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The aim of the present work was to develop pharmaceutical combinational dosage form for simultaneous treatment of patients with type 2 diabetes with at high-risk of coronary disease associated comorbidities. Metformin, an antidiabetic drug is used to treat the diabetic patient and combined with Simvastatin which is HMG-CoA reductase inihibitor drug to treat the high-risk coronary disease simultaneously. In this formulation, three batches were prepared by the direct compression method. Preformulation parameters such as identification, solubility, melting point, compatibility studies, Precompression parameters such as bulk density, tapped density, angle of repose, Hausner ratio, compressibility index, and Post-compression parameters like weight uniformity, hardness, drug content, thickness, in-vitro drug release. In-vitro drug release of all formulations, B1, B2, and B3 was carried out in 0.1N HCl for 2hrs and 10 hrs in phosphate buffer (pH 6.8) dissolution media. Among all the formulations, B3 was an optimized batch. B3 formulations showed drug release of 85% for Metformin Hydrochloride and 93% for Simvastatin over a period of 12hrs. [ABSTRACT FROM AUTHOR]

The study on the effect of polymer concentration on in vitro drug release profile revealed that there is a change in vitro drug release parameters (t50, t80, and MDT) with a change in polymer concentration. Fraction of HPMC K4M, HPMC K 100 M, and Ethyl Cellulose were required to be 15, 10, and 7 mg respectively for designing optimized batch F7. The release rate of Colchicine decreased proportionally with an increase in the concentration of ethyl Cellulose and HPMC K100 M. Also the high amount of HPMC K4M leads to the less initial release and sustain effect. A theoretical drug release profile was generated using pharmacokinetic parameters of Colchicine. The value of t50 and t80 of theoretical drug release profile was found to be 242 min and 529 min respectively. The similarity factor f2 was applied between the in vitro drug release profile of optimizing batches and theoretical profile, which indicate a decent similarity between all in vitro drug release profiles (f2 = 68.28 for F7). All the batches except F1shows the value of f2 value within a range. Batch F7 showed the highest f2 (f2 = 68.28) among all the batches and this similarity was also reflected in t50 (≈ 256 min) and t80 (≈ 554 min) values. A 23 full factorial design was applied to systemically optimize in vitro drug release profile. The HPMC K4M (X1), Concentration of HPMC K100 M (X2), and concentration of EC (X3) were selected as independent variables. The time required for 50% drug released (t50), the time required for 80% drug release (t80), similarity factor f2, and mean dissolution time (MDT) were selected as dependent variables. The results of full factorial design indicate that the HPMC K4M (X1), Concentration of HPMC K100 M (X2), and concentration of EC (X3) have a significant effect on in vitro drug release profile. To find out the release mechanism the in vitro release data were fitted in the Korsmeyer-Peppas equation. All Batches except F1 and F3 show Anomalous diffusion-controlled release (combined mechanism of diffusion and case II transport). [ABSTRACT FROM AUTHOR]

Bisoprolol is a type of antihypertensive drug (β-blocker). It is a poorly water-soluble and highly permeable drug that belongs to class II biopharmaceutical classification. This investigation represents the formulation development of bisoprolol to sustain the drug release. Different types of polymers like hypromellose, xanthan gum, avicel, poly ethylene glycol (PEG) were used in this study. Three different formulations were developed by using different excipients at various ratios. The granules were evaluated for bulk density, tapped density, flow property whereas tablets were evaluated for thickness, hardness, weight variation, compressibility index, uniformity of content, disintegration time, and drug release profile. The concentration of the diffused drug was measured using a UV-visible spectrophotometer at λmax= 225 nm. Granules showed good flow ability and all the formulations passed the quality. Among all the formulations, F-2 and F-3 showed better efficiency. PEG along with hypermellose, and guar gum showed a good combination for sustaining the drug release. [ABSTRACT FROM AUTHOR]

