Quinine sulphate pellets for flexible pediatric drug dosing: formulation development and evaluation of taste-masking efficiency using the electronic tongue.

The purpose of this study was to develop a taste-masked quinine sulphate dosage form as a flexible pediatric formulation tool. Pellets were produced as they offer more flexibility to body weight dose adaptation and therefore represent an alternative to tablet breaking in pediatrics. Quinine sulphate pellets were produced via extrusion-spheronisation. Next pellets were coated using Eudragit E PO to obtain a taste-masked formulation. Using 15% dibutyl sebacate (based on polymer weight) as a plasticizer in the formulation caused rapid pellet agglomeration during storage at 40 degrees C and 75% relative humidity. Using stearic acid (15% based on polymer weight) as plasticizer yielded pellets which were less sensitive to sticking. Quinine sulphate release in water within the first 5 min of dissolution testing: 9.2%, 5.9% and 2.1% of the drug dose was released from pellets coated with 10%, 20% and 30% (w/w) Eudragit E PO, respectively. These observations correlated well with the bitterness score of the formulations determined via the Astree electronic tongue and its Bitterness Prediction Module, showing that 20% (w/w) Eudragit E PO was required to obtain a homogeneous film and to delay quinine sulphate release sufficiently to mask the bitterness after drug administration. In acid medium immediate quinine sulphate release was obtained.     

Characterization of moisture-protective polymer coatings using differential scanning calorimetry and dynamic vapor sorption

The aim of this study was to evaluate the moisture-protective ability of different polymeric coatings. Free films and film-coated tablets (with cores containing freeze-dried garlic powder) were prepared using aqueous solutions/dispersions of hydroxypropyl methylcellulose (HPMC), Opadry AMB [a poly(vinylalcohol)-based formulation] and Eudragit E PO [a poly(methacrylate-methylmethacrylate)]. The water content of the systems upon open storage at 75% relative humidity (RH) and 22 degrees C (room temperature) was followed gravimetrically. Furthermore, polymer powders, free films and coated tablets were analyzed by differential scanning calorimetry (DSC) and dynamic vapor sorption (DVS). The type of polymer strongly affected the resulting water uptake kinetics of the free films and coated tablets. DSC analysis revealed whether or not significant physical changes occurred in the coatings during storage, and whether the water vapor permeability was water concentration dependent. Using DVS analysis the critical glass transition RH of Opadry AMB powder and Opadry AMB-coated tablets at 25 degrees C could be determined: 44.0% and 72.9% RH. Storage below these threshold values significantly reduces water penetration. Thus, DVS and DSC measurements can provide valuable information on the nature of polymers used for moisture protection.     

陈香露白露薄膜衣片的研制

目的:制备陈香露白露薄膜衣片,提高药物稳定性。方法:选用不同的粘合剂制备片芯,再选用不同的包衣材料进行包衣,比较陈香露白露薄膜衣片与糖衣片的稳定性。结果:采用10%聚乙烯吡咯烷酮乙醇液为粘合剂制备片芯,用隔离材料玉米阮将片芯保护,采用上海卡乐康公司的黄色或红棕色胃溶性包衣粉制备的陈香露白露薄膜衣片在外观质量上优于其它材料制备的成品,尤其是防渗油和防潮性方面优势明显;薄膜衣片稳定性优于糖衣片。结论:陈香露白露薄膜衣片质量稳定,制备工艺简单。     

Formulation studies of tableted oral rehydration salt mixtures

Dehydration following non-specific diarrhoea may be prevented by oral administration of a simple glucose/salt mixture. A solution tablet of this mixture would have advantages of stability under environmental exposure and transport if the costs could be held within reasonable limits. The moisture adsorption and compression characteristics of Oral Rehydration Salts (ORS) ingredients have been studied. Combinations of ingredients resulted in a moisture adsorption higher than that of the individual components. This may be explained in terms of critical relative humidity, RHo, and environmental relative humidity RHi. Preparation of a stable ORS solution tablet therefore requires protection of moisture adsorbing components from the environment. The present UNICEF ORS mixture compacted easily by direct compression but gave fragile tablets, which were hygroscopic. This can be reduced by film coating the electrolyte component as granules with a resin (Eudragit L), or by simulating direct compression of the glucose as a compression-coating around the precompressed electrolytes. The packaging of compression-coated solution tablets in inexpensive polyethylene bags may lengthen the shelf-life and make the preparation less costly than the currently supplied ORS powders packed in laminated aluminium sachets. The increased dissolution lag time for the compacted tablet is a disadvantage that can be overcome by instructions to crush the product immediately before use.     

