Polymer Hydroxypropyl Methylcellulose Research Articles

Influence of the pelletizing process parameters on the breakage behaviour of the received alumina oxide pellets

Pelletizing is a common optimization process of the mechanical properties of various powder materials. The improvement of flow behaviour, dosage and the increase of bulk density are only a few the goals that this size enlargement concedes. Anyway, the properties of the produced pellets depend on many factors, whose influence is not completely studied. In order to investigate the effect of process parameters on the mechanical strength of final products, industrially produced alumina oxide ( $${\gamma }$$ - $$\mathrm{Al}_{2}\mathrm{O}_{3})$$ granules as primary model particles were pelletized in a laboratory rotating pan-pelletizer (spheronizer). The processing time for all pelletizing batches was 20 min. Solution of viscoelastic polymer—hydroxypropyl methylcellulose was used as binder. Its concentration was increased until finding of the most suitable binder content for the model pellets. The rotational velocity of the pan-pelletizer was varied in order to find the optimal speed, which provides pellets with improved properties. The influence of the process parameters on the received pellet product properties like density and porosity, size distribution, breakage behaviour and breakage probability was also analysed. The solid bonds between the single primary particles were investigated using light and scanning electron microscope. The conclusions from the experimental work help us to understand the basics of pelletizing processes and tend to develop and facilitate the operating principle with particle populations in science and industry. The result should provide base for carrying out of Discrete Element Method simulations, which should enlighten the process of irregular pellet breakage.

Electrospun amorphous medicated nanocomposites fabricated using a Teflon-based concentric spinneret

AbstractFacile methods to improve the dissolution rate of poorly water-soluble drugs are highly sought after. In this study, a modified coaxial electrospinning process was exploited to create medicated amorphous nanocomposites, an approach characterized by the application of a Teflon-coated coaxial spinneret. The hydrophilic polymer hydroxypropyl methylcellulose and the active ingredient tamoxifen citrate (TAM) were selected as the drug carrier and model drug, respectively. Their electrospun nanocomposites showed linear morphology with the drug presented in an amorphous state. The loaded cargoes could be released from the nanocomposites simultaneously when they were placed in the dissolution media, showing faster dissolution rates than their counterparts (physical mixtures). Based on the reasonable application of the polymeric carrier, the reported protocols not only provided an approach to enhance the dissolution of poorly water-soluble drugs, but also exhibited a method to facilitate the implementation of coaxial electrospinning.

Shear Strength and Compression Coefficient for Conditioned Sand Subjected to Earth Chamber Stress Levels

Ground conditioning agents are often needed when performing earth pressure balance shield tunneling in sand soils due to its high internal friction, low plastic ductility, and low compressibility. In this work, vane shear and compression tests for standard sand were performed using a homemade test device, and three types of conditioning agents composed of foam, bentonite slurry, and polymer were used in the tests. The effects of the agents on shear strength and compressibility of the conditioned soils were investigated under a typical earth chamber stress level as high as 2 bar. The measured results show that foam does better in reducing shear strength and improving the compressibility of the conditioned soils than bentonite slurry and polymer. Significant increases in the compressibility of foam‐conditioned soils can be achieved using foam, and the shear strength of the conditioned sand can be decreased by more than 30% with an initial injection ratio of 40% foam. The bentonite‐ and polymer‐conditioned sands have similar compressibility. The HPMC (hydroxypropyl methylcellulose) polymer does better in decreasing the shear strength of the conditioned soils than other liquid soil conditioners. The influences of the device shear rate on the shear strength of the conditioned soils are also presented.

