Formulation and evaluation of Buccal mucoadhesive tablets of diclofenac sodium using 23 factorial designs

Buccal tablets

Diclofenac sodium

Drug release

Mucoadhesion

Mucoadhesive tablets

Release kinetics

Advanced subunit vaccine delivery technologies: From vaccine cascade obstacles to design strategies

Designing and manufacturing safe and effective vaccines is a crucial challenge for human health worldwide. Research on adjuvant-based subunit vaccines is increasingly being explored to meet clinical needs. Nevertheless, the adaptive immune responses of subunit vaccines are still unfavorable, which may partially be attributed to the immune cascade obstacles and unsatisfactory vaccine design. An extended understanding of the crosstalk between vaccine delivery strategies and immunological mechanisms could provide scientific insight to optimize antigen delivery and improve vaccination efficacy. In this review, we summarized the advanced subunit vaccine delivery technologies from the perspective of vaccine cascade obstacles after administration. The engineered subunit vaccines with lymph node and specific cell targeting ability, antigen cross-presentation, T cell activation properties, and tailorable antigen release patterns may achieve effective immune protection with high precision, efficiency, and stability. We hope this review can provide rational design principles and inspire the exploitation of future subunit vaccines.

Quality Control Study of Different Products from Famotidine Tablets in the Iraqi Market / Estudio de Control de Calidad de Diferentes Productos de Tabletas de Famotidina en el Mercado Iraquí

Background: In developing countries, particularly in Iraq, the use of generic medicines has been increasing in recent years, primarily as a cost-saving measure in healthcare provision. In the Iraqi market, famotidine tablets are available from different pharmaceutical companies. As a result, regular pre-marketing quality testing is required to check the quality and identify which product might safely substitute the innovator product in the event of the innovator brand's unavailability or high cost. Objective: various quality control tests have been conducted to determine the Pharmaceutical Equivalence of the different generic and brands of Famotidine film-coated tablets marketed in Iraq. Materials and Methods: Four different samples of the most commonly available Famotidine 20 mg tablets in the Iraqi market were tested for drug contents, friability, and hardness. Additionally, the in-vitro drug release and kinetics were evaluated. Results: slight differences in the products' content were found; however, they were within the acceptable requirement of British Pharmacopeia (BP) and The United States Pharmacopoeia (USP) 30, NF 25. Similarly, the friability and hardness were within the excellent range according to the B.P. and USP. The results of our study indicated that the tested brand (Famodin) and the three generic products (Famosam, Ulceran, and Famodar) of Famotidine tablets have a unique pattern of in-vitro release profiles. However, all the tested brands and generic pills complied with the USP specifications for the immediate release dosage forms except for Famosam. Release kinetic for the four tested products indicates first-order kinetic models. Conclusion: The findings revealed that nearly all of the tested Famotidine tablet brands and generics met the pharmacopeial requirements for oral tablets. As a result, if acquiring the innovative brand of famotidine tablets is difficult to obtain, healthcare providers may be advised to use the tested products instead

Antecedentes: En los países en vías de desarrollo, especialmente en Irak, el uso de medicamentos genéricos ha aumentado en los últimos años, principalmente como medida de ahorro en la prestación de servicios sanitarios. En el mercado iraquí, los comprimidos de famotidina están disponibles en diferentes empresas farmacéuticas. Por ello, es necesario realizar periódicamente pruebas de calidad previas a la comercialización para comprobar la calidad e identificar qué producto podría sustituir con seguridad al producto innovador en caso de que éste no esté disponible o tenga un coste elevado. Objetivo: se han realizado varias pruebas de control de calidad para determinar la Equivalencia Farmacéutica de los diferentes genéricos y marcas de Famotidina comprimidos recubiertos con película comercializados en Irak. Materiales y métodos: Se analizaron cuatro muestras diferentes de los comprimidos de 20 mg de Famotidina más comunes en el mercado iraquí para determinar el contenido de fármaco, la friabilidad y la dureza. Además, se evaluó la liberación in-vitro del fármaco y su cinética. Resultados: Se encontraron ligeras diferencias en el contenido de los productos; sin embargo, estaban dentro de los requisitos aceptables de B.P. y de la Farmacopea de Estados Unidos (USP) 30, NF 25. Así mismo, la friabilidad y la dureza estaban dentro del rango excelente según la B.P. y la USP. Los resultados de nuestro estudio indicaron que la marca probada (Famodin) y los tres productos genéricos (Famosam, Ulceran y Famodar) de comprimidos de famotidina tienen un patrón único de perfiles de liberación in-vitro. Sin embargo, todas las marcas y los comprimidos genéricos probados cumplieron con las especificaciones de la USP para las formas farmacéuticas de liberación inmediata, excepto Famosam. La cinética de liberación de los cuatro productos probados indica modelos cinéticos de primer orden. Conclusiones: Los resultados revelaron que casi todas las marcas y genéricos de comprimidos de Famotidina probados cumplían los requisitos farmacopeicos para los comprimidos orales. En consecuencia, si resulta difícil adquirir la marca innovadora de comprimidos de famotidina, se puede aconsejar a los profesionales sanitarios que utilicen los productos probados en su lugar