A comparative in vitro assessment of the drug release performance of pH-responsive polymers for ileo-colonic delivery

The aim of this study was to investigate the in vitro dissolution characteristics of pH-responsive polymers in a variety of simulated fluids. Prednisolone tablets were fabricated and coated with the following polymer systems: Eudragit S (organic solution), Eudragit S (aqueous dispersion), Eudragit FS (aqueous dispersion) and Eudragit P4135 (organic solution). Dissolution tests were conducted using a pH change method whereby tablets were transferred from acid to buffer. Three different buffer media were investigated: two compendial phosphate buffers (pH range 6.8-7.4) and a physiological buffer solution (Hanks buffer) with very similar ionic composition to intestinal fluid (pH 7.4). There was considerable drug release from tablets coated with Eudragit P4135 in acid, prompting discontinuation of further investigations of this polymer. Eudragit S (organic solution), Eudragit S (aqueous dispersion) and Eudragit FS on the other hand prevented drug release in acid, though subsequent drug release in the buffer media was found to be influenced by the duration of tablet exposure to acid. At pH 7.4 drug release rate from the polymer coated tablets was similar in the two compendial media, however in the physiological buffer, they were found to differ in the following order: Eudragit S (aqueous dispersion)>Eudragit FS>Eudragit S (organic solution). The results indicate that the tablets coated with the newer Eudragit FS polymer would be more appropriate for drug delivery to the ileo-colonic region in comparison to the more established Eudragit S. More importantly, however, dissolution in the physiological buffer was found to be markedly slower for all the coated tablets than in the two compendial buffers, a result akin to reported slower dissolution of enteric coated tablets in vivo. There is therefore the need to adequately simulate the ionic composition of the intestinal fluid in the dissolution media.     

Cellactose a co-processed excipient: a comparison study

This article describes the differences in compaction properties between microcrystalline cellulose (MCC) and alpha-lactose monohydrate physical mixture, and microcrystalline cellulose co-processed with alpha-lactose monohydrate (Cellactose). The different compaction parameters are not only compared for the pure materials but also for the lubricated powders with magnesium stearate. Magnesium stearate does not facilitate the densification of either the physical mixture or Cellactose during compaction. The difference in tablet relaxation of the physical mixture and Cellactose indicates that the negative effect of the lubricant on the interparticle bonding of Cellactose particles is smaller than the physical mixture particles because after compaction, the structure in the Cellactose tablet is completely different from that in the physical mixture tablet. However, a larger increase in tablet relaxation at a high compression speed was found for both Cellactose and the physical mixture at different lubricant concentrations: 1.0% and 0.0%. Accordingly, the decrease in tablet strength was larger for the physical mixture tablets than for the Cellactose tablets when lubrication was applied. The examination of the tablet strengths of tablets compressed from physical mixtures of different ratios of alpha-lactose monohydrate and MCC proved the positive effect of cellulose on the tensile strength of tablets. Co-processing of MCC with alpha-lactose monohydrate showed extra contribution on the tablet strength of a physical mixture with the same mixing ratio. This extra contribution of Cellactose was attributed only to the interfacial attraction of the particles.     

Cellactose® a Co-processed Excipient: A Comparison Study

This article describes the differences in compaction properties between microcrystalline cellulose (MCC) and α-lactose monohydrate physical mixture, and microcrystalline cellulose co-processed with α-lactose monohydrate (Cellactose®). The different compaction parameters are not only compared for the pure materials but also for the lubricated powders with magnesium stearate. Magnesium stearate does not facilitate the densification of either the physical mixture or Cellactose during compaction. The difference in tablet relaxation of the physical mixture and Cellactose indicates that the negative effect of the lubricant on the interparticle bonding of Cellactose particles is smaller than the physical mixture particles because after compaction, the structure in the Cellactose tablet is completely different from that in the physical mixture tablet. However, a larger increase in tablet relaxation at a high compression speed was found for both Cellactose and the physical mixture at different lubricant concentrations: 1.0% and 0.0%. Accordingly, the decrease in tablet strength was larger for the physical mixture tablets than for the Cellactose tablets when lubrication was applied. The examination of the tablet strengths of tablets compressed from physical mixtures of different ratios of α-lactose monohydrate and MCC proved the positive effect of cellulose on the tensile strength of tablets. Co-processing of MCC with α-lactose monohydrate showed extra contribution on the tablet strength of a physical mixture with the same mixing ratio. This extra contribution of Cellactose was attributed only to the interfacial attraction of the particles.     