Matrix tablet-containing solid dispersion is not suitable for sustained release delivery of beclomethasone dipropionate

Objective: In the present study, an attempt was made to enhance the solubility of beclomethasone dipropionate by solid dispersion method followed by formulating and evaluating the sustained release matrix tablets-containing solid dispersion of beclomethasone dipropionate to overcome its lacuna of short elimination half-life. Materials and Methods: Solid dispersion was prepared by using β-cyclodextrin and polyethylene glycol 6000 as a carrier by physical mixture, solvent evaporation, and kneading methods and evaluated for percentage yield, drug content, and in vitro dissolution studies. The selected formulation of solid dispersion was subjected for preparation of sustained release tablets by direct compression method using matrix polymers hydroxypropyl methyl cellulose (HPMC) K 15 and guar gum and evaluated for thickness, weight variation, hardness, friability, drug content, and in vitro drug release studies. Results: The Fourier-transform infrared spectroscopy study revealed no interaction between the drug and polymers. The powder possessed good flow properties before the compression. The results of in vitro dissolution studies were not satisfactory to achieve sustained release of the drug from the formulation. Conclusion: The aim was to formulate sustained release matrix tablets of beclomethasone dipropionate which was not achieved, hence it was concluded that the matrix tablets prepared using HPMC K 15 and guar gum-containing solid dispersion of beclomethasone dipropionate is not a suitable approach for the sustained release delivery of beclomethasone dipropionate.

Development and evaluation of multiparticulate biphasic system for the treatment of circadian diseases

Multiparticulate systems have biopharmaceutical advantages when compared to the monolithic systems, once they allow different patterns of drug release and can be used in different treatments. The aim of the present work was to develop a biphasic controlled release delivery system, using propranolol hydrochloride (PROP) that can be used for the treatment of circadian diseases. This system was obtained by the combination of cellulosic polymers hydroxypropyl methylcellulose (HPMC) and ethylcellulose (EC) in a 2² factorial experimental design, which allowed the optimization of the development stage. The pellets produced and used in biphasic formulations were evaluated for physical and chemical characteristics and presented acceptable results. The immediate fraction obtained showed the complete release in 30 min while the others kept the release of the drug for 24 h. This study showed that the combination of beads with different releasing characteristics allowed to obtain different release profiles, which can be modulated according to the pathological needs, especially with regard to circadian diseases that suffer alterations throughout the day.

DEVELOPMENT AND EVALUATION OF GASTRORETENTIVE FLOATING TABLETS OF A QUINAPRIL HCL BY DIRECT COMPRESSION TECHNIQUE

Objective: The present study was undertaken with an objective to design, develop and evaluate gastro retentive floating tablets of an antihypertensive drug, quinapril HCl, which release the drug in a sustained manner over a period of 12 h.Methods: In this research work, we used hydrophilic polymer hydroxypropyl methylcellulose (HPMC K4M), the gas generating agent sodium bicarbonate and citric acid at different ratios for the preparation of tablets. A 32 factorial design was applied systematically; the amount of HPMC K4M (X1) and the amount of citric acid (X2) were selected as independent variables. The dependent variables chosen were percentage drug release at 6 h (Q6), percentage drug release at 12 h (Q12) and floating lag time. The high concentration of HPMC K4M and citric acid gives a sustained release for quinapril HCl floating tablets. The tablets were prepared by direct compression technique and evaluated for tablet thickness, hardness, weight variation, friability, floating lag time and In vitro drug release.Results: The In vitro drug release indicated the floating dosage forms showed slower release when the concentration of HPMC K4M increases. Formulation F4 having ratio 25:8 (HPMC K4M: citric acid) was considered as an optimised formulation which shows satisfactory sustained drug release and remained buoyant on the surface of the medium for more than 12 h. It can also conclude that floating drug delivery system of quinapril HCl can be successfully formulated as an approach to increase gastric residence time and thereby improving its bioavailability.Conclusion: The developed effervescent based floating tablets are a promising floating drug delivery system for oral sustained administration of quinapril HCl.

Peningkatan Laju Disolusi Ketoprofen Dengan Teknik Co-Grinding Menggunakan Polimer Hydroxypropyl Methylcellulose E6

