Liquisolid Technology Research Articles

Norfloxacin as a model hydrophobic drug with unique release from liquisolid formulations prepared with PEG200 and Synperonic PE/L-61 non-volatile liquid vehicles

The purpose of the study is to investigate dissolution behaviour of norfloxacin as a model hydrophobic drug through application of liquisolid technology. Norfloxacin was prepared as liquisolid formulations using either flowability or compressibility liquisolid tests. The dissolution profiles were evaluated and compared to counterpart conventional norfloxacin tablets. Two non-volatile liquid vehicles were used in the preparation of norfloxacin liquisolid formulations; Poly Ethylene Glycol (PEG200) and Synperonic PE/L-61. The liquisolid formulations of norfloxacin were tested according to the specification of British Pharmacopoeia (BP) quality control tests. Moreover, the pre-preparation evaluation tests, such as powder flowability Carr index, differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR), were applied for further investigation of the physicochemical properties of the liquisolid formulations. The results indicated that the percentage of norfloxacin release in acetate buffer solution (pH=4.0) is higher than in distilled water. Also, at the first 20min, the percentage of the drug release is higher only in the decreased amount of liquid vehicle formulations compared with the conventional tablet. Generally, the conventional tablet dissolution profile is either similar or higher than liquisolid tablets. Moreover, Synperonic PE/L-61 liquisolid tablets showed higher dissolution profiles than PEG200 liquisolid tablets, although the solubility of norfloxacin in PEG200 (2.507mg/ml) is much higher than in Synperonic PE/L-61 (0.167mg/ml). In conclusion, increasing the percentage of liquid vehicle in the prepared norfloxacin liquisolid formulations does not necessarily lead to increase in the percentage of the drug release in distilled water dissolution medium.

Application of liquisolid technology for enhancing solubility and dissolution of rosuvastatin.

Rosuvastatin is a poorly water soluble drug and the rate of its oral absorption is often controlled by the dissolution rate in the gastrointestinal tract. Hence it is necessary to increase the solubility of the Rosuvastatin. Several liquisolid tablets formulations containing various drug concentrations in liquid medication (ranging from 15% to 25% w/w) were prepared. The ratio of Avicel PH 102 (carrier) to Aerosil 200 (coating powder material) was kept 10, 20, 30. The prepared liquisolid systems were evaluated for their flow properties and possible drug-excipient interactions by Infrared spectra (IR) analysis, differential scanning calorimetry (DSC) and X- ray powder diffraction (XRPD). The liquisolid system showed acceptable flow properties. The IR and DSC studies demonstrated that there is no significant interaction between the drug and excipients. The XRPD analysis confirmed formation of a solid solution inside the compact matrix. The tabletting properties of the liquisolid compacts were within the acceptable limits. Liquisolid compacts demonstrated significantly higher drug release rates than those of conventional and marketed tablet due to increasing wetting properties and surface area of the drug. This study shows that liquisolid technique is a promising alternative for improvement of the dissolution rate of water insoluble drug.

LIQUISOLID TECHNIQUE: AN APPROACH FOR ENHANCEMENT OF SOLUBILITY

Liquisolid technique is also known as powder solution technology. It is the technique which deals with the solubility enhancement of poorly soluble drugs. As these days there are many drugs in the market with poor solubility which leads to poor dissolution and bioavailability, so solubility is becoming rate limiting factor in the development of new drugs. To overcome this problem there are many techniques but liquisolid technique is most promising technique which is discussed in this article. Liquisolid is mainly composed of drug, non volatile solvent, carrier material, coating material, and disintegrant. In liquisolid technique carrier and coating material which should be in the ratio of 20:1 is mixed into the non volatile solvent and then disintegrant is added and final material is compressed into tablets. Hence, the liquisolid technology allows the transformation of liquid systems into solid drug delivery systems. Both immediate and sustained release of drug can also be achieved with the help of liquisolid technique. For sustained release of drug hydrophilic polymer like Hydroxy Propyl Methyl Cellulose can be the best option. The purpose of this article is to describe about the liquisolid technique like basics, classification, preformulation studies, characterisation, precompression studies, formulation of tablet, postcompression studies, advantages, disadvantages, applications.

