Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DOSAGE FORMS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,747 records · Page 97Linked to original sources
PubMedDate not supplied

[The interchangeability of excipient formulations and the eventual consequences].

Excipients are used to prepare dosage forms in order to facilitate the administration and the efficacy of drugs through better handling of the manufacturing process and an increase in the stability of the dosage forms as well. They are produced, as for drugs, by lots and although they correspond to official Pharmacopoeian monographs, they may vary from batch to batch. This can alter the physico-chemical properties as well as their functionalities. Even for classical and non-critical tableting excipients, tablets prepared with the same excipient (microcrystalline cellulose) but originating from several suppliers may display very dramatic differences: the main difference concerns the in vitro dissolution rate which can consequently affect the bioavailability. Switching from one excipient to another is still possible but the similarity in behaviour of the dosage form must be demonstrated by relevant tests including functionality tests.

Biological Availability↗
PubMed2006

Effects of controlled-release on the pharmacokinetics and absorption characteristics of a compound undergoing intestinal efflux in humans.

OBJECTIVE: The number of active pharmaceutical ingredients (API) undergoing inhibitable and saturable intestinal efflux is considerable. As a consequence, absorption and bioavailability may depend on the intestinal concentration profile of the drug and may vary as a function of dose and release rate of the drug from the dosage form. The impact of controlled versus immediate-release on the absorption of P-glycoprotein substrates is currently unknown. Thus, the main focus of the present study was a comparison of the pharmacokinetics of the P-gp model substrate talinolol following administration of immediate-release (IR) and controlled-release (CR) tablets to healthy human volunteers with a particular focus on the absorption characteristics of the active pharmaceutical ingredients. METHODS: Talinolol immediate-release (Cordanum), 100mg), one controlled-release (100mg) and two controlled-release tablets (200mg) were administered as single doses to fasting healthy volunteers in a crossover design with a 1 week washout period between treatments. Sufficient blood and urine samples were drawn and analysed using a specific HPLC method with UV detection to describe the resulting plasma and urinary excretion versus time profiles. RESULTS: The bioavailability of talinolol in term of AUC(0-->infinity) for IR talinolol was approximately twice as high as compared to the administration of the same dose in a controlled-release dosage form. After administration of talinolol IR tablets, the drug was rapidly absorbed and reached maximum concentrations C(max) of 204.5 ng/ml+/-121.8 (means+/-S.D.) 2h after dosing. The terminal half-life of the drug averaged 19.8h following IR administration in comparison to 32 h under CR dosing conditions. Following administration of the IR dosage form, significant secondary peaks were observed in one healthy subject. Secondary peaks were not clearly apparent in the CR plasma profiles. CONCLUSION: The present study demonstrates a considerable loss of bioavailability of drugs that are substrates of intestinal secretory transporters upon their administration in controlled-release dosage forms.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2002

Mathematical methods for quantification and comparison of dissolution testing data.

In recent years, drug release/dissolution from solid dosage forms has been the subject of intense and profitable scientific developments. Whenever a new solid dosage form is developed or produced, it is necessary to ensure that drug dissolution occurs in an appropriate manner. The pharmaceutical industry and the registration authorities do focus, nowadays, on drug dissolution studies. The quantitative analysis of the values obtained in dissolution/release tests is easier when mathematical formulas that express the dissolution results as a function of some of the dosage forms characteristics are used. This work discusses the analysis of data obtained for dissolution profiles under different media pH conditions using mathematical methods of analysis described by Moore and Flanner. These authors have described difference factor (f1) and similarity factor (f2), which can be used to characterise drug dissolution/release profiles. In this work we have used these formulas for evaluation of dissolution profiles of the conventional tablets in different pH of dissolution medium (range of physiological variations).

Journal Article↗
PubMedDate not supplied

[Bioavailability of phloroglucinol in man].