Phase transformation in thiamine hydrochloride tablets: Influence on tablet microstructure, physical properties, and performance

The objective of this article was to monitor phase transformation in thiamine hydrochloride, from a nonstoichiometric hydrate (NSH) to a hemihydrate (HH), in stored tablets, prepared both by direct compression and wet granulation, and to relate the storage-induced phase transformation with changes in tablet microstructure, physical properties, and performance. Raman spectroscopy revealed complete NSH → HH transformation in tablets, within 30 h of storage at 40°C/75% relative humidity. When the tablets were prepared by wet granulation of NSH alone, there was a marked increase in both tablet volume and hardness on storage. However, when microcrystalline cellulose (MCC) was included in granulation, the resulting stored tablets also exhibited a pronounced increase in disintegration time. In contrast, tablets prepared by dry processing via compression of a NSH-MCC physical mixture did not exhibit any changes in properties, despite the in situ solid form conversion. Scanning electron microscopy revealed growth of needle-like HH crystals in all stored tablets and mercury porosimetry revealed considerable changes in the pore size distribution during storage. Longer storage led to crystal growth (Ostwald ripening), causing further gradual but less dramatic changes in properties. The phase transformation and the complex interparticulate associations in the tablet influenced the changes in tablet microstructure, compact physical properties, and product behavior.     

The effect of tablet formulation and hardness on in vitro release of cephalexin from Eudragit L100 based extended release tablets

Eighteen batches of cephalexin extended release tablet were prepared by wet granulation method by using Eudragit L100. The effect of the concentration of Eudragit L100, microcrystalline cellulose and tablet hardness on cephalexin release was studied. The formulated tablets were also characterized for physical and chemical parameters. The dissolution results showed that a higher amount of Eudragit in tablet composition and higher tablet hardness resulted in reduced drug release. An increased amount of microcrystalline cellulose in tablet composition resulted in enhanced drug release. Tablet composition of 13.3% w/w Eudragit L100 and 6.6 to 8% w/w microcrystalline cellulose with hardness of 7-11 kg/cm2 gave predicted release for 6 h. The in vitro release was compared with a marketed tablet. Physical and chemical parameters of all formulated tablets were within acceptable limits. The effect of storage on in vitro release and physicochemical parameters of tablets was evaluated and two batches among formulated eighteen batches found to be in acceptable limits.     

Development and evaluation of the tablets coated with the novel formulation termed thin-layer sugarless coated tablets

The purpose of this study was to develop and evaluate the thin-layer sugarless coated tablets containing Vitamin C, Vitamin E, Vitamin B2, calcium pantothenate, and L-cysteine. As a result of the formulation study, three coating layers, 2% under coating (UC), 38% build-up coating (BC), and 5% syrup coating (SC) were necessary for sufficient impact toughness, elegant appearance, and improvement of appearance stability after storage at 25 degrees C/75% RH for 6 months under open conditions. We demonstrated that the thin-layer sugarless coated tablets are superior to the sugar-coated tablets in terms of small tablet size and stability of calcium pantothenate. It was due to the coating method, the continuous spray mist method, which can minimize the thicknesses of coating layers and the moisture content in the tablets. We also demonstrated that the thin-layer sugarless coated tablets are superior to the film-coated tablets in terms of masking ability of the unpleasant odor and the appearance, stability of the appearance, and low hygroscopicity. It was due to the dense, opaque, and stable coating layers mainly consist of erythritol. We revealed that thin-layer sugarless coated tablets have both advantages of film-coated tablets and sugar-coated tablets.     

Novel time and site specific “tablets in capsule” system for nocturnal asthma treatment

The objective of present work was to develop a “tablets in capsule” system for facilitating both immediate and pulsatile drug deliveries of theophylline to mimic the circadian rhythm of nocturnal asthma. The system comprised of capsule filled with two tablets, first pulse and second pulse tablet prepared by wet granulation method. First pulse tablet was not coated and was responsible for providing loading dose whereas; second pulse tablet was coated with Eudragit L100 and Eudragit S100 to release drug in colon after specific lag time. Two independent variables, amount of polymers and coating thickness, were optimized by 3² full factorial design. The optimum formulation consisted of Eudragit L100: Eudragit S100 in 1:1.5 ratio and coating thickness of 20 % (w/w). In vitro drug release of “tablets in capsule” system in three different media (pH 1.2, pH 6.8, and pH 7.4) revealed immediate and pulsatile release patterns.     