The present investigation of this study was to develop Captopril SR matrix tablets that provide complete drug release that starts in the stomach to rapidly alleviate the symptoms and continues in the intestine to maintain its effect. Drug-polymer compatibility studies by FTIR gave confirmation about their purity and showed no interaction between drug and selected polymers. Various formulations were developed by using release rate controlling and gel-forming polymers like HPMC K100, ethyl cellulose and sodium CMC by direct compression method. Cellulose derivatives have been widely used in the formulation of hydrophilic matrix tablet for sustained drug delivery. From among all the developed formulations, F7 formulation sustained the drug release for longer period of time as compared to other formulations. So, F7 was selected as the best formulation. The best formulation was found to be stable during stability studies for two months. Thus, best formulation satisfied physicochemical parameters and in vitro drug release profile requirements for a sustained drug delivery system. [ABSTRACT FROM AUTHOR]

INTRODUCTION Domperidone is a unique compound with gastro kinetic and antiemetic effects. It is used in the management of disorder by impaired motility like gastroesophageal reflux (in some instances), gastroparesis, dyspepsia, heartburn, epigastric pain, nausea, vomiting, and colonic inertia. The sustained release system is a widely accepted approach for slow drug release over an extended period to address the challenges of conventional oral delivery, including dosing frequency, drug safety, and efficacy. The study aims to formulate a domperidone sustained release tablet and compare the dissolution rate with the marketed formulations. MATERIAL AND METHODS Sustained release matrix tablets of domperidone were prepared by wet granulation method using different polymers such as HPMC K4M, ethyl cellulose, Gum acacia. Pre-compression studies like angle of repose, bulk density, tapped density, Carr's index, and Hausner's ratio, and post-compression studies like weight variation, thickness, hardness, friability, drug content, and in-vitro drug release were evaluated. RESULTS The release profile of domperidone sustained-release tablets was studied spectrophotometrically. The in-vitro dissolution study suggests the minimum %-cumulative drug release with 98.33% in F5. The %-cumulative drug release was maximum in F3 with 99.69%. The in-vitro drug release of all the formulations was non-significant compared to the marketed formulation (p<0.05), exhibiting the sustained-release property by all the formulations. CONCLUSION The pre-compression study concludes the better flow property of the granules of different formulations. The sustained release domperidone tablets were prepared successfully by the wet granulation method. The post-compression parameters of different formulations were within the acceptable range. [ABSTRACT FROM AUTHOR]

Objectives: The objective of the current study was to formulate a sustained release (SR) formulation for pravastatin. Pravastatin is a lipid lowering, biopharmaceutical classification class-III agent. Materials and Methods: SR tablets of pravastatin were prepared using variable amounts of hydroxy methyl propyl cellulose (HPMC) K4M and sodium carboxy methyl cellulose in various proportions by direct compression in a 32 factorial design. The amounts of the polymers HPMC K4M and sodium carboxy methyl cellulose required to obtain prolonged release of drug were chosen as independent variables, X1 and X2, respectively, whereas times taken for 10%, 50%, 75%, and 90% drug release were chosen as dependent variables. Results: Nine formulations were developed and were checked using pharmacopoeial tests. The results showed that all the factorial batches were within the standard limits. The dissolution parameters of all formulations were subjected to kinetic fitting and various statistical parameters were determined. Polynomial equations were developed and verified for dependent variables. Formulation F5, containing 25 mg of HPMC K4M and 25 mg of sodium carboxy methyl cellulose, was the formulation most similar (similarity factor f2=89.559, difference factor f1=1.546) to the marketed product (Pravachol). Conclusion: The best formulation (F5) follows Higuchi's kinetics and non-Fickian diffusion zero order kinetics (n=1.083). [ABSTRACT FROM AUTHOR]

Blue emitting perovskite ink obtained from cesium lead halide quantum dots bearing chlorine (CsPbClxBr3−x, 0 < x ≤ 3) suffers from the low photoluminescence quantum yield and poor stability. Cesium lead bromine (CsPbBr3) quantum dots free of chlorine have more stable crystal structure and fewer crystal defects. Precise control of crystal sizes and surface passivation components of CsPbBr3 quantum dots is crucial for the best use of quantum confinement effect and blueshift of emission wavelength to blue region. Here, by polymerizing acrylamide under UV-light irradiation to form polymer gel networks in dimethyl sulfoxide (DMSO) with CsPbBr3 precursors and passivating agents trapped, we successfully prepared novel sustained release tablets with different shapes and sizes. Thanks to the limitation of the polymer networks on solvent releasing, the resulting CsPbBr3 quantum dots have the average size of 1.1 ± 0.2 nm. On the basis of the excellent quantum confinement effect and optimized surface passivation, the obtained PQD ink can emit high quality blue light for more than 6 weeks. This work elucidates a new and convenient technique to prepare blue emission perovskite quantum dots ink with high stability and photoluminescence quantum yield and provides a great potential technology for the preparation of perovskite optoelectronic devices. [ABSTRACT FROM AUTHOR]