This work reports a bioavailability study between two oral dosage forms containing 125.2 mg active phloroglucinol. Twelve healthy volunteers subjects received a sublingual administration of both dosage forms, a flash liberation tablet and a freeze-dried reference tablet (lyoc), according to a randomized and cross-over design. An accurate, sensitive and specific high performance liquid chromatographic method was developed for the determination of free phloroglucinol as well as its conjugated metabolites, that allowed as to clarify phloroglucinol pharmacokinetic behaviour in man, specially its important metabolisation, its poor systemic bioavailability after oral administration and its total urinary elimination mainly under metabolized form. Total plasmatic phloroglucinol pharmacokinetic profiles led to pertinent parameters needed for statistical bioequivalence study, i.e. T1/2 alpha, T1/2 beta, AUC, Tmax, Cmax and MRT. The mean comparative values of these parameters showed the equivalent performances of both oral dosage forms studied and the statistical tests performed (ANOVA, Westlake and two one-sided t test) concluded to their bioequivalence.

Animals↗
PubMed2001

Patterns of prescription and drug use in ophthalmology in a tertiary hospital in Delhi.

AIMS: The present study was carried out to describe the patterns of prescription and drug use in Ophthalmology in out-patients at Dr Rajendra Prasad (R.P.) Centre for Ophthalmic Sciences of All India Institute of Medical Sciences (A.I.I.M.S.), New Delhi. METHODS: Prescriptions of 1017 out-patients were audited through a specially designed form and analysed for the following: average number of drugs per prescription, duration of treatment (recorded or not), dosage forms prescribed, frequency of administration (recorded or not), number of encounters with antibiotics and percentage of drugs prescribed by generic name. RESULTS: Prescription analysis showed that the average number of drugs per prescription was 3.03. Duration of treatment was recorded for only 26.4% of the drugs prescribed. The maximum number of drugs prescribed were in the form of eye drops (76%), followed by tablets (10.9%), ointments (6.4%), syrups (1%), capsules (0.7%), lotions (0.3%) and injections (0.1%). No dosage form was recorded for 4.6% of the drugs prescribed. The frequency of administration was recorded for only 77.9% of the drugs prescribed. The number of antibiotics prescribed was 1059 which constitutes 34.2% of the total number of drugs prescribed. The percentage of drugs prescribed by generic name was only 35%. CONCLUSIONS: The results obtained in this study indicated an awareness of polypharmacy but a high incidence of common prescription writing errors such as not recording the duration of therapy, frequency of administration and dosage form. Moreover prescribing by generic name was also low.

Drug Prescriptions↗
PubMed1991

Vulvovaginitis: the role of patient compliance in treatment success.

Vulvovaginitis caused by Candida organisms accounts for a large number of annual office visits to physicians, often for recurrent infection. Despite the availability of many effective antifungal preparations, treatment failures continue to occur because of poor compliance with therapy. Several factors may foster noncompliance. Those involving the patient include denial of illness, misconceptions regarding the nature of the infection or its treatment, a misunderstanding of symptomatic relief versus microbiologic cure, dislike of the dosage form, nonsupport of the sexual consort, or intolerance of side effects. The cost of treatment, inconvenient dosage form, and prolonged duration of therapy may also contribute to noncompliance. This article offers suggestions for optimizing compliance and successful treatment. Two perceived means to this end are improved patient education and the use of short-term therapy in convenient dosage form.

Antifungal Agents↗
PubMed1983

Comparison of bioavailability for phenytoin products prepared by wet granulation in normal subjects and epileptic patients.

A 20% phenytoin (PHT) plain mixture with excipients (20%PM) and three PHT products prepared by wet granulation, which are 20% fine granule (20%FG), 99% air-dried fine granule (99%FG-A) and 99% freeze-dried fine granule (99%FG-F), were prepared. The extents of PHT absorption from these products and the Aleviatin Fine Granules (97%FG) prepared with microcrystalline PHT powder were compared with those from commercially available PHT powder (Aleviatin) and tablet (Hydantol Tablet 25 mg), which are of the Pharmacopoeia of Japan grade, in healthy adult volunteers. In single dose study, the extents of PHT absorption from the powder, 20%PM, 20FG, 99%FG-A, 99%FG-F, 97%FG and tablet were 89.7, 92.2, 99.0, 96.7, 99.1, 99.1 and 99.3%, respectively. The property of almost complete absorption of PHT from the product was shown in the 20%FG, 99%FG-F and 97%FG similar to the tablet. In multiple dose study, the minimum and the average estimated free concentrations of PHT at steady-state for 99%FG-F and 97%FG were nearly equal to those for the tablet, and were higher than those for the powder. In epileptic patients, the plasma PHT concentrations were increased when dosage form was changed from the powder to 99%FG-F. However, the plasma PHT concentrations were scarcely altered when dosage form was changed from the tablet to 99%FG-F. The change in dosage forms from the tablet to 99%FG-F and 97%FG or opposite direction can be done without causing toxicity in epileptic patients, so long as these products are used at the same amounts as PHT.