Study on the quality standard of Kuipingning gastric floating tablets / 中国药房

OBJECTIVE To establish the quality standard of Kuipingning gastric floating tablets. METHODS Kuipingning gastric floating tablets were prepared and investigated in terms of property ，weight difference and friability. Crydalis yanhusuo was identified qualitatively by thin layer chromatography （TLC）method. High performance liquid chromatography method was used to determine the content of total anthraquinones in Rheum palmatum ，and set the content limit of total anthraquinones. The floating performance and release degree of the preparation were investigated ，and the release kinetic process was fitted. RESULTS Kuipingning gastric floating tablets prepared in this study were gray white to gray tablets with slight smell and bitter taste ；the weight difference and friability were all in line with relevant regulations ；the established TLC method possessed strong specificity and could accurately identify C. yanhusuo . The average content of total anthraquinones in R. palmatum was 17.95 mg/tablet，and its content limit would not be less than 14.36 mg/tablet. The initial floating time of the preparation was no more than 10 s，and the holding time was more than 8 h. The release kinetics process accorded with the Retger-Peppas release model. CONCLUSIONS The method established in this study shows good reliability ，stability and feasibility ，and can effectively control the quality of Kuipingning gastric floating tablets.

Redefinition to bilayer osmotic pump tablets as subterranean river system within mini-earth via three-dimensional structure mechanism

Defining and visualizing the three-dimensional (3D) structures of pharmaceuticals provides a new and important tool to elucidate the phenomenal behavior and underlying mechanisms of drug delivery systems. The mechanism of drug release from complex structured dosage forms, such as bilayer osmotic pump tablets, has not been investigated widely for most solid 3D structures. In this study, bilayer osmotic pump tablets undergoing dissolution, as well as after dissolution in a desiccated solid state were examined, and visualized by synchrotron radiation micro-computed tomography (SR-μCT). In situ formed 3D structures at different in vitro drug release states were characterized comprehensively. A distinct movement pattern of NaCl crystals from the push layer to the drug layer was observed, beneath the semi-permeable coating in the desiccated tablet samples. The 3D structures at different dissolution time revealed that the pushing upsurge in the bilayer osmotic pump tablet was directed via peripheral "roadways". Typically, different regions of the osmotic front, infiltration region, and dormant region were classified in the push layer during the dissolution of drug from tablet samples. According to the observed 3D microstructures, a "subterranean river model" for the drug release mechanism has been defined to explain the drug release mechanism.

Evaluation of eggshell membrane as an alternative biopolymeric matrix for delivery of nimesulide / Avaliação da membrana da casca do ovo como uma matriz biopolimérica alternativa para entrega de nimesulida / Evaluación de la membrana de la cáscara de huevo como una matriz de biopolímero alternativa para la administración de nimesulida

SUMMARY Introduction: Eggshell membrane (ESM) is a tissue found between the eggshell and the albumen of eggs that has attractive properties for use in drug delivery systems. Aim: To incorporate in ESM and used it as a model drug in release studies. The color change and FTIR analysis of the biopolymer proved the incorporation of nimesulide in ESM. Results: The drug uptake was 176.83 and 122.69 mg g-1 by natural and cross-linked ESM. Release studies were carried out using a spectrophotometric flow system in simulated intestinal fluid pH 7.4. The release profiles showed that after 60 minutes 54.55 and 42.58 % of the drug were released from natural and cross-linked ESM, respectively. Kinetics parameters indicated that drug release was better described by the Higuchi model and through a non-Fickian release. Conclusion: Considering these results is proved that ESM has the potential to become a polymeric matrix for drug release systems.