Telah dilakukan peningkatan laju disolusi ketoprofen sebagai model zat aktif yang sukar larut air dengan teknik penggilingan bersama (co-grinding) dengan polimer hidrofilk hydroxypropyl methylcellulose E6 (HPMC) menggunakan alat mortar grinder. Tiga formula disiapkan dengan perbandingan zat aktif : polimer 1:2, 1:1, dan 2:1 (b/b), dan campuran fisik dibuat dengan menggunakan perbandingan 1:1 (b/b). Difraktogram sinar-X menunjukkan terjadinya penurunan intensitas puncak ketoprofen. Termogram DSC menunjukkan terjadinya penurunan titik leleh ketoprofen. Analisis FTIR menunjukkan tidak terdapat interaksi kimia antara zat aktif dengan polimer. Pada penelitian ini didapatkan bahwa kelarutan obat meningkat dengan meningkatnya konsentrasi polimer. Dispersi padat rasio 1:2 menunjukkan peningkatan kelarutan terbesar (6,5 kali). Tidak seperti kelarutan, laju disolusi ketoprofen meningkat dengan menurunnya kosentrasi polimer karena terbentuknya lapisan difusi yang tebal oleh polimer. Dispersi padat resio 2:1 menunjukkan peningkatan disolusi tertinggi (2,1 kali).

FORMULATION AND EVALUATION OF SIMVASTATIN GASTRORETENTIVE DRUG DELIVERY SYSTEM

Objective: The aim of this study was to formulate and evaluate gastro retentive drug delivery system (GRRDS) using an effervescent approach for simvastatin.Methods: Floating tablets were prepared using directly compressible polymers hydroxypropyl methylcellulose (HPMC) K100M, HPMC K4M and carboxymethylcellulose sodium (NaCMC). The prepared tablets were subjected to pre-formulation studies like Compressibility index, Hausner ratio and post compression parameters like buoyancy/floating test and In vitro dissolution study.Results: Drug-excipient compatibility studies performed with the help of FTIR instrument indicated that there were no interactions. The DSC thermogram of the formulations revealed that crystalline form of simvastatin existed in the formulation which was confirmed by X-ray powder diffraction. Dissolution studies indicated that there was a decrease in the drug release with an increase in the polymer viscosity. The tablets prepared with low-viscosity grade HPMC K4M exhibited short Buoyancy Lag Time and floated for a longer duration as compared with formulations containing high viscosity grade HPMC K100M. The ‘n’ value for dissolution studies for all the formulations was found to be in the range of 0.647 to 0.975 indicating non-Fickian or anomalous drug transport. Conclusion: The drug release rate and floating duration of tablets depended on the nature of the polymer and other added excipients. The release rate of the drug can be optimized by using different ratios of polymers and other excipients. The formulation F8 achieved the optimized batch and complied with all the properties of the tablets.

Solubility Enhancement of a BCS Class II Drug Using Granulated Fumed Silica as an Adsorbent

Aim: The aim of this study was to improve solubility and dissolution characteristics of Ibuprofen using granulated fumed silica (Aeroperl®300) as a carrier. Methods: Ibuprofen-silica complex was prepared by solvent evaporation technique using ethanol as the solvent. Formulation I and II consisted of polymers hydroxypropyl methylcellulose (HPMC E5) and Polyvinyl Pyrrolidone (PVP K-30) respectively. Each formulation was prepared using 1:1:1 and 1:1:2 ratio of drug, polymer and silica. Dried powder obtained was characterized using Differential Scanning Calorimetry (DSC), Powder X-Ray Diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and Polarized Light Microscopy (PLM). In-vitro dissolution studies were carried out using three different media including Phosphate buffer (pH 6.8), 0.1N Hydrochloric Acid (pH 1.2) and de-ionized water. Results: Drug loading up to 30% w/w was successfully achieved with 1:1:1 ratio formulations. Physical characterization data confirmed change of crystalline Ibuprofen into amorphous form after processing. Maximum solubility increment of 33-37% was achieved in Phosphate buffer with formulations II A and II B within the first 5 minutes of dissolution as compared to the control (pure drug). Conclusion: Enhancement in drug solubility and subsequent dissolution rate can be attributed to adsorption of amorphous drug molecules onto porous silica that readily desorb on contact with dissolution media. High porosity and huge surface area of silica makes it a potential candidate for improving delivery of poorly soluble drugs.