Design and Technology of Liquisolid Compacts

During the emergence of a new drug it is very important to ensure its systemic bioavailability. Majority of the drugs in the developmental pipelines confronts with the problem of poor solubility; which will result in reduced dissolution rate there by hampering its bioavailability. Here comes the need of liquisolid technique which is a novel and promising approach to overcome these consequences. This technique utilizes the powder solution technology which is based upon the dissolution of the insoluble drug in the nonvolatile solvent and admixture of drug loaded solutions with appropriate carrier and coating materials to convert into acceptably flowing and compressible powders. The liquisolid technology can also be used both for the enhancement and the retardation of drug release by suitably altering the adjuvants. This aricle highlights the relevancy, formulation and designing of the liquisolid systems.

Spironolactone release from liquisolid formulations prepared with Capryol™ 90, Solutol® HS-15 and Kollicoat® SR 30 D as non-volatile liquid vehicles

The purpose of the study is to enhance dissolution of spironolactone as a model hydrophobic drug through application of liquisolid technology. Spironolactone is prepared as liquisolid formulations, and its dissolution property is evaluated and compared to that of conventional spironolactone tablets and pure spironolactone. Three non-volatile liquid vehicles were used in the design of spironolactone liquisolid formulations, Capryol™ 90, Synperonic® PE/L61 in combination with Solutol® HS-15 at a ratio of 1:1, and Kollicoat® SR 30 D. Spironolactone liquisolid formulations were tested according to British Pharmacopoeia (BP) quality control tests. Furthermore, the prepared liquisolid powder formulations were evaluated via differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) and scanning electron microscopy. Also, liquisolid formulations were subjected to testing of storage stability at high relative humidity. The results indicated that most of liquisolid tablets met the BP requirements. Dissolution results indicate that release of spironolactone was significantly increased (P<0.05) through liquisolid formulations, compared to pure drug. Liquisolid powder formulations formulated from a combination of Synperonic® PE/L61–Solutol® HS-15 showed highest dissolution. DSC thermograms from liquisolid formulations revealed that drug endothermic peak was disappeared after processing. Dissolution, DSC and FT-IR data after storage demonstrated that there were no significant changes in the formulations after storage. In conclusion, the liquid vehicles used within spironolactone liquisolid formulations enhanced drug dissolution rate.

Preparation and comparative evaluation of liquisolid compacts and solid dispersions of Valsartan

The aim of the present study was to increase the solubility of a poorly water soluble BCS class II drug, valsartan. Liquisolid technology and solid dispersion by kneading method were techniques used to improve the solubility of the drug by using non-volatile solvents and some hydrophilic carriers. Liquisolid compacts were prepared by dissolving the drug in suitable non volatile solvents. The various non volatile solvents used were PG, PEG, and glycerine. The carrier coating materials play an important role in improving the solubility of the drug. The dissolution rate of the drug was increased by using propylene glycol as non-volatile solvent at 20:1 ratio of carrier to coating material. Solid dispersion by kneading method were another attempt to improve solubility the various carrier materials used were PVP K 30, PEG 6000 and mannitol, these carriers are used in various ratios to improve its solubility. The dissolution rate of drug using solid dispersion kneading method with mannitol was increased at 1:3 ratio. The DSC and FTIR studies revealed no drug excipients interactions, whereas XRD revealed the reduced crystalinity of drug, which showed enhanced solubility. From the results it was concluded that the liquisolid compacts enhanced the solubility of valsartan in comparison to traditional solid dispersion method.DOI: http://dx.doi.org/10.3329/sjps.v4i2.10440 S. J. Pharm. Sci. 4(2) 2011: 48-57

Assessment of dissolution profile of Pantoprazole tablets available in Bangladesh

The aim of the present study was to increase the solubility of a poorly water soluble BCS class II drug, valsartan. Liquisolid technology and solid dispersion by kneading method were techniques used to improve the solubility of the drug by using non-volatile solvents and some hydrophilic carriers. Liquisolid compacts were prepared by dissolving the drug in suitable non volatile solvents. The various non volatile solvents used were PG, PEG, and glycerine. The carrier coating materials play an important role in improving the solubility of the drug. The dissolution rate of the drug was increased by using propylene glycol as non-volatile solvent at 20:1 ratio of carrier to coating material. Solid dispersion by kneading method were another attempt to improve solubility the various carrier materials used were PVP K 30, PEG 6000 and mannitol, these carriers are used in various ratios to improve its solubility. The dissolution rate of drug using solid dispersion kneading method with mannitol was increased at 1:3 ratio. The DSC and FTIR studies revealed no drug excipients interactions, whereas XRD revealed the reduced crystalinity of drug, which showed enhanced solubility. From the results it was concluded that the liquisolid compacts enhanced the solubility of valsartan in comparison to traditional solid dispersion method.DOI: http://dx.doi.org/10.3329/sjps.v4i2.10441 S. J. Pharm. Sci. 4(2) 2011: 58-62

