1. A controlled release dosage form comprising:
(i) a tablet core comprising a pharmaceutically active ingredient and one or more pharmaceutically acceptable matrix forming polymers, the tablet core releases the active ingredient with a release profile of active ingredient for 0 to at least 50% by weight release of active ingredient defined by the equations
y=k*tn
in which y is the fraction of active ingredient released
k is the kinetic constant
t is time
n is the release exponent
and n is the range 0.30 to 0.65
(ii) a substantially insoluble casing extended over the tablet core covering between 25 to 99% of the surface area of the tablet core, the casing resulting from electrostatic deposition of a powder comprising fusible particles onto the tablet core and fusing the particles to form a thin film such that the said electrostatic coated tablet releases the active ingredient with a release profile of active ingredient for 0 to at least 50% by weight release of active ingredient defined by the equations
y=k*tn
in which y is the fraction of active ingredient released
k is the kinetic constant
t is time
n is the release exponent
and n is the range 0.70 to 1.0.
2. A solid pharmaceutical dosage form as claimed in claim 1 in which the insoluble casing covers from 65 to 95% of the surface area of the tablet core.
3. A solid pharmaceutical dosage form as claimed in claim 1 in which the tablet core comprises two major opposing surfaces separated by one or more sidewalls at least the major surfaces being covered by the casing.
4. A solid pharmaceutical dosage form as claimed in claim 1 in which the tablet core comprises two major opposing surfaces separated by one or more sidewalls one major surface and the one or more sidewalls being covered by the casing.
5. A solid pharmaceutical dosage form as claimed in claim 1 in which the controlled release dosage form has a release profile in which n=0.7 to 1.0 over from 0 to at least 70% by weight release of the active ingredient.
6. A solid pharmaceutical dosage form as claimed in claim 1 in which the release profile of the controlled release dosage form requires at least 4 hours to achieve 70% by weight release of active ingredient.
7. A solid pharmaceutical dosage form as claimed in claim 1 in which the tablet core comprises a binder selected from acacia, alginic acid, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, dextrin, ethylcellulose, gelatin, glucose, guar gum, hydrogenated vegetable oil, hydroxypropylmethylcellulose, magnesium aluminium silicate, Maltodextrin, methylcellulose, polyethylene oxide, povidone, sodium alginate and hydrogenated vegetable oils.
8. A solid pharmaceutical dosage form as claimed in claim 1 in which the tablet core additionally comprises a release rate controlling polymer is selected from polymethacrylates, ethylcellulose, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, sodium carboxymethylcellulose, calcium carboxymethylcellulose, acrylic acid polymer, polyethylene glycol, polyethylene oxide, carrageenan, cellulose acetate, glyceryl monostearate and zein.
9. A solid pharmaceutical dosage form as claimed in claim 1 in which the tablet core additionally comprises a diluent selected from lactose, cellulose, dicalcium phosphate, sucrose, dextrose, fructose, xylitol, mannitol, sorbitol, calcium sulphate, starches, calcium carbonate, sodium carbonate, dextrates, dextrin, kaolin, lactitol, magnesium carbonate, magnesium oxide, maltitol, maltodextrin and maltose.
10. A solid pharmaceutical dosage form as claimed in claim 1 in which the tablet core comprises a hydrophobic matrix containing an active ingredient, a hydrophilic matrix containing an active ingredient, or a mixture of hydrophilic and hydrophobic materials.
11. A solid pharmaceutical dosage form as claimed in claim 1 in which the active ingredient is selected from acid-peptic and motility influencing agents, laxatives, antidiarrheials, colorectal agents, pancreatic enzymes and bile acids, antiarrhythmics, antianginals, diuretics, anti-hypertensives, anti-coagulants, anti-thrombotics, fibrinolytics, haemostatics, hypolipidaemic agents, anti-anaemia and neurotropenia agents, hypnotics, anxiolytics, anti-psychotics, anti-depressants, anti-emetics, anti-convulsants, CNS stimulants, analgesics, anti-pyretics, anti-migraine agents, non-steroidal anti-inflammatory agents, anti-gout agents, muscle relaxants, neuro-muscular agents, steroids, hypoglycaemic agents, hyperglycaemix agents, diagnostic agents, antibiotics, anti-fungals, anti-malarials, anti-virals, immunosuppressants, nutritional agents, vitamins, electrolytes, anorectic agents, appetite suppressants, bronchodilators, expectorants, anti-tussives, mucolytes, decongestants, anti-glaucoma agents, oral contraceptive agents, diagnostic and neoplastic agents.
