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At least 649 records · Page 36Linked to original sources
PubMed1985

Intramuscular piroxicam, a new dosage form, in the treatment of acute musculoskeletal disorders.

Ten investigators in Austria, Belgium, Denmark, Germany and Switzerland participated in an open trial of intramuscular piroxicam involving 135 patients with selected acute sprains, tendinitis or low back pain. The drug was given in the recommended regimen of 40 mg once daily for 2 days and 20 mg once daily thereafter. Statistically significant improvement from baseline in pain was evident within 1 hour of the initial dose, an effect which was enhanced over a 12-hour period and which lasted for 24 hours. After 3 days of intramuscular injections, pain, tenderness, morning stiffness and back elongation were markedly improved. Subsequent treatment with either intramuscular or oral piroxicam further improved these symptoms and most patients recovered their normal physical activity within a week. The drug was well tolerated; twenty-five patients (18.5%) reported side-effects possibly related to piroxicam. Nearly all were mild or moderate in severity with only six resulting in disruption of therapy. Most adverse reactions involved the upper gastrointestinal tract, but there were no reports of gastric bleeding. Except for a few patients with injection site pain, the side-effect profile was similar to that established with the oral dosage form. Toleration was regarded as excellent or good in about 84% of the patients. The results indicate that intramuscular piroxicam can provide rapid and effective therapy with good toleration in the treatment of acute musculoskeletal disorders.

Adult↗
PubMedDate not supplied

D-optimal mixture design: optimization of ternary matrix blends for controlled zero-order drug release from oral dosage forms.

The objective of the present study was to develop a tablet formulation with a zero-order drug release profile based on a balanced blend of three matrix ingredients. To accomplish this goal, a 17-run, three-factor, two-level D-Optimal mixture design was employed to evaluate the effect of Polyox (X1), Carbopol (X2), and lactose (X3) concentrations on the release rate of theophylline from the matrices. Tablets were prepared by direct compression and were subjected to an in vitro dissolution study in phosphate buffer at pH 7.2. Polynomial models were generated for the responses Y4 (percent released in 8 h) and Y6 (similarity factor or f2). Fitted models were used to predict the composition of a formulation that would have a similar dissolution profile to an ideal zero-order release at a rate of 8.33% per hour. When tested, dissolution profile of the optimized formulation was comparable to the reference profile (f2 was 74.2, and n [release exponent] was 0.9). This study demonstrated that a balanced blend of matrix ingredients could be used to attain a zero-order release profile. Optimization was feasible by the application of response surface methodology, which proved efficient in designing controlled-release dosage forms.

Acrylates↗
PubMed2006

Bioavailability and in vivo release behavior of controlled-release multiple-unit theophylline dosage forms in beagle dogs, cynomolgus monkeys, and göttingen minipigs.

To determine the usefulness of monkey as an animal model, bioavailability and in vivo release behaviors of theophylline (TP) after oral administration of controlled-release beads in dogs, monkeys, and minipigs were evaluated. Controlled-release beads were prepared using a centrifugal-fluid type granulator, that is, CF-granulator, and Ethylcellulose (EC) was used as controlled-release coating agent. Aqueous solution and EC-coated beads, which contained TP were orally administered to animals after at least 1-week intervals. In dogs and minipigs, their relative bioavailabilities of EC-coated beads were 33.1% and 47.0%, respectively, and in vivo TP release from EC-coated beads in the gastrointestinal tract of dogs and minipigs were not reflected in vitro data. In monkeys, relative bioavailability of EC-coated beads was 80.0% and the highest among the three species, and release amount of TP from EC-coated beads at 24 h after oral administration was 82.8% and 92.4%, which was almost correlated to in vitro data. Therefore, the discrepancy of the relative bioavailability in three species is considered to be due to the difference of in vivo release behavior of TP. The monkey may be useful animal model for bioavailability studies of controlled-release dosage forms of TP from the viewpoint of in vitro-in vivo release correlation.

Animals↗
PubMed2006

Formulation of solid dosage forms to overcome gastric pH interaction of the factor Xa inhibitor, BMS-561389.