The objective of present investigation is to design and characterise sustained release Simvastatin and immediate release of Labetalol HCl, a bilayer tablet. The combination therapy of Simvastatin and Labetalol HCl can be useful in severe cardiovascular disease such as hypertension, angina pectoris, congestive heart failure which may occur along with increasing cholesterol level in the blood, while this combination remain preferable choice to the patient as compared to single dosage form. The bi-layer tablet is suitable for sequential release of two drugs in combination which are compatible with each other. Objective of present investigation is to prepare bi-layer tablet in which one layer is sustained while another one is immediate release. For the preparation of bi-layer tablet, different super disintegrants like cross carmellose cellulose, micro crystalline cellulose is used for immediate release and HPMC and Carbapol as controlled release polymer. The pre-formulation parameter such as solubility, melting point, compatibility study (FTIR) were studied. Pre-compression parameter such as angle of repose, bulk density, tapped density, hausner's ratio and compressibility index were studied. The tablets were evaluated by physical and chemical parameters such as weight uniformity, hardness, thickness, diameter, friability, drug content, disintegration time and in-vitro drug release. The dissolution data were subjected to various release kinetic model to recognize the mechanism of drug release. [ABSTRACT FROM AUTHOR]

The objective of research was to explore the suitability of lipids like compritol 888 ATO and stearic acid as release retardant to develop sustained release (SR) tablets. The SR micromatrices of lipid (s) and glipizide were prepared (LM1- LM6) as intermediate product by fusion method and assessed for various pharmacotechnical properties. Micromatrices were formulated as SR tablets (F1-F6) by direct compression method and subjected to Pharmacopoeial and Non Pharmacopoeial tests. In vitro drug release behavior of SR tablets demonstrated incomplete release of drug from compitrol based formulations whereas stearic acid based formulations (F4-F6) released more than 90% drug in 12 h with F5 displaying maximum %CDR of 95.70 ± 0.78%. A t50% of 3 h exhibited by F5 was significantly lower (2.7 h) than of marketed formulation (Glytop SR® (t50% = 5.7 h)). Similarity and dissimilarity factor for F5, with reference to Glytop SR® was 21.65% and 26.34% respectively, suggesting F5 has potential to exercise better control on drug release. Scanning Electron Microscopy (SEM) revealed drug particles embedded in stearic acid micromatrices that were confirmed by The X-ray powder diffraction (XRPD) and simultaneously Diffuse Reflectance Infrared Fourier Transform (DRIFT) confirmed the stability of F5. Conclusively, stearic acid explored as a suitable lipidic release retardant for development of SR tablet of glipizide that were stable for the test period of 6 months.

Aceclofenac is a newer non-steroidal anti-inflammatory drug (NSAID's) with good analgesic and anti-rheumatic properties. In the present study five brands of marketed SR tablets of Aceclofenac were taken and subjected to evaluate the different parameters as well as to perform the bio-equivalence study of the same tablets. The preformulation studies were carried out first. The drug showed absorption maxima at 275 nm in phosphate buffer pH 7.4. The linearity were observed between 1-10 mcg/nm. The FTIR spectra of Aceclofenac also comply with the standard monographs and principle peaks were shown. After the preformulation studies of the drug, the tablets were evaluated for the uniformity of weight, hardness, friability, drug content and in-vitro release study. All tablets were found within the acceptance criteria as per the official standards. The in-vitro dissolution test was carried out for 12 hours using USP-2 (paddle) dissolution test apparatus at 50 rpm. All tablets have shown the excellent in-vitro release profile. The all marketed tablets released the drug in a sustained pathway. The Af4 marketed formulation showed the maximum cumulative drug release. On the basis of in-vitro release study, the all marketed formulation of aceclofenac were found to be bio-equivalent. [ABSTRACT FROM AUTHOR]