12. A solid pharmaceutical dosage form as claimed in claim 1 in which the tablet core comprises a polymeric material which swells on contact with aqueous liquid, said swellable polymeric material being selected from cross-linked sodium carboxymethylcellulose, cross-linked hydroxypropylcellulose, high molecular weight hydroxypropylcellulose, carboxymethylamide, potassium methacrylatedivinylbenzene copolymer, polymethylmethacrylate, cross-linked polyvinylpyrrolidone and high molecular weight polyvinylalcohols.
13. A solid pharmaceutical dosage form as claimed in claim 1 in which the casing comprises a polymer resin selected from polymethacrylates, cellulose and its derivatives, cellulose ethers and esters and cellulose acetate phthalate.
14. A solid pharmaceutical dosage form as claimed in claim 1 in which the casing additionally comprises one or more adjuvants selected from opacifiers, colourants, plasticisers, flow aids and charge control materials.
15. A solid pharmaceutical dosage form as claimed in claim 14 in which the casing comprises a plasticiser selected from polyethylene glycols, triethyl citrate, acetyltributyl citrate, acetyltriethyl citrate, tributyl citrate, diethyl phthalate, dibutyl phthalate, dimethyl phthalate, dibutyl sebacate and glyceryl monostearate.
16. A solid pharmaceutical dosage form as claimed in claim 1 in which the casing has an average thickness of from 20 to 50 \u03bcM.
17. A solid pharmaceutical dosage form as claimed in claim 1 in which the casing results in a weight gain of less than 4% by weight of the tablet core.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A lubricating system for an internal combustion engine, comprising:
an oil tank provided in an engine body having a crankcase which rotatably bears a crankshaft fitted with a centrifugal clutch at one end portion thereof and which defines a crank chamber;
a feed pump for supplying oil in said oil tank to a portion to be supplied with the oil of said engine body; and
a scavenging pump for returning the oil collecting in a bottom portion of said crank chamber into said oil tank;
wherein said oil tank is provided in said engine body adjacent, in the direction along the axis of said crankshaft, to said centrifugal clutch contained in a clutch containing chamber communicating with the inside of said crank chamber;
a wall portion partitioning the inside of said oil tank and said clutch containing chamber from each other is provided with an opening portion for communication between said clutch containing chamber and the inside of said oil tank; and
said opening portion is located on the outer side relative to the outermost rotational locus of said centrifugal clutch as viewed in the direction along the axis of said crankshaft,
wherein said oil tank includes a crankcase cover joined to said crankcase in a manner for defining said clutch containing chamber between the oil tank and said crankcase and a tank cover joined to said crankcase cover, and
a return hole, for returning into said oil tank the oil discharged from an oil pressure control unit attached to said crankcase cover at a portion corresponding to an upper side of said oil tank, is provided in said crankcase cover so as to communicate with the inside of said oil tank,
wherein said crankcase cover includes a rib that is integral therewith and projects therefrom for leading to said return hole the oil discharged from said oil pressure control unit attached to said crankcase cover.
2. The lubricating system for an internal combustion engine as set forth in claim 1, wherein said opening portion is disposed on the upper side relative to the axis of rotation of said crankshaft.
3. The lubricating system for an internal combustion engine as set forth in claim 1, wherein said oil tank provided at the crankcase cover constituting a part of the engine that is adjacent, in a direction along the axis of the crankcase, to the centrifugal clutch contained in the clutch containing chamber communicating with the inside of the crank chamber.
4. The lubricating system for an internal combustion engine as set forth in claim 2, wherein said oil tank includes a crankcase cover constituting a part of the engine body that is adjacent, in a direction along the axis of the crankshaft, to the centrifugal clutch contained in the clutch containing chamber communicating with the inside of the crank chamber.
5. The lubricating system adapted for use with an internal combustion engine as set forth in claim 3, wherein said oil pressure control unit is attached to said crankcase cover at a portion corresponding to a skew upper side of the oil tank.
6. The lubricating system adapted for use with an internal combustion engine as set forth in claim 4, wherein said oil pressure control unit is attached to said crankcase cover at a portion corresponding to a skew upper side of the oil tank.