PURPOSE: The purpose of the study was to investigate the specific mechanism by which elevated gastric pH reduces the absorption of BMS-561389, a factor Xa inhibitor, and to develop a solid formulation strategy to overcome this gastric pH interaction. METHODS: A dissolution method in an acetate buffer at pH 5.5 was used to evaluate the dissolution behavior of the tablet formulation. A precipitation model was used to screen different excipients for their potential to minimize the pH-dependent absorption of BMS-561389. Excipients that showed promise in the precipitation model were incorporated in modified tablet formulations. Dissolution rate of the modified tablets was also determined by the acetate buffer method. A canine model for pH-dependent absorption was subsequently used to evaluate the tablet formulations. RESULTS: Dissolution studies suggested that the reduced absorption of the original formulation was the result of the precipitation of the poorly water-soluble free base during the initial dissolution of the salt. Modified tablets containing organic acids, sulfobutylether-beta-cyclodextrin, or povidone showed enhanced dissolution as compared with the original formulation. Drug absorption from the tablet containing tartaric acid was substantially independent of gastric pH in the canine model. CONCLUSION: A multitier approach was successful in identifying a solid dosage form that minimizes the pH-dependent absorption of this drug candidate.

Animals↗
PubMed1989

Determination of the optimum solvent system for extraction of minoxidil from a tablet dosage form.

Several pharmaceutical solvent systems commonly employed by the pharmacist during the extemporaneous dispensing of minoxidil topical solution using Loniten tablets were evaluated. These included ethanol, propylene glycol, water and a commercially available liquid, Vehicle/N. A total of twenty-five (10 mg) Loniten tablets were pulverized in a wedgewood mortar for five minutes. The tablet powder was then dissolved in the experimental solvent system and stirred thoroughly for ten minutes. The liquid dispersion was filtered using the vacuum filter method and the powder residue was then washed twice to obtain a fixed volume of the filtrate. The concentration of minoxidil in each solvent system was determined spectrophotometrically at the wavelength range of 280 to 282 nm depending upon the solvent. The amount of minoxidil extracted in each sample was calculated using the previously constructed standard curve in the respective solvent system. From the data obtained, it was concluded that Vehicle/N is the optimum solvent for such use, and the drug recovery was about 99%. Whereas, the mixture of methanol/propylene glycol/water at a volume ratio of 6:2:2 was observed to be the second best with a drug recovery of 97%. The addition of sodium lauryl sulfate had no effect in enhancing the solubility of drug when used in a solvent with poor recovery profile of drug. Also, the presence of excipients of the tablet dosage form did not interfere with the extraction process of minoxidil.

Minoxidil↗
PubMed2003

Ion-association method for the colorimetric determination of neomycin sulphate in pure and dosage forms.

A simple, fairly rapid, sensitive and accurate method is described for the colorimetric determination of neomycin sulphate (NMS), based on the measurement of the absorbance of the extracted organic soluble ion-association complex formed between neomycin dictation and a bulky counter anion. Different chromotropic acid azo dyes were examined as counter ions. The effect of pH, the counter ion concentration, sequence of addition and solvents for extraction were also illustrated. The most suitable system is based on reagent VIII (pH 7.5) with chloroform as the extraction solvent. The use of other counter ions, in conjunction with their respective solvents, was found to be less sensitive. The neomycin-reagent VIII system exhibits negligible or no interference when used for the determination of up to 58 microgml(-1) of NMS in the presence of several drug excipiences. The method has been used for the determination of up to 58 microgml(-1) with a good recovery (99.8+/-1.5%), and the precision is supported by the low relative standard deviation </=1.35%. The sensitivity is discussed and the results are compared with the official method. The proposed method was applied successfully to the determination of NMS in pure and dosage forms, with a good precision and accuracy compared to the official one.

Anti-Bacterial Agents↗
PubMedDate not supplied

Determination of cimetidine, famotidine, and ranitidine hydrochloride in the presence of their sulfoxide derivatives in pure and dosage forms by high-performance thin-layer chromatography and scanning densitometry.

