Solid dispersion

Pravastatin is widely used antihyperlipidemic drug, exhibits poor aqueous solubility and low dissolution rate, which limit its oral bioavailability. The present study focuses on the design, development and evaluation of the pravastatin solid dispersion tablets prepared by the direct comparison method to enhance dissolution efficiency. Solid dispersions were characterized by using the FTIR, Melting point Analysis, and calibration studies, while the flow properties such as bulk density, tapped density, angle of repose, Carr’s index were determined to ensure suitable compressibility.

Donepezil HCl is an anti Alzheimer’s drug of the acetylcholinesterase class. It is widely used in treatment of Alzheimer’s disease and to control dementia. Orodispersable Tablets (ODTs) containing Donepezil HCl was prepared using super-disintegrant (croscarmellose sodium) by direct compression method using solid dispersion technique to mask the taste of the drug. Three types of excipient were used to mask the taste namely Mannitol, PEG 6000 and PVP K 30 in three different ratios (i.e. 1:1, 1:2, 1:3) using solvent evaporation method in solid dispersion technique. The optimized formulation shows the minimum disintegration time of 50 sec and release maximum amount of drug in 10 min. Short term stability studies indicated no significant changes in hardness, friability, in vitro disintegration time, drug content and in vitro drug release.

Lornoxicam is a non steroidal anti-inflammatory drug (NSAID) of the oxicam class. It belongs to BCS class II substance with low solubility and high permeability. The aim of current research is to formulate solid dispersion incorporated Fast disintegrating tablets of Lornoxicam to enhance the dissolution rate and aqueous solubility and to enable faster onset of action. Solid dispersions are prepared with polymers like Kolliwax GMS, Soluplus and HPMC in three different ratios 1:1:1, 1:2:1 and 1:3:1. Formulations were characterized for drug content studies, drug release studies and drug-polymer interactions using Fourier transform infrared spectroscopy (FTIR) spectrum. The solid dispersions can be evaluated by in-vitro dissolution studies. The optimized solid dispersion SD9 was further used to prepare fast disintegrating tablet by direct compression method using 33 Response surface method (3 variables and 3 levels of superdisintegrants) by using Design of experiment software with superdisintegrants like locust bean gum, gum karaya, Plant ago ovata. The values of pre-compression parameters evaluated were within prescribed limits that indicated good free flowing properties. The data obtained of post-compression parameters such as weight variation, hardness, friability, content uniformity, disintegration time (33 sec) and percentage drug release was maximum in LF24(99.21±1.87%) and was found to superior over conventional formulation. It can be concluded that fast disintegrating tablets using Lornoxicam solid dispersion could be used to improve better patient compliance in the effective management of pain and inflammation.

The present study involved preparation of solid dispersions of Olmesartan medoxomil to improve the aqueous solubility and dissolution rate in order to enhance bioavailability. Olmesartan is a BCS Class II anti-hypertensive drug, having low aqueous solubility and low bioavailability of 26%.  In the present study, solid dispersions of Olmesartan with different carriers like Poloxamer 407, PEG 4000  and crospovidone in different ratios (1 : 1, 1 : 2, 1 : 3, 1 : 4) were prepared by solvent evaporation method.  The formulations were further characterized for percentage yield, drug content, in vitro release study,  and stability study. In vitro release studies revealed that the solid dispersions prepared by solvent evaporation method crospovidone (1 : 4) was considered as the best formulation because of its faster drug release among all formulations.  Infrared spectroscopy (IR) studies revealed that no interactions exist between drug and polymer. Powder X-ray diffraction studies showed a significant decrease in crystalline nature of drug in solid dispersions. In conclusion, solid dispersions of Olmesartan in crospovidone (1:4) have shown to be a promising approach to enhance the bioavailability of Olmesartan.

The present work aimed at preparing fast dissolving buccal films of Isradipine solid dispersion, since Isradipine is a poorly soluble drug and the rate of absorption is often controlled by the rate of dissolution. The purpose of developing a dosage form for a very quick onset of action and for improved bioavailability along with the convenience of administration i.e. without the problem of swallowing and using water. The rate of dissolution can be increased by incorporating the drug in a fast dissolving buccal film as a solid dispersion that prepared using polyethylene glycol (PEG4000) or polyvinyl pyrrolidone (PVP k30). The fast dissolving films of Isradipine solid dispersion were prepared by solvent casting method using Lycoat RS720 polymer and glycerin as a plasticizer. The formulated films were evaluated for their physiochemical parameters like disintegration time, surface pH, thickness & weight of the films, percent moisture absorption, folding endurance, drug content and stability testing. Different factors affecting the dissolution rate of solid dispersion and fast dissolving film were studied. It was seen that as the ratio of drug to PEG4000 or PVP k30 in solid dispersion increased the release rate increased and the solvent evaporation method gave greater drug release than fusion method. In fast dissolving film it was seen that as the concentration of Lycoat RS720 increased the release rate decreased and as the concentration of glycerin increased the release rate increased. Formulation F6 showed 98.89% drug release from the film within 7 minutes which is an essential character for faster absorption.