RESUMO Introdução: a membrana da casca do ovo (MCO) é um tecido encontrado entre a casca e o albúmen de ovos que possui propriedades atrativas para uso em sistemas de liberação de fármacos. Objetivo: incorporar à MCO e utilizá-la como fármaco modelo em estudos de liberação. Mudança de coloração e análises de FTIR do biopolímero comprovaram a incorporação da nimesulida na MCO. A incorporação do fármaco foi de 176,83 e 122,69 mg g-1 na MCO natural e reticulada, respectivamente. Resultados: os estudos de liberação foram realizados usando um sistema de fluxo espectrofotométrico em fluido intestinal simulado pH 7,4. Os perfis de liberação mostraram que após 60 minutos 54,55 e 42,58 % do medicamento foram liberados da MCO natural e reticulada, respectivamente. Os parâmetros cinéticos indicaram que a liberação do fármaco foi mais bem descrita pelo modelo de Higuchi e por meio de uma liberação não Fickiana. Conclusão: considerando estes resultados, fica comprovado que a MCO tem potencial para se tornar uma matriz polimérica para sistemas de liberação de fármacos.

RESUMEN Introducción: La membrana de cáscara de huevo (MCH) es un tejido que se encuentra entre la cáscara de huevo y la albúmina de los huevos que tiene propiedades atractivas para su uso en sistemas de administración de fármacos. Objetivo: Incorporar en MCH y utilizarla como fármaco modelo en estudios de liberación. El cambio de color y el análisis FTIR del biopolímero demostraron la incorporación de nimesulida en MCH. Resultados: La captación del fármaco fue de 176,83 y 122,69 mg g-1 por MCH natural y reticulado. Los estudios de liberación se llevaron a cabo utilizando un sistema de flujo espectrofotométrico en líquido intestinal simulado pH 7,4. Los perfiles de liberación mostraron que después de 60 minutos el 54,55 y el 42,58 % del fármaco se liberó de la MCH natural y reticulada, respectivamente. Los parámetros cinéticos indicaron que la liberación del fármaco se describió mejor mediante el modelo de Higuchi y mediante una liberación no Fickian. Conclusión: De acuerdo con estos resultados, el MCH tiene el potencial de convertirse en una matriz polimérica para sistemas de liberación de fármacos.

Multiparticulate Drug Delivery System For Gastrointestinal Tuberculosis

Drug solubility poses numerous challenges in design of formulations for drugs with poor aqueous solubility. Ethionamide is an antitubercular drug belonging to biopharmaceutical classification system class II drug having less aqueous solubility. Nanosuspensions were prepared by using various solvents such as methanol, ethanol, acetone and chloroform and it was prepared using anti-solvent precipitation technique by using probe sonication. Various stabilizers such as tocopherolpolythytlene glycol succinate, polyvinylpyrrolidone and tween 80 singly or in combination were studied. A 32 factorial design was employed to study the effect of independent variables, concentration of stabilizers and stirring speed on particle size and cumulative percent drug release. The particle size of the optimized batch was 97.54 ± 8.47 nm with polydispersity index of 0.36 and zeta potential -10.1 ± 2.3 mV. The cumulative percent drug release of optimized batch was found to be 95.01 ± 1.16% in 60 min. Optimized batch was ultracentrifuged and evaluated for saturation solubility studies, stability and powder X-ray Diffraction studies. Optimized nanosuspension was loaded on Espheres by spraying in a coating pan and then coating of Eudragit controlled release polymers. The coated Espheres were evaluated for drug content, friability, scanning electron microscopy, ex-vivo permeation studies and drug release kinetics studies. The friability value for primary coated sphere was found to be 0.8 ± 0.12% and for secondary was 1% and the best fit model was found to be Korsmeyer-Peppas model which is indicative of diffusion controlled release. Ex vivo diffusion studies revealed a moderate increase in permeability.