Objective: The purpose of the present research investigation was to formulate sustained release (SR) formulations for losartan potassium using 32 factorial designs. Methods: Losartan potassium is an antihypertensive agent, non-peptide angiotensin-II receptor (type AT1) blocker, and BCS class-III agent. SR tablet formulations of losartan potassium were formulated using variable quantities of hydroxymethyl propyl cellulose (HPMC) K100M and xanthan gum in combinations by direct compression technique. The amount of polymers, HPMC K100M, and xanthan gum required to achieve the drug release was selected as independent variables, X1 and X2, respectively, whereas time required to release 10% (t10%), 50% (t50%), 75% (t75%), and 90% (t90%) of drug from formulation was selected as dependent variables. Nine formulations were prepared and evaluated for various pharmacopoeial tests. Results: The results reveal that all formulations were found to be with in the pharmacopoeial limits and in vitro drug release profiles of all formulations were subjected to kinetic modeling. The statistical parameters such as intercept, slope, and correlation coefficient were determined. Polynomial equations were developed for dependent variables. Validity of developed polynomial equations was checked by designing two checkpoint formulations (C1 and C2). According to SUPAC guidelines, formulation (F4) containing mixture of 15% HPMC K100M and 20% xanthan gum is the most identical formulation (similarity factor f2 = 86.747, dissimilarity factor f1 = 1.760, and no significant difference, t = 0.0477) to marketed product (LOSACAR). Conclusion: Best Formulation F4 follows the first-order, Higuchi kinetics, and the mechanism of drug release was found to be non-Fickian diffusion anomalous transport (n = 0.825). [ABSTRACT FROM AUTHOR]

Purpose: The present study was explored to develop a sustained release matrix tablet of Indapamide, a low-dose thiazide-type diuretic, using hydroxylpropyl methylcellulose (Methocel K15MCR) in various proportions as release controlling factor. Methods: The tablets were formulated using direct compression method. The powers for tableting were evaluated for angle of response, loose bulk density, tapped bulk density, compressibility index, total porosity and drug content etc. The tablets were subjected to thickness, weight variation test, drug content, hardness, friability, and in vitro dissolution studies. Results: The granules showed satisfactory flow properties, compressibility index, and drug content. All the formulated tablets complies pharmacopoeia specifications. The release kinetics of the drug decreased exponentially with the addition of polymer concentration. Indapamide release rate was observed to be the highest with the lowest concentration of polymer used. The release mechanism was explored with zero order, first order, Higuchi and Krosmeyer equations. Stability tests of the drug showed no notable changes in the rate of drug release, related substances and drug content. Conclusion: In the context, it can be suggested that this formulation of sustained release Indapamide tablets can be marketed to treat patients with hypertension ensuring proper healthcare.

The aim of the present work was to develop once-daily sustained release microsponges formulations of Nicorandil, a potent potassium channel opener used in cardiovascular diseases and it has low oral bioavailability (70%) and half-life 1 h. So, it is good candidate for sustained release formulations based on microsponge technology. The microsponges were prepared by using quasi-emulsion solvent diffusion method. Scanning Electron Microscopy (SEM) revealed that the microsponges of nicorandil with Eudragit - RSPO and HPMC K100M were smooth, porous, glossy and discrete spherical. The actual drug content and encapsulation efficiency of batch M1 to M9 were obtained in range of 62.05 ± 0.31 to 80.69 ± 0.43 and 64.41 ± 1.71 to 70.58 ± 1.12, respectively. The microsponges formulations were subjected to in-vitro release studies and the results were evaluated kinetically and statically. The best fitted model was found to be Korsmeyer - Peppas model (R² = 0.9992) for M6 batch. The 'n' value for Korsmeyer - Peppas model was between 0.5 and 1.0 which is indicative of non-Fickian diffusion. Statistical analysis using ANOVA yielded a p value of 0.572 for all the formulations, indicating that there was no significant difference among them. [ABSTRACT FROM AUTHOR]

