prepared by the emulsion-evaporation procedure. VIII. IN VITRO RELEASE STUDIES In vitro release studies should in principle be useful for quality control as well as for the prediction of in vivo kinetics. Unfortunately, due to the very small size of the par-ticles, the release rate observed in vivo can differ greatly from the release obtained in a buffer solution. However, in vitro release studies remain very useful for quality control as well as for evaluation of the influence of process parameters on the release rate of active compounds. In vitro drug release from microdispersed systems has been exten-sively reviewed by Washington [65]. Depending on the type of polyester, drug release from nanoparticles can take place through several processes, of which the following appear to be the most important: (1) The drug may diffuse out of the carrier through the solid matrix; to allow complete release from the carriers, (the concentration of drug in the release medium should re-main infinitely low, which condition is known as sink condition); (2) The solvent may penetrate the nanoparticles and dissolve the drug, which then diffuses out into the re-lease medium. Depending on the physico-chemical characteristics of the particles, wa-ter can enter the particles through narrow pores or by hydration. Once the drug is dis-solved, the drug diffuses out of the particles. Here again, since diffusion is driving the

1998 ◽  
pp. 204-216

Author(s):  
Chinmaya Keshari Sahoo ◽  
Amiyakanta Mishra ◽  
Amaresh Prusty ◽  
S. Ram Mohan Rao ◽  
Jimidi Bhaskar

The present study was undertaken to develop floating tablets of lamivudine. The tablets were prepared by direct compression method. The prepared tablets were evaluated for pre compression parameters, post compression parameters, in vitro drug release study and in vitro buoyancy study. Among the prepared formulations F4 batch show 90.98% drug release in 12 h. The in vitro release kinetics were analyzed for different batches by different pharmacokinetic models such as zero order, first order, Higuchi, and Korsmeyer Peppas. The result of optimized formulation releases drug up to 12 h in a controlled manner and follows Higuchi kinetics. Short term stability study at 40±2ºC/75±5% RH for three months on the best formulation was performed showing no significant changes in thickness, hardness, friability, drug content and in vitro drug release.


Author(s):  
R. PAWAR ◽  
S. JAGDALE ◽  
D. RANDIVE

Objective: The present study aimed to develop a new SR metformin hydrochloride (MH) gastroretentive formulation with novel excipient (NE), which has better floatation and can be prepared with more simple pharmaceutical techniques for the treatment of diabetes Mellitus. Methods: A gastro-retentive floating matrix tablet (GFT) formulation of MH was prepared using various concentrations of PEO (Polyox WSR-303) and hydroxypropyl methylcellulose K100M (HPMC K100 M) and Floating agent (novel excipient) to achieve desirable TFT, FLT and drug release. The wet granulation method was selected using isopropyl alcohol as a binder for the preparation of tablets. D-optimal non-simplex mixture design was used for the selection of suitable polymer concentrations and floating agents. Release kinetics was used to determine the mechanism of drug release. Results: It was observed that GFT with optimum quantities of PEO, HPMC K100M, and the floating agent showed 100 % of drug release in 24h with FT up to 24h and minimum FLT of less than 2 min. Formulation with an in vitro release profile slower to the marketed sample was prepared. Conclusion: A sustained-release (GFT) of MH tablets using PEO-, HPMC K100M, and an effervescent system was successfully prepared. AGFT formulation with an in vitro release profile slower to the marketed sample that releases MH for 24h may suitable for once-daily dosing can be prepared.


2021 ◽  
Vol 11 (3-S) ◽  
pp. 65-73
Author(s):  
Keyur S. Patel ◽  
Akshar N. Rao ◽  
Deepa R. Patel ◽  
Dhaval M. Patel ◽  
Advaita B. Patel

The objective of the present study was to develop gastroretentive floating tablets of quetiapine fumarate. The gastroretentive floating tablets of quetiapine fumarate were formulated using natrosol 250 HHX as a sustained release polymer and sodium bicarbonate as a gas forming agents.  A 32 factorial design was employed to study the influence of concentration of natrosol HHX 250 (X1) and concentration of sodium bicarbonate (X2) on the dependent variables % drug release at 1h (Y1), % drug release at 8 h (Y2) and floating lag time (Y3). The optimized formulation (O1) showed floating lag time 49 ± 3 sec and % drug release 99.54± 0.81 at 12 h. The in vitro release of F1-F9 batches were found in between 99.95 ± 1.18 %  to  86.32 ±1.71 % at 12 h. Floating lag time of F1-F9 batches were found to be 25± 2 sec to 178 ± 3 sec. FTIR studies shown that there was no  interaction between quetiapine fumarate and excipients. From the factorial design batches it was found that floating lag time was decreased with increasing the amount of sodium bicarbonate and decreasing the amount of natrosol 250 HHX. Here % release of drug was decreased with increase the extent of natrosol 250 HHX. The in-vitro release kinetics revealed Korsmeyer-Peppas model is followed and drug release is by anomalous diffusion. Keywords: Quetiapine fumarate, Natrosol 250 HHX, Sodium bicarbonate, Gastroretentive floating tablets


Author(s):  
Deborah Ejiogu Chioma ◽  
Felix Sunday Yusuf

Metoclopramide hydrochloride is a dopamine receptor antagonist, used mostly for stomach and esophageal problems as it is a prokinetic agent. The aim of the present study was to design and evaluate the suppositories of Metoclopramide HCl.  Six different, rectal suppositories were developed by fusion (pour-moulding) method by employing various hydrophilic and hydrophobic polymeric bases like gelatin, PEG-400 and hydrogenated vegetable oil using propylene glycol as plasticizer and beeswax as hardening agent.  Metoclopramide HCl suppositories were evaluated for appearance, weight variation, drug content uniformity, liquefaction time and temperature, micro-melting range, disintegration and in-vitro release study.  The in-vitro release rate data was evaluated statistically and was found that from all the formulations the drug release is by diffusion mechanism. Optimum formulation of batch S1 has shown 83.427% Metoclopramide HCl in a study of 2 hrs. These drug release results are supported by the disintegration time of suppositories. Lesser the disintegration time faster the drug release. All formulations has shown zero, first and Higuchi release kinetics. The result suggests that the Metoclopramide HCl suppositories can be prepared by employing hydrophilic and hydrophobic polymers.


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