Adolescent↗
PubMed2006

In vitro - in vivo correlation: from theory to applications.

A key goal in pharmaceutical development of dosage forms is a good understanding of the in vitro and in vivo performance of the dosage forms. One of the challenges of biopharmaceutics research is correlating in vitro drug release information of various drug formulations to the in vivo drug profiles (IVIVC). Thus the need for a tool to reliably correlate in vitro and in vivo drug release data has exceedingly increased. Such a tool shortens the drug development period, economizes the resources and leads to improved product quality. Increased activity in developing IVIVCs indicates the value of IVIVCs to the pharmaceutical industry. IVIVC can be used in the development of new pharmaceuticals to reduce the number of human studies during the formulation development as the main objective of an IVIVC is to serve as a surrogate for in vivo bioavailability and to support biowaivers. It supports and/or validates the use of dissolution methods and specification settings. This is because the IVIVC includes in vivo relevance to in vitro dissolution specifications. It can also assist in quality control for certain scale-up and post-approval changes (SUPAC). With the proliferation of modified-release products, it becomes necessary to examine the concept of IVIVC in greater depth. Investigations of IVIVC are increasingly becoming an integral part of extended release drug development. There must be some in vitro means of assuring that each batch of the same product will perform identically in vivo. This review article represents the FDA guidance, development, evaluation, and validation of an IVIVC to grant biowaivers, and to set dissolution specifications for oral dosage forms, biopharmaceutics classification systems (BCS), BCS biowaivers, application of BCS in IVIVC development and concept of mapping. The importance of dissolution media and methodology and pharmacokinetic studies in the context of IVIVC has been highlighted. The review also covers the literature examples of IVIVCs regarding internal and external validation, compendial dissolution assessment, formulation dependency of IVIVCs, and IVIVCs of pure enantiomers versus racemate drugs. The same principles of IVIVC used for oral extended release products may be applied for non-oral products such as parenteral depot formulations and novel drug delivery systems as well.

Biological Availability↗
PubMed1979

Appropriate nitroxoline dosage regimen design.

Clinically used dosage regimen of nitroxoline, three times 100 mg daily, was proved to be inappropriate because the successfulness of medical treatment was rarely sufficient. Nitroxoline, used as urinary antiseptic, exhibits its antibacterial activity in concentrations higher than 6 mg/l, as demonstrated in many "in vitro" experiments. This work deals with the most appropriate nitroxoline dosage form as well as with the optimal dosage regimen design. The data were obtained by the aid of the suitable pharmacokinetic model and multiple dosing simulation on analog-hybrid computer EAI 580. From the several studied alternatives two usable dosage forms with the necessary dose and corresponding dosage interval were selected.

Anti-Infective Agents, Urinary↗
PubMedDate not supplied

Formulation studies on modified releasing amoxicillin trihydrate microcapsules.

In vitro researches and in vivo animal experiments show that, generally the antibiotic concentration should be above minimum inhibitory concentration for optimal efficiency. There is also direct and indirect evidence from human trials to support this claim. Consequently, a modified-release dosage form of the beta-lactam antibiotics might be therapeutically more efficient than the existing conventional products, which are rapidly absorbed to produce transient peaks in serum drug levels. In our study, Amoxicillin was chosen as the model drug, because it is currently one of the most widely prescribed oral semisynthetic penicillins. By using various types of polymers and different formulations of them, we tried to improve a microparticular system. We succeeded in obtaining optimal production of particulars in the prepared microcapsule form with the solvent evaporation technique. By applying suitable pharmaceutical technological production parameters, the production of the dosage form which releases modified-release form of the model antibiotic is provided. Production processes and availability for the aim is controlled by using the pharmaceutical technological tests, mainly with the methods according to USP XXIV. Consequently compared to the classical Amoxicillin trihydrate dosage forms used in treatment, we managed to form the microcapsule structure containing modified release.

Amoxicillin↗
PubMed1979

Comparative pharmacokinetics and relative bioavailability for different preparations of nitrofurantoin.