Polysaccharide gums because of their biocompatibility, biodegradability and non-immunogenic properties are considered as the best choice for preparing sustained release tablets as compared to their synthetic counterpart. The cross linking of natural gums in matrix tablets increase the sustained release property of matrix tablets. Isoniazid is a first line therapy of tuberculosis, belongs to BCS I with half-life of 3-4 hours. These characteristics make isoniazid a good candidate for sustained release dosage form. Karaya gum crossed linked with trisodium tri metaphosphate was used as release rate retardant for preparing isoniazid cross-linked matrix tablet. Total 8 sustained release formulations were prepared. Both granules and tablets were evaluated under in vitro condition against different parameters. Dissolution studies were performed with all eight formulations for 12 hours using USP apparatus I. Four formulations designated as F1, F2, F3, F4 have drug and karaya gum while other four formulations F5, F6, F7, F8 have drug and crossed linked polymer in ratios of 1:1, 1:2, 1:3 and 1:4 respectively. Dissolution data was analyzed by using different kinetic models. Best fit model for most efficient formulation was zero order while release mechanism was super case I. Formulation 8 showed sufficiently slow release kinetics and about 83% of drug was released in 10 hours, indicating that cross-linked karaya gum proved efficient in preparing sustained release tablets. [ABSTRACT FROM AUTHOR]

Matrix systems are the satisfactory platform for the sustained release system; as it is an approach in which the dissolved or dispersed drug is divided homogenously in an inert matrix. The inert matrix may be hydrophilic or hydrophobic. Sustained release is a mechanism used in oral dosage form to dissolve slowly and release a drug over time. Acarbose is a water-soluble drug. It is usually prescribed to patients who are diabetic or prone to diabetes. Development of gastro retentive doses form is required so as to enhance the retention of drug in the body, controlled release & to maintain uniform drug concentration in the body. Acarbose is an oral hypoglycemic agent which is reversible inhibitor of alpha-glucosidase enzymes in the brush border of small intestine and pancreatic alphaamylase. So as to develop a gastro retentive dosage form using Acarbose as an ideal candidate an attempt is made to formulate Acarbose as sustained release tablet using HPMC K100 M as polymer in various ratios. Cellulose derivatives have been extensively used in formulation of hydrophilic matrix tablet for sustained drug delivery. The present study was carried out to perform preformulation, formulation, assessment & study of release kinetics of Acarbose sustained release matrix tablet. Sustained release matrix tablet was successfully prepared by direct compression technique. The batch F5 showed the best results when compared with other batches prepared, with having drug content 98.40 %, cumulative % drug release 76.28 % up to 8 hours and hardness 5.7 Kg/cm³ & swelling index 131.06 ± 0.72 % which shows good swelling index and shows that the diffusion mechanism was followed. Release kinetics showed that the in-vitro release curve was fitted under Higuchi model having R2 value of 0.996 which was highest when compared to other models showed that the drug released from diffusion mechanism. [ABSTRACT FROM AUTHOR]

Purpose: To formulate matrix type sustained-release (SR) tablets of tizanidine hydrochloride (TH) for prolonged drug release and improvement in motor activity after spinal injuries. Methods: Matrix tablets were prepared by the wet granulation method using four polymers (hydroxyl propyl methyl cellulose [HPMC] K 100, ethyl cellulose [EC], guar gum, and polyvinylpyrrolidone (PVP K30) and characterized for hardness, friability, drug content, swelling, weight variation, in vitro drug release, and in vivo motor function activity using the spinal injury rat model. Results: All tablets showed good drug content, hardness, and other physicochemical properties. The tablet formulations showed a percent drug release ranging from 92.54 ± 1.02 to 98.56 ± 1.26 % at the end of 12 h. Using the spinal injury rat model, negative control had a motor activity of only 12.75 %, while F4 (containing HPMC, EC, and PVP) and F5 (containing EC, guar gum, and PVP) had motor activities of 62.25% and 57.5%, respectively, compared with 68.0 % for normal controls. Conclusion: SR matrix tablets of TH showed significant improvement in motor activity in post-traumatic spinal injury rat model. [ABSTRACT FROM AUTHOR]

