Description
Retaining the successful previous editions' programmed instructional format, this book improves and updates an authoritative textbook to keep pace with compounding trends and calculations – addressing real-world calculations pharmacists perform and allowing students to learn at their own pace through examples.
- Connects well with the current emphasis on self-paced and active learning in pharmacy schools
- Adds a new chapter dedicated to practical calculations used in contemporary compounding, new appendices, and solutions and answers for all problems
- Maintains value for teaching pharmacy students the principles while also serving as a reference for review by students in preparation for licensure exams
- Rearranges chapters and rewrites topics of the previous edition, making its content ideal to be used as the primary textbook in a typical dosage calculations course for any health care professional
- Reviews of the prior edition: "...a well-structured approach to the topic..." (Drug Development and Industrial Pharmacy) and "...a perfectly organized manual that serves as a expert guide..." (Electric Review)
Table of Contents
Preface xiii
Chapter 1 Review of Basic Mathematical Principles1
1.1. Significant Figures 2
1.2. Rounding Off 4
1.3. Fractions 5
1.4. Exponents and Powers 8
1.5. Estimation 10
1.6. Units 12
1.7. Ratio 15
1.8. Proportion 15
1.9. Dimensional Analysis 18
Practice Problems 21
Chapter 2 Systems of Measurement 31
2.1. Metrology 31
2.2. The Metric System 32
2.3. The English Systems 33
2.3.1. The Avoirdupois System 33
2.3.2. The Apothecary or Troy System 33
2.4. Measurement of Weight 33
2.4.1. Metric Weight 33
2.4.2. English Weight 35
2.4.2.1. Avoirdupois Weight 35
2.4.2.2. Apothecary Weight 36
2.4.3. Practical Weight Equivalents 36
2.5. Measurement of Volume 38
2.5.1. Metric Volume 38
2.5.2. English Volume 39
2.5.3. Practical Volume Equivalents 39
2.6. Measurement of Length 41
2.7. Intersystem Relationships 43
2.8. Household Equivalents and Metric Estimation 44
Practice Problems 49
Chapter 3 Prescriptions and Medication Orders 54
3.1. Prescribing Authority 55
3.2. Components 57
3.3. Practices to Prevent Medication Errors 58
3.4. Common Abbreviations 60
3.5. Outpatient Prescription Drug Orders 69
3.5.1. Prescriptions for Manufactured Drug Products 69
3.5.2. Prescriptions for Compounded Drug Products 69
3.5.2.1. Types of Compounded Orders 70
3.5.2.2.1. Formulation Based on Total Quantity 70
3.5.2.3.2. Formulation Based on Single Dosage Unit 71
3.6. Inpatient Medication Orders 72
3.7. Interpretation 77
3.8. Calculations to Check “DEA” Numbers 77
3.9. Reducing and Enlarging Formulas 80
3.10. Parts Formulas 87
Practice Problems 90
Chapter 4 Weighing and Measuring in Pharmacy Practice 103
4.1. Measurement Errors 103
4.2. Indication of Error 104
4.2.1. Absolute Error: Indication of Error Based on Maximum Deviation and Significant Figures 104
4.2.2. Relative Error: Indication of Error Based on Percentage of Estimated Value 107
4.3. Tolerance in Prescription Compounding and Pharmaceutical Manufacturing 108
4.4. Weighing and Measuring 109
4.4.1. Electronic Balances 109
4.4.2. Prescription Balances: Class A, Torsion 110
4.4.2.1. Sensitivity Requirement (SR) 110
4.4.2.2. Minimum Weighable Quantity (MWQ) or Least Weighable Quantity (LWQ) 110