Design and study of ibuprofen disintegrating sustained-release tablets comprising coated pellets.

One challenge in tableting of sustained-release multiparticulates is maintaining the desired drug release after compaction. The aim of this study was to design sustained-release ibuprofen tablets which upon oral ingestion rapidly disintegrate into sustained-release pellets in which the integrity of the pellet core and/or coat is preserved. First free films composed of Eudragit RS 30D and RL 30D in 4:1 ratio and containing different levels of triethyl citrate (TEC) were prepared and tested to optimize the plasticizer level. Cured Eudragit based pellets with 60% ibuprofen loading which in our previous study showed proper mechanical properties for compression were coated with Eudragit RS 30D/RL 30D (4:1) containing 20% triethyl citrate at different coating levels. The mechanical properties of the coated pellets were tested. Polymer coated pellets were compacted into tablets either alone or with a blend of excipients comprising Avicel, PEG 4000, cross-linked PVP. A 3(2) full factorial design was used to optimize the filler blend composition. Effects of pellet to filler ratio, compression force and granulation of filler on tablet characteristics were investigated. Results of mechanical test showed that the coating of cured pellets had no significant effect on yield point and elastic modulus of the pellets. In the case of 5% coating level sustained release of ibuprofen over a period of 24h was achieved. The results obtained from tableting procedure showed that by selecting suitable filler blend (60% Avicel, 10% cross-linked PVP and 30% PEG 4000), compression force, and granulation of filler it was possible to prepare sustained-release tablets containing high ratio of coated pellets (even 80%) with desirable strength, disintegration time, and drug release rate. It was observed that compression force, pellet to filler ratio, composition of filler blend and granulation of fillers had no effect on drug release rate from compacted pellets but had significant influence on tablet strength, friability, and disintegration time. SEM graphs and in vitro release profiles for compacted pellets showed no apparent damage to the coated pellets as a result of the compaction process.     

Design,optimization and evaluation of mesalamine matrix tablet for colon drug delivery system

The aim of the present investigation was to develop and evaluate matrix tablet of mesalamine for colonic delivery by using Eudragit RSPO, RLPO and combination of both. The tablets were further coated with different concentration of pH-dependent methacrylic acid copolymers (Eudragit S100), by dip immerse method. The physicochemical parameters of all the formulations were found to be in compliance with the pharmacopoeial standards. The in vitro drug release study was conducted using sequential dissolution technique at pH 1.2 (0.1N) HCl, phosphate buffers pH 6.8 and 7.4, with or without rat cecal content mimicking different regions of gastro intestinal tract. The result demonstrated that the tablet containing Eudragit RLPO coated with Eudragit S100 (1 %) showed a release of 94.91 % for 24 h whereas in the presence of rat cecal content the drug release increases to about 98.55 % for 24 h. The uncoated tablets released the drug within 6 h. The in vitro release of selected formulation was compared with marketed formulation (Octasa MR). In vitro dissolution kinetics followed the Higuchi model via non-Fickian diffusion controlled release mechanism. The stability studies of tablets showed less degradation during accelerated and room temperature storage conditions. The enteric coated Eudragit S100 coated matrix of mesalamine showing promising site specific drug delivery in the colon region.     

Formulation of sublingual promethazine hydrochloride tablets for rapid relief of motion sickness

The delivery of antihistaminic agents via the oral route is problematic, especially for elderly patients. This study aimed to develop a sublingual formulation of promethazine hydrochloride by direct compression, and to mask its intensely bitter taste. Promethazine hydrochloride (PMZ) sublingual tablets prepared by direct compression were optimized using Box-Behnken full factorial design. The effect of a taste-masking agent (Eudragit E 100, X1), superdisintegrant (crospovidone; CPV, X2) and lubricant (sodium stearyl fumarate; SSF, X3) on sublingual tablets’ attributes (responses, Y) was optimized. The prepared sublingual tablets were characterized for hardness (Y1), disintegration time (Y2), initial dissolution rate (IDR; Y3) and dissolution efficiency after 30 min (Dissolution Efficiency (DE); Y4). The obtained results showed a significant positive effect of the three independent factors on tablet hardness (P < 0.05), and the interactive effect of Eudragit E 100 and CPV on tablet hardness was significant. Disintegration time was mainly affected by Eudragit E 100 and CPV concentrations. Moreover, IDR was employed to assess the taste masking effect, lower values were obtained at higher Eudragit E 100 concentration despite it was statistically insignificant (p > 0.05). Optimized formulation that was suggested by the software was composed of: Eudragit E 100 (X1) = 2.5% w/w, CPV (X2) = 4.13% w/w, and SSF (X3) = 1.0% w/w. The observed values of the optimized formula were found to be close to the predicted optimized values. The Differential Scanning Calorimetric (DSC) studies indicated no interaction between PMZ and tablet excipients.     

