Controlled release reservoir mini tablets approach for controlling the drug release of Galantamine Hydrobromide

The objective of this study is to explore and investigate the reservoir mini tablets approach to control the release of Galantamine Hydrobromide in comparison to desired release profile to the Innovator formulation Razadyne ER capsules as disclosed in US Patent 7,160,559 which is granted to Janseen Pharmaceutica NV. The core mini tablets were prepared using the direct compression and wet granulation methods. These core mini tablets were further coated with Galantamine Hydrobromide in two different portions; 70% as controlled release and 30% as immediate release and then filled in empty hard gelatin capsule shells. The dissolution profiles of each formulation were compared to those of Razadyne ER capsules and the mean dissolution time (MDT), dissolution efficiency (DE%) and dissolution similarity (f2 factor) were calculated. It was observed that core formulation plays an important role in controlling the drug release as well as maintaining pH independent drug release profile. The release mechanism of GAH from reservoir mini tablet formulation follows Higuchi and first order. These results imply that controlled release reservoir mini tablets which further filled into empty hard gelatin capsule shells can be a suitable method to formulate controlled release Galantamine hydrobromide.     

Development and in vivo evaluation of novel monolithic controlled release compositions of galantamine hydrobromide as against reservoir technology

The objective of this study is to develop and in vivo evaluation of novel monolithic matrix mini tablets approach to control the release of galantamine hydrobromide (GAH) in comparison with desired release profile to the Innovator formulation Razadyne^® ER capsules. The direct compression method was employed for preparation of matrix mini tablets as against reservoir multiparticulate pellets of innovator formulation. The matrix swellings, dissolution similarity, mean dissolution time and dissolution efficiency of formulations were evaluated. It was found that increase in the concentration of high viscosity hydroxypropylcellulose (HPC) results reduction in release rate. The drug release was shown to be pH dependent with faster rate at lower pH. The release of GAH followed first order shifting to dissolution dependent by increase of HPC content. The formulation showed stability of drug release. In vivo prediction was done by Wagner–Nelson method. Prediction errors were estimated for C_max and area under curve (AUC) and found to be not exceeding 15%. In vivo study in human volunteers confirmed the similarity between test and innovator formulations and pharmacokinetic values were comparable between actual and predicted. These results suggest that novel monolithic matrix approach could be suitable technique to formulate controlled release GAH.     

Preparation and in vitro evaluation of slow release ketoprofen microcapsules formulated into tablets and capsules.

Ketoprofen powder was encapsulated with Eudragit RL/RS polymer solutions in isopropanol-acetone 1:1, using a simple and rapid method. Microcapsules were prepared using Eudragit solutions with different RL/RS ratios. The encapsulation process produces free-flowing microcapsules with good drug content and marked decrease in dissolution rate. The retardation in release profile of ketoprofen from microcapsules was a function of the polymer ratio employed in the encapsulation process. In vitro release of ketoprofen from microcapsules either filled in gelatin capsules or compressed into tablets, using calcium sulphate as diluent, confirmed the efficiency of the encapsulation process for preparing prolonged release medication. A capsule formulation with optimum sustained-release profile was suggested.     

Preparation and in vitro evaluation of slow release ketoprofen microcapsules formulated into tablets and capsules

Abstract

Ketoprofen powder was encapsulated with Eudragit RL/RS polymer solutions in isopropanol-acetone 1:1, using a simple and rapid method. Microcapsules were prepared using Eudragit solutions with different RL/RS ratios. The encapsulation process produces free-flowing microcapsules with good drug content and marked decrease in dissolution rate. The retardation in release profile of ketoprofen from microcapsules was a function of the polymer ratio employed in the encapsulation process. In vitro release of ketoprofen from microcapsules either filled in gelatin capsules or compressed into tablets, using calcium sulphate as diluent, confirmed the efficiency of the encapsulation process for preparing prolonged release medication. A capsule formulation with optimum sustained-release profile was suggested.     