4.4.2.3. Percent Error 111
4.4.3. Volumetric Devices for Pharmaceutical Measurements 114
4.4.3.1. The Meniscus and Effect of Viscosity 114
4.4.3.2. Graduates 114
4.4.3.3. Pipets (Pipettes) 115
4.4.3.4. Syringes 115
4.4.3.5. Droppers 116
4.5. Aliquot Method and Triturations 119
4.5.1. Solid–Solid Aliquot Method 119
4.5.2. Solid–Solid Triturations 122
4.5.3. Liquid–Liquid Aliquots and Triturations 131
4.5.4. Solid–Liquid Aliquots 136
4.5.5. Serial Dilutions 140
4.6. Density 142
4.7. Specific Gravity 144
Practice Problems 145
Chapter 5 Dosage Calculations 160
5.1. Calculations Involving Dose, Size, Number of Doses, Amount Dispensed, and Quanity of a Specific Ingredient in a Dose 161
5.2. Dosage Measured By Drops 169
5.3. Dosage Based on Body Weight 171
5.4. Dosage Based on Body Surface Area (BSA) 174
5.5. Pediatric and Geriatric Dose Calculations 181
5.6. Chemotherapy Dose Calculations 184
Practice Problems 187
Chapter 6 Drug Concentration Expressions 203
6.1. Concentration 204
6.2. Percentage Strength Expressions 204
6.2.1. Percent Volume-in-Volume 204
6.2.2. Percent Weight-in-Weight 205
6.2.3. Percent Weight-in-Volume 206
6.2.4. Default Rules for Percentage Expressions 208
6.2.5. Prescriptions and Formulations with Ingredients Listed as Percentage 210
6.2.6. Using Specific Gravity to Calculate the Exact Amount of Solvent in a Solution 215
6.2.7. Converting % w/w into %w/v Using Specific Gravity 217
6.3. Stock Solutions, Concentrates, and Triturations 218
6.4. Saturated Solutions 222
6.5. Ratio Strength Expressions 224
6.5.1. Ratio Volume-in-Volume 224
6.5.2. Ratio Weight-in-Volume 225
6.5.3. Ratio Weight-in-Weight 226
6.6. Other Pharmaceutical Expressions of Drug Concentration 230
6.6.1. Milligrams Per Milliliter (mg/mL) 230
6.6.2. Milligrams Percent (mg%) and Miligrams Per Deciliter (mg/dL) 231
6.6.3. Parts Per Million (ppm) and Parts Per Billion (ppb) 232
6.6.4. Millimols, Milliequivalents, and Milliosmols Per Unit of Volume 234
Practice Problems 235
Chapter 7 Dilution and Concentration 257
7.1. Problem-Solving Methodologies 258
7.1.1. Concentration Principle 258
7.1.2. Mass Balance Equation 260
7.1.2.1. Dilution of Powders or Solid Mixtures 261
7.1.2.2. Mixing Different Strengths 265
7.1.2.3. Modifying the Drug Concentration of a Prepared Product: Increasing Drug Concentration 267
7.1.3. The CQ Equation: Concentration X Quantity 268
7.1.3.1. Expanded CQ Equation 272
7.1.4. Algebraic Calculations Using the Concentration Equation and the CQ Equation 275
7.1.5. Alligation Alternate 283
7.1.5.1. Use of Alligation When Combining More Than Two Products 287
7.2. So, Which Method Should I Use? 291
7.2.1. Stock Solutions Diluted by the Patient 293
Practice Problems 296
Chapter 8 Isotonicity 310
8.1. Principles 310
8.2. Sodium Chloride Equivalent Values 312
8.3. Isotonicity by the Sodium Chloride Equivalent Method 315
8.3.1. Sodium Chloride Equivalent: Method 1 315
8.3.2. Sodium Chloride Equivalent: Method 2 318
8.4. Other Tonicity Agents 319
8.5. Isotonicity When One Ingredient is Already Isotonic 321
8.6. Isotonic Buffered Solutions 323
8.6.1. Using the White–Vincent Method to Adjust Tonicity 323
8.7. Other Methods 326
8.8. Determination of the Tonicity of a Solution (Hypotonic, Isotonic, or Hypertonic) 329
Practice Problems 330