Formulation development and Evaluation of immediate and sustained release Bilayer Tablets Containing Amitriptyline HCl and Pregabalin for the treatment of Neuropathic Pain

The objective of proposed study was to prepare Bilayer tablet comprising Amitriptyline HCl (AMT) and pregabalin (PGB) for effective treatment of neuropathic pain. AMT was formulated as immediate release (IR) layer using disintegrants such as starch whereas PGB was formulated as sustained release (SR) layer using polymers hydroxypropyl methyl cellulose (HPMC) K100M for increasing with a view to deliver the drug at sustained manner in gastrointestinal tract and consequently into systemic circulation. Tablet blends were evaluated through various pre-compression tests, compressed by wet granulation method and evaluated. As disintegrant, starch at 14.70% concentration produced excellent results by immediately releasing AMT to exert its anti-depression and other additional beneficial effects. K100M grade of HPMC produced excellent SR efficiency at 1: 1 drug-polymer ratio whereas extended of the dosage form for long-lasting effect of the therapeutic agent. Final formulation released 98.92% drug in 45 min and 97.27% drug in 12 h, in vitro from respective layers. Pre-compression and post-compression parameters of optimized IR layer comprising AMT and SR layer comprising PGB exhibit satisfactory results. Bilayer tablet of AMT and PGB may prove to be very effective as a combination therapy for the treatment of neuropathic pain by sequential release of the drug.

Development and Characterization of Bilayer Sustained Release Tablets of Tramadol HCl and Acetaminophen

The aim of the present study was to develop bilayer sustained release tablets of to improve patient compliance of two drugs, tramadol and paracetamol. Immediate release layer contained both drugs tramadol hydrochloride and acetaminophen while the sustained release layer was designed only for the tramadol hydrochloride. Hydrophobic polymers Eudragit L-100, Eudragit S-100 and hydrophilic polymer hydroxy propyl methyl cellulose (HPMC K15), and wet granulation technique to produce bilayer matrix tablets. FTIR studies revealed no incompatibility among the ingredients. Out of 16 trials developed and characterized for weight variation, thickness, diameter, hardness, and friability, F16 showed promising result with immediate layer releasing drug 29% in 2 hours followed by sustained release 77% drug over 12 hours and followed zero order release. Therefore, bilayer sustained release tablets of tramadol with simultaneous loading of Paracetamol can be developed using Eudragit S-100 and hydroxyl propyl methylcellulose (HPMC K15) at equimolar content levels.

Development and optimization of pluronic® F127 and HPMC based thermosensitive gel for the skin delivery of metoprolol succinate

The aim of the present investigation was to prepare and optimize suitable combination of polymers hydroxypropyl methylcellulose (HPMC) and pluronic® F127 (PN F127) for the development of thermosensitive gel of Metoprolol succinate (MS) using central composite design (CCD). The effect of formulation factors (concentration of HPMC and PN F127) on responses such as cumulative percentage release (CPR) of MS, bioadhesive force (BF) and viscosity was measured statistically. Quadratic model was found to be best fit model among different models used in the study. The optimum conditions were found to be 0.92% of HPMC and 15% of PN F127. Under these conditions, the predicted CPR, BF and viscosity were found to be 84.94 μg/cm2, 41.56 gf and 48.94 Pa s, respectively. Ex vivo permeation of MS from optimized thermosensitive gel across abdominal skin of rat demonstrated highest flux (64.35 μg/cm2/h) for the gel formulation containing 1,8-cineole (5% w/w). The hypotensive activity was performed on normotensive rabbits and the results showed that the optimized formulation prolonged the activity up to 12 h. The above findings indicated that thermosensitive gel of MS for skin application exhibited strong potential against hypertension and expected to provide a better alternative to oral MS formulations.

Tailoring the mucoadhesive and sustained release characteristics of mesalamine loaded formulations for local treatment of distal forms of ulcerative colitis