Matrix formation in sustained release tablets: possible mechanism of dose dumping

Conditions under which poly(ethyl acrylate, methyl methacrylate) 2:1 (poly(EA-MMA), Eudragit NE) forms a stable matrix were investigated in tablets with diclofenac sodium (DS) as an active substance. DS was granulated with the aqueous polymer dispersion. Granules and/or tablets were cured under various temperature and humidity conditions. A six position rotating disk (200 rpm) apparatus was used for the release studies conducted in 37 degrees C acid then phosphate buffer (0.4 M) pH 6.8 or buffer only as the dissolution media. Morphological characteristics of the tablet surface were observed under SEM. Changes in tablet structure upon curing were evaluated through changes in tablet mechanical characteristics. Modulus of rupture, Young's modulus, AUC, AUC(max), where AUC=AUC(max), were determined by the three-point bending test. Some poorly cured tablets dose-dumped when placed directly into buffer but not if first placed in acid and then buffer. A higher content of polymer in the matrix, led to formation of a stronger polymer network upon higher curing temperature and/or longer curing duration, whereas relative humidity had a minor effect.     

热熔挤出法增加布洛芬的溶出度并掩盖其苦味

目的:制备布洛芬固体分散体,以增加布洛芬的溶出度并掩盖其苦味。方法:取布洛芬原料药与丙烯酸树脂Eudragit EPO,以1∶1.5(w/w)混合,采用热熔挤出法制备布洛芬固体分散体。用差示扫描量热法和粉末X射线衍射法分析布洛芬在Eudragit EPO中的分散状态。测定固体分散体、物理混合物和市售布洛芬片剂的溶出度,并评价布洛芬固体分散体的掩味效果。结果:布洛芬晶体结构的特征峰在差示扫描量热和粉末X射线衍射图中消失。在磷酸盐缓冲液中,固体分散体的溶出速度大于物理混合物和布洛芬片。志愿者对布洛芬固体分散体的味觉评价优于物理混合物和布洛芬原料。结论:热熔挤出法制备的Eudragit EPO固体分散体能增加布洛芬的溶出度,并有明显的掩味效果。     

An investigation into the in vivo performance variability of pH responsive polymers for ileo-colonic drug delivery using gamma scintigraphy in humans

Gastrointestinal performance of tablets coated with pH responsive acrylic polymers (Eudragit) was investigated in human volunteers. Tablet cores were coated with Eudragit S dissolved in ethanol (organic), Eudragit S aqueous dispersion (aqueous), or Eudragit FS aqueous dispersion. Eight fasted volunteers received the tablets in a two-way crossover design-treatment 1: Eudragit S (organic) and Eudragit FS coated tablets; treatment 2: Eudragit S (aqueous) and Eudragit FS coated tablets. Eudragit FS coated tablets were included in both treatments to assess its intra-subject performance. Tablets were radiolabelled and followed by gamma scintigraphy; the disintegration times and positions were recorded. Tablets coated with Eudragit S (aqueous) disintegrated in all volunteers mainly in the proximal to mid small intestine. Eudragit S (organic) tablets failed to disintegrate in three out of eight volunteers, while disintegration was in the ileo-caecal junction and ascending colon in all others. Eudragit FS coated tablets disintegrated in 14 out of the 16 administrations. The Eudragit FS coated tablets that did disintegrate exhibited consistent intra- and inter-subject performance, with the site of disintegration focused on the ileo-caecal junction and ascending colon. These in vivo results correlate better with our published in vitro dissolution data in physiological bicarbonate buffers compared to phosphate buffers.     

Properties of tablets containing granulations of ibuprofen and an acrylic copolymer prepared by thermal processes.