Quetiapine Fumarate is a antipsychotic agent indicated for treatment of Schizophrenia and Bipolar disorder. Quetiapine Fumarate is BCS Class II drug which is  poorly water soluble and may show dissolution limited absorption. Hence to improve dissolution rate and bioavailability, Solid dispersion of Quetiapine Fumarate by Solvent Evaporation method were prepared using 1:1, 1:2, 1:3, 1:4 and 1:5 ratios of Quetiapine Fumarate and Polyvinyl Pyrrolidone K30(PVP K30). The solid dispersion (SD) was characterized for physical appearance, solubility, FTIR, DSC, XRD studies and in vitro dissolution studies. FTIR study revealed that there was no drug-carrier chemical interaction in Solid dispersion. DSC studies revealed that, the peak observed for the melting of Quetiapine Fumarate is found to be absent in SD with PVP K30 carrier. XRD studies suggested that there has been a large change in the nature of Quetiapine Fumarate in the solid dispersion. Solubility of Quetiapine Fumarate from SD increased in distilled water. The drug content was found to be high and uniformly distributed in the formulation. The in vitro dissolution studies were carried using USP type II (paddle) type dissolution apparatus. The prepared Solid dispersion showed marked increase in the dissolution rate of Quetiapine Fumarate than that of pure drug. The Solid dispersion with PVP K30 (1:5) by Solvent evaporation method showed faster dissolution rate as compared to other Solid dispersions. It is concluded that dissolution of the Quetiapine Fumarate could be improved by the Solid dispersion.

Fast dissolving tablets are the tablets which dissolves rapidly and shows higher bioavailability than conventional tablets. The concept of formulating Fast dissolving tablets of Carvedilol (antihypertensive drug) offer suitable and practical approach in serving the desired objective of faster disintegration and dissolution characteristic with increase bioavailability and to know the effects of two natural superdisintegrants (Hibiscus Rosa, Linseed Mucilage). In the present work solid dispersion were prepared by solvent evaporation method for improving the bioavailability with beta cyclodextrin as a carrier to increase the solubility of the drug. And after compressing the tablet , heat is applied to create pores in tablet as it contain camphor as subliming agent which increase the porosity and cause faster release of drug from the tablet. Comparison between these two natural superdisintegrants was done by taking different ratios individually and in combination. Combination of these two superdisintegrants shows synergistic effect when it is compared to individually. Prepared tablets were subjected to different evaluation parameters such as hardness, friability, weight variation, drug content uniformity, in vitro disintegration time, wetting time, in vitro dissolution studies and stability studies are carried out by using the best formulation. From all the formulations prepared and tested, F11 was found to be the best formulation.

Fast dissolving tablets are the tablet which dissolves rapidly and shows higher bioavailability than conventional tablets. The concept of formulating Fast dissolving tablets of Famotidine (H2 –receptor antagonist) offer suitable and practical approach in serving the desired objective of faster disintegration and dissolution characteristic with increase bioavailability and to know the effects of two synthetic superdisintegrant (Croscarmellose sodium and Sodium starch glycolate). In the present work two methods of solid dispersion were compared for improving the bioavailability i.e. Solvent Evaporation and Fusion method with PVP K30 as a carrier to increase the solubility of the drug. Comparison between these two synthetic superdisintegrant was done by taking different ratios and in combination. Three different combination of these superdisintegrant shows synergistic effect when it is compared to individual. Prepared tablets were subjected to different evaluation parameters such as hardness (2.84±0.15 kg/cm2 to 3.01±0.20 kg/cm2), friability (not more than 0.680±0.0173), weight variation (197.6±1.42 mg to 202.6±1.90 mg), drug content uniformity (97.84±0.35 to 100.23±0.71%), in vitro disintegration time (21.0±0.81 sec to 108.33±0.47 sec), wetting time (29.33±0.47 to 113.33±1.24 sec), in vitro dissolution studies and stability studies are carried out by using the best formulation. From all the formulations prepared and tested, F9 was found to the best formulation.

Fast dissolving tablets are the tablets which dissolves rapidly and shows higher bioavailability than conventional tablets. The concept of formulating Fast dissolving tablets of Loratadine (antiallergic drug) offer suitable and practical approach in serving the desired objective of faster disintegration and dissolution characteristic with increase bioavailability and to know the effects of three synthetic superdisintegrants (Crosscarmeloss sodium, Sodium starch glycolate and Crospovidone). In the present work two methods of solid dispersion were compared for improving the bioavailability i.e Solvent Evaporation and Fusion method with beta cyclodextrin as a carrier to increase the solubility of the drug. Comparison between these three synthetic superdisintegrants was done by taking different ratios individually and in combination. Combination of these three superdisintegrants shows synergistic effect when it is compared to individually. Prepared tablets were subjected to different evaluation parameters such as hardness, thickness, friability, weight variation, drug content uniformity, in vitro disintegration time, wetting time, in vitro dissolution studies and stability studies are carried out by using the best formulation. From all the formulations prepared and evaluated F11 was found to the best formulation. Key words: Fast dissolving tablets, Solid dispersion, Crosscarmeloss sodium, Sodium starch glycolate, Crospovidone, Evaluation parameters.

In the present study, Solid Dispersion of Propranolol Hydrochloride were prepared using solvent evaporation technique using PEG 4000, PVP K-30 and PVA. However absolute bioavailability of Propranololo Hydrochloride is about 30% . To increase the solubility, solid dispersion was prepared. Preliminary solubility analysis was carried out for the selection of carriers and solid dispersion was prepared with PVA, PEG 4000, PVP-K30. These solid dispersions were analyzed for the solubility and In-vitro dissolution profile, solid dispersion of drug with PEG 4000 had shown enhanced solubility with improved dissolution rate. Further FTIR, DSC, SEM studies were carried out. Solid dispersion prepared with PEG 4000 shows the presence of amorphous form confirmed by the characterization study .The study also shows that dissolution rate of Propranolol Hydrochloride can be enhanced to considerable extent by solid dispersion technique with PEG 4000.