Human amniotic membrane as a drug carrier – An in-vitro study using fortified cefazolin ophthalmic solution

Purpose: Our previous study demonstrated the drug reservoir function of human amniotic membrane (HAM) using stable moxifloxacin as a model drug. The purpose of the present study is to evaluate whether HAM can be used as a drug carrier for extended release of extemporaneous preparation of cefazolin. Methods: HAM Buttons (1 Control, 5 Test) were incubated in a freshly prepared (1 ml) sterile topical solution of cefazolin 5% (w/v) for 3 h and 24 h at two different temperatures. The groups were designated as follows: Group IA: Soaking duration 3 h at 4°C; Group IB: Soaking duration 3 h at room temperature; Group IIA: Soaking duration 24 h at 4°C; and Group IIB: Soaking duration 24 h at room temperature. The release kinetics of cefazolin from different groups of drug-laden HAM was studied for a period of 5 days. Samples were assayed for estimation of cefazolin content at different time intervals by High Performance Liquid Chromatography (HPLC) with Photodiode array (PDA) detector. Results: Three-hour cefazolin treatment with HAM at 4°C caused high drug entrapment (24%) compared to room temperature (11%; P < 0.005); however, the release kinetics was not significantly different between Group IA and IB as well as Group IIA and IIB up to the study period. Increase in drug treatment duration did not show increase in entrapment, but caused two-fold (IA Vs IIA) and 1.6-fold (IB Vs IIB) less drug entrapment at 4°C and room temperature, respectively. Conclusion: The results reveal that HAM may be a suitable drug carrier for extended delivery of fortified formulations without compromising stability.

Progress in Research Drug Eluting Stents Drug-looding and Drug Release Kinetics / 中国医疗器械杂志

Drug eluting stents are one of the main devices of coronary intervention, which play a therapeutic role through the combination of medical devices. Drug is an important part of the drug eluting stents. The loading method, the type of carrier, drug and carrier interaction and the preparation process of the drug directly affect the drugs release kinetics characteristics of the device and the final treatment. According to the characteristics of the drug coating, drug coated stents can be divided into non-degradable polymers drug coated stents, biodegradable polymers drug coated stents and polymer-free drug eluting stents. This article discussed the stent coating process and drug release kinetics of the three types of drug eluting stent.

Preparation and in vitro & in vivo evaluation of cephalexin matrix tablets

The purpose of the study is to develop cephalexin controlled-release matrix tablets by using lower proportions of release retardant polymer and to establish their in vitro & in vivo correlation. Tablets were compressed by incorporating polymers in a matrix form along with drug which prolong the drug release. Twelve formulations were prepared by mixing ethyl cellulose (EC) and hydroxypropyl methylcellulose (HPMC) (three different viscosity grades) in various proportions. F-1 to F-4 formulations were prepared by incorporating drug, HPMC K4M and ethyl cellulose in 100 : 5 : 5, 100 : 10 : 5, 100 : 15 : 5 and 100 : 20 : 5; similarly, F-5 to F-8 were prepared with HPMC K15M; and F-9 to F-12 were prepared with HPMC K100M using a wet granulation process maintained same proportions, along with drug and EC. Tablets were evaluated for their pre-compression and post-compression characteristics and they were found to be in limits. From the dissolution testing, F-4 showed 100.34% medicament release in 12 h. In vivo studies were conducted on rabbit and pharmacokinetic parameters of the optimized formulation were evaluated using HPLC method. It was found that matrix tablets showed increased t1/2 and decreased Kel. The design signified that the drug release rate from tablets was influenced by the small proportion (around 7% of a tablet weight) of polymer mixture and it controlled 100% medicament release upto 12 h effectively with the low grade viscosity of HPMC combination, with good in vitro & in vivo correlation.

Preparation and Properties of Rifampicin-loaded Pluronic L61-PBSu Nanoparticles / 中国药学杂志

OBJECTIVE: To study the preparation of pluronic-modified biodegradable poly(butylene succinate) (PBSu) nanoparticles (NPs) and evaluate the release kinetics of the drug-loaded PBSu NPs and the cytotoxicity of the NPs, so as to provide a new platform for the application of biodegradable PBSu in drug delivery. METHODS: Pluronic L61-modified PBSu NPs were prepared by emulsification method, and the morphology of the NPs was observed by transmission electron microscopy. The in vitro release kinetics of the rifampicin-loaded L61-PBSu NPs at 37 ℃ was studied. The cytotoxicity of the L61-PBSu NPs against human ovarian cancer cells (OVCAR-3) was evaluated by MTT assay. RESULTS: The drug-loaded NPs had a unimodal distribution with an average size of (140±7) nm. The drug encapsulation efficiency attained 64.98%. The release time reached 27 h when the cumulative release percentage was 90%. The release kinetics followed non-Fickian mechanism. The NPs demonstrated very low cytotoxicity against OVCAR-3 cancer cells. Modification by L61 improved biocompatibility. CONCLUSION: The Pluronic-modified PBSu NPs are easy to prepare, biocompatible, and show great promise as a new passive targeting platform for controlled release of insoluble drugs.