Suitability of various excipients as carrier and coating materials for liquisolid compacts

Context: The liquisolid technology is a promising technique for the release enhancement of poorly soluble drugs. With this approach, liquids such as solutions or suspensions of poorly soluble drugs in a non-volatile liquid vehicle are transformed into acceptably flowing and compressible powders. As fast-release liquisolid compacts require a high amount of liquid vehicle, more effective tableting excipients for liquid adsorption are needed to reduce tablet weight.Objective: The aim of this study was to investigate the suitability of various novel tableting excipients as carrier and coating materials for liquisolid compacts.Materials and methods: Liquisolid compacts containing the liquid drug tocopherol acetate (TA) as model drug and various excipients were prepared. The effect of liquid drug content on the flowability and tabletability of the liquisolid powder blends as well as the disintegration of the liquisolid compacts was studied. From this data, the maximum liquid adsorption capacity of the respective mixtures of carrier and coating materials could be determined.Results and discussion: The liquid adsorption capacity depends on the specific surface area of the investigated excipients. Fujicalin® and especially Neusilin® are more effective carrier materials for liquid adsorption than Avicel®, which is often used for liquisolid systems. Moreover, Florite® and Neusilin® turned out to be more suitable as coating materials than the commonly used Aerosil® due to their better tableting properties.Conclusion: If Neusilin® is used as carrier and coating material instead of Avicel® (carrier material) and Aerosil® (coating material), the TA adsorption capacity is increased by a factor of 7.

Drug release from liquisolid systems: speed it up, slow it down

Introduction: Today, the properties of many new chemical entities have shifted towards higher molecular weights and this in turn increases the lipophilicity hence decreasing aqueous solubility. The low solubility of drugs usually has in vivo consequences such as low bioavailability, increased chance of food effect and incomplete release from the dosage form.Areas covered: The present review discusses the advantages of the liquisolid technology in formulation design of poorly water soluble drugs for dissolution enhancement and highly water soluble drugs for slow release pattern.Expert opinion: With the advent of high throughput screening and combinatorial chemistry, it has been shown that most of the new chemical entities have a high lipophilicity and poor aqueous solubility, hence poor bioavailability. In order to improve the bioavailability, the release rate of these drugs should be enhanced. Although there are multiple technologies to tackle this issue, they are not cost effective due to the involvement of sophisticated machinery, advanced preparation techniques and complicated technology. As the liquisolid technology uses a similar production process as the conventional tablets, this technology to improve the release rate of poorly water soluble drugs will be cost effective. This technology also has the capability to slow down drug release and allows preparing sustained release tablets with zero order drug release pattern. The excipients required for this technology are conventional and commonly available in the market. The technology is in the early stages of its development with extensive research currently focused on. It is envisaged that the liquisolid compacts could play a major role in the next generation of tablets.

Liquisolid technology for dissolution rate enhancement or sustained release

Importance of the field: Most of the drugs that have been invented are of BCS Class II. Therefore, dissolution rate enhancement is the key aspect for absorption of these drugs. Liquisolid technology is very efficient in the dissolution rate enhancement of these drugs. Moreover, use of other polymers such as Eudragit and hydroxypropyl methylcellulose in the liquisolid approach can cause sustained release of drugs. This review focuses on the formulation approaches of liquisolid tablets or compacts along with its fundamental principles.Areas covered in this review: The review focuses on the developments in liquisolid technology from 1998 to 2009 with in vitro and in vivo performance of the dosage forms prepared using this technology.What the reader will gain: Benefits of this review include a concise evaluation of this technology by focusing on the scope of future developments to be done using this technique.Take home message: Liquisolid technology, the next generation of powder solution technology, can be helpful for enhancing dissolution rates of poorly water-soluble drugs as well as effective at sustaining drug release.