In a single-dose study three different dosage forms of nitrofurantoin tablets are compared in order to attain a longer duration of efficacy by means of sustained-release dosage forms. In particular, bioavailability and the rate constants are estimated and show for one dosage form significant advantages. The measured serum and urine concentration levels are evaluated with a two-compartment model of first order which assumed the sustained release of the drug in an exponential manner.

Adult↗
PubMed2000

Design and in vivo evaluation of an oral delivery system for insulin.

PURPOSE: To develop an oral controlled release system for insulin. METHODS: The polymer-inhibitor conjugates carboxymethylcellulose (CMC)-Bowman-Birk inhibitor and CMC-elastatinal were homogenized with polycarbophil-cysteine conjugate, insulin, and mannitol, compressed to 2 mg microtablets and enteric coated with a polymethacrylate. The protective effect of this delivery system for insulin towards enzymatic degradation, as well as the release profile, was evaluated in vitro. In addition, the effect of the dosage form on glucose levels of diabetic mice was determined. RESULTS: Tablets containing the CMC-inhibitor conjugates showed a strong protective effect for insulin. Whereas 91.6 +/- 7.4% (mean +/- SD, n = 3) of insulin in the dosage form without the inhibitor conjugates has been degraded within 3 h of incubation in an artificial intestinal fluid containing physiological concentrations of trypsin, chymotrypsin, and elastase, 49.7 +/- 5.5% (mean +/- SD, n = 3) of insulin remained stable in the delivery system containing the polymer-inhibitor conjugates. Additionally, polycarbophil-cysteine (PCP-Cys) provides high cohesiveness of the dosage form, due to the formation of interas well as intramolecular disulfide bonds within the polymer matrix. According to this, a controlled release of insulin could be achieved over a time period of 10 h. Furthermore, in vivo studies in diabetic mice showed a decrease in basal glucose levels of 20% to 40% during a time period of 80 h. CONCLUSIONS: Mucoadhesive polymer-inhibitor conjugates might represent a promising excipient in delivery systems for oral (poly)peptide delivery.

Acrylic Resins↗
PubMed1997

The effect of intestinal bacteria adherence on drug diffusion through solid films under stationary conditions.

PURPOSE: To study the in vitro and in vivo the role of surface bacterial adhesion on the diffusion of model drugs at stationary conditions. METHODS: Salicylic acid (SA) diffusion through ethyl cellulose (EC) films was measured in vitro in side-by-side diffusion cells with and without E. coli of intestinal origin. Insulin (I) release from paper strips coated or uncoated with pectin films, with or without antibiotic treatment, was measured in vivo in conscious rats after cecal implantation by comparing blood glucose levels at Tmax of the pharmacodynamic effect. RESULTS: During five hours of diffusion studies which were performed immediately following incubation of EC films with bacteria, the diffusion rate of SA throughout the films was 2.72-fold lower in the presence of bacteria compared with the diffusion rate in the control studies conducted without bacteria. The mean blood glucose levels dropped in the rat to 40.6 +/- 21.6% of glucose basal levels within 2.4 +/- 1.4 h when uncoated I solid carriers were used. Glucose levels did not change for pectin-coated dosage forms. After antibiotic treatment which prevented the formation of bacterial biofilm on the surface of the I solid dosage forms, blood glucose levels dropped to 22.0 +/- 4.7% and 50.9 +/- 20.5% of glucose basal levels within 7.4 +/- 2.6 h and 1.8 +/- 0.9 h for pectin uncoated or coated dosage forms, respectively. Maximum bacterial adherence occurred at stationary conditions (RPM = 0), while at maximum agitation (200 RPM), almost no adherence occurred. CONCLUSIONS: (a) Bacterial adherence shows down the diffusion rate of SA through EC films; (b) Under stationary conditions bacterial adherence may also interfere with drug release from biodegradable (pectin) films; (c) Successful functioning of biodegradable colon-specific delivery systems depends on agitation and surface friction in the lumen of the colon.

Animals↗
PubMed2002

[Liberation of potential local anesthetics from colloidal dispersions].