Evaluating on correlation between in vivo absorption kinetics and in vitro release kinetics of multiple components contained in gbe sustained-release pellets / 中草药

Objective The relationship between the in vivo absorption kinetics and the in vitro release kinetics of various components (including flavonoids and terpenoids) contained in Ginkgo biloba extract (GBE) sustained-release pellets were evaluated using multi-component integration kinetics which could provide a reference for more accurate assessment of in vitro and in vivo correlation. Methods The release rates in vitro of main ingredients (quercetin, isorhamnetin, bilobalide, ginkgolide A, ginkgolide B and ginkgolide C) were detected by HPLC-MS/MS. The integrated drug concentration was calculated, and the release rates in vitro of integrated components were then depicted according to the results. Plasma was collected at different time points after oral administration of GBE sustained-release pellets, multiple components contained in GBE sustained-release pellets were then determined. A novel approach of self-defined weighting coefficient (Wj) based on the area under the curve from zero to infinity AUC0—∞ had been created to obtain the holistic pharmacokinetic profiles of GBE sustained-release pellets. To evaluation the in vitro-in vivo correlation of GBE sustained-release pellets, the percent of integrated in vivo absorption calculated by the Wagner-Nelson methodwas plotted versus the percent of integrated in vitro drug release at the same time. Results The components contained in sustained- release pellets had a good release, the Wj of each component in GBE sustained-release pellets were as follows: quercetin, 0.248 1; isorhamnetin, 0.009 2; bilobalide, 0.228 2; ginkgolide A, 0.296 4; ginkgolide B, 0.132 4; ginkgolide C, 0.090 3. The in vivo-in vitro correlation equation was Y = 0.930 8 X + 12.84, r = 0.962 9, indicated that the correlation between in vivo absorption kinetics and in vitro release kinetics is good. Conclusion The efficacy of the herbal medicines depends on a variety of components combined effect, using the integrated pharmacokinetic to analyze IVIVC could take the characteristic of each component into account, which is helpful for the study of the correlation between in vivo absorption kinetics and in vitro release kinetics.

Characteristics of materiome release kinetics and visual evaluation of different types of Liuwei Dihuang Pills / 中草药

Objective To investigate the characteristics of materiome release kinetics of Liuwei Dihuang Pills (LDP), and to evaluate its visualization. Methods According to the 2015 edition of Chinese Pharmacopia, using the evaluation methods of release kinetics of Chinese material medica to determine the materiomics release kinetics and the releasecharacteristic of LDP by the paddle method. Then f2 fit factor was calculated and evaluated on other types of LDP in comparison with water-bindered pills and condensed pills as, which are two most common preparations in the market. Moreover, materiome release spectrum and release increment spectrum were used, hoping to quantify, integrate and visualise the materiome release characteristics of different types of LDP. Results The kinetic characteristics of the LDP accord with the Weibull release model, T50 and Td were calculated, and there are significant differences between different types of pills (P < 0.05) in addition to condensed pills and water pills. Also, some differences and similarities in the materiomics release characteristic by f2 fit factor were found in the study. Materiome release spectrum and release increment spectrum can be used to quantify, integrate and visualise the materiome release characteristics of LDP on different types. Conclusion The materiomics release kinetics can be applied to quantify, integrate and visualise the materiome release characteristic of LDP on different types. Basically in agreement with the saying, “water pills from the facilitation, honey pills take the slow, paste pills from the late of, wax-wrapped pills take the difficult”.