Cefixime is an antibiotic useful for the treatment of a number of bacterial infections. It is a third generationcephalosporin. The bactericidal action of cephalosporin is due to the inhibition of cell wall synthesis. It binds to one of the penicillin binding proteins (PBPs) which inhibit the final transpeptidation step of the peptidoglycan synthesis in the bacterial cell wall, thus inhibiting biosynthesis and arresting cell wall assembly resulting in bacterial cell death. Recently biopolymer was used as material for conventional as well as novel dosage form development. The biopolymer was isolated from the seed of Glycine max (Soybean) by non solvent addition method. The merits of biopolymers have over synthetic polymers are low cost, natural origin, nontoxic, biocompatible, biodegradable, environmental friendly processing, local availability, better patient tolerance as well as public acceptance. The polymer were subjected to its physicochemical, phytochemical and micromeritic studies. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to prepare sustained release tablet of moisture sensitive drug like Ranitidine Hydrochloride for treatment of gastroesophageal reflux disease along with the improvement of moisture stability to get better therapeutic efficacy. Materials and Methods: Pan coating technique was used for coating of the tablet. Film coating was done using Eudragit RLPO and Eugragit EPO as coating polymer. 3 full factorial design was applied for optimization purpose, and 9 runs were conducted. In that Eudragit RLPO and Eudragit EPO taken as an independent variables and moisture gain and Cummulative Drug Release (CDR) were taken as dependent variables. Drug and excipient compatibility was done using differential scanning calorimetry and Fourier transform infrared spectroscopy study. The tablet was evaluated for precompression parameter and all postcompression parameter. Stability study was carried out at room temperature (30°C ± 2°C/65% ± 5% relative humidity). Final formulation was compared with marketed formulation RANTEC 300. Result: Tablets were passing out all precompression parameter along with postcompression parameter. Stability study shows that the parameter such as hardness, friability, and dissolution are in the range. Hence, there is no significant change shown after stability study. Our final formulation was compared with marketed formulation RANTEC 300 and result demonstrates that our final formulation have less moisture gain and give release up to 12 h. Conclusion: The result of present study demonstrates that final formulation has less moisture gain and getting desired CDR for sustained release of drug. On the basis of all study, it was concluded that the tablet was coated by combination of Eudragit RLPO 10% and Eudragit EPO 10% give better result. This formation provided promising approach for the drug release up to 12 h for moisture sensitive drug like ranitidine hydrochloride. [ABSTRACT FROM AUTHOR]

Purpose: The present study was explored to develop a sustained release matrix tablet of Indapamide, a low-dose thiazide-type diuretic, using hydroxylpropyl methylcellulose (Methocel K15MCR) in various proportions as release controlling factor. Methods: The tablets were formulated using direct compression method. The powers for tableting were evaluated for angle of response, loose bulk density, tapped bulk density, compressibility index, total porosity and drug content etc. The tablets were subjected to thickness, weight variation test, drug content, hardness, friability, and in vitro dissolution studies. Results: The granules showed satisfactory flow properties, compressibility index, and drug content. All the formulated tablets complies pharmacopoeia specifications. The release kinetics of the drug decreased exponentially with the addition of polymer concentration. Indapamide release rate was observed to be the highest with the lowest concentration of polymer used. The release mechanism was explored with zero order, first order, Higuchi and Krosmeyer equations. Stability tests of the drug showed no notable changes in the rate of drug release, related substances and drug content. Conclusion: In the context, it can be suggested that this formulation of sustained release Indapamide tablets can be marketed to treat patients with hypertension ensuring proper healthcare. [ABSTRACT FROM AUTHOR]

Recently, controlled release drug delivery has become the standards in the modern pharmaceutical design and intensive research has been undertaken in achieving much better drug product effectiveness, reliability and safety. Oral Extended release drug delivery medication will continue to account for the largest share of drug delivery systems. Hence, in this work to formulate tablets in order to avoid the first pass metabolism and increase the bioavailability. Hence in this work an attempt was made to formulate extended release system in order to achieve plasma concentration profile up to 24 hrs. The extended release formulations are the type of formulations which will improves the therapeutic index of drug concentration. These formulations make the drug available over extended time period after oral administration. The extended release product will optimize therapeutic effect and safety of a drug at the same time improving the patient convenience and compliance. Here an attempt was made to formulate the Delayed Drug release in to the systemic circulation. Which will give detailed information about the formulation and formulation requirements to develop the ideal Delayed drug release formulation. [ABSTRACT FROM AUTHOR]