A selective, precise, and accurate method was developed for the determination of cimetidine (C), famotidine (F), and ranitidine hydrochloride (R x HCl) in the presence of their sulfoxide derivatives. The method involves quantitative densitometric evaluation of mixtures of the drugs and their derivatives after separation by high-performance thin-layer chromatography on silica gel plates (10 x 20 cm) with ethyl acetate-isopropanol-20% ammonia (9 + 5 + 4, v/v) as the mobile phase for both C and F and ethyl acetate-methanol-20% ammonia (10 + 2 + 2, v/v) as the mobile phase for R x HCl; Rf values for C, F, and R x HCl and their corresponding derivatives were 0.85 and 0.59, 0.73 and 0.41, and 0.56 and 0.33, respectively. Developing time was approximately 20 min. For densitometric evaluation, peak areas were recorded at 218, 265, and 313 nm for C, F, and R x HCl, respectively. The relationship between concentration and the corresponding peak area was plotted for the ranges of 5-50 microg/spot for C and 2-20 microg/spot for F and R x HCl. Mean recoveries were 100.39 +/- 1.33, 99.77 +/- 1.30, and 100.09 +/- 0.69% for C, F, and R x HCl, respectively. The proposed method was used successfully for stability testing of the pure drugs in the presence of up to 90% of their degradates, in bulk powder and dosage forms. The results obtained were analyzed statistically and compared with those obtained by the official methods.

Calibration↗
PubMed2006

Stability-indicating HPTLC determination of imatinib mesylate in bulk drug and pharmaceutical dosage form.

A simple, selective, precise and stability-indicating high-performance thin-layer chromatographic method of analysis of imatinib mesylate both as a bulk drug and in formulations was developed and validated. The method employed HPTLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of chloroform:methanol (6:4, v/v). The system was found to give compact spot for imatinib mesylate (R(f) value of 0.53+/-0.02). Densitometric analysis of imatinib mesylate was carried out in the absorbance mode at 276 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r(2)=0.9966+/-0.0013 with respect to peak area in the concentration range 100-1000 ng per spot. The mean value+/-S.D. of slope and intercept were 164.85+/-0.72 and 1168.3+/-8.26 with respect to peak area. The method was validated for precision, recovery and robustness. The limits of detection and quantitation were 10 and 30 ng per spot, respectively. Imatinib mesylate was subjected to acid and alkali hydrolysis, oxidation and thermal degradation. The drug undergoes degradation under acidic, basic, oxidation and heat conditions. This indicates that the drug is susceptible to acid, base hydrolysis, oxidation and heat. Statistical analysis proves that the method is repeatable, selective and accurate for the estimation of said drug. The proposed developed HPTLC method can be applied for identification and quantitative determination of imatinib mesylate in bulk drug and dosage forms.

Antineoplastic Agents↗
PubMed1978

Theophylline bioavailability following chronic dosing of an elixir and two solid dosage forms.

Theophylline bioavailability following chronic dosing of an elixir and two commercial tablet formulations (I and II) relative to an acute dose of elixir was evaluated in healthy volunteers. Both tablet formulations contained ephedrine. In addition, Tablet I contained hydroxyzine hydrochloride, and Tablet II contained phenobarbital. The mean area under the serum concentration-time curve (AUC) calculated either from time 0 leads to infinity for a single dose or over one dosing interval after repetitive doses was the highest after chronic administration of the elixir. The AUC after chronic elixir, in fact, was statistically different from the values after acute elixir (p less than 0.05) and Tablet II (p less than 0.05). There was, however, a large variation in the elimination half-life among the four theophylline treatments. The mean t 1/2 was the longest after chronic elixir followed by Tablet I, Tablet II, and acute elixir. The AUC values for the four treatments, when corrected for differences in t 1/2, were no longer significantly different, indicating that the extent of theophylline absorption was essentially the same from all three tested products. The time to peak and the peak serum concentration also did not differ among treatments. The prolongation in t 1/2 following chronic treatment with the elixir and its subsequent shortening during tablet administration suggest an initial inhibition followed by induction of theophylline metabolism. The changes may be due to the prolonged treatment with theophylline itself or the other drug ingredients in the dosage form.