Direct delivery of sustained therapeutic levels of mesalamine (MS) via rectal systems to manage distal forms of ulcerative colitis was studied. The High molecular weight hydroxypropyl methylcellulose (HPMC K4M) polymer was combined with hydrophilic surfactants to control polymer hydration process allowing optimization of the mucoadhesive and controlled drug release properties for the rectal systems. Physical mixtures and granules of MS and HPMC K4M were prepared and in vitro characterized using scanning electron microscope, differential scanning calorimetry and X-ray diffraction techniques. Rectal formulations were prepared utilizing MS-HPMC K4M mixtures in different polyethylene glycol (PEG) combination bases. The developed rectal formulations were investigated for physical, mucoadhesion, in-vitro drug release and swelling characteristics. Results revealed acceptable physical characteristics of the prepared formulations with good content uniformity and minimum weight variation. Sustained release patterns of MS form HPMC K4M based formulations were observed. Formulations prepared using high proportions of the polymer or PEG 400 showed higher extent of mucoadhesion, swelling and greatly extended drug release time. Efficacy of an optimized formulation was assessed using the acetic acid induced colitis model in rats and compared to a reference polymer-free formulation of the drug. Clinical evaluation included bleeding from rectum, consistency of animal stool and colon/body weight ratio. Furthermore, histopathological analysis was carried out to evaluate the degree of inflammation and mucosal damage. Overall results showed a significant enhancement in the clinical pictures and colon histopathology of animals treated by the sustained release mucoadhesive formulation compared to the reference polymer free formulation and the non-treated colitis group.

Supersaturation of zafirlukast in fasted and fed state intestinal media with and without precipitation inhibitors

Poor water solubility is a bottle neck in the development of many new drug candidates, and understanding and circumventing this is essential for a more effective drug development. Zafirlukast (ZA) is a leukotriene antagonist marketed for the treatment of asthma (Accolate®). ZA is poorly water soluble, and is formulated in an amorphous form (aZA) to improve its solubility and oral bioavailability. It has been shown that upon dissolution of aZa, the concentration of ZA in solution is supersaturated with respect to its stable crystalline form (ZA monohydrate), and thus, in theory, the bioavailability increases upon amorphization of ZA. The polymers hydroxypropylmethylcellulose (HPMC) and polyvinylpyrrolidone (PVP), often used as stabilizers of the supersaturated state, are in the excipient list of Accolate®. It is not recommended to take Accolate® with food, as this reduces the bioavailability by 40%.The aim of this study was to investigate the effect of simulated fasted and fed state intestinal media as well as the effect of HPMC and PVP on the supersaturation and precipitation of ZA in vitro.Supersaturation of aZA was studied in vitro in a small scale setup using the μDiss Profiler™. Several media were used for this study: One medium simulating the fasted state intestinal fluids and three media simulating different fed state intestinal fluids. Solid state changes of the drug were investigated by small angle x-ray scattering. The duration wherein aZA was maintained at a supersaturated state was prolonged in the presence of HPMC and lasted more than 20h in the presence of PVP in a fasted state intestinal medium. The presence of PVP increased the concentration of drug dissolved in the supersaturated state. The duration of supersaturation was shorter in fed than in a fasted state simulated intestinal media, but the concentration during supersaturation was higher. It was thus not possible to predict any positive or negative food effects from the dissolution/precipitation curves from different media. Lipolysis products in the fed state simulated media seemed to cause both a negative effect on the duration of supersaturation, and an increased drug concentration during supersaturation. In contrast, when testing the effect of a fed state simulated medium compared to the fasted state medium, in the presence of PVP, a clear negative effect was seen on the dissolution/precipitation curved of the fed state medium. The drug concentration during supersaturation was marginally different in the two media, but a precipitation of ZA was seen in the fed state medium, which was not observed in the fasted state medium. Solid state transformation from aZA to ZA monohydrate (mhZA) upon precipitation of the supersaturated solutions was confirmed by small angle x-ray scattering. All of these results can explain the described in vivo behavior of ZA. For ZA simple dissolution experiments in vitro can be used to examine supersaturation, effectiveness of PI and potential food effects on these.

Effect of polymer type and drug dose on the in vitro and in vivo behavior of amorphous solid dispersions