Fatty acid and water-soluble polymer-based controlled release drug delivery system

Sustained release capsule formulations based on three components, drug, water-soluble polymer, and water-insoluble fatty acid, were developed. Theophylline, acetaminophen, and glipizide, representing a wide spectrum of aqueous solubility, were used as model drugs. Povidone and hydroxypropyl cellulose were selected as water-soluble polymers. Stearic acid and lauric acid were selected as water-insoluble fatty acids. Fatty acid, polymer, and drug mixture was filled into size #0 gelatin capsules and heated for 2 h at 50 °C. The drug particles were trapped into molten fatty acid and released at a controlled rate through pores created by the water-soluble polymer when capsules were exposed to an aqueous dissolution medium. Manipulation of the formulation components enabled release rates of glipizide and theophylline capsules to be similar to commercial Glucotrol XL tablets and Theo-24 capsules, respectively. The capsules also exhibited satisfactory dissolution stability after exposure to 30 °C/60% relative humidity (RH) in open Petri dishes and to 40 °C/75% RH in closed high-density polyethylene bottles. A computational fluid dynamic-based model was developed to quantitatively describe the drug transport in the capsule matrix and the drug release process. The simulation results showed a diffusion-controlled release mechanism from these capsules.     

Comparison of WHO and US FDA biowaiver dissolution test conditions using bioequivalent doxycycline hyclate drug products

Objectives The dissolution characteristics of immediate‐release doxycycline hyclate products with certified in‐vivo bioequivalence to the innovator product were tested with a view to possible application of biowaiver‐based approval. Methods Five products were tested using US Pharmacopeia Apparatus 2: Antodox 100 mg hard gelatin capsules, Doxycyclin AL 100 T tablets, Doxycyclin‐ratiopharm 100 soft gelatin capsules, Doxycyclin STADA 100 mg tablets and Doxy‐Wolff 100 mg tablets. Three compendial buffers were used as dissolution media: simulated gastric fluid without pepsin, pH 1.2, acetate buffer, pH 4.5, and simulated intestinal fluid without pancreatin, pH 6.8. Results were obtained at two paddle speeds recommended for biowaiver applications: 75 rpm (World Health Organization; WHO) and 50 rpm (US Food and Drug Administration; US FDA). Key findings The results for the tablets and hard gelatin capsules indicate that a paddle speed of 75 rpm is more representative than 50 rpm, since 75 rpm generates dissolution profiles corresponding more closely to the in‐vivo profiles than those at 50 rpm. For evaluating soft gelatin capsule formulations with lipid fill, both US FDA and WHO methods were found to be over‐discriminating. Conclusions Bioequivalence of immediate‐release doxycycline hyclate tablets and hard gelatin capsules, but not soft gelatin capsules, can be evaluated in vitro using the biowaiver dissolution test conditions specified by the WHO.     

The influence of polymorphism on the manufacturability and in vitro dissolution of sulindac-containing hard gelatin capsules

Abstract

Context: Drug polymorphism could affect drug product dissolution, manufacturability, stability and bioavailability/bioequivalence. The impact of polymorphism on the manufacturability and in vitro dissolution profiles of sulindac capsules has not been studied yet.

Objective: To evaluate the impact of polymorphism on the manufacturability and in vitro dissolution of sulindac hard gelatin capsules.

Materials and methods: Sulindac crystal forms I and II (SLDI and SLDII, respectively) were prepared and characterized. Powder formulations containing one of the polymorphs, lactose and magnesium stearate (at three different levels) were prepared and their flow properties determined. Hard gelatin capsules were filled with the formulations and tested for fill-weight variations. Drug dissolution for SLDI- and SLDII-containing hard gelatin capsules was determined.

Results: Differences in flow properties for each polymorph were observed, as well as for their formulations, which in turn affected capsule weight homogeneity. Statistically significant differences in the rate and extent of drug release were observed between SLDI- and SLDII-containing capsules.

Discussion: Formulations containing SLDI showed a better manufacturability and a better dissolution profile than those with SLDII.

Conclusion: Sulindac crystalline form I was the best candidate for hard gelatin capsule formulation because of its technological and in vitro dissolution properties.     

