Solid Dispersions: A Review

Author(s):  
Sumant Saini ◽  
Yashwant .

Solid dispersions are one of the most promising strategies to improve the oral bioavailability of poorly water soluble drugs. By reducing drug particle size to the absolute minimum, and hence improving drug wettability, bioavailability may be significantly improved. This article reviews the various preparation techniques for solid dispersion and compiles some of the recent technology transfers. The different types of solid dispersions based on the molecular arrangement have been highlighted. Some of the practical aspects to be considered for the preparation of solid dispersions, such as selection of carrier, solvent and methods of physicochemical characterization, along with an insight into the molecular arrangement of drugs in solid dispersions are also discussed. In this review, it is intended to discuss the recent advances related on the area of solid dispersions.

2020 ◽  
Vol 14 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Ritu Kaushik ◽  
Vikas Budhwar ◽  
Deepak Kaushik

The oral bioavailability enhancement of poorly water-soluble medicaments is still one of the most complicated aspects of the formulation development. Various approaches are currently available for solubility and rate of dissolution enhancement such as salt formation, solubilization and reduction of particle size, each with its own limitations and advantages. Solid dispersion is one of the most suitable approaches for the formulation development of poorly water-soluble drugs. The popularity of solid dispersion is evident from the increasing number of patent applications and patents granted in this field during recent years. This article reviews the various approaches for the preparation of solid dispersion such as a solvent melting, hot-melt extrusion method, solvent evaporation method, cryogenic processing approaches etc. from the perspective of patents filed or granted for these techniques. Some of the aspects taken into account before the preparation of solid dispersions are carrier selection and physicchemical testing along with an insight into the molecular arrangement of medicaments in solid dispersion. The manuscript further highlights various commercial patented technology platforms such as Solumertm, Hovione and Kinetisol which are based on the concept of solid dispersions.


Pharmaceutics ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 745
Author(s):  
Thao T. D. Tran ◽  
Phuong H. L. Tran

Physicochemical characterization is a crucial step for the successful development of solid dispersions, including the determination of drug crystallinity and molecular interactions. Typically, the detection of molecular interactions will assist in the explanation of different drug performances (e.g., dissolution, solubility, stability) in solid dispersions. Various prominent reviews on solid dispersions have been reported recently. However, there is still no overview of recent techniques for evaluating the molecular interactions that occur within solid dispersions of poorly water-soluble drugs. In this review, we aim to overview common methods that have been used for solid dispersions to identify different bond formations and forces via the determination of interaction energy. In addition, a brief background on the important role of molecular interactions will also be described. The summary and discussion of methods used in the determination of molecular interactions will contribute to further developments in solid dispersions, especially for quick and potent drug delivery applications.


Author(s):  
Meka Lingam ◽  
Vobalaboina Venkateswarlu

The low aqueous solubility of celecoxib (CB) and thus its low bioavailability is a problem.    Thus, it is suggested to improve the solubility using cosolvency and solid dispersions techniques. Pure CB has solubility of 6.26±0.23µg/ml in water but increased solubility of CB was observed with increasing concentration of cosolvents like PEG 400, ethanol and propylene glycol. Highest solubility (791.06±15.57mg/ml) was observed with cosolvency technique containing the mixture of composition 10:80:10%v/v of water: PEG 400: ethanol. SDs with different polymers like PVP, PEG were prepared and subjected to physicochemical characterization using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), differential scanning calorimetry (DSC), solubility and dissolution studies. These studies reveals that CB exists mainly in amorphous form in prepared solid dispersions of PVP, PEG4000 and PEG6000 further it can also be confirmed by solubility and dissolution rate studies. Solid dispersions of PV5 and PV9 have shown highest saturation solubility and dissolution rate


2017 ◽  
Vol 23 (3) ◽  
pp. 350-361 ◽  
Author(s):  
Hisham Al-Obaidi ◽  
Mridul Majumder ◽  
Fiza Bari