This study investigated the non-sink in vitro dissolution behavior and in vivo performance in rats of celecoxib (CCX) amorphous solid dispersions with polyvinyl acetate (PVA), polyvinylpyrrolidone (PVP) and hydroxypropyl methylcellulose (HPMC) at different drug doses. Both in vitro and in vivo, the amorphous solid dispersions with the hydrophilic polymers PVP and HPMC led to higher areas under both, the in vitro dissolution and the plasma concentration–time curves (AUC) compared to crystalline and amorphous CCX for all doses. In contrast, the amorphous solid dispersion with the hydrophobic polymer PVA showed a lower AUC both in vitro and in vivo than crystalline CCX. For crystalline CCX and CCX:PVA, the in vitro AUC was limited by the low solubility of the drug and the slow release of the drug from the hydrophobic polymer, respectively. For the supersaturating formulations, amorphous CCX, CCX:PVP and CCX:HPMC, the in vitro performance was mainly dependent on the dissolution rate and precipitation/crystallization inhibition of the polymer. As expected, the crystallization tendency increased with increasing dose, and therefore the in vitro AUCs did not increase proportionally with dose. Even though the in vivo AUC for all formulations increased with increasing dose, the relative bioavailability decreased significantly, indicating that the supersaturating formulations also crystallized in vivo and that the absorption of CCX was solubility-limited. These findings underline the importance of evaluating relevant in vitro doses, in order to rationally assess the performance of amorphous solid dispersions and avoid confusion in early in vivo studies.

Piroxicam /β-cyclodextrin complex included in cellulose derivatives-based matrix microspheres as new solid dispersion-controlled release formulations

AbstractNew formulations capable to enhance piroxicam (PRX) water solubility and at the same time to control and adjust its release have been developed. For this purpose, two methods have been used and combined to achieve this goal, namely complexation and microencapsulation by O/W emulsion solvent evaporation. In order to modify the drug release, first, microparticles composed of pure PRX and ethylcellulose (EC) or mixtures of EC and hydroxypropylmethylcellulose (HPMC) were prepared, and then, other micropaticles containing the,β-cyclodextrin/piroxicam (,β-CD/PRX) complex obtained by the solvent evaporation technique and EC or a mixture of EC and HPMC were produced and tested. These formulations were characterized by FT-IR, XRD, optical microscopy, and SEM methods. Drug dissolution tests were carried out in acidic media at pH = 1.2 and 37 °C. Depending on the microparticles composition, their size (dio) ranged between 49 pm and 121 pm and PRXioaded varied from 10.8 % to 27.7 %. The effect of complexation and HPMC polymer on the drug release was investigated; the results demonstrated that the Higuchi’s release constant significantly increased when using the EC/HPMC mixture as a matrix with pure PRX or only EC as a matrix with the ,β-CD/PRX complex. The results are remarkably promising since the combination of these processes provided new SD-CR formulations of piroxicam which enabled simultaneous enhancement and control of its release from the carriers.

Preparation and characterization of gatifloxacin-loaded sodium alginate hydrogel membranes supplemented with hydroxypropyl methylcellulose and hydroxypropyl cellulose polymers for wound dressing.

Introduction:The aim of this study is to evaluate gatifloxacin-loaded sodium alginate hydrogel membranes, supplemented with glycerol (a plasticizer), glutaraldehyde (a cross-linking agent), and hydroxypropyl methylcellulose (HPMC) or hydroxypropyl cellulose (HPC) polymers, as potential wound dressing materials based on their physicochemical properties and the sustain-release phenomenon.Materials and Methods:The physicochemical properties of the prepared hydrogel membranes were evaluated by several methods including Fourier transform infrared and differential scanning calorimetry. Different techniques were used to assess the swelling behavior, tensile strength and elongation, % moisture absorption, % moisture loss, water vapor transmission rate (WVTR), and microbial penetration for the hydrogel membranes. In vitro gatifloxacin release from the hydrogel membranes was examined using the United States Pharmacopeia XXIII dissolution apparatus. Four kinetics models (zero-order, first-order, Higuchi equation, and Korsmeyer-Peppas equation) were applied to study drug release kinetics.Results:The addition of glycerol, glutaraldehyde, HPMC, and HPC polymers resulted in a considerable increase in the tensile strength and flexibility/elasticity of the hydrogel membranes. WVTR results suggest that hydrated hydrogel membranes can facilitate water vapor transfer. None of the hydrogel membranes supported microbial growth. HPMC-treated and HPC-treated hydrogel membranes allow slow, but sustained, release of gatifloxacin for 48 h. Drug release kinetics revealed that both diffusion and dissolution play an important role in gatifloxacin release.Conclusions:Given their physicochemical properties and gatifloxacin release pattern, HPMC-treated and HPC-treated hydrogel membranes exhibit effective and sustained drug release. Furthermore, HPMC-treated and HPC-treated hydrogel membranes possess physiochemical properties that make them effective and safe wound dressing materials.