In situ-formed asymmetric membrane capsule for osmotic release of poorly water-soluble drug

A non-disintegrating, in situ-formed, asymmetric membrane, polymeric capsular system, offering improved osmotic effect, was used to deliver poorly water-soluble drug in a controlled manner. The poorly water-soluble drug ketoprofen was selected as a model drug to demonstrate how controlled release characteristics can be manipulated by design of in situ-formed polymeric capsule with an asymmetric membrane and core formulations. In situ-formed, asymmetric membrane capsule was made by dry method via precipitation of asymmetric membrane on the walls of hard gelatin capsule. Resulting asymmetric membrane composed of a dense outer region with fewer pores and a lighter inner porous region. The present study evaluates the influence of variables based on two-factor composite design, namely, ethylcellulose and osmogen (sodium chloride), apart from studying effect of varying osmotic pressures of dissolution medium and level of pore-former concentration (glycerol) on drug release. Statistical significance was tested at P < 0.05. Results showed the best formulation (F-5) to closely corresponded to extra design checkpoint formulation by a similarity (f2) value of 95.41 and capsules made with 15% w/v EC, 50 mg sodium chloride, 8% w/v glycerol and 30 mg citric acid (F-11), to achieve therapeutic concentration within first hour of dissolution not observed with any other formulations used in the study. Drug release followed Fickinan diffusion and was independent of pH but dependent on the osmotic pressure of the dissolution medium.     

Challenges and opportunities in the encapsulation of liquid and semi-solid formulations into capsules for oral administration

The encapsulation of liquids and semi-solids provides solutions for convenient delivery through improved oral absorption of poorly water-soluble drugs. In addition, low dose (content uniformity), highly potent (containment), low melting point drugs, those with a critical stability profile and those for which a delayed release is required are candidates for liquid or semi-solid formulations. Both hard and soft capsules can be considered and in each case the capsule wall may comprise gelatin or some other suitable polymer such as hypromellose. The choice of a hard or soft capsule will depend primarily on the components of the formulation which provides the best absorption characteristics as well as on the physical characteristics, such as the viscosity of the formulation and the temperature at which the product needs to be filled. Numerous excipients are available for formulation of lipid-based systems and their compatibilities with hard gelatin capsules have been tested. The availability of new enhanced manufacturing equipment has brought new opportunities for liquid-filled hard capsules. Filling and sealing technologies for hard capsules, provides the formulator with the flexibility of developing formulations in-house from small scale, as required for Phase I studies, up to production.     

The influence of additives on the presentation of a drug in hard gelatin capsules

The influence of the concentration of lactose, magnesium stearate and sodium lauryl sulphate on the in vitro dissolution and the drug content of hard gelatin capsules filled under conditions which result in a maximum tapped bulk density, has been evaluated by a factorially-designed experiment. The 3 factors have a significant effect on both drug release and capsule filling. Interactions between the 3 factors, however, limit the exact quantification of the magnitude of their influence by a simple linear model. A quadratic relation, when only 2 factors are considered, can be used to provide a prediction of the influence of these factors. The relations between 2 factors are demonstrated as contours of equal in vitro drug release and equal drug content of capsule, at constant concentrations of the third factor. The contours show the important influence of lactose concentration on drug release and capsule filling, and the large changes in response which can occur by the addition of a third factor. They also provide a clear guide to the formulation of hard gelatin capsules.     

The influence of additives on the presentation of a drug in hard gelatin capsules.

The influence of the concentration of lactose, magnesium stearate and sodium lauryl sulphate in the in vitro dissolution and the drug content of hard gelatin capsules filled under conditions which result in a maximum tapped bulk density, has been evaluated by a factorially-designed experiment. The 3 factors have a significant effect on both drug release and capsule filling. Interactions between the 3 factors, however, limit the exact quantification of the magnitude of their influence by a simple linear model. A quadratic relation, when only 2 factors are considered, can be used to provide a prediction of the influence of these factors. The relations between 2 factors are demonstrated as contours of equal in vitro drug release and equal drug content of capsule, at constant concentrations of the third factor. The contours show the important influence of lactose concentration drug release and capsule filling, and the large changes in response which can occur by the addition of a third factor. They also provide a clear guide to the formulation of hard gelatin capsules.     