Chapter 9 Dosage Calculations of Electrolytes 340
9.1. Molarity and Molality 341
9.1.1. Mols and Millimols 341
9.1.2. mmol/mL, mmol/L 344
9.2. Electrolyte Dissociation, Valence, Equivalent, and Equivalent Weight 344
9.3. Milliequivalents, mEq/mL, mEq/L 347
9.3.1. Problem-Solving Methods for Milliequivalents 348
9.4. Osmolarity (Osmolar Strength) 354
9.4.1. Milliosmoles and mOsm/L 355
Practice Problems 366
Chapter 10 Calculations for Injectable Medications And Sterile Fluids 378
10.1. Reconstitution of Dry Powders 378
10.1.1. Reconstituting with Volumes Other Than Those on Manufacturer’s Label 380
10.1.2. Considering Powder Volume 383
10.1.3. Powders as Compounding Sources of Drugs 385
10.2. Calculations Related to Units/ml (Insulin, Heparin) and Other Units of Potency 386
10.2.1. Calculations of Insulin Single Dose and Combinations 387
10.2.2. Calculations of Heparin Doses 391
10.3. Intravenous Admixtures 392
10.4. Extemporaneous IV Fluids 395
10.5. Flow Rates in Intravenous Sets 397
Practice Problems 399
Chapter 11 Enteral and Parenteral Nutrition 413
11.1. Screening and Assessment of Nutritional Needs 414
11.1.1. Body Mass Index (BMI), Waist Circumference, and Associated Disease Risks 414
11.1.2. Assessment of Malnutrition 416
11.2. Enteral Nutrition 416
11.3. Parenteral Nutrition (PN): 2-in-1 and 3-in-1 Formulations 418
11.4. Calculation of Nutritional Requirements 420
11.4.1. Caloric Requirement Equations 420
11.4.2. Fluid Requirement 425
11.4.3. Protein Requirement (Nitrogen) 425
11.4.4. Carbohydrate and Fat Requirements 428
11.4.5. Micronutrient Requirements (Electrolytes, Vitamins, and Trace Elements) 428
11.5. Calculations for Compounding Parenteral Nutrition 429
11.5.1. Calculation of Electrolytes 430
11.5.2. Calculation of Carbohydrate and Fat 433
11.5.3. Calculation of Protein 435
11.5.4. Calculation of Other Additives 438
11.6. Calculations Related to the Design of a PN 444
Practice Problems 446
Chapter 12 Miscellaneous Practical Calculations in Contemporary Compounding 458
12.1. Compounding with Manufactured Dosage Forms 459
12.1.1. Nonsterile Products 460
12.1.2. Sterile Products 463
12.2. Suppository Calculations 465
12.2.1. Calibration of Molds 465
12.3. Determination of Amount of Base/powder Occupied by the Drug(s): Solid Dosage Forms 466
12.3.1. Density Factor Method 467
12.3.2. Quantity/Volume of Base Occupied by Drug (or Density Ratio Method) 474
12.3.3. Dosage Replacement Factor Method 475
12.4. Lozenges and Lollipops 479
12.4.1. Lozenge/Lollipop Mold Calibration 479
12.5. Selecting a Capsule Size 480
12.5.1. The Rule of Sixes 480
12.5.2. The Rule of Seven 482
12.5.3. Volume Occupied by Active Ingredient in a Capsule 484
12.6. Primary Emulsion Calculations (4:2:1 Ratio) 485
12.7. A Little Touch of Veterinary Compounding 487
Practice Problems 489
Appendices 499
Appendix 1 Systems of Measurement 500
Appendix 2 Chemical Elements and Atomic Weights 502
Appendix 3 Calibration of Medicinal Dropper 503
Appendix 4 Solutions Used to Compound PN 504
Appendix 5 Conversions: Temperature, Time, Proof Strength 507
Appendix 6 HLB System 511
Appendix 7 Drug as a Base Versus Salt or Ester 514
Appendix 8 pH, Buffers, and Buffer Capacity 517
Appendix 9 Normal Concentration 525
Appendix 10 Biologics for Immunization 527
Literature Consulted 529
Index 531