In vitro evaluation of sustained released matrix tablets containing ibuprofen: a model poorly water-soluble drug

ABSTRACT A matrix system was developed that releases ibuprofen (IB) over a 12-hour period and the influence of the polymer type and concentration on the release rate of the drug was evaluated. Tablets containing different concentrations of Carbopol (CP), hydroxypropyl methylcellulose (HPMC), or ethyl cellulose (EC) were prepared using direct compression and the drug content, content uniformity, hardness, friability, dissolution performance, and in vitro release kinetics were examined. Formulated tablets were found to be within acceptable limits for physical and chemical parameters. The release kinetics of the Carbopol(r)971P 8% formulation showed the best linearity (r 2 =0.977) in fitting zero-order kinetics, suggesting the release rate was time independent. The drug release from tablets containing 8% CP was extended over approximately 18 hours and the release kinetics were nearly linear, suggesting that this system has the potential to maintain constant plasma drug concentrations over 12 hours, which could reduce the frequency of administration and the occurrence of adverse effects associated with repeated administration of conventional IB tablets.

A Five-Year Stability Study of Controlled-Release Diltiazem Hydrochloride Tablets Based on Poly(Ethylene Oxide).

The aim of this study is to investigative the stability of poly(ethylene oxide) (PEO) matrix tablets containing diltiazem hydrochloride (DTZ) after five-year storage at room temperature. DTZ matrix tablets containing different molecular weights (MW) of PEO and electrolytes (sodium carbonate anhydrous Na2CO3, potassium chloride KCl and pentasodium tripolyphosphate anhydrous PSTPP) were prepared. The fresh and stored tablets were evaluated by DTZ content, in vitro drug release rates and kinetics as well as DSC. All the PEO’s matrix tablets showed no significant changes in release rate, kinetics and drug content. The release rates of DTZ following five-year storage were slightly increased as the MW of PEO increased from 900,000 to 8,000,000. Also, it was clear that the addition of electrolyte drastically slowed the release rates of DTZ from fresh and stored tablets. DSC thermograms and similarity factor (ƒ2) depicted good system stability for all stored tablets. This is the first five-year long-term stability study reported concerning DTZ/PEO matrix tablets with different MW, which proved its stability for several years. This study might throw light on the dramatic difference observed between this study and the reported data of accelerated stability testing under stress conditions found in the literature.

Fabrication of Bucco-matrix tablets of Amoxicillin trihydrate on the basis of release and permeation kinetics.

Drug release kinetics from matrix dosage form is governed by polymer swelling and erosion, drug dissolution/diffusion and polymeric combination. For the preparation of controlled release dosage form, hydrophilic, swellable polymers in optimum combination are essential. The major objective of the current study is to prepare Amoxicillin trihydrate-loaded bucco-matrix tablets by direct compression technique and to study the effect of ratio of HPMCK100M and HPMCK15M used in the formulation on the basic properties and on drugrelease and permeation kinetics. The tablets offered satisfactory physicochemical results. The buccal strength, detachment force and bond strength of the tablets were good enough to hold the tablets in the buccal region. The drug release data generated during in vitro drug release study of bucco-matrix tablets in phosphate buffer pH 6.8 were evaluated by zero-order, first-order, Higuchi, Korsmeyer – Peppas, and Kopcha models. Release exponent (n) of Korsmeyer- Peppas equation of the formulations exhibited diffusion as the principal mechanism of drug release. It was further confirmed by Kopcha model. Evaluation of diffusion and erosion terms in the Kopcha model showed that diffusion dominated swelling or erosion process through out the study. The permeation kinetics of the drug showed linearity when studied across goat buccal mucosa. Permeation coefficient of drug decreased with increase in % swelling index of the formulations.

Monolithic LC method applied to fesoterodine fumarate low dose extended-release tablets:Dissolution and release kinetics / 药物分析学报

A dissolution test for fesoterodine low dose extended-release tablets using liquid chromato-graphic (LC) method equipped with a C18 monolithic column was developed and validated. LC system was operated isocratically at controlled temperature (40 1C) using a mobile phase of acetonitrile:methanol:0.03 M ammonium acetate (pH 3.8) (30:15:55, v/v/v), run at a flow rate of 1.5 mL/min and detected at 208 nm. The best dissolution conditions for this formulation were achieved using a USP apparatus 2 (paddle) at 100 rpm and 900 mL of phosphate buffer at pH 6.8 as the dissolution medium. Validation parameters such as the specificity, linearity, accuracy, precision, and robustness were evaluated according to international guidelines, giving results within the acceptable range. The kinetic parameters of drug release were also investigated using model-dependent methods and the dissolution profiles were best described by the Higuchi model. The validated dissolution test can be applied for quality control of this formulation.

The Application of Factorial Experimental Design in Capsule Coating for Potential Colon Targeting of an Antiamebic Drug.