Cross-linking of hard gelatin carbamazepine capsules: effect of dissolution conditions on in vitro drug release.

The aim of this study was to determine if the use of both enzyme and surfactant in the dissolution medium changes the in vitro drug release from cross-linked hard gelatin capsules containing a water-insoluble drug. Hard gelatin capsules were cross-linked by a controlled exposure to formaldehyde resulting in different stressed capsules and carbamazepine (CBZ) was chosen as a drug model. In vitro dissolution studies were conducted using simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) with enzymes. Sodium lauryl sulfate (SLS) was added in the dissolution medium at a concentration of 2% m/v both in SGF and SIF with pepsin and pancreatin, respectively. The percentage of CBZ dissolved was reduced by increasing the degree of gelatin cross-linking. For unstressed hard gelatin capsules, 36% of the CBZ was released after 1 h, lowering to 5% for highly stressed hard gelatin capsules in the SGF. A similar effect was observed with SIF. In the case of moderately stressed hard gelatin capsules, addition of enzyme in the dissolution medium enhanced the percentage of CBZ dissolved. The dissolution level increased from 12% to 39% in SGF with pepsin for hard gelatin capsules cross-linked with 1500 ppm formaldehyde. On the contrary, the use of enzyme in the dissolution medium did not increase the dissolution of CBZ from highly stressed hard gelatin capsules. Surprisingly, the addition of SLS in the medium did not allow the release of the CBZ both in SGF and in SIF. The results of this study demonstrate that the use of enzyme in the dissolution medium is justified for moderately cross-linked hard gelatin capsules. However, the action of a surfactant added in the medium containing enzyme remains unclear.     

In vitro characterization and release study of Ambroxol hydrochloride matrix tablets prepared by direct compression

A series of either hydrophilic or hydrophobic polymers were used to prepare controlled release Ambroxol hydrochloride (AMX) matrix tablets by direct compression. Both the compatibility and flow properties of AMX/polymer mixtures were investigated. The effect of the amount and type of polymer on the physical properties and in vitro drug release was studied and compared to commercially available Ambroxol^® SR capsules. A kinetic study of the release profile of AMX from the prepared matrix tablets was performed. All excipients used in the study were compatible with the model drug. AMX/drug mixtures containing sodium alginate (NA) and hydroxypropylmethyl cellulose (HPMC) showed better flow properties than other polymers used in the study. The in vitro drug release studies showed that matrix tablets formulae containing 10% HPMC (S7) or a combination of 30% NA and 5% HPMC (Ah) exhibited a higher ability to control the release of AMX. The kinetic study revealed that a diffusion controlled mechanism prevailed except when carbopol was used. Formula Ah followed a non-fickian diffusion mechanism similar to Ambroxol^® SR capsules. Both formulae S7 and Ah could be considered as potential candidates for formulation of AMX controlled release matrix tablets.     

Effect of fill weight, capsule shell, and sinker design on the dissolution behavior of capsule formulations of a weak acid drug candidate BMS-309403

Two strengths of BMS-309403 capsules were developed from a common stock granulation. Dissolution testing of the capsules was conducted utilizing the USP apparatus 2 (paddle) with a neutral pH dissolution medium. Unexpectedly, the lower-strength capsules exhibited slower dissolution than the higher-strength capsules filled with the same stock granulation. Higher variability was also observed for the lower-strength capsules. This was found to be mainly caused by a low fill weight in a relatively large size hard gelatin capsule shell. Instead of bursting open, some gelatin capsule shells softened and collapsed onto the granulation, which delayed the release of the active drug. The problem was aggravated by the use of coil sinkers which hindered the medium flow around the capsules. Switching from the gelatin capsule shells to the HPMC (hydroxypropyl methylcellulose) shells reversed the dissolution rate ranking between the two capsule strengths. However, both dissolved at a slower rate initially than the gelatin capsules due to the inherent dissolution rate of the HPMC shells at pH 6.8. Notably, the HPMC shells did not occlude the granulation as observed with the gelatin shells. The study demonstrated that the dissolution of capsule formulations in neutral pH media was significantly affected by the fill weight, sinker design, and capsule shell type. Careful selection of these parameters is essential to objectively evaluate the in vitro drug release.     