Adult↗
PubMed1992

Laser diffraction estimation of particle size distribution of slightly water-soluble drugs coexisting with additives: application to solid dosage forms.

A simple and quantitative evaluation method for particle size distribution (fx(r)) of slightly water-soluble drugs dispersed in an aqueous medium together with other water-insoluble additives was developed using a laser diffraction method. The particle size distribution function of the powder mixture, (f(r)), was assumed as f(r) = phi x.fx(r) + phi a.fa(r), where phi is the volume fraction of each component dispersed in a measurement medium and fa(r) is the distribution function of another water-insoluble additive "a". In order to calculate fx(r) from f(r), it is necessary to know the density of drug and additive in the measurement medium, d(x) and d(a), but this is difficult to determine since particles usually swell in the medium. Thus, a method was developed to use their relative value, delta a (= da/dx). As a practical application, oxolinic acids (OA) of three sizes (OA-S (about 2 microns), OA-M (about 7 microns) and OA-L (about 24 microns)) were used as model drugs. delta a values were determined for various additives using the mixture of OA-S and each additive. Then, using delta as, fx(r) of OA-M or OA-L in the mixture containing OA-M or OA-L and additives was calculated from the f(r) experimentally determined for the mixture. They agreed well with their original distributions. The method was applied to some dosage forms, and the results obtained had good correlation with those from turbidity, wet sieving or dissolution test.

Algorithms↗
PubMed2002

Design of controlled-release solid dosage forms of alginate and chitosan using microwave.

The influence of microwave irradiation on the drug release properties of alginate, alginate-chitosan and chitosan beads was investigated. The beads were prepared with the highest possible concentration of polymer by an extrusion method. Sulphathiazole was selected as a model drug. The beads were subjected to microwave irradiation at various combinations of irradiation power and time. The profiles of drug dissolution, drug content, drug stability, drug polymorphism, drug-polymer interaction, polymer crosslinkage and complexation were determined by dissolution testing, drug content assay, differential scanning calorimetry (DSC) and fourier transform infra-red spectroscopy (FTIR). The chemical stability of the drug entrapped in the beads was unaffected by the microwave irradiation. However, the drug in the chitosan beads underwent polymorphic changes. Polymorphic changes were prevented by means of drug-alginate interaction in alginate and alginate-chitosan beads. Changes in the polymorphic state of drug were found to have insignificant effect on the drug release profiles of chitosan beads. The release-retarding property of alginate and alginate-chitosan beads was significantly enhanced by subjecting the beads to microwave irradiation. Positively charged calcium ions and chitosan are known to interact with negatively charged alginate. DSC and FTIR analyses indicated that the reduction in rate and extent of drug released from the treated beads was primarily due to additional formation of non-ionic bonds, involving alginate crosslinkage and alginate-chitosan complexation. The results showed that microwave technology can be employed in the design of solid dosage forms for controlled-release application without the use of noxious chemical agents.

Alginates↗
PubMed2003

Two simple methods for the estimation of albendazole and its dosage forms using chloramine-T.

Two simple, rapid and reliable methods for the determination of albendazole are described. Both methods involve the use of chloramine-T as the oxidimetric reagent. In the titrimetric method, a known excess of chloramine-T is added to an acidified solution of sample, and after a specified time, the residual oxidant is determined iodometrically. Spectrophotometric procedure also involves the addition of a measured excess of chloramine-T in buffer medium of pH 2.70+/-0.1 and after the reaction is ensured to be complete, the surplus oxidant is determined by a well established colour reaction involving metol and primary arylamine that results in charge-transfer complex measurable at 520 nm. In both methods, the amount of chloramine-T corresponds to the drug content. Reaction conditions were examined and optimised. Titrimetry is based on a 1:3 stoichiometric reaction between albendazole and chloramine-T and is applicable in the range of 1-15 mg. In spectrophotometry, the absorbance was found to decrease linearly with increasing concentration of albendazole, which is corroborated by the calculated correlation coefficient value of -0.9998. The system obeys Beer's law for 2.5-25 microg x ml(-1) of albendazole. The molar absorptivity and Sandell sensitivity were calculated to be 6.24 x 10(3) l mol(-1) cm(-1) and 42.54 ng cm(-2), respectively. The limits of detection and quantification were calculated to be 1.15 and 3.83 microg x ml(-1), respectively. The proposed methods were successfully applied to the determination of albendazole in commercially available dosage forms. The reliability of the assays was established by parallel determination by the official method and recovery studies.