Development of a new single unit dosage form of propranolol HCl extended release non-effervescent floating matrix tablets: In vitro and in vivo evaluation

ABSTRACT The objective of the present investigation was to develop extended release non-effervescent floating matrix tablets of Propranolol Hydrochloride (PPH) to extend the gastric residence time (GRT) and prolong the drug release after oral administration. Different viscosity grades of Hydroxypropyl methylcellulose (HPMC) polymers such as HPMC K4M, HPMC K15M and HPMC K100M were used as drug release retardants. Glyceryl behinate (Compritol 888 ATO) and Glyceryl monosterate (Precirol ATO 5) were used as low density lipids in order to get the desired buoyancy over a prolonged period of time. The drug excipients compatibility study was carried out by using Differential Scanning Calorimetry (DSC). All the formulations were prepared by direct compression technique. The prepared tablets were evaluated for their physical characters, in vitro drug release and in vitro buoyancy. The release and floating property depends on the polymer type, polymer proportion, lipid type and lipid proportions. The drug release profiles of all the formulations were subjected to Zero order, First order, Higuchi and Peppas kinetic models, and the optimized formulation (F7) followed the Peppas model (R2= 0.987) with non-Fickian diffusion mechanism(n>0.5). The optimized formulation was subjected for in vivo radiographic studies in healthy human volunteers (n=3). These studies revealed a mean gastric residence time of 5 h (n=3). Key words: Propranolol HCl, Compritol 888 ATO, Precirol ATO 5, Non-effervescent, Floating drug delivery system and Gastric residence time.

Formulation and in vitro evaluation of a fast-disintegrating/sustained dual release bucoadhesive bilayer tablet of captopril for treatment of hypertension crises.

Hypertension crisis is one of the main health problems and its effective treatment is of high importance. For this purpose, fast-disintegrating and sustained release formulations of captopril, as a drug of choice, were prepared using conventional mucoadhesive polymers hydroxypropyl methylcellulose (HPMC), sodium carboxymethyl cellulose (Na-CMC), hydroxypropyl cellulose (HPC), Carbopol 934 (CP934) and sodium alginate (Na-alg). The optimum sustained release formulations were selected based on mean dissolution time (MDT). The swellability and mucoadhesive properties of selected formulations were assessed and compared. A direct relationship between swelling and release rates/adhesiveness of sustained release formulations was observed. The results showed that formulations containing combination of CP934 and cellulose-based polymers had the highest swellability, sustainability and adhesion strength. These formulations prolonged drug release up to 8 h showing good fitness to Korsemeyer-Peppas model. Moreover, the adopted fast-disintegrating tablet could release up to 100% of drug within 3 min in oral pH. Finally, a dual fast-disintegrating/sustained release bucoadhesive bilayer tablet consisting of optimized formulations was prepared releasing 30% of the drug initially within 15 min and the remaining up to 8 h which could be considered as an appropriate formulation for the treatment of hypertension crises.

Novel Controlled Release Polymer-Lipid Formulations Processed by Hot Melt Extrusion.

The aim of the study was to investigate the effect of novel polymer/lipid formulations on the dissolution rates of the water insoluble indomethacin (INM), co-processed by hot melt extrusion (HME). Formulations consisted of the hydrophilic hydroxypropyl methyl cellulose polymer (HPMCAS) and stearoyl macrogol-32 glycerides-Gelucire 50/13 (GLC) were processed with a twin screw extruder to produce solid dispersions. The extrudates characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and hot stage microscopy (HSM) indicated the presence of amorphous INM within the polymer/lipid matrices. In-line monitoring via near-infrared (NIR) spectroscopy revealed significant peak shifts indicating possible interactions and H-bonding formation between the drug and the polymer/lipid carriers. Furthermore, in vitro dissolution studies showed a synergistic effect of the polymer/lipid carrier with 2-h lag time in acidic media followed by enhanced INM dissolution rates at pH > 5.5.