7. A lubricating system for an internal combustion engine, comprising:
an oil tank;
a feed pump for supplying oil in said oil tank to an engine body; and
a scavenging pump for returning the oil collecting in a bottom portion of a crank chamber into said oil tank;
wherein said oil tank is provided in said engine body adjacent, in a direction along an axis of a crankshaft, to a centrifugal clutch that is in communication with an inside of said crank chamber;
a wall portion partitioning an inside of said oil tank and a clutch containing chamber from each other, said wall portion being provided with an opening portion for communication between said clutch containing chamber and the inside of said oil tank; and
said opening portion being located on an outer side relative to an outermost rotational locus of said centrifugal clutch as viewed in the direction along the axis of said crankshaft,
wherein said oil tank includes a crankcase cover joined to a crankcase in a manner for defining said clutch containing chamber between the oil tank and said crankcase and a tank cover joined to said crankcase cover, and
a return hole, for returning into said oil tank the oil discharged from an oil pressure control unit attached to said crankcase cover at a portion corresponding to an upper side of said oil tank, is provided in said crankcase cover so as to communicate with the inside of said oil tank,
wherein said crankcase cover includes a rib that is integral therewith and projects therefrom for leading to said return hole the oil discharged from said oil pressure control unit attached to said crankcase cover.
8. The lubricating system for an internal combustion engine as set forth in claim 7, wherein said opening portion is disposed on the upper side relative to the axis of rotation of said crankshaft.
9. The lubricating system for an internal combustion engine as set forth in claim 7, wherein said oil tank is provided at the crankcase cover constituting a part of the engine body that is adjacent, in a direction along the axis of the crankshaft, to the centrifugal clutch contained in the clutch containing chamber communicating with the inside of the crank chamber.
10. The lubricating system for an internal combustion engine as set forth in claim 8, wherein said oil tank is provided at the crankcase cover constituting a part of the engine body that is adjacent, in a direction along the axis of the crankshaft, to the centrifugal clutch contained in the clutch containing chamber communicating with the inside of the crank chamber.
11. The lubricating system adapted for use with an internal combustion engine as set forth in claim 9, wherein said oil pressure control unit is attached to said crankcase cover at a portion corresponding to a skew upper side of the oil tank.
12. The lubricating system adapted for use with an internal combustion engine as set forth in claim 10, wherein said oil pressure control unit is attached to said crankcase cover at a portion corresponding to a skew upper side of the oil tank.
13. A lubricating system adapted for use with an internal combustion engine, comprising:
an oil tank;
a feed pump adapted for supplying oil in said oil tank to an engine body; and
a scavenging pump adapted for returning the oil collecting in a bottom portion of a crank chamber into said oil tank, and in order to contrive a reduction in size of the engine body, said oil tank is provided in said engine body adjacent, in a direction along an axis of a crankshaft, to a centrifugal clutch that is in communication with an inside of said crank chamber, and is shaped so as to overlap an axial end of the crankshaft and a portion of a water pump;
a wall portion partitioning an inside of said oil tank and a clutch containing chamber from each other, said wall portion being provided with an opening portion for communication between said clutch containing chamber and the inside of said oil tank; and
said opening portion being located on an outer side relative to an outermost rotational locus of said centrifugal clutch as viewed in the direction along the axis of said crankshaft,
wherein said oil tank includes a crankcase cover joined to a crankcase by a plurality of bolts in a manner for defining said clutch containing chamber between the oil tank and said crankcase and a tank cover joined to said crankcase cover, and
a return hole, for returning into said oil tank the oil discharged from an oil pressure control unit attached to said crankcase cover at a portion corresponding to an upper side of said oil tank, is provided in said crankcase cover so as to communicate with the inside of said oil tank,
wherein said crankcase cover includes a rib that is integral therewith and projects therefrom for leading to said return hole the oil discharged from said oil pressure control unit attached to said crankcase cover.
14. The lubricating system adapted for use with an internal combustion engine as set forth in claim 13, wherein said opening portion is disposed on an upper side relative to the axis of rotation of said crankshaft.
15. The lubricating system adapted for use with an internal combustion engine as set forth in claim 14, wherein said oil tank includes a crankcase cover attached to a crankcase by a plurality of bolts in a manner for defining said clutch containing chamber between the oil tank and said crankcase and a tank cover joined to said crankcase cover, and
a return hole, for returning into said oil tank the oil discharged from an oil pressure control unit attached to said crankcase cover at a portion corresponding to an upper side of said oil tank, is provided in said crankcase cover so as to communicate with the inside of said oil tank.
16. The lubricating system adapted for use with an internal combustion engine as set forth in claim 13, wherein said oil pressure control unit is attached to said crankcase cover at a portion corresponding to a skew upper side of the oil tank.
17. The lubricating system adapted for use with an internal combustion engine as set forth in claim 13, when the engine is viewed in an axial direction of the crankshaft, an oil sump and an output shaft are disposed on opposite lateral sides of the oil tank.
18. The lubricating system adapted for use with an internal combustion engine as set forth in claim 13, when the engine is viewed in an axial direction of the crankshaft, the oil tanks extends further on both lateral sides of the crankshaft than an outermost rotational locus of the centrifugal clutch.