Crystalline and amorphous dispersions have been the focus of academic and industrial research due to their potential role in formulating poorly water-soluble drugs. This review looks at the progress made starting with crystalline carriers in the form of eutectics moving towards more complex crystalline mixtures. It also covers using glassy polymers to maintain the drug as amorphous exhibiting higher energy and entropy. However, the amorphous form tends to recrystallize on storage, which limits the benefits of this approach. Specific interactions between the drug and the polymer may retard this spontaneous conversion of the amorphous drug. Some studies have shown that it is possible to maintain the drug in the amorphous form for extended periods of time. For the drug and the polymer to form a stable mixture they have to be miscible on a molecular basis. Another form of solid dispersions is pharmaceutical co-crystals, for which research has focused on understanding the chemistry, crystal engineering and physico-chemical properties. USFDA has issued a guidance in April 2013 suggesting that the co-crystals as a pharmaceutical product may be a reality; but just not yet! While some of the research is still oriented towards application of these carriers, understanding the mechanism by which drug-carrier miscibility occurs is also covered. Within this context is the use of thermodynamic models such as Flory-Huggins model with some examples of studies used to predict miscibility.


INDIAN DRUGS ◽  
2013 ◽  
Vol 50 (06) ◽  
pp. 13-19
Author(s):  
R. O Sonawane ◽  
◽  
S. Nayak ◽  
M. D. Chaudhari ◽  
V. V. Pande

The poorly water soluble drugs tend to have low bioavailability and this can be improved by several methods. Solid dispersion is a promising formulation approach to improve solubility and dissolution and ultimately oral bioavailability of these drugs. The aim of this study was to prepare and characterize solid dispersion of anti-diabetic glimepiride, a BCS class II drug, with the hydrophilic carrier PVP K30 by solvent evaporation and microwave induced fusion methods. Scanning electron microscopy (SEM), X–ray powder diffractometry (XRD) and differential scanning calorimetric (DSC) were used to evaluate the physical state of the drug. The solid dispersions were also evaluated for drug content, solubility and dissolution studies. Solid dispersions prepared by solvent evaporation method were showed maximum enhancement of solubility and dissolution in comparison to that prepared by other method.


Author(s):  
RUCHI AGRAWAL ◽  
ABID RAZA ◽  
OM PRAKASH PATEL

Objective: This review article explores solid dispersions (SDs) as one of the suitable approaches to formulate poorly water-soluble drugs. The objective of this review on SD techniques is to explore their utility as a feasible, simple, and economically viable method for augmentation of dissolution of hydrophobic drugs. Methods: Various types of SDs are classified and compared. Use of surfactants to stabilize the SDs and their potential advantages and disadvantages has been discussed. Different techniques for preparing and evaluating SDs are appraised along with discussions on scalability and industrial production. Review of the current research on SD along with future trends is also offered. Results: Based on the various researches, SDs offer an efficient means of improving bioavailability while concurrently contributing to lower toxicity and dose-reduction. Conclusion: Solid-dispersions have been and continue to be one of the key technologies for solving the issue of poor solubility for newer hydrophobic molecules which are being discovered. This would give a new lease of life for such drugs enabling them to be delivered in an effective way.


2019 ◽  
Vol 9 (2) ◽  
pp. 231-240
Author(s):  
Khosro Adibkia ◽  
Solmaz Ghajar ◽  
Karim Osouli-Bostanabad ◽  
Niloufar Balaei ◽  
Shahram Emami ◽  
...  