The objective of this study was to investigate the properties of tablets containing granulations of ibuprofen (Ibu) and Ammonio Methacrylate Copolymer, Type B (Eudragit RS PO) prepared by hot-melt processing. Tablets were compressed from granules prepared by hot-melt granulation (HMG) or direct compression (DC). For the hot-melt extrusion (HME) process, tablets were prepared by cutting the extrudate, manually. The physicochemical properties of tablets were investigated using thermal analysis, powder X-ray diffraction analysis, tablet hardness, and drug dissolution. The effect of thermal treatment of tablets on the dissolution characteristics of Ibu was also investigated. The results demonstrated that the Ibu lowered the glass transition temperature (Tg) of the Eudragit RS PO and the softened polymer functioned as a thermal binder in the granulation. Ibu was demonstrated to be an effective plasticizer for Eudragit RS PO in the thermal processes. The efficiency of the granulation process increased with increasing levels of Eudragit RS PO in the powder blend. Higher levels of Eudragit RS PO in the tablets prepared by HMG or HME resulted in a decrease in the dissolution rate of the Ibu. An increase in the amount of Ibu in the tablets prepared by HMG or DC led to a decrease in the initial dissolution rate of the Ibu. Following the thermal treatment of the Ibu tablets prepared by HMG, the dissolution rate was significantly decreased due to structural changes in the tablets that resulted from the fusion and coalescence of plasticized polymer particles, causing a reduction in tablet porosity. The Ibu tablets prepared by HME demonstrated minimal changes in their release properties following thermal treatment even at temperatures higher than the Tg of the polymer. HME was shown to be a novel method to prepare matrix tablets and stable dissolution properties were obtained when tablets were stored at 40 degrees C for 30 days.     

Wax beads as cushioning agents during the compression of coated diltiazem pellets.

Placebo particles were mixed with film-coated diltiazem pellets to evaluate them as cushioning agents during tabletting in order to protect the film coat from damage. The cushioning properties of alpha-lactose monohydrate granules, microcrystalline cellulose pellets and wax/starch beads were evaluated by comparing the dissolution profile of the coated pellets before and after compression (compression force 10 kN). Only the tablet formulations containing wax/starch beads provided protection to the film coat. However, the dissolution rate of tablets formulated with waxy maltodextrin/paraffinic wax placebo beads was too slow as the tablets did not disintegrate. Adding 50% (w/w) drum-dried corn starch/Explotab/paraffinic wax beads to the formulation was the optimal amount of cushioning beads to provide sufficient protection for the film coat and yield disintegrating tablets. Using a compression simulator, the effect of precompression force and compression time on the dissolution rate was found to be insignificant. The diametral crushing strength of tablets containing 50% (w/w) drum-dried corn starch/Explotab/paraffinic wax beads was about 25.0 N (+/-0.3 N), with a friability of 0.4% (+/-0.04%). This study demonstrates that adding deformable wax pellets minimizes the damage to film-coated pellets during compression.     

Calculation of the Penetration Depth of X-rays in Intact Pharmaceutical Film-Coated Tablets by Microdiffractometory

Purpose (i) Develop a method to calculate the penetration depth of X-rays in intact film-coated tablets, and validate it using model bilayer tablets. (ii) Characterize the physical form of drug in intact pharmaceutical film-coated tablets by XRD.Materials and Methods An equation for the calculation of the penetration depth of X-rays, as a function of the incident angle, was derived. Model bilayer tablets were prepared to validate the calculation method. The upper layer of the tablets consisted only of microcrystalline cellulose, while the lower layer was a mixture of cerium oxide (10% w/w), blue dye (5% w/w) and microcrystalline cellulose. The total tablet thickness was 3,500 μm, with the upper layer thickness ranging from 200 to 700 μm. The diffracted intensity of a cerium oxide peak in the lower layer was determined using a microdiffractometer system (CuKα radiation) with a two-dimensional area detector. The calculated penetration depth of X-rays was compared with that determined by XRD. After validation of the XRD method, commercial ibuprofen tablets were characterized.Results The penetration depth calculated by the method developed in this study was, in general, in good agreement with that determined experimentally by XRD. In commercial ibuprofen tablets, the coating material exhibited peaks due to TiO₂ (25.4°2θ) and Fe₂O₃ (33.3°). However, these did not interfere with the characteristic peak of ibuprofen (22.2°).Conclusion We developed a method for calculation of penetration depth of X-rays in film-coated tablets and validated it using the model bilayer tablets. This method enables the characterization of the active pharmaceutical ingredient in different regions (at different depths) of the film-coated tablet. Since the technique is nondestructive, the same tablet can be repeatedly analyzed during stability studies.An erratum to this article can be found at