Abstract: Sustained release (SR) tablets containing solid dispersions (SD) granules of a poorly water-soluble drug were prepared to investigate the controlled pH-independent release of the drug. Losartan potassium (LST), an anti-hypertensive agent was chosen as a model drug because of its pH-dependent solubility and short elimination half-life. Poloxamer 188 was used as an SD carrier. A free-flowing SD granule was prepared by adsorbing the melt of the drug and poloxamer 188 onto the surface of an adsorbent, Aerosil 300 (fumed silicon dioxide), followed by direct compression with polyethylene oxide (PEO, 5×106) to obtain an SD-loaded SR (SD-SR) matrix tablet. Differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) revealed partially amorphous structures of the drug in the SD granules. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) images indicated adsorption of SD granules onto the surface of the adsorbent. The SD granules dissolved completely within 10min, a dissolution rate much higher than that of pure LST. Moreover, pH-independent sustained release of LST from the SD-SR tablet was achieved for 2h in gastric fluid (pH 1.2) and for 10h in intestinal fluid (pH 6.8). A combination of SD techniques using surface adsorption and SR concepts is a promising approach to control the release rate of poorly water-soluble drugs in a pH-independent manner. [Copyright &y& Elsevier]

Abstract: Zein is an alcohol soluble protein of corn origin that exhibits hydrophobic properties. Pseudolatexes are colloidal dispersions containing spherical solid or semisolid particles less than 1μm in diameter and can be prepared from any existing thermoplastic water-insoluble polymer. The novel plasticized film-coating pseudolatex of zein was studied in formulation of sustained-release tablets containing very water-soluble drug. Film formation of plasticized aqueous dispersion was compared with film forming properties of plasticized organic solvent system (ethanol) of zein. The water vapor permeability (WVP), water uptake and erosion, and moisture sorption were evaluated with free films. The tablets containing metoprolol tartrate as a model drug were used in pan-coating experiments. Aqueous film coatings plasticized with PEG 400 exhibited very low water uptake. No significant difference in WVP, moisture sorption and erosion were found between aqueous films and organic solvent-based films of zein plasticized with PEG 400. The atomic force microscopy (AFM) images on microstructure of films showed that colloidal particle size of zein in the aqueous films was smaller than that observed in the solvent-based films. In addition, the aqueous-based films were more compact and smoother than the respective solvent-based films. The aqueous zein-coated tablets containing very water-soluble drug (metoprolol tartrate) exhibited clear sustained-release dissolution profiles in vitro, while the respective solvent-based film-coated tablets showed much faster drug release. Furthermore, aqueous zein-coated tablets had lower water absorption at high humidity conditions. In conclusion, the plasticized aqueous dispersion (pseudolatex) of zein can be used for moisture resistant film coating of sustained-release tablets containing very water-soluble drug. [Copyright &y& Elsevier]

The pharmacokinetics and bioequivalency of a newly developed sustained-release bupropion tablet was studied in six dogs after single oral administration and compared with a regular tablet (RT) in randomized two-period crossover design. A sensitive and rapid HPLC method was developed and validated for the quantitative determination of bupropion in dog plasma. The compound and the internal standard (I.S.) (hydroxyethylfludiazepam) were extracted from the plasma samples by liquid–liquid extraction. The extracts were analyzed by a reversed-phase HPLC with 50 mmol/l phosphate buffer (pH 5.5)–methanol (45:55, v/v) as the eluent. The assay was specific for bupropion. The calibration curves were linear in the range between 1 and 750 ng/ml. The validated lower limit of quantification was 1 ng/ml. The overall precision (expressed as R.S.D.) of quality controls were within 15%. The method was successfully applied to the bioequivalency study of bupropion in the two formulations. The Cmax of sustained-release tablet (ST) was significantly lower than that of the RT and the Tmax was significantly longer than that of the RT (P<0.05). The relative bioavailability of the ST was (99.1±1.51)%, the results of ANOVA and two one sided tests indicated that the new ST exhibited good sustained release properties and was bioequivalent to the RT. [Copyright &y& Elsevier]