Albendazole↗
PubMed2004

HPTLC method for guggulsterone. I. Quantitative determination of E- and Z-guggulsterone in herbal extract and pharmaceutical dosage form.

A sensitive, selective, precise and robust high-performance thin-layer chromatographic method of analysis of E and Z stereoisomers of guggulsterone (the hypolipidemic agent in the gum-resin exudates of Commiphora mukul) both as a bulk drug and in formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of toluene-acetone (9:1, v/v). Densitometric analysis of guggulsterone was carried out in the absorbance mode at 250 nm. This system was found to give compact spots for E- and Z-guggulsterone (Rf value of 0.38 +/- 0.02 and 0.46 +/- 0.02, respectively) following double development of chromatoplates with the same mobile phase. The linear regression analysis data for the calibration plots for E- and Z-guggulsterone showed good linear relationship with r2 = 0.9977 +/- 0.054 and 0.9975 +/- 0.068, respectively, in the concentration range of 100-6000 ng/spot. The mean value of slope and intercept were 0.11 +/- 0.006 and 0.11 +/- 0.005, 14.26 +/- 0.56 and 10.92 +/- 0.76, respectively, for E- and Z-guggulsterone. The method was validated for precision, robustness and recovery. The limit of detection and quantitation were 12, 10 and 24, 20 ng/spot, respectively, for E- and Z-guggulsterone. Statistical analysis proves that the method is repeatable and selective for the estimation of the said drug. Since the proposed mobile phase effectively resolves the E- and Z-isomers of guggulsterone, this HPTLC method can be applied for identification and quantitation of these isomers in herbal extracts and pharmaceutical dosage form.

Calibration↗
PubMed2006

Quantitative analysis of irbesartan in commercial dosage forms by kinetic spectrophotometry.

The objective of this work is to develop a new kinetic spectrophotometric method for the determination of irbesartan in pharmaceutical formulations. The method is based on the reaction of carboxylic acid group of the oxidized irbesartan with a mixture of potassium iodate (KIO(3)) and iodide (KI) to form yellow colored triiodide ions in aqueous medium at 30+/-1 degrees C. The reaction is followed spectrophotometrically by measuring the rate of change of absorbance at 352 nm. The initial-rate and fixed-time (DeltaA) methods are adopted for constructing the calibration curves, which were found to be linear over the concentration ranges of 10.0-60.0 and 7.5-60.0 microg ml(-1) respectively. The regression analysis of calibration data yielded the linear equations: rate=-2.138 x 10(-6)+1.058 x 10(-4)C and DeltaA=-3.75 x 10(-3)+3.25 x 10(-3)C for initial rate and fixed time (DeltaA) methods, respectively. The limit of detection for initial rate and fixed time methods are 0.21 and 2.40 mug ml(-1), respectively. The various activation parameters such as E(a), DeltaH++, DeltaS++ and DeltaG++ are also calculated for the reaction and found to be 70.95+/-0.43 kJ mol(-1), 68.48+/-0.21 kJ mol(-1), 16.54+/-0.24 J K(-1) mol(-1) and -4.94+/-0.07 kJ mol(-1), respectively. The proposed methods are optimized and validated as per the guidelines of International Conference on Harmonisation (U.S.A.). The point and interval hypothesis tests have been performed which indicate that there is no significant difference between the proposed methods and the reference method. The methods have been successfully applied to the determination of irbesartan in commercial dosage forms.

Algorithms↗