Aim: The application of factorial experimental design to evaluate the effect of particle size, capsule surface coating and binder concentration on the in vitro controlled release profile of metronidazole from encapsulated granules. Methodology: Metronidazole granules were prepared by the wet granulation technique and encapsulated in hard gelatin capsule shells. Eudragit® L-100 and Landolphia owariensis latex served as primary and secondary coatings respectively on 50 or 75% of capsule surface. The three formulation factors (% capsule surface coating, matrix former concentration and particle size) were subjected to a 2x3x4 factorial design experiment using the software (JMP 4.0.4, SAS Inc. USA). Gradient drug release studies were conducted in three media; firstly in media of pH 1.2 for 2 h, pH 6.8 for 3 h and finally pH 7.4 until exhaustion of drug release. The drug release data were subjected to kinetic treatment to establish operational release kinetics such as zero order, first order, Higuchi, Hixon Crowell and Kitazawa, while the power law enabled the prediction of mechanism of drug release. Results: Results showed that % capsule surface coated with Landolphia owariensis latex and particle size significantly (p<0.05) contributed to time of drug release (T7.4) at pH 7.4. In tandem with this, maximum amount of drug released (D7.4) at pH 7.4 was significantly (p<0.05) affected by particle size alone. A few batches were characterized by anomalous transport while over 80% were associated with super case 11 type of release. Conclusion: We therefore conclude that, factorial experimental design identified Landolphia owariensis latex coating and particle size of granules as being chiefly responsible for drug release variations.

Formulation and evaluation of dexamethasone loaded stearic acid nanoparticles by hot homogenization method.

Dexamethasone is a type of steroid medication having anti-inflammatory and immunosuppressant effects. One of the major problems with this drug is its low solubility in water which results into poor bioavailability after oral administration. So the objective of the present work is to improve the solubility and dissolution rate of dexamethasone using its solid lipid nano particles (SLNPs) with stearic acid as solid lipid, lutrol F-68 as surfactant and tween-80 as stabilizer. SLNPs are prepared by hot homogenization method at different ratio of drug, lipid, surfactant and stabilizer and designated as DNP1 to DNP6. In vitro dissolution study was performed using the USP type II apparatus (paddle method) at 50 rpm to a temperature of 37°±0.5°C in distilled water containing 0.75% w/v SLS (sodium lauryl sulfate). The absorbance of sample was measured spectrophotometrically at λmax 239nm on a UV-Visible spectrophotometer. Release pattern of drug was found to follow zero order, first order and Korsmeyer-Peppas equations. Improvement of dissolution was observed in all the solid lipid nano particles as compared to pure drug. Pure drug showed only 27.25% release in 50 min whereas the dexamethasone SLNPs showed faster (66.19%) in vitro drug release. Hence, this finding indicates that dexamethasone SLNPs prepared by hot homogenization method can be used to enhance the dissolution rate and to show novel application to this drug delivery system.

Formulation and evaluation of dexamethasone loaded stearic acid nanoparticles by hot homogenization method.

Dexamethasone is a type of steroid medication having anti-inflammatory and immunosuppressant effects. One of the major problems with this drug is its low solubility in water which results into poor bioavailability after oral administration. So the objective of the present work is to improve the solubility and dissolution rate of dexamethasone using its solid lipid nano particles (SLNPs) with stearic acid as solid lipid, lutrol F-68 as surfactant and tween-80 as stabilizer. SLNPs are prepared by hot homogeniza-tion method at different ratio of drug, lipid, surfactant and stabilizer and designated as DNP1 to DNP6. In vitro dissolution study was performed using the USP type II apparatus (paddle method) at 50 rpm to a temperature of 37°±0.5°C in distilled water containing 0.75% w/v SLS (sodium lauryl sulfate). The absorbance of sample was measured spectrophotometrically at λmax 239nm on a UV-Visible spectrophotometer. Release pattern of drug was found to follow zero order, first order and Korsmeyer-Peppas equations. Improvement of dissolution was observed in all the solid lipid nano particles as compared to pure drug. Pure drug showed only 27.25% release in 50 min whereas the dexamethasone SLNPs showed faster (66.19%) in vitro drug release. Hence, this finding indicates that dexamethasone SLNPs prepared by hot homogenization method can be used to enhance the dissolution rate and to show novel application to this drug delivery system.