Purpose: In the current study, electrospraying was directed as a novel alternative approach to improve the physicochemical attributes of gliclazide (GLC), as a poorly water-soluble drug, by creating nanocrystalline/amorphous solid dispersions (ESSs). Methods: ESSs were formulated using Eudragit® RS100 and polyethylene glycol (PEG) 6000 as polymeric carriers at various drug: polymer ratios (i.e. 1:5 and 1:10) with different total solution concentrations of 10, 15, and 20% w/v. Morphological, physicochemical, and in-vitro release characteristics of the developed formulations were assessed. Furthermore, GLC dissolution behaviors from ESSs were fitted to various models in order to realize the drug release mechanism. Results: Field emission scanning electron microscopy analyses revealed that the size and morphology of the ESSs were affected by the drug: polymer ratios and solution concentrations. The polymer ratio augmentation led to increase in the particle size while the solution concentration enhancement yielded in a fiber establishment. Differential scanning calorimetry and powder X-ray diffraction investigations demonstrated that the ESSs were present in an amorphous state. Furthermore, the in vitro drug release studies depicted that the samples prepared employing PEG 6000 as carrier enhanced the dissolution rate and the model that appropriately fitted the release behavior of ESSs was Weibull model, where demonstrating a Fickian diffusion as the leading release mechanism. Fourier-transform infrared spectroscopy results showed a probability of complexation or hydrogen bonding, development between GLC and the polymers in the solid state. Conclusion: Hence the electrospraying system avails the both nanosizing and amorphization advantages, therefore, it can be efficiently applied to formulating of ESSs of BCS Class II drugs.


Author(s):  
Sanjoy Kumar Das

Improving oral bioavailability of drugs those given as solid dosage forms remains a challenge for the formulation scientists due to solubility problems. The dissolution rate could be the rate-limiting process in the absorption of a drug from a solid dosage form of relatively insoluble drugs. Therefore increase in dissolution of poorly soluble drugs by solid dispersion technique presents a challenge to the formulation scientists. Solid dispersion techniques have attracted considerable interest of improving the dissolution rate of highly lipophilic drugs thereby improving their bioavailability by reducing drug particle size, improving wettability and forming amorphous particles. The term solid dispersion refers to a group of solid products consisting of at least two different components, generally a hydrophilic inert carrier or matrix and a hydrophobic drug. This article reviews historical background of solid dispersion technology, limitations, classification, and various preparation techniques with its advantages and disadvantages. This review also discusses the recent advances in the field of solid dispersion technology. Based on the existing results and authors’ reflection, this review give rise to reasoning and suggested choices of carrier or matrix and solid dispersion procedure.


Author(s):  
Navneet Sharma ◽  
Sabna Kotta ◽  
Mohd Aleem ◽  
Shubham Singh ◽  
Rakesh Kumar Sharma

In the last decade, there has been a mounting concern in lipid-based formulations to deliver water-soluble drugs. Lipid-based drug delivery systems are one of the budding and promising technologies designed to tackle the poor bioavailability problems. This chapter stresses the different mechanisms of lipophilic drug absorption along with its advantages and limitations. It points out the different mechanisms of how lipid-based excipients and the different formulations interact with the absorption process. This review provides a comprehensive summary about the lipid formulation classification scheme (LFCS), a guide for the selection of appropriate formulation and commonly used excipients for lipid-based formulations, along with the important factors to be considered in formulation design and excipient selection. This review also focuses on the formulation of solid lipid-based formulations, important evaluation aspects, and commercial formulations available for the purpose.


Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1679
Author(s):  
Thao T.D. Tran ◽  
Phuong H.L. Tran

In recent decades, solid dispersions have been demonstrated as an effective approach for improving the bioavailability of poorly water-soluble drugs, as have solid dispersion techniques that include the application of nanotechnology. Many studies have reported on the ability to change drug crystallinity and molecular interactions to enhance the dissolution rate of solid dispersions using hydrophilic carriers. However, numerous studies have indicated that insoluble carriers are also promising excipients in solid dispersions. In this report, an overview of solid dispersion strategies involving insoluble carriers has been provided. In addition to the role of solubility and dissolution enhancement, the perspectives of the use of these polymers in controlled release solid dispersions have been classified and discussed. Moreover, the compatibility between methods and carriers and between drug and carrier is mentioned. In general, this report on solid dispersions using insoluble carriers could provide a specific approach and/or a selection of these polymers for further formulation development and clinical applications.


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