Evaluation of pharmaceutical availability of drugs from topical preparations is usually aimed to evaluate the capability of the dosage form to release the drug for its therapeutic action. Permeation cells have been used for this purpose, employing solid membranes including cellophane. Within a study of phenylcarbamic acid derivatives with local anaesthetic effect, the present paper evaluates the dosage form for topical administration containing potential drug XIX M, the chemical name N-[2-(2-heptyloxyphenylcarbamoyloxy)-ethyl]-morpholinium chloride and potential drug XXII B, the chemical name N-[2-(2-octyloxyphenylcarbamoyloxy)-ethyl]-dimethylammonium chloride. The selected auxiliary substance in the formulation of the dosage form was a cellulose derivative--methylcellulose in increasing concentrations from 0.5 to 1.5%. On the basis of the obtained results it can be stated that the examined polymer methylcellulose with increasing concentration decelerated the release of both potential drugs approximately in the same way and that it can be used in practice to prolong the local anaesthetic effect.

Anesthetics, Local↗
PubMed2000

[Nomenclature of drug forms--overview of development and the present state].

If the names used for dosage forms in pharmacopoeias and professional literature are examined, changes are found which are not always connected with extended knowledge about preparations, or the development of new variants of the dosage form. The same finding holds true for their classification into systematic groups. The problem has become particularly topical within the framework of international co-operation. The objective of the present paper is to inform about the steps aiming at standardisation of their nomenclature at least in Europe.

Czech Republic↗
PubMed2003

Disintegration of magnetic tablets in human stomach evaluated by alternate current biosusceptometry.

Oral administration is the most convenient route for drug therapy. The knowledge of the gastrointestinal transit and specific site for drug delivery is a prerequisite for development of dosage forms. The aim of this work was to demonstrate that is possible to monitor the disintegration process of film-coated magnetic tablets by multi-sensor alternate current Biosusceptometry (ACB) in vivo and in vitro. This method is based on the recording of signals produced by the magnetic tablet using a seven sensors array and signal-processing techniques. The disintegration was confirmed by signals analysis in healthy human volunteers' measurements and in vitro experiments. Results showed that ACB is efficient to characterize the disintegration of dosage forms in the stomach, being a research tool for the development of new pharmaceutical dosage forms.

Adult↗
PubMed1999

Aging processes in pharmaceutical polymers.

In the practical field of solid pharmaceutical formulations, studies of the physical aging of polymers and the stability of dosage forms are of great importance. Polymers are the additives used to convert pharmacologically active compounds into pharmaceutical dosage forms suitable for administration to patients, and thus a knowledge of the physical aging effects on the stability of final products is essential. In this review, the author attempts to elucidate the fundamental concepts of physical aging in polymers, and correlate the effects of physical aging on the properties with changes in solid dosage form stability.

Journal Article↗
PubMed2006

Formulation and development of gastroretentive drug delivery system for ofloxacin.

The aim of the present study was to develop a delivery system wherein the retention of ofloxacin could be achieved for increased local action in gastric region against Helicobacter pylori infection. The formulation was optimized on the basis of in vitro buoyancy and in vitro release in citrate phosphate buffer (pH 3). The hydrodynamically balanced capsules were prepared by physical mixing of various grades of HPMC and poly(ethylene oxide) (PEO) alone as well as in combinations. Cellulose acetate pthalate, liquid paraffin, and ethyl cellulose were used as release modifiers so as to maintain release of drug over a period of 12 h. The capsules prepared with PEOWSR 60K and drug coated with 2.5% ethyl cellulose gave the best in vitro percentage release and were taken as the optimized formulations. Various grades of Eudragit and PEO were used in combination for formulating floating microspheres using solvent diffusion technique for preparation of multiple unit system. The use of two different solvents (dichloromethane and ethanol) that differed in the rate of diffusion led to formation of a hollow core in the microspheres, which was partially responsible for the flotation ability. The in vitro release of the floating capsules and microspheres was found to be 96.02% and 95.83% in 12 h, respectively. Both the dosage forms follow Higuchi model for release from formulations. By fitting the in vitro release data of single unit dosage form into zero-order, first-order, and Higuchi model, it could be concluded that the release followed Higuchi model, as the correlation coefficient (R2 value) was higher than those in the other two release models. In both cases of single and multiple unit dosage form, R2 values for Higuchi model were found to be good, showing that drug release followed non-Fickian diffusion mechanism.

Administration, Oral↗