Alternative Manufacturing Concepts for Solid Oral Dosage Forms From Drug Nanosuspensions Using Fluid Dispensing and Forced Drying Technology

Flexible manufacturing technologies for solid oral dosage forms with a continuous adjustability of the manufactured dose strength are of interest for applications in personalized medicine. This study explored the feasibility of using microvalve technology for the manufacturing of different solid oral dosage form concepts. Hard gelatin capsules filled with excipients, placebo tablets, and polymer films, placed in hard gelatin capsules after drying, were considered as substrates. For each concept, a basic understanding of relevant formulation parameters and their impact on dissolution behavior has been established. Suitable matrix formers, present either on the substrate or directly in the drug nanosuspension, proved to be essential to prevent nanoparticle agglomeration of the drug nanoparticles and to ensure a fast dissolution behavior. Furthermore, convection and radiation drying methods were investigated for the fast drying of drug nanosuspensions dispensed onto polymer films, which were then placed in hard gelatin capsules. Changes in morphology and in drug and matrix former distribution were observed for increasing drying intensity. However, even fast drying times below 1 min could be realized, while maintaining the nanoparticulate drug structure and a good dissolution behavior.     

Effect of Fill Weight,Capsule Shell,and Sinker Design on the Dissolution Behavior of Capsule Formulations of a Weak Acid Drug Candidate BMS‐309403

Two strengths of BMS‐309403 capsules were developed from a common stock granulation. Dissolution testing of the capsules was conducted utilizing the USP apparatus 2 (paddle) with a neutral pH dissolution medium. Unexpectedly, the lower‐strength capsules exhibited slower dissolution than the higher‐strength capsules filled with the same stock granulation. Higher variability was also observed for the lower‐strength capsules. This was found to be mainly caused by a low fill weight in a relatively large size hard gelatin capsule shell. Instead of bursting open, some gelatin capsule shells softened and collapsed onto the granulation, which delayed the release of the active drug. The problem was aggravated by the use of coil sinkers which hindered the medium flow around the capsules. Switching from the gelatin capsule shells to the HPMC (hydroxypropyl methylcellulose) shells reversed the dissolution rate ranking between the two capsule strengths. However, both dissolved at a slower rate initially than the gelatin capsules due to the inherent dissolution rate of the HPMC shells at pH 6.8. Notably, the HPMC shells did not occlude the granulation as observed with the gelatin shells. The study demonstrated that the dissolution of capsule formulations in neutral pH media was significantly affected by the fill weight, sinker design, and capsule shell type. Careful selection of these parameters is essential to objectively evaluate the in vitro drug release.     

Modified conventional hard gelatin capsules as fast disintegrating dosage form in the oral cavity.

Fast disintegrating capsules for administration in the oral cavity were prepared either by perforation or by vacuum-drying of conventional hard capsules. When compared to other fast disintegrating dosage forms (e.g. lyophilized sponges or tablets), these capsules have various advantages, in particular, a high drug loading capacity and no compression steps. The disintegration time of conventional hard gelatin capsules (HGC) was reduced from 91 to 39 s by introducing 6-10 small holes (diameter =25-50 microm) into the capsule shell. Vacuum-drying of conventional hard gelatin capsules resulted in brittle capsules, which broke rapidly in the oral cavity. The brittleness of the hard gelatin capsules correlated well with their moisture content. The critical moisture value for sufficient brittleness of hard gelatin capsules was <4% w/w. In contrast, HPMC capsules remained flexible, even at low moisture content. The moisture uptake of various capsule fillers was in the order of Avicel PH101 > lactose > Avicel PH112 > or = mannitol. Hard gelatin capsules filled with mannitol and packaged in bottles with silica gel kept their desired brittleness during 6 months storage at various relative humidities.     

In situ lyophilisation of nifedipine directly in hard gelatine capsules

Hydrophobic drugs present a challenge due to: (i) adhesion and agglomeration; hence the choice of the suitable processing technique to have the drugs into orally administered dosage forms is critical. (ii) Poor dissolution and poor aqueous solubility; hence poor bioavailability. A novel method which is in situ lyophilisation directly in hard gelatin capsule shells was used in this research to enhance the dissolution of nifedipine (a model hydrophobic drug) in the presence of co-povidone, Pluronic^®F-127 and inulin as enhancement excipients (to the best of our knowledge those excipients have not been previously used with nifedipine in lyophilised forms).

Solutions of nifedipine and excipients in a range of concentrations (0.5, 1, 5 and 10%w/v) were prepared using a co-solvent system of tert- butyl alcohol/water mixture. These solutions were filled directly into bodies of size 000 hard gelatin capsule shells and freeze dried. Pure drug and all formulations were characterised by solubility, wetting studies and in vitro dissolution. Also, conformational integrity and thermal characteristics of nifedipine formulations were investigated using FT-IR spectroscopy and differential scanning calorimetry (DSC), respectively. The in situ lyophilisation of nifedipine with excipients, looks a promising method not only to improve the hydrophobic drug dissolution but also to be cost effective.     

In Situ Phase-Transited Asymmetric Membrane Capsules: A Means for Achieving Delayed and Osmotic Release for pH Solubility-Dependant Drugs

In the present study, an in situ nondisintegrating polymeric capsular system in achieving delayed as well as improved osmotic flow for the model drug cefadroxil was developed. In situ formed asymmetric membrane capsule was prepared by precipitation of the asymmetric membrane (AM) on the walls of conventional hard gelatin capsules in fabricated glass holders via a dry phase inversion process. The effect of different formulation variables were studied based on a 2(3) factorial design as one variable changed from one level to another, namely, the level of osmogen, ethylcellulose, and pore former, apart from studying the effect of varying osmotic pressure and agitation intensity on drug release. Scanning electron microscopy showed an outer, dense, non-porous region and an inner, lighter, porous region for the prepared AM inside, and a gelatin layer outside. Statistical testing (Dunnett multiple comparison test) was applied for in vitro drug release (n = 6) at P < 0.05. The best formulation in the design closely corresponded to the extra design checkpoint formulation by a similarity (f(2)) value of 96.18. The drug release was independent of the agitation intensity but dependent on the osmotic pressure of the dissolution media. The release kinetics followed the Higuchi model, and the mechanism of release was Fickian diffusion. LAY ABSTRACT: The asymmetric membrane capsule (AMC) is a unique drug delivery system that looks like a conventional hard gelatin capsule but has significant advantages over it. In the present study, a system was made that had an outer disintegrating hard gelatin capsule and an inner nondisintegrating polymeric capsular system for delivering a model drug cefadroxil. The inner nondisintegrating polymeric capsular system was the AMC, which was prepared by precipitation of the asymmetric membrane (AM) on the walls of conventional hard gelatin capsules in fabricated glass holders via a dry phase inversion process. The effect of different formulation variables that might affect the drug release were studied based on a 2(3) factorial design. The formulation variables were level of osmogen, ethylcellulose, and pore former. The effect of varying osmotic pressure and agitation intensity on drug release was also studied. Scanning electron microscopy showed an outer, dense, nonporous region and an inner, lighter, porous region for the prepared AM inside, and a gelatin layer outside. Statistical testing was applied for in vitro drug release. Results showed the drug release to be independent of the agitation intensity but dependent on the osmotic pressure of the dissolution media. The release kinetics followed the Higuchi model, and the mechanism of release was Fickian diffusion.     

Influence of the physicochemical properties and concentration of native and modified potato starch on the release of a hydrophobic drug from hard gelatin capsules.

The influence of the physicochemical properties and concentration of potato starch and sodium starch glycolate on the release of phenacetin from hard gelatin capsules is examined. Smaller quantities of sodium starch glycolate are necessary to improve the disintegration of the encapsulated powder mass and the drug release, compared to blends with potato starch. From the ratio of the absolute particle diameter increase to the mean pore diameter of the encapsulated powder mass no prediction about capsule disintegration could be made, contrary to tablets. A better correlation seems to exist between the total volume increase of the starch grains and the